Microwave-assisted extraction with water for fast extraction and simultaneous RP-HPLC determination of phenolic acids in radix Salviae Miltiorrhizae.

PubMed

Fang, Xinsheng; Wang, Jianhua; Zhou, Hongying; Jiang, Xingkai; Zhu, Lixiang; Gao, Xin

2009-07-01

An optimized microwave-assisted extraction method using water (MAE-W) as the extractant and an efficient HPLC analysis method were first developed for the fast extraction and simultaneous determination of D(+)-(3,4-dihydroxyphenyl) lactic acid (Dla), salvianolic acid B (SaB), and lithospermic acid (La) in radix Salviae Miltiorrhizae. The key parameters of MAE-W were optimized. It was found that the degradation of SaB was inhibited when using the optimized MAE-W and the stable content of Dla, La, and SaB in danshen was obtained. Furthermore, compared to the conventional extraction methods, the proposed MAE-W is a more rapid method with higher yield and lower solvent consumption with a reproducibility (RSD <6%). In addition, using water as extractant is safe and helpful for environment protection, which could be referred to as green extraction. The separation and quantitative determination of the three compounds was carried out by a developed reverse-phase high-performance liquid chromatographic (RP-HPLC) method with UV detection. Highly efficient separation was obtained using gradient solvent system. The optimized HPLC analysis method was validated to have specificity, linearity, precision, and accuracy. The results indicated that MAE-W followed by HPLC-UV determination is an appropriate alternative to previously proposed method for quality control of radix Salviae Miltiorrhizae.

Simultaneous treatment (cell disruption and lipid extraction) of wet microalgae using hydrodynamic cavitation for enhancing the lipid yield.

PubMed

Lee, Ilgyu; Han, Jong-In

2015-06-01

Simultaneous treatment (combining with cell disruption and lipid extraction) using hydrodynamic cavitation (HC) was applied to Nannochloropsis salina to demonstrate a simple and integrated way to produce oil from wet microalgae. A high lipid yield from the HC (25.9-99.0%) was observed compared with autoclave (16.2-66.5%) and ultrasonication (5.4-26.9%) in terms of the specific energy input (500-10,000 kJ/kg). The optimal conditions for the simultaneous treatment were established using a statistical approach. The efficiency of the simultaneous method was also demonstrated by comparing each separate treatment. The maximum lipid yield (predicted: 45.9% and experimental: 45.5%) was obtained using 0.89% sulfuric acid with a cavitation number of 1.17 for a reaction time of 25.05 min via response surface methodology. Considering its comparable extractability, energy-efficiency, and potential for scale-up, HC may be a promising method to achieve industrial-scale microalgae operation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Simultaneous determination of azathioprine and 6-mercaptopurine by high-performance liquid chromatography.

PubMed

Van Os, E C; McKinney, J A; Zins, B J; Mays, D C; Schriver, Z H; Sandborn, W J; Lipsky, J J

1996-04-26

A specific, sensitive, single-step solid-phase extraction and reversed-phase high-performance liquid chromatographic method for the simultaneous determination of plasma 6-mercaptopurine and azathioprine concentrations is reported. Following solid-phase extraction, analytes are separated on a C18 column with mobile phase consisting of 0.8% acetonitrile in 1 mM triethylamine, pH 3.2, run on a gradient system. Quantitation limits were 5 ng/ml and 2 ng/ml for azathioprine and 6-mercaptopurine, respectively. Peak heights correlated linearly to known extracted standards for 6-mercaptopurine and azathioprine (r = 0.999) over a range of 2-200 ng/ml. No chromatographic interferences were detected.

Determination of ethyl glucuronide in hair: a rapid sample pretreatment involving simultaneous milling and extraction.

PubMed

Mönch, Bettina; Becker, Roland; Nehls, Irene

2014-01-01

A combination of simultaneous milling and extraction known as micropulverized extraction was developed for the quantification of the alcohol marker ethyl glucuronide (EtG) in hair samples using a homogeneous reference material and a mixer mill. Best extraction results from 50 mg of hair were obtained with 2-mL plastic tubes containing two steel balls (∅ = 5 mm), 0.5 mL of water and with an oscillating frequency of 30 s(-1) over a period of 30 min. EtG was quantified employing a validated GC-MS procedure involving derivatization with pentafluoropropionic acid anhydride. This micropulverization procedure was compared with dry milling followed by separate aqueous extraction and with aqueous extraction after manual cutting to millimeter-size snippets. Micropulverization yielded 28.0 ± 1.70 pg/mg and was seen to be superior to manually cutting (23.0 ± 0.83 pg/mg) and equivalent to dry grinding (27.7 ± 1.71 pg/mg) with regard to completeness of EtG extraction. The option to process up to 20 samples simultaneously makes micropulverization especially valuable for the high throughput of urgent samples.

Direct thermal desorption in the analysis of cheese volatiles by gas chromatography and gas chromatography-mass spectrometry: comparison with simultaneous distillation-extraction and dynamic headspace.

PubMed

Valero, E; Sanz, J; Martínez-Castro, I

2001-06-01

Direct thermal desorption (DTD) has been used as a technique for extracting volatile components of cheese as a preliminary step to their gas chromatographic (GC) analysis. In this study, it is applied to different cheese varieties: Camembert, blue, Chaumes, and La Serena. Volatiles are also extracted using other techniques such as simultaneous distillation-extraction and dynamic headspace. Separation and identification of the cheese components are carried out by GC-mass spectrometry. Approximately 100 compounds are detected in the examined cheeses. The described results show that DTD is fast, simple, and easy to automate; requires only a small amount of sample (approximately 50 mg); and affords quantitative information about the main groups of compounds present in cheeses.

Carbon nanotube-based benzyl polymethacrylate composite monolith as a solid phase extraction adsorbent and a stationary phase material for simultaneous extraction and analysis of polycyclic aromatic hydrocarbon in water.

PubMed

Al-Rifai, Asma'a; Aqel, Ahmad; Wahibi, Lamya Al; ALOthman, Zeid A; Badjah-Hadj-Ahmed, Ahmed-Yacine

2018-02-02

A composite of multi-walled carbon nanotubes incorporated into a benzyl methacrylate-co-ethylene dimethacrylate porous monolith was prepared, characterized and used as solid phase adsorbent and as stationary phase for simultaneous extraction and separation of ten polycyclic aromatic hydrocarbons, followed by nano-liquid chromatography analysis. The extraction and chromatographic parameters were optimized with regard to the extraction efficiency and the quality of chromatographic analytes separation. Under the optimized conditions, all PAHs were separated in 13 min with suitable resolution values (Rs = 1.74-3.98). Addition of a small amount of carbon nanotubes (0.1% with respect to monomers) to the polymerization mixture increased the efficiency for the separation column to over 41,700 plates m -1 for chrysene at flow rate of 0.5 μL min -1 . The method showed a wide linear range (1-500 μg L -1 with R 2 more than 0.9938), acceptable extraction repeatability (RSDs < 6.4%, n = 3) and reproducibility (RSDs < 12.6%, five parallel-made solid phase extraction cartridges) and satisfactory detection limits (0.02-0.22 μg L -1 ). Finally, the proposed method was successfully applied to the detection of polycyclic aromatic hydrocarbons in environmental water samples. After a simple extraction procedure with preconcentration factor equal to 100, the average recovery values in ultra-pure, tap and sea water samples were found to be in the range 81.3-95.4% with %RSD less than 6.4. Again, the presence of carbon nanotubes (0.3% relatively to monomers) in native polymer enhanced the extraction performance for the solid phase adsorbent up to 78.4%. The application of the monoliths modified with CNTs in extraction and nano-scale liquid chromatography for analysis of environmental samples offered several advantages; it demonstrated an acceptable precision, low detection limits, good reproducibility, satisfying recoveries and wide dynamic linear ranges. Copyright © 2018. Published by Elsevier B.V.

Subzero-Temperature Liquid-Liquid Extraction Coupled with UPLC-MS-MS for the Simultaneous Determination of 12 Bioactive Components in Traditional Chinese Medicine Gegen-Qinlian Decoction.

PubMed

Shi, Zhihong; Li, Zhimin; Zhang, Shulan; Fu, Hongna; Zhang, Hongyi

2015-09-01

Based on the phase separation phenomenon of acetonitrile-water system at subzero temperature, a subzero-temperature liquid-liquid extraction coupled with ultra-performance liquid chromatography tandem quadrupole mass spectrometry : UPLC-MS-MS) method was developed for the simultaneous determination of 12 bioactive components in Gegen-Qinlian decoction. After optimization, the extraction conditions were set as follows: 3.0 mL of aqueous sample solution (pH 5.86) was extracted with 2 mL of acetonitrile at -35°C for 35 min. The separated acetonitrile phase was diluted 10-fold with water before UPLC-MS-MS analysis. Separation was performed on a Waters ACQUITY UPLC(®)BEH C18 column (2.1 × 100 mm i.d., 1.7 µm) with ammonium formate buffer solution (20 mmol L(-1), pH 3.2, adjusted by formic acid) and acetonitrile as mobile phase with gradient elution. Twelve target components could be separated within 10 min and quantified in multiple reaction monitoring mode, both positive and negative ionization modes were employed. Limits of detection were in the range of 0.0003-0.0451 μg mL(-1). Relative standard deviation values for intra- and interday precision were <2.71 and 8.94%, respectively. The established method provides a simple and effective framework for the quality control of Gegen-Qinlian decoction and related traditional Chinese medicinal preparations. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Simultaneous quantification of major flavonoids in "Bawanghua", the edible flower of Hylocereus undatus using pressurised liquid extraction and high performance liquid chromatography.

PubMed

Yi, Yan; Zhang, Qing-Wen; Li, Song-Lin; Wang, Ying; Ye, Wen-Cai; Zhao, Jing; Wang, Yi-Tao

2012-11-15

A pressurised liquid extraction (PLE) and high performance liquid chromatography (HPLC) method was developed for simultaneous quantification of six major flavonoids in edible flower of Hylocereus undatus. In order to achieve the baseline separation of two pairs of isomers, the HPLC conditions were optimised with different kind of reversed phase columns and mobile phase gradient programs. In addition, the solvent concentration, extraction temperature, extraction time and flush cycle for PLE were also optimised. Zorbax SB-C8 (100×2.1 mm, 1.8 μm) column was chosen with acetonitrile and water containing 0.1% trifluoroacetic acid as mobile phase, the six analytes were eluted with baseline separation. The calibration curves showed good linearity (r(2)>0.9994) with LODs and LOQs less than 0.90 and 3.60 ng respectively. The RSDs for intra- and inter-day repeatability was not more than 1.09% and 1.79% respectively. The overall recovery of the assay was 96.9-105.2%. The sample was stable for at least 12 h. The newly established method was successfully applied to quantify six flavonoids in different parts of "Bawanghua", and the commercial samples from different locations. Copyright © 2012 Elsevier Ltd. All rights reserved.

A modified approach for isolation of essential oil from fruit of Amorpha fruticosa Linn using microwave-assisted hydrodistillation concatenated liquid-liquid extraction.

PubMed

Chen, Fengli; Jia, Jia; Zhang, Qiang; Gu, Huiyan; Yang, Lei

2017-11-17

In this work, a modified technique was developed to separate essential oil from the fruit of Amorpha fruticosa using microwave-assisted hydrodistillation concatenated liquid-liquid extraction (MHD-LLE). The new apparatus consists of two series-wound separation columns for separating essential oil, one is the conventional oil-water separation column, and the other is the extraction column of components from hydrosol using an organic solvent. Therefore, the apparatus can simultaneously collect the essential oil separated on the top of hydrosol and the components extracted from hydrosol using an organic solvent. Based on the yield of essential oil in the first and second separation columns, the effects of parameters were investigated by single factor experiments and Box-Behnken design. Under the optimum conditions (2mL ethyl ether as the extraction solvent in the second separation column, 12mL/g liquid-solid ratio, 4.0min homogenate time, 35min microwave irradiation time and 540W microwave irradiation power), satisfactory yields for the essential oil in the first separation column (10.31±0.33g/kg) and second separation column (0.82±0.03g/kg) were obtained. Compared with traditional methods, the developed method gave a higher yield of essential oil in a shorter time. In addition, GC-MS analysis of the essential oil indicated significant differences of the relative contents of individual volatile components in the essential oils obtained in the two separation columns. Therefore, the MHD-LLE technique developed here is a good alternative for the isolation of essential oil from A. fruticosa fruit as well as other herbs. Copyright © 2017 Elsevier B.V. All rights reserved.

Simultaneous determination of arsenic and mercury species in rice by ion-pairing reversed phase chromatography with inductively coupled plasma mass spectrometry.

PubMed

Fang, Yong; Pan, Yushi; Li, Peng; Xue, Mei; Pei, Fei; Yang, Wenjian; Ma, Ning; Hu, Qiuhui

2016-12-15

An analytical method using reversed phase chromatography-inductively coupled plasma mass spectrometry for arsenic and mercury speciation analysis was described. The effect of ion-pairing reagent on simultaneous separation of four arsenic (arsenite, arsenate, monomethlyarsonate and dimethylarsinate) and three mercury species (inorganic mercury (Hg(II)), methylmecury and ethylmercury) was investigated. Parameters including concentrations and pH of the mobile phase were optimized. The separation and re-equilibration time was attained within 20min. Meanwhile, a sequential extraction method for arsenic and mercury in rice was tested. Subsequently, 1% HNO3 microwave-assisted extraction was chosen. Calibration curves based on peak area measurements were linear with correlation coefficient greater than 0.9958 for each species in the range studied. The detection limits of the species were in the range of 0.84-2.41μg/L for arsenic and 0.01-0.04μg/L for mercury, respectively. The proposed method was then successfully applied for the simultaneous determination of arsenic and mercury species in rice flour standard material and two kinds of rice from local markets. Copyright © 2016 Elsevier Ltd. All rights reserved.

Simultaneous separation and determination of six arsenic species in Shiitake (Lentinus edodes) mushrooms: Method development and applications.

PubMed

Chen, Shuangyang; Yuan, Biao; Xu, Jiajia; Chen, Guitang; Hu, Qiuhui; Zhao, Liyan

2018-10-01

A method for simultaneously separating six arsenic (As) species was established by ultrasound-assisted extraction-anion exchange chromatography coupled with inductively coupled plasma mass spectrometry. Six As species could be well separated within 15 min when 0.3 M acetic acid and 25 mM NH 4 H 2 PO 4 were used as the extraction solvent and mobile phase, respectively. Under optimized conditions, the limits of detection and recovery of As species and the relative standard deviation were in the ranges of 0.31-0.59 μg/L, 94.30-102.75%, and 1.63-3.72%, respectively. Furthermore, the established method was successfully applied to fresh Shiitake (Lentinus edodes) mushrooms and processed products. The inorganic As contents of all samples ranged from 0.204 to 0.500 mg/kg, half of samples (>0.400 mg/kg) were close to the maximum contaminant level allowed by the Chinese (0.5 mg/kg). The health risk index estimation results indicated that no particular risk of As exposure to Chinese consumers existed in L. edodes. Copyright © 2018 Elsevier Ltd. All rights reserved.

Simultaneous determination of radionuclides separable into natural decay series by use of time-interval analysis.

PubMed

Hashimoto, Tetsuo; Sanada, Yukihisa; Uezu, Yasuhiro

2004-05-01

A delayed coincidence method, time-interval analysis (TIA), has been applied to successive alpha- alpha decay events on the millisecond time-scale. Such decay events are part of the (220)Rn-->(216)Po ( T(1/2) 145 ms) (Th-series) and (219)Rn-->(215)Po ( T(1/2) 1.78 ms) (Ac-series). By using TIA in addition to measurement of (226)Ra (U-series) from alpha-spectrometry by liquid scintillation counting (LSC), two natural decay series could be identified and separated. The TIA detection efficiency was improved by using the pulse-shape discrimination technique (PSD) to reject beta-pulses, by solvent extraction of Ra combined with simple chemical separation, and by purging the scintillation solution with dry N(2) gas. The U- and Th-series together with the Ac-series were determined, respectively, from alpha spectra and TIA carried out immediately after Ra-extraction. Using the (221)Fr-->(217)At ( T(1/2) 32.3 ms) decay process as a tracer, overall yields were estimated from application of TIA to the (225)Ra (Np-decay series) at the time of maximum growth. The present method has proven useful for simultaneous determination of three radioactive decay series in environmental samples.

Simultaneous determination of carbohydrates and simmondsins in jojoba seed meal (Simmondsia chinensis) by gas chromatography.

PubMed

Lein, Sabine; Van Boven, Maurits; Holser, Ron; Decuypere, Eddy; Flo, Gerda; Lievens, Sylvia; Cokelaere, Marnix

2002-11-22

Separate methods for the analyses of soluble carbohydrates in different plants and simmondsins in jojoba seed meal are described. A reliable gas chromatographic procedure for the simultaneous quantification of D-pinitol, myo-inositoL sucrose, 5-alpha-D-galactopyranosyl-D-pinitol. 2-alpha-D-galactopyranosyl-D-pinitol, simmondsin, 4-demethylsimmondsin, 5-demethylsimmondsin and 4,5-didemethylsimmondsin as trimethylsilyl derivatives in jojoba seed meal has been developed. The study of different extraction mixtures allowed for the quantitative recovery of the 9 analytes by a mixture of methanol-water (80:20, v/v) in the concentration range between 0.1 and 4%. Comparison of the separation parameters on three different capillary stationary phases with MS detection allowed for the choice of the optimal gas chromatographic conditions for baseline separation of the analytes.

[Simultaneous determination of 33 primary aromatic amines in polystyrene and polyethylene masterbatches for foods by ultra-performance liquid chromatography-tandem mass spectrometry

PubMed

Man, Zhengyin; Wang, Quanlin; Li, Hesheng; Zhang, Aizhi; Shen, Jian

2015-03-01

A comprehensive analytical method based on ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UPLC-MS/MS) has been developed for the simultaneous determination of 33 primary aromatic amines (PAAs) in polystyrene (PS) and polyethylene (PE) masterbatches for foods. The PS masterbatches were dissolved with dichloromethane, and methanol was added to precipitate after extraction by ultrasound extraction. Then the extract was purified by passing through a carbon graphite solid phase extraction column. The PE masterbatches were swelled and extracted with dichloromethane by ultrasound. The purified PS solution and PE extract were concentrated, and diluted to 2 mL with methanol-water (1:9, v/v), and filtered through the membranes of 0.22 µm before UPLC-MS/MS analysis. The analytes were separated on a BEH Phenyl column (100 mm x 2.1 mm, 1.7 µm), eluted by gradient with 0.07% (v/v) formic acid in methanol-water (1:9, v/v). The PAAs were detected by UPLC-MS/MS under multiple reaction monitoring (MRM) mode and quantified by the internal standard method. The separation conditions, fragment voltages and collision energies were optimized. The impacts of extraction times, extraction solvents and concentration methods on recoveries were studied. The limits of detection for the 33 primary aromatic amines were 6-10 µg/kg, and the limits of quantitation were 20-30 µg/kg. The mean recoveries of the two different masterbatch products at three spiked levels of 20, 100, 200 µg/kg were 61.3%-119.8%, and the relative standard deviations were 1.4%-14.8%. The experimental results indicated that the method is simple, rapid, sensitive, accurate, and can meet the related requirements for determination.

Simultaneous Separation of Manganese, Cobalt, and Nickel by the Organic-Aqueous-Aqueous Three-Phase Solvent Extraction

NASA Astrophysics Data System (ADS)

Shirayama, Sakae; Uda, Tetsuya

2016-04-01

This research outlines an organic-aqueous-aqueous three-phase solvent extraction method and proposes its use in a new metal separation process for the recycling of manganese (Mn), cobalt (Co), and nickel (Ni) from used lithium ion batteries (LIBs). The three-phase system was formed by mixing xylene organic solution, 50 pct polyethylene glycol (PEG) aqueous solution, and 1 mol L-1 sodium sulfate (Na2SO4) aqueous solution. The xylene organic solution contained 2-ethylhexylphosphonic acid (D2EHPA) as an extractant for Mn ion, and the Na2SO4 aqueous solution contained 1 mol L-1 potassium thiocyanate (KSCN) as an extractant for Co ion. Concentrations of the metal ions were varied by dissolving metal sulfates in the Na2SO4 aqueous solution. As a result of the experiments, Mn, Co, and Ni ions were distributed in the xylene organic phase, PEG-rich aqueous phase, and Na2SO4-rich aqueous phase, respectively. The separation was effective when the pH value was around 4. Numerical simulation was also conducted in order to predict the distribution of metal ions after the multi-stage counter-current extractions.

Application of phase-trafficking methods to natural products research.

PubMed

Araya, Juan J; Montenegro, Gloria; Mitscher, Lester A; Timmermann, Barbara N

2010-09-24

A novel simultaneous phase-trafficking approach using spatially separated solid-supported reagents for rapid separation of neutral, basic, and acidic compounds from organic plant extracts with minimum labor is reported. Acidic and basic ion-exchange resins were physically separated into individual sacks ("tea bags") for trapping basic and acidic compounds, respectively, leaving behind in solution neutral components of the natural mixtures. Trapped compounds were then recovered from solid phase by appropriate suspension in acidic or basic solutions. The feasibility of the proposed separation protocol was demonstrated and optimized with an "artificial mixture" of model compounds. In addition, the utility of this methodology was illustrated with the successful separation of the alkaloid skytanthine from Skytanthus acutus Meyen and the main catechins and caffeine from Camellia sinensis L. (Kuntze). This novel approach offers multiple advantages over traditional extraction methods, as it is not labor intensive, makes use of only small quantities of solvents, produces fractions in adequate quantities for biological assays, and can be easily adapted to field conditions for bioprospecting activities.

Application of Phase-Trafficking Methods to Natural Products Research

PubMed Central

Araya, Juan J.; Montenegro, Gloria; Mitscher, Lester A.; Timmermann, Barbara N.

2010-01-01

A novel simultaneous phase-trafficking approach using spatially separated solid-supported reagents (SSR) for rapid separation of neutral, basic, and acidic compounds from organic plant extracts with minimum labor is reported. Acidic and basic ion exchange resins were physically separated into individual sacks (“teabags”) for trapping basic and acidic compounds respectively, leaving behind in solution neutral components of the natural mixtures. Trapped compounds were then recovered from solid phase by appropriate suspension in acidic or basic solutions. The feasibility of the proposed separation protocol was demonstrated and optimized with an “artificial mixture” of model compounds. In addition, the utility of this methodology was illustrated with the successful separation of the alkaloid skytanthine from Skytanthus acutus Meyen and the main catechins and caffeine from Camellia sinensis L. (Kuntze). This novel approach offers multiple advantages over traditional extraction methods, as it is not labor intensive, makes use of only small quantities of solvents, produces fractions in adequate quantities for biological assays, and can be easily adapted to field conditions for bioprospecting activities. PMID:20704309

Simultaneous determination of nicotine and cotinine in serum using high-performance liquid chromatography with fluorometric detection and postcolumn UV-photoirradiation system.

PubMed

Yasuda, Makoto; Ota, Tatsuhiro; Morikawa, Atsushi; Mawatari, Ken-ichi; Fukuuchi, Tomoko; Yamaoka, Noriko; Kaneko, Kiyoko; Nakagomi, Kazuya

2013-09-01

A simple and rapid method for the simultaneous determination of serum nicotine and cotinine using high-performance liquid chromatography (HPLC)-fluorometric detection with a postcolumn ultraviolet-photoirradiation system was developed. Analytes were extracted from alkalinized human serum via liquid-liquid extraction using chloroform. The organic phase was back-extracted with the acidified aqueous phase, and the analytes were directly injected into an ion-pair reversed-phase HPLC system. 6-Aminoquinoline was used as an internal standard. Nicotine, cotinine, and 6-aminoquinoline were separated within 14min. The extraction efficiency of nicotine and cotinine was greater than 91%. The linear range was 0.30-1000ng for nicotine and 0.06-1000ng for cotinine. In serum samples from smokers, the concentrations of nicotine and cotinine were 8-15ng/mL and 156-372ng/mL, respectively. Copyright © 2013 Elsevier B.V. All rights reserved.

Simultaneous analysis of guaiacol and vanillin in a vanilla extract by using high-performance liquid chromatography with electrochemical detection.

PubMed

Takahashi, Makoto; Sakamaki, Shizuka; Fujita, Akira

2013-01-01

We developed and validated a new high-performance liquid chromatographic analysis for electrochemically detecting guaiacol and vanillin as important components in vanilla extract. Separation was achieved with Capcell Pak C-18 MG, the potential of the working electrode being set at +1000 mV. The respective calibration curves for guaiacol and vanillin were linear in the range of 1.60-460 µg/L and 5.90-1180 µg/L. The respective limits for the quantities of guaiacol and vanillin were 1.60 µg/L and 2.36 µg/L. The related standard deviations of the intra- and inter-day precision of the retention time and peak area were all less than 4%. The recovery of guaiacol and vanillin was both more than 97%, all of the validation data being within an acceptable range. This analysis method is well suited for the simultaneous and convenient analysis of guaiacol and vanillin in a vanilla extract to evaluate the quality of the vanilla extract.

Simultaneous separation and detection of actinides in acidic solutions using an extractive scintillating resin.

PubMed

Roane, J E; DeVol, T A

2002-11-01

An extractive scintillating resin was evaluated for the simultaneous separation and detection of actinides in acidic solutions. The transuranic extractive scintillating (TRU-ES) resin is composed of an inert macroporous polystyrene core impregnated with organic fluors (diphenyloxazole and 1,4-bis-(4-methyl-5-phenyl-2-oxazolyl)benzene) and an extractant (octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide in tributyl phosphate). The TRU-ES resin was packed into FEP Teflon tubing to produce a flow cell (0.2-mL free column volume), which is placed into a scintillation detection system to obtain pulse height spectra and time series data during loading and elution of actinides onto/from the resin. The alpha-particle absolute detection efficiencies ranged from 77% to 96.5%, depending on the alpha energy and quench. In addition to the on-line analyses, off-line analyses of the effluent can be conducted using conventional detection methods. The TRU-ES resin was applied to the quantification of a mixed radionuclide solution and two actual waste samples. The on-line characterization of the mixed radionuclide solution was within 10% of the reported activities whereas the agreement with the waste samples was not as good due to sorption onto the sample container walls and the oxidation state of plutonium. Agreement between the on-line and off-line analyses was within 35% of one another for both waste samples.

Simultaneous separation of copper, cadmium and cobalt from sea-water by co-flotation with octadecylamine and ferric hydroxide as collectors.

PubMed

Cabezon, L M; Caballero, M; Cela, R; Perez-Bustamante, J A

1984-08-01

A method is proposed for the simultaneous quantitative separation of traces ofCu(II), Cd(II) and Co(II) from sea-water samples by means of the co-flotation (adsorbing colloid flotation) technique with ferric hydroxide as co-precipitant and octadecylamine as collector. The experimental parameters have been studied and optimized. The drawbacks arising from the low solubility of octadecylamine and the corresponding sublates in water have been avoided by use of a 6M hydrochloric acid-MIBK-ethanol (1:2:2 v v ) mixture. The results obtained by means of the proposed method have been compared with those given by the usual ammonium pyrrolidine dithiocarbamate/MIBK extraction method.

Selective ionic liquid ferrofluid based dispersive-solid phase extraction for simultaneous preconcentration/separation of lead and cadmium in milk and biological samples.

PubMed

Fasih Ramandi, Negin; Shemirani, Farzaneh

2015-01-01

For the first time, a selective ionic liquid ferrofluid has been used in dispersive solid phase extraction (IL-FF-D-SPE) for simultaneous preconcentration and separation of lead and cadmium in milk and biological samples combined with flame atomic absorption spectrometry. To improve the selectivity of the ionic liquid ferrofluid, the surface of TiO2 nanoparticles with a magnetic core as sorbent was modified by loading 1-(2-pyridylazo)-2-naphtol. Due to the rapid injection of an appropriate amount of ionic liquid ferrofluid into the aqueous sample by a syringe, extraction can be achieved within a few seconds. In addition, based on the attraction of the ionic liquid ferrofluid to a magnet, no centrifugation step is needed for phase separation. The experimental parameters of IL-FF-D-SPE were optimized using a Box-Behnken design (BBD) after a Plackett-Burman screening design. Under the optimum conditions, the relative standard deviations of 2.2% and 2.4% were obtained for lead and cadmium, respectively (n=7). The limit of detections were 1.21 µg L(-1) for Pb(II) and 0.21 µg L(-1) for Cd(II). The preconcentration factors were 250 for lead and 200 for cadmium and the maximum adsorption capacities of the sorbent were 11.18 and 9.34 mg g(-1) for lead and cadmium, respectively. Copyright © 2014 Elsevier B.V. All rights reserved.

Simultaneous Determination of Fluoroquinolones and Sulfonamides Originating from Sewage Sludge Compost

PubMed Central

Herodes, K.

2017-01-01

A simultaneous method for quantitative determination of traces of fluoroquinolones (FQs) and sulfonamides (SAs) in edible plants fertilized with sewage sludge was developed. The compounds were extracted from the plants by rapid and simple liquid extraction followed by extracts clean-up using solid phase extraction. The eluent additive 1,1,1,3,3,3-hexafluoro-2-propanol was used for liquid chromatographic detection to achieve separation of structurally similar antimicrobials like ciprofloxacin and norfloxacin. Identification and quantification of the compounds were performed using high-performance liquid chromatography with electrospray ionization mass spectrometry in selected reaction monitoring mode. Method was validated and extraction recoveries of FQs and SAs ranged from 66% to 93%. The limit of quantifications was from 5 ng/g in the case of ofloxacin to 40 ng/g for norfloxacin. The method precision ranged from 1.43% to 2.61%. The developed novel method was used to evaluate the plats antimicrobial uptake (potato (Solanum tuberosum L.), carrot (Daucus carota L.), lettuce (Lactuca sativa L.), and wheat (Triticum vulgare L.)) from soil and migration of the analytes inside the plants. PMID:28695191

Simultaneous, untargeted metabolic profiling of polar and nonpolar metabolites by LC-Q-TOF mass spectrometry.

PubMed

Kirkwood, Jay S; Maier, Claudia; Stevens, Jan F

2013-05-01

At its most ambitious, untargeted metabolomics aims to characterize and quantify all of the metabolites in a given system. Metabolites are often present at a broad range of concentrations and possess diverse physical properties complicating this task. Performing multiple sample extractions, concentrating sample extracts, and using several separation and detection methods are common strategies to overcome these challenges but require a great amount of resources. This protocol describes the untargeted, metabolic profiling of polar and nonpolar metabolites with a single extraction and using a single analytical platform. © 2013 by John Wiley & Sons, Inc.

Preparation of a dual-enzyme co-immobilized capillary microreactor and simultaneous screening of multiple enzyme inhibitors by capillary electrophoresis.

PubMed

Lin, Pingtan; Zhao, Shulin; Lu, Xin; Ye, Fanggui; Wang, Hengshan

2013-08-01

A CE method based on a dual-enzyme co-immobilized capillary microreactor was developed for the simultaneous screening of multiple enzyme inhibitors. The capillary microreactor was prepared by co-immobilizing adenosine deaminase and xanthine oxidase on the inner wall at the inlet end of the separation capillary. The enzymes were first immobilized on gold nanoparticles, and the functionalized gold nanoparticles were then assembled on the inner wall at the inlet end of the separation capillary treated with polyethyleneimine. With the developed CE method, the substrates and products were baseline separated within 3 min. The activity of the immobilized enzyme can be directly detected by measuring the peak height of the products. A statistical parameter Z' factor was recommended for evaluation of the accuracy of a drug screening system. In the present study, it was calculated to be larger than 0.5, implying a good accuracy. Finally, screening a small compound library containing two known enzyme inhibitors and 20 natural extracts by the proposed method was demonstrated. The known inhibitors were identified, and some natural extracts were found to be positive for two-enzyme inhibition by the present method. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

One-step zymogram method for the simultaneous detection of cellulase/xylanase activity and molecular weight estimation of the enzyme.

PubMed

Cano-Ramírez, Claudia; Santiago-Hernández, Alejandro; Rivera-Orduña, Flor Nohemí; Pineda-Mendoza, Rosa María; Zúñiga, Gerardo; Hidalgo-Lara, María Eugenia

2017-02-01

Here, we describe a zymographic method for the simultaneous detection of enzymatic activity and molecular weight (MW) estimation, following a single electrophoresis step. This involved separating cellulase and xylanase activities from bacteria and fungi, obtained from different sources, such as commercial extracts, crude extract and purified proteins, under denaturing conditions, by 10% polyacrylamide gel electrophoresis, using polyacrylamide gels copolymerized with 1% (w/v) carboxymethylcellulose or beechwood xylan as substrates. Then, enzymes were refolded by treatment with 2.5% Triton X-100 in an appropriate buffer for each enzymatic activity, and visualized by Coomassie blue staining for MW estimation. Finally, Congo red staining revealed bio-active cellulase and xylanase bands after electrophoretic separation of the proteins in the preparations. This method may provide a useful additional tool for screening of particular cellulase and xylanase producers, identification and MW estimation of polypeptides that manifest these activities, and for monitoring and control of fungal and bacterial cellulase and xylanase production. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Supervised non-negative tensor factorization for automatic hyperspectral feature extraction and target discrimination

NASA Astrophysics Data System (ADS)

Anderson, Dylan; Bapst, Aleksander; Coon, Joshua; Pung, Aaron; Kudenov, Michael

2017-05-01

Hyperspectral imaging provides a highly discriminative and powerful signature for target detection and discrimination. Recent literature has shown that considering additional target characteristics, such as spatial or temporal profiles, simultaneously with spectral content can greatly increase classifier performance. Considering these additional characteristics in a traditional discriminative algorithm requires a feature extraction step be performed first. An example of such a pipeline is computing a filter bank response to extract spatial features followed by a support vector machine (SVM) to discriminate between targets. This decoupling between feature extraction and target discrimination yields features that are suboptimal for discrimination, reducing performance. This performance reduction is especially pronounced when the number of features or available data is limited. In this paper, we propose the use of Supervised Nonnegative Tensor Factorization (SNTF) to jointly perform feature extraction and target discrimination over hyperspectral data products. SNTF learns a tensor factorization and a classification boundary from labeled training data simultaneously. This ensures that the features learned via tensor factorization are optimal for both summarizing the input data and separating the targets of interest. Practical considerations for applying SNTF to hyperspectral data are presented, and results from this framework are compared to decoupled feature extraction/target discrimination pipelines.

Applicability of multisyringe chromatography coupled to on-line solid-phase extraction to the simultaneous determination of dicamba, 2,4-D, and atrazine.

PubMed

Chávez-Moreno, C A; Guzmán-Mar, J L; Hinojosa-Reyes, L; Hernández-Ramírez, A; Ferrer, L; Cerdà, V

2012-07-01

Simultaneous determination of three herbicides (dicamba, 2,4-D, and atrazine) has been achieved by on-line solid-phase extraction (SPE) coupled to multisyringe chromatography (MSC) with UV detection. The preconcentration conditions were optimized; a preconcentration flow rate of 0.5 mL min(-1) and elution at 0.8 mL min(-1) were the optimum conditions. A C(18) (8 mm i.d.) membrane extraction disk conditioned with 0.3 mol L(-1) HCl in 0.5% MeOH was used. A 3-mL sample was preconcentrated, then eluted with 0.43 mL 40:60 water-MeOH. A C(18) monolithic column (25 mm × 4.6 mm) was used for chromatographic separation. Separation of the three compounds was achieved in 10 min by use of 0.01% aqueous acetic acid-MeOH (60:40) as mobile phase at a flow rate of 0.8 mL min(-1). The limits of detection (LOD) were 13, 57, and 22 μg L(-1) for dicamba, 2,4-D, and atrazine, respectively. The sampling frequency was three analyses per hour, and each analysis consumed only 7.3 mL solvent. The method was applied to spiked water samples, and recovery between 85 and 112% was obtained. Recovery was significantly better than in the conventional HPLC-UV method. These results indicated the reliability and accuracy of this flow-based method. This is the first time this family of herbicides has been simultaneously analyzed by on-line SPE-MSC using a monolithic column.

Simultaneous determination of 11 phthalate esters in bottled beverages by graphene oxide coated hollow fiber membrane extraction coupled with supercritical fluid chromatography.

PubMed

Lou, Chaoyan; Guo, Dandan; Zhang, Kai; Wu, Can; Zhang, Peimin; Zhu, Yan

2018-05-12

Phthalate esters (PAEs) are a group of serious environmental pollutants, which lead to carcinogenicity or tumorigenicity in human body. In this study, a rapid, sensitive and green method by graphene oxide coated hollow fiber membrane extraction (GO-HFME) coupled with supercritical fluid chromatography (SFC) was proposed for the determination of 11 phthalate esters in bottled beverages. Graphene oxide (GO) was prepared and coated onto a porous hollow fiber membrane (HFM) to reinforce the efficiency of membrane extraction. The modified hollow fiber membrane was employed for the extraction of phthalate esters from bottled beverages prior to the determination by the supercritical fluid chromatography with UV detection. To achieve the maximum extraction efficiency, several parameters were investigated including GO concentration, extraction time, desorption solution and desorption time. SFC variables including stationary phase, modifier composition and percentage, column temperature, flow rate and backpressure were studied to improve the separation conditions. Under these optimized conditions, all the studied 11 phthalate esters were well separated and simultaneously determined in 7 min by SFC. The performance of the developed method was evaluated. Good linearity was observed (R ≥ 0.999) in the range of 0.02-10.0 μg/mL with limit of detection (LOD, S/N = 3) ranging from 1.5 to 3.0 ng/mL. Recoveries of all the PAEs for the spiked samples were between 92.1% and 99.3% with satisfactory relative standard deviations (RSD) less than 5.9%. The proposed method is time-saving, green, simple and robust, which will be an alternative way to the analysis of PAEs in real samples. Copyright © 2018 Elsevier B.V. All rights reserved.

Development and evaluation of a gas chromatographic method for the determination of triazine herbicides in natural water samples

USGS Publications Warehouse

Steinheimer, T.R.; Brooks, M.G.

1984-01-01

A multi-residue method is described for the determination of triazine herbicides in natural water samples. The technique uses solvent extraction followed by gas chromatographic separation and detection employing nitrogen-selective devices. Seven compounds can be determined simultaneously at a nominal detection limit of 0.1 ??g/L in a 1-litre sample. Three different natural water samples were used for error analysis via evaluation of recovery efficiencies and estimation of overall method precision. As an alternative to liquid-liquid partition (solvent extraction) for removal of compounds of interest from water, solid-phase extraction (SPE) techniques employing chromatographic grade silicas with chemically modified surfaces have been examined. SPE is found to provide rapid and efficient concentration with quantitative recovery of some triazine herbicides from natural water samples. Concentration factors of 500 to 1000 times are obtained readily by the SPE technique.A multi-residue method is described for the determination of triazine herbicides in natural water samples. The technique uses solvent extraction followed by gas chromatographic separation and detection employing nitrogen-selective devices. Seven compounds can be determined simultaneously at a nominal detection limit of 0. 1 mu g/L in a 1-litre sample. As an alternative to liquid-liquid partition (solvent extraction) for removal of compounds of interest from water, solid-phase extraction (SPE) techniques employing chromatographic grade silicas with chemically modified surfaces have been examined. SPE is found to provide rapid and efficient concentration with quantitative recovery of some triazine herbicides from natural water samples. Concentration factors of 500 to 1000 times are obtained readily by the SPE technique.

In-line micro-matrix solid-phase dispersion extraction for simultaneous separation and extraction of Sudan dyes in different spices.

PubMed

Rajabi, Maryam; Sabzalian, Sedigheh; Barfi, Behruz; Arghavani-Beydokhti, Somayeh; Asghari, Alireza

2015-12-18

A novel, simple, fast, and miniaturized method, termed in-line micro-matrix solid-phase dispersion (in-line MMSPD), coupled with high performance liquid chromatography (HPLC) was developed for the simultaneous extraction and determination of Sudan dyes (i.e. Sudan I-IV, Sudan orange G, Sudan black B, and Sudan red G) with the aid of an experimental design strategy. In this method, a matrix solid-phase dispersion (MSPD) column including a suitable mixture of polar sorbents was inserted in the mobile phase pathway, and while the interfering compounds were retained, the analytes were eluted and entered into the analytical column. In this way, the extraction, elution, and separation of the analytes were performed sequentially. Under the optimal experimental conditions (including the amount of sample, 0.0426g; amount of dispersant phase, 0.0216g of florisil, 0.0227g of silica, 0.0141g of alumina; and blending time, 112s), the limits of detection (LODs), limits of quantification, linear dynamic ranges, and recoveries were obtained to be 0.3-15.3μgkg(-1), 1-50μgkg(-1), 50-28,000μgkg(-1), and 94.5-99.1%, respectively. The results obtained showed that determination of the selected Sudan dyes in food samples using an enough sensitive and a simple analytically validated method like in-line MMSPD may offer a suitable screening method, which could be useful for food analysis and adulteration. Copyright © 2015 Elsevier B.V. All rights reserved.

Simultaneous determination of phenolic acids and flavonoids in rice using solid-phase extraction and RP-HPLC with photodiode array detection.

PubMed

Irakli, Maria N; Samanidou, Victoria F; Biliaderis, Costas G; Papadoyannis, Ioannis N

2012-07-01

An analytical method based on an optimized solid-phase extraction procedure and followed by high-performance liquid chromatography (HPLC) separation with diode array detection was developed and validated for the simultaneous determination of phenolic acids (gallic, protocatechuic, 4-hydroxy-benzoic, vanillic, caffeic, syringic, p-coumaric, ferulic, sinapic, and cinnamic acids), flavanols (catechin and epicatechin), flavonols (myricetin, quercetin, kaempferol, quercetin-3-O-glucoside, hyperoside, and rutin), flavones (luteolin and apigenin) and flavanones (naringenin and hesperidin) in rice flour (Oryza sativa L.). Chromatographic separation was carried out on a PerfectSil Target ODS-3 (250 mm × 4.6 mm, 3 μm) column at temperature 25°C using a mobile phase, consisting of 0.5% (v/v) acetic acid in water, methanol, and acetonitrile at a flow rate 1 mL min(-1) , under gradient elution conditions. Application of optimum extraction conditions, elaborated on both Lichrolut C(18) and Oasis HLB cartridges, have led to extraction of phenolic acids and flavonoids from rice flour with mean recoveries 84.3-113.0%. The developed method was validated in terms of linearity, accuracy, precision, stability, and sensitivity. Repeatability (n = 5) and inter-day precision (n = 4) revealed relative standard deviation (RSD) <13%. The optimized method was successfully applied to the analysis of phenolic acids and flavonoids in pigmented (red and black rice) and non-pigmented rice (brown rice) samples. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development and validation of an HPLC method for the simultaneous determination of tocopherols, tocotrienols and carotenoids in cereals after solid-phase extraction.

PubMed

Irakli, Maria N; Samanidou, Victoria F; Papadoyannis, Ioannis N

2011-06-01

The increasing interest in antioxidant properties of cereal and cereal-based products has prompted the development of a simple and reliable HPLC method for the simultaneous determination of important phytochemicals like tocopherols (T), tocotrienols (T3) and carotenoids. Separation was carried out on a Nucleosil 100 C(18) column, 5 μm (250 mm × 4.6 mm) thermostated at 25 °C, using a linear gradient elution system starting with methanol and ending with a mixture of methanol-isopropanol-acetonitrile. All separated compounds including the internal standard (α-tocopherol acetate) were eluted within 16 min and detected by dual detection: fluorescence for tocopherols and tocotrienols at 290 nm excitation and 320 nm emission and UV-vis photodiode array detection for lutein and β-carotene at 450 nm. Detection limits ranged from 0.2 μg/g (β-carotene) to 1.60 μg/g (α-tocopherol). The intra- and inter-assay coefficients of variation were calculated by using cereals with different levels of lipophilic antioxidants. The extraction method involved sample saponification and clean-up by solid-phase extraction (SPE). The extraction recoveries obtained using OASIS HLB SPE cartridges and dichloromethane as eluent were in the range of 90.2-110.1%, with RSD lower than 10%. The method was successfully applied to cereals: durum wheat, bread wheat, rice, barley, oat, rye, corn and triticale. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Simultaneous determination of delta-9-tetrahydrocannabinol cannabidiol and cannabinol in edible oil using ultra performance liquid chromatography-tandem mass spectrometry].

PubMed

Zhang, Aizhi; Wang, Quanlin; Mo, Shijie

2010-11-01

A method for the simultaneous determination of delta-9-tetrahydrocannabinol (THC), cannabidiol (CBD) and cannabinol (CBN) in edible oil was developed using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The target compounds were extracted with methanol, purified by an LC-Alumina-N solid phase extraction cartridge, separated and detected by the UPLC-MS/MS. Quantitative analysis was corrected by an isotope internal standard method using delta-9-THC-D3 as internal standard. Average recoveries for the target compounds varied from 68.0% to 101.6% with the relative standard deviations ranging from 7.0% to 20.1% at three spiked levels. The limits of detection (LOD) of the method were from 0.06-0.17 microg/kg and the limits of quantification (LOQ) were in the range of 0.20-0.52 microg/kg. The results showed that the method is able to meet the requirements for the simultaneous determination of THC, CBD and CBN in edible oil.

[Simultaneous determination of 9 ultraviolet stabilizers in food plastic packaging materials by solid phase extraction-high performance liquid chromatography].

PubMed

Zhang, Juzhou; Li, Jing; Shao, Dongliang; Yao, Bangben; Jiang, Junshu

2012-02-01

An effective high performance liquid chromatographic (HPLC) method has been developed for the simultaneous determination of 9 ultraviolet stabilizers in food plastic packaging materials. The food packaging samples were firstly extracted by methanol-ethyl acetate, and then purified by a C18 solid-phase extraction (SPE) column. The target compounds were separated on a ZORBAX SB-C18 column (250 mm x 4.6 mm, 5 microm) in gradient elution mode using methanol and water as mobile phases. The detection wavelength was at 310 nm. The linear plots of the nine ultraviolet stabilizers were obtained between 0.2 and 10 mg/L, with the correlation coefficients of above 0. 999 for the nine ultraviolet stabilizers. The limits of detection for this method were in the range from 0.05 to 0.1 mg/L. The recoveries spiked in commercial food plastic packaging materials were in the range of 70.2% - 89.0% with the relative standard deviations of 0.4% - 4.5%. The results indicated that the method is simple, accurate, and suitable for the simultaneous determination of the nine ultraviolet stabilizers in food plastic packaging materials.

Selective separation of copper over solder alloy from waste printed circuit boards leach solution.

PubMed

Kavousi, Maryam; Sattari, Anahita; Alamdari, Eskandar Keshavarz; Firozi, Sadegh

2017-02-01

The printed circuit boards (PCBs) from electronic waste are important resource, since the PCBs contain precious metals such as gold, copper, tin, silver, platinum and so forth. In addition to the economic point of view, the presence of lead turns this scrap into dangerous to environment. This study was conducted as part of the development of a novel process for selective recovery of copper over tin and lead from printed circuit boards by HBF 4 leaching. In previous study, Copper with solder alloy was associated, simultaneously were leached in HBF 4 solution using hydrogen peroxide as an oxidant at room temperature. The objective of this study is the separation of copper from tin and lead from Fluoroborate media using CP-150 as an extractant. The influence of organic solvent's concentration, pH, temperature and A/O phase ratio was investigated. The possible extraction mechanism and the composition of the extracted species have been determined. The separation factors for these metals using this agent are reported, while efficient methods for separation of Cu (II) from other metal ions are proposed. The treatment of leach liquor for solvent extraction of copper with CP-150 revealed that 20% CP-150 in kerosene, a 30min period of contact time, and a pH of 3 were sufficient for the extraction of Cu(II) and 99.99% copper was recovered from the leached solution. Copyright © 2016. Published by Elsevier Ltd.

Data Reduction of Laser Ablation Split-Stream (LASS) Analyses Using Newly Developed Features Within Iolite: With Applications to Lu-Hf + U-Pb in Detrital Zircon and Sm-Nd +U-Pb in Igneous Monazite

NASA Astrophysics Data System (ADS)

Fisher, Christopher M.; Paton, Chad; Pearson, D. Graham; Sarkar, Chiranjeeb; Luo, Yan; Tersmette, Daniel B.; Chacko, Thomas

2017-12-01

A robust platform to view and integrate multiple data sets collected simultaneously is required to realize the utility and potential of the Laser Ablation Split-Stream (LASS) method. This capability, until now, has been unavailable and practitioners have had to laboriously process each data set separately, making it challenging to take full advantage of the benefits of LASS. We describe a new program for handling multiple mass spectrometric data sets collected simultaneously, designed specifically for the LASS technique, by which a laser aerosol is been split into two or more separate "streams" to be measured on separate mass spectrometers. New features within Iolite (https://iolite-software.com) enable the capability of loading, synchronizing, viewing, and reducing two or more data sets acquired simultaneously, as multiple DRSs (data reduction schemes) can be run concurrently. While this version of Iolite accommodates any combination of simultaneously collected mass spectrometer data, we demonstrate the utility using case studies where U-Pb and Lu-Hf isotope composition of zircon, and U-Pb and Sm-Nd isotope composition of monazite were analyzed simultaneously, in crystals showing complex isotopic zonation. These studies demonstrate the importance of being able to view and integrate simultaneously acquired data sets, especially for samples with complicated zoning and decoupled isotope systematics, in order to extract accurate and geologically meaningful isotopic and compositional data. This contribution provides instructions and examples for handling simultaneously collected laser ablation data. An instructional video is also provided. The updated Iolite software will help to fully develop the applications of both LASS and multi-instrument mass spectrometric measurement capabilities.

Demodulation of moire fringes in digital holographic interferometry using an extended Kalman filter.

PubMed

Ramaiah, Jagadesh; Rastogi, Pramod; Rajshekhar, Gannavarpu

2018-03-10

This paper presents a method for extracting multiple phases from a single moire fringe pattern in digital holographic interferometry. The method relies on component separation using singular value decomposition and an extended Kalman filter for demodulating the moire fringes. The Kalman filter is applied by modeling the interference field locally as a multi-component polynomial phase signal and extracting the associated multiple polynomial coefficients using the state space approach. In addition to phase, the corresponding multiple phase derivatives can be simultaneously extracted using the proposed method. The applicability of the proposed method is demonstrated using simulation and experimental results.

Simultaneous separation and identification of limonoids from citrus using liquid chromatography-collision-induced dissociation mass spectra.

PubMed

Jayaprakasha, Guddadarangavvanahally K; Dandekar, Deepak V; Tichy, Shane E; Patil, Bhimanagouda S

2011-01-01

Limonoids are considered as potential cancer chemopreventive agents and are widely distributed in the Citrus genus as aglycones and glucosides. In the present study, reversed-phase HPLC coupled with CID mass spectra was developed for the simultaneous separation and identification of aglycones and glucosides of limonoids from citrus. Five aglycones such as limonin, deacetyl nomilin, ichangin, isolimonoic acid and nomilin were identified by positive ion CID MS/MS, whereas five glucosides, viz. limonin glucoside, isoobacunoic acid glucoside, obacunone glucoside, deacetyl nomilinic acid glucoside and nomilinic acid glucoside were analyzed by negative ion CID mass spectra. The developed method was successfully applied to complex citrus samples for the separation and identification of aglycones and glucosides. Citrus seeds were extracted with methanol and partially purified and analyzed by LC-CID mass spectra. The separation was achieved by C-18 column; eight limonoids were identified by comparing the retention times and mass spectral fragmentation. To the best of our knowledge, this is the first report on the identification of citrus limonoids using CID technique. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Application of liquid-liquid microextraction for the effective separation and simultaneous determination of 11 pharmaceuticals in wastewater samples using HPLC-MS/MS.

PubMed

Diuzheva, Alina; Balogh, József; Jekő, József; Cziáky, Zoltán

2018-05-17

A dispersive liquid-liquid microextraction method for the simultaneous determination of 11 pharmaceuticals has been developed. The method is based on a microextraction procedure applied to wastewater samples from different regions of Hungary followed by high performance liquid chromatography with mass spectrometry. The effect of the nature of the extractant, dispersive solvent, different additives and extraction time were examined on the extraction efficiently of the dispersive liquid-liquid microextraction method. Under optimal conditions, the linearity for determining the pharmaceuticals was in the range of 1-500 ng mL -1 , with the correlation coefficients ranging from 0.9922 to 0.9995. The limits of detection and limits of quantification were in the range 0.31-6.65 and 0.93-22.18 ng mL -1 , respectively. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Determination of selected neurotoxic insecticides in small amounts of animal tissue utilizing a newly constructed mini-extractor.

PubMed

Seifertová, Marta; Čechová, Eliška; Llansola, Marta; Felipo, Vicente; Vykoukalová, Martina; Kočan, Anton

2017-10-01

We developed a simple analytical method for the simultaneous determination of representatives of various groups of neurotoxic insecticides (carbaryl, chlorpyrifos, cypermethrin, and α-endosulfan and β-endosulfan and their metabolite endosulfan sulfate) in limited amounts of animal tissues containing different amounts of lipids. Selected tissues (rodent fat, liver, and brain) were extracted in a special in-house-designed mini-extractor constructed on the basis of the Soxhlet and Twisselmann extractors. A dried tissue sample placed in a small cartridge was extracted, while the nascent extract was simultaneously filtered through a layer of sodium sulfate. The extraction was followed by combined clean-up, including gel permeation chromatography (in case of high lipid content), ultrasonication, and solid-phase extraction chromatography using C 18 on silica and aluminum oxide. Gas chromatography coupled with high-resolution mass spectrometry was used for analyte separation, detection, and quantification. Average recoveries for individual insecticides ranged from 82 to 111%. Expanded measurement uncertainties were generally lower than 35%. The developed method was successfully applied to rat tissue samples obtained from an animal model dealing with insecticide exposure during brain development. This method may also be applied to the analytical treatment of small amounts of various types of animal and human tissue samples. A significant advantage achieved using this method is high sample throughput due to the simultaneous treatment of many samples. Graphical abstract Optimized workflow for the determination of selected insecticides in small amounts of animal tissue including newly developed mini-extractor.

SLURRY SOLVENT EXTRACTION PROCESS FOR THE RECOVERY OF METALS FROM SOLID MATERIALS

DOEpatents

Grinstead, R.R.

1959-01-20

A solvent extraction process is described for recovering uranium from low grade uranium bearing minerals such as carnotit or shale. The finely communited ore is made up as an aqueous slurry containing the necessary amount of acid to solubilize the uranium and simultaneously or subsequently contacted with an organic solvent extractant such as the alkyl ortho-, or pyro phosphoric acids, alkyl phosphites or alkyl phosphonates in combination with a diluent such as kerosene or carbon tetrachlorids. The extractant phase is separated from the slurry and treated by any suitable process to recover the uranium therefrom. One method for recovering the uranium comprises treating the extract with aqueous HF containing a reducing agent such as ferrous sulfate, which reduces the uranium and causes it to be precipitated as uranium tetrafluoride.

[Simultaneous determination of five synthetic sweeteners in food by solid phase extraction-high performance liquid chromatography-evaporative light scattering detection].

PubMed

Liu, Fang; Wang, Yan; Wang, Yuhong; Zhou, Junyi; Yan, Chao

2012-03-01

A high performance liquid chromatographic method with evaporative light scattering detection (HPLC-ELSD) was developed for the simultaneous determination of five synthetic sweeteners (acesulfame-K, saccharin sodium, sodium cyclamate, sucralose and aspartame) in food. The sweeteners were extracted by 0.1% (v/v) formic acid buffer solution. The extract of sample was cleaned up and concentrated with solid phase extraction (SPE) cartridge. Then the sweeteners were separated on a C18 column (3 microm) using 0.1% (v/v) formic acid buffer (adjusted to pH = 3.5 with aqueous ammonia solution)-methanol (61: 39, v/v) as mobile phase, and finally detected by ELSD. The results showed that the reasonable linearity was achieved for all the analytes over the range of 30 - 1000 mg/L with the correlation coefficients (r) greater than 0.997. The recoveries for the five sweeteners ranged from 85.6% to 109.0% at three spiked concentrations with the relative standard deviations (RSDs) lower than 4.0%. The limits of detection (LODs, S/N = 3) were 2.5 mg/L for both acesulfame-K and sucralose, 3 mg/L for saccharin sodium, 10 mg/L for sodium cyclamate, and 5 mg/L for aspartame. The method is simple, sensitive and low cost, and has been successfully applied to the simultaneous determination of the five synthetic sweeteners in food.

A combination strategy for extraction and isolation of multi-component natural products by systematic two-phase solvent extraction-(13)C nuclear magnetic resonance pattern recognition and following conical counter-current chromatography separation: Podophyllotoxins and flavonoids from Dysosma versipellis (Hance) as examples.

PubMed

Yang, Zhi; Wu, Youqian; Wu, Shihua

2016-01-29

Despite of substantial developments of extraction and separation techniques, isolation of natural products from natural resources is still a challenging task. In this work, an efficient strategy for extraction and isolation of multi-component natural products has been successfully developed by combination of systematic two-phase liquid-liquid extraction-(13)C NMR pattern recognition and following conical counter-current chromatography separation. A small-scale crude sample was first distributed into 9 systematic hexane-ethyl acetate-methanol-water (HEMWat) two-phase solvent systems for determination of the optimum extraction solvents and partition coefficients of the prominent components. Then, the optimized solvent systems were used in succession to enrich the hydrophilic and lipophilic components from the large-scale crude sample. At last, the enriched components samples were further purified by a new conical counter-current chromatography (CCC). Due to the use of (13)C NMR pattern recognition, the kinds and structures of major components in the solvent extracts could be predicted. Therefore, the method could collect simultaneously the partition coefficients and the structural information of components in the selected two-phase solvents. As an example, a cytotoxic extract of podophyllotoxins and flavonoids from Dysosma versipellis (Hance) was selected. After the systematic HEMWat system solvent extraction and (13)C NMR pattern recognition analyses, the crude extract of D. versipellis was first degreased by the upper phase of HEMWat system (9:1:9:1, v/v), and then distributed in the two phases of the system of HEMWat (2:8:2:8, v/v) to obtain the hydrophilic lower phase extract and lipophilic upper phase extract, respectively. These extracts were further separated by conical CCC with the HEMWat systems (1:9:1:9 and 4:6:4:6, v/v). As results, total 17 cytotoxic compounds were isolated and identified. In general, whole results suggested that the strategy was very efficient for the systematic extraction and isolation of biological active components from the complex biomaterials. Copyright © 2016 Elsevier B.V. All rights reserved.

[Simultaneous analysis of aromatic aldehydes and coumarins with high pressure liquid chromatography. Application to wines and brandies stored in oak barrels].

PubMed

Salagoity-Auguste, M H; Tricard, C; Sudraud, P

1987-04-17

Aromatic aldehydes (vanillin, syringaldehyde, coniferaldehyde and sinapaldehyde) and coumarins (esculetin, umbelliferone, scopoletin and methylumbelliferone) are natural wood compounds. Storage of wines and brandies in oak barrels increases notably aldehydes and coumarins (particularly scopoletin) concentrations. These compounds were separated by high-performance liquid chromatography, on hydrocarbon bonded reversed-phase packings, with a water-acetonitrile elution gradient. They were first extracted from wines and brandies by diethyl ether and then injected on chromatographic column. A double detection was used to determine simultaneously aromatic aldehydes and coumarins by UV absorption and fluorescence respectively.

Simultaneous separation and determination of 15 organic UV filters in sunscreen cosmetics by HPLC-ESI-MS/MS.

PubMed

Meng, X; Ma, Q; Bai, H; Wang, Z; Han, C; Wang, C

2017-08-01

A comprehensive methodology for the simultaneous determination of 15 multiclass organic UV filters in sunscreen cosmetics was developed using high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Sunscreen cosmetics of various matrices, such as toning lotion, emulsion, cream and lipstick, were analysed. Ultrasound-assisted extraction (UAE) was utilized as the extraction technique for sample preparation. The 15 UV filters were chromatographically separated by two groups of mobile phase system on an XBridge C 18 analytical column (150 × 2.1 mm I.D., 3.5 μm particle size) and quantified using HPLC-ESI-MS/MS. The quantitation was performed using the external calibration method. The established method was validated in terms of linearity, sensitivity, specificity, accuracy, stability, intraday and interday precisions, recovery and matrix effect. The method was also applied for the determination of UV filters in commercial sunscreen cosmetics. The experimental results demonstrated that the developed method was accurate, rapid and sensitive and can be used for the analytical control of sunscreen cosmetics. © 2016 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Solid-phase extraction versus matrix solid-phase dispersion: Application to white grapes.

PubMed

Dopico-García, M S; Valentão, P; Jagodziñska, A; Klepczyñska, J; Guerra, L; Andrade, P B; Seabra, R M

2007-11-15

The use of matrix solid-phase dispersion (MSPD) was tested to, separately, extract phenolic compounds and organic acids from white grapes. This method was compared with a more conventional analytical method previously developed that combines solid liquid extraction (SL) to simultaneously extract phenolic compounds and organic acids followed by a solid-phase extraction (SPE) to separate the two types of compounds. Although the results were qualitatively similar for both techniques, the levels of extracted compounds were in general quite lower on using MSPD, especially for organic acids. Therefore, SL-SPE method was preferred to analyse white "Vinho Verde" grapes. Twenty samples of 10 different varieties (Alvarinho, Avesso, Asal-Branco, Batoca, Douradinha, Esganoso de Castelo Paiva, Loureiro, Pedernã, Rabigato and Trajadura) from four different locations in Minho (Portugal) were analysed in order to study the effects of variety and origin on the profile of the above mentioned compounds. Principal component analysis (PCA) was applied separately to establish the main sources of variability present in the data sets for phenolic compounds, organic acids and for the global data. PCA of phenolic compounds accounted for the highest variability (77.9%) with two PCs, enabling characterization of the varieties of samples according to their higher content in flavonol derivatives or epicatechin. Additionally, a strong effect of sample origin was observed. Stepwise linear discriminant analysis (SLDA) was used for differentiation of grapes according to the origin and variety, resulting in a correct classification of 100 and 70%, respectively.

[Simultaneously preparation of grams of high purity tyrosol, crenulatin and salidroside from Rhodiola crenulata].

PubMed

Luo, Xin; Wang, Xue-jing; Li, Shi-ping; Zhang, Qiao; Zhao, Yi-wu; Huang Wen-zhe; Wang, Zhen-zhong; Xiao, Wei

2015-04-01

Tyrosol, crenulatin and salidroside are the main active constituents of Rhodiola crenulata, with extensive pharmacological activities. In the study, grams of high purity tyrosol, crenulatin and salidroside were simultaneously separated from R. crenulata by the first time. Firstly, R. crenulata was extracted by 70% alcohol. Then, with the yields of three compounds as the index, the macroporous resin was optimized. At last, grams of high purity tyrosol, crenulatin and salidroside were isolated by D-101 macroporousresin, purified by column chromatography. Detected by HPLC, the purity of three compounds were higher than 98%. This method has the advantages of simple process and operation, less dosage of organic solvent, highly yield and reproducibility, suitable for the simultaneously preparation of tyrosol, crenulatin and salidroside.

[Simultaneous determination of 33 primary aromatic amines of free state in fine pigments by ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry].

PubMed

Man, Zhengyin; Wang, Quanlin; Li, Hesheng; Zhang, Aizhi

2014-12-01

A comprehensive analytical method based on ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UPLC-MS/MS) has been developed for the simultaneous determination of 33 primary aromatic amines (PAAs) in fine pigments such as gouache paint, oil painting pigment and acrylic paint. The primary aromatic amines in samples were extracted with acetonitrile. Then the extract was concentrated by centrifugation and nitrogen blow, finally diluted to 2 mL with methanol-water (1:9, v/v) and filtered through 0. 22 im membrane before UPLC-MS/MS analysis. The analytes were separated on a BEH Phenyl column (100 mm x 2. 1 mm, 1. 7 1µm) with 0. 07% (v/v) formic acid in methanol-water as mobile phases in gradient elution. The PAAs were detected by UPLC-MS/MS under multiple reaction monitoring (MRM) mode and quantified by the internal standard method. The separation conditions, fragment voltages and collision energies were optimized. The impacts of extraction times, extraction solvents and concentration methods on recoveries were studied. The limits of detection and limits of quantitation for the 33 primary aromatic amines were 5-50 µg/kg and 15-150 µg/kg respectively. The mean recoveries of three different dye products at three spiked levels were 70. 1% - 115. 8%. The relative standard deviations were 2. 1% - 15%. The expenmental results indicated that the method is simple, rapid, sensitive, accurate and can meet the requirements for the determination.

Application of mixed cloud point extraction for the analysis of six flavonoids in Apocynum venetum leaf samples by high performance liquid chromatography.

PubMed

Zhou, Jun; Sun, Jiang Bing; Xu, Xin Yu; Cheng, Zhao Hui; Zeng, Ping; Wang, Feng Qiao; Zhang, Qiong

2015-03-25

A simple, inexpensive and efficient method based on the mixed cloud point extraction (MCPE) combined with high performance liquid chromatography was developed for the simultaneous separation and determination of six flavonoids (rutin, hyperoside, quercetin-3-O-sophoroside, isoquercitrin, astragalin and quercetin) in Apocynum venetum leaf samples. The non-ionic surfactant Genapol X-080 and cetyl-trimethyl ammonium bromide (CTAB) was chosen as the mixed extracting solvent. Parameters that affect the MCPE processes, such as the content of Genapol X-080 and CTAB, pH, salt content, extraction temperature and time were investigated and optimized. Under the optimized conditions, the calibration curve for six flavonoids were all linear with the correlation coefficients greater than 0.9994. The intra-day and inter-day precision (RSD) were below 8.1% and the limits of detection (LOD) for the six flavonoids were 1.2-5.0 ng mL(-1) (S/N=3). The proposed method was successfully used to separate and determine the six flavonoids in A. venetum leaf samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Determination of Five Major 8-Prenylflavones in Leaves of Epimedium by Solid-Phase Extraction Coupled with Capillary Electrophoresis

PubMed Central

Xie, Juan-ping; Xiang, Ji-ming; Zhu, Zhong-liang

2016-01-01

A simple, accurate and reproducible method which is based on the capillary electrophoresis, coupled with solid-phase extraction, has been developed for simultaneous determination of multiple 8-prenylflavones from Chinese Herba Epimedii. In this study, the author has mainly illustrated the experimental process and research results of five major components including epimedin C, icariin, diphylloside A, epimedoside A and icarisoside A that have been extracted and identified from Herba Epimedii for the first time. Experimental conditions have been optimized to achieve the best separation efficiency for the following factors: the buffer pH, buffer concentration and applied voltage. The experiment can be conducted through two separable stages: the first stage is to obtain the crude extracts through the solid-phase extraction; and the second stage is to further separate five major components by using the capillary electrophoresis. The separation of the five components and the analysis of the experiment are relatively fast and can be completed within 20 min. The concentration ranges of the construction of standard curves of five major 8-prenylflavones are 32.0–395.0, 23.4–292.0, 42.1–526.0, 18.8–233.5 and 29.7–371.0 µg mL−1 respectively, which have showed acceptable linearity with a correlation coefficient, r ≥ 0.999. The coefficient varies within 2.0% for both intra- and inter-days tests. The recoveries of five components range from 92.3 to 104.1%. The relative standard deviations of recoveries of five components range from 1.2 and 2.8%. This new method will facilitate the extraction and expedite the determination of medical components from Herba Epimedii. PMID:26865656

[The research on separating and extracting overlapping spectral feature lines in LIBS using damped least squares method].

PubMed

Wang, Yin; Zhao, Nan-jing; Liu, Wen-qing; Yu, Yang; Fang, Li; Meng, De-shuo; Hu, Li; Zhang, Da-hai; Ma, Min-jun; Xiao, Xue; Wang, Yu; Liu, Jian-guo

2015-02-01

In recent years, the technology of laser induced breakdown spectroscopy has been developed rapidly. As one kind of new material composition detection technology, laser induced breakdown spectroscopy can simultaneously detect multi elements fast and simply without any complex sample preparation and realize field, in-situ material composition detection of the sample to be tested. This kind of technology is very promising in many fields. It is very important to separate, fit and extract spectral feature lines in laser induced breakdown spectroscopy, which is the cornerstone of spectral feature recognition and subsequent elements concentrations inversion research. In order to realize effective separation, fitting and extraction of spectral feature lines in laser induced breakdown spectroscopy, the original parameters for spectral lines fitting before iteration were analyzed and determined. The spectral feature line of' chromium (Cr I : 427.480 nm) in fly ash gathered from a coal-fired power station, which was overlapped with another line(FeI: 427.176 nm), was separated from the other one and extracted by using damped least squares method. Based on Gauss-Newton iteration, damped least squares method adds damping factor to step and adjust step length dynamically according to the feedback information after each iteration, in order to prevent the iteration from diverging and make sure that the iteration could converge fast. Damped least squares method helps to obtain better results of separating, fitting and extracting spectral feature lines and give more accurate intensity values of these spectral feature lines: The spectral feature lines of chromium in samples which contain different concentrations of chromium were separated and extracted. And then, the intensity values of corresponding spectral lines were given by using damped least squares method and least squares method separately. The calibration curves were plotted, which showed the relationship between spectral line intensity values and chromium concentrations in different samples. And then their respective linear correlations were compared. The experimental results showed that the linear correlation of the intensity values of spectral feature lines and the concentrations of chromium in different samples, which was obtained by damped least squares method, was better than that one obtained by least squares method. And therefore, damped least squares method was stable, reliable and suitable for separating, fitting and extracting spectral feature lines in laser induced breakdown spectroscopy.

Dual-cloud point extraction coupled to high performance liquid chromatography for simultaneous determination of trace sulfonamide antimicrobials in urine and water samples.

PubMed

Nong, Chunyan; Niu, Zongliang; Li, Pengyao; Wang, Chunping; Li, Wanyu; Wen, Yingying

2017-04-15

Dual-cloud point extraction (dCPE) was successfully developed for simultaneous extraction of trace sulfonamides (SAs) including sulfamerazine (SMZ), sulfadoxin (SDX), sulfathiazole (STZ) in urine and water samples. Several parameters affecting the extraction were optimized, such as sample pH, concentration of Triton X-114, extraction temperature and time, centrifugation rate and time, back-extraction solution pH, back-extraction temperature and time, back-extraction centrifugation rate and time. High performance liquid chromatography (HPLC) was applied for the SAs analysis. Under the optimum extraction and detection conditions, successful separation of the SAs was achieved within 9min, and excellent analytical performances were attained. Good linear relationships (R 2 ≥0.9990) between peak area and concentration for SMZ and STZ were optimized from 0.02 to 10μg/mL, for SDX from 0.01 to 10μg/mL. Detection limits of 3.0-6.2ng/mL were achieved. Satisfactory recoveries ranging from 85 to 108% were determined with urine, lake and tap water spiked at 0.2, 0.5 and 1μg/mL, respectively, with relative standard deviations (RSDs, n=6) of 1.5-7.7%. This method was demonstrated to be convenient, rapid, cost-effective and environmentally benign, and could be used as an alternative tool to existing methods for analysing trace residues of SAs in urine and water samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Rapid separation and identification of phenolics in crude red grape skin extracts by high performance liquid chromatography coupled to diode array detection and tandem mass spectrometry.

PubMed

Ji, Mei; Li, Chen; Li, Qiang

2015-10-02

A rapid and efficient method was established for the simultaneous determination of structures and configurations for 45 phenolics isolated from crude red grape skin extracts without extensive sample preparation. Separation and compound assignments were achieved using high performance liquid chromatography coupled to diode array detection and tandem mass spectrometry (HPLC-DAD-MS(2)). A Poroshell 120 EC-C18 (100mm×3.0mm, 2.7μm) column was employed to separate the phenolics, which were eluted using a gradient of acetonitrile and water acidified with 0.2% formic acid. Phenolics were identified by comparison of their UV-vis spectra, mass spectra and MS(2) data with those in the literature. Using this procedure, five compounds were detected for the first time in Vitis amurensis. Good separation of most phenolics was achieved in 26min. The methods described here can be used for the characterization of phenolics in a variety of grapes and grape products. Copyright © 2015 Elsevier B.V. All rights reserved.

Striatal and Hippocampal Entropy and Recognition Signals in Category Learning: Simultaneous Processes Revealed by Model-Based fMRI

PubMed Central

Davis, Tyler; Love, Bradley C.; Preston, Alison R.

2012-01-01

Category learning is a complex phenomenon that engages multiple cognitive processes, many of which occur simultaneously and unfold dynamically over time. For example, as people encounter objects in the world, they simultaneously engage processes to determine their fit with current knowledge structures, gather new information about the objects, and adjust their representations to support behavior in future encounters. Many techniques that are available to understand the neural basis of category learning assume that the multiple processes that subserve it can be neatly separated between different trials of an experiment. Model-based functional magnetic resonance imaging offers a promising tool to separate multiple, simultaneously occurring processes and bring the analysis of neuroimaging data more in line with category learning’s dynamic and multifaceted nature. We use model-based imaging to explore the neural basis of recognition and entropy signals in the medial temporal lobe and striatum that are engaged while participants learn to categorize novel stimuli. Consistent with theories suggesting a role for the anterior hippocampus and ventral striatum in motivated learning in response to uncertainty, we find that activation in both regions correlates with a model-based measure of entropy. Simultaneously, separate subregions of the hippocampus and striatum exhibit activation correlated with a model-based recognition strength measure. Our results suggest that model-based analyses are exceptionally useful for extracting information about cognitive processes from neuroimaging data. Models provide a basis for identifying the multiple neural processes that contribute to behavior, and neuroimaging data can provide a powerful test bed for constraining and testing model predictions. PMID:22746951

Determination of trigonelline, nicotinic acid, and caffeine in Yunnan Arabica coffee by microwave-assisted extraction and HPLC with two columns in series.

PubMed

Liu, Hongcheng; Shao, Jinliang; Li, Qiwan; Li, Yangang; Yan, Hong Mei; He, Lizhong

2012-01-01

A simple, rapid method was developed for simultaneous extraction of trigonelline, nicotinic acid, and caffeine from coffee, and separation by two chromatographic columns in series. The trigonelline, nicotinic acid, and caffeine were extracted with microwave-assisted extraction (MAE). The optimal conditions selected were 3 min, 200 psi, and 120 degrees C. The chromatographic separation was performed with two columns in series, polyaromatic hydrocarbon C18 (250 x 4.6 mm id, 5 microm particle size) and Bondapak NH2 (300 x 3.9 mm id, 5 microm particle size). Isocratic elution was with 0.02 M phosphoric acid-methanol (70 + 30, v/v) mobile phase at a flow rate of 0.8 mL/min. Good recoveries and RSD values were found for all analytes in the matrix. The LOD of the three compounds was 0.02 mg/L, and the LOQ was 0.005% in the matrix. The concentrations of trigonelline, nicotinic acid, and caffeine in instant coffee, roasted coffee, and raw coffee (Yunnan Arabica coffee) were assessed by MAE and hot water extraction; the correlation coefficients between concentrations of the three compounds obtained were close to 1.

Method of high purity silane preparation

DOEpatents

Tsuo, Y. Simon; Belov, Eugene P.; Gerlivanov, Vadim G.; Zadde, Vitali V.; Kleschevnikova, Solomonida I.; Korneev, Nikolai N.; Lebedev, Eugene N.; Pinov, Akhsarbek B.; Ryabenko, Eugene A.; Strebkov, Dmitry S.; Chernyshev, Eugene A.

2000-01-01

A process for the preparation of high purity silane, suitable for forming thin layer silicon structures in various semiconductor devices and high purity poly- and single crystal silicon for a variety of applications, is provided. Synthesis of high-purity silane starts with a temperature assisted reaction of metallurgical silicon with alcohol in the presence of a catalyst. Alcoxysilanes formed in the silicon-alcohol reaction are separated from other products and purified. Simultaneous reduction and oxidation of alcoxysilanes produces gaseous silane and liquid secondary products, including, active part of a catalyst, tetra-alcoxysilanes, and impurity compounds having silicon-hydrogen bonds. Silane is purified by an impurity adsorption technique. Unreacted alcohol is extracted and returned to the reaction with silicon. Concentrated mixture of alcoxysilanes undergoes simultaneous oxidation and reduction in the presence of a catalyst at the temperature -20.degree. C. to +40.degree. C. during 1 to 50 hours. Tetra-alcoxysilane extracted from liquid products of simultaneous oxidation and reduction reaction is directed to a complete hydrolysis. Complete hydrolysis of tetra-alcoxysilane results in formation of industrial silica sol and alcohol. Alcohol is dehydrated by tetra-alcoxysilane and returned to the reaction with silicon.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zalupski, Peter R.; Klaehn, John R.; Peterman, Dean R.

The feasibility of simultaneous separation of uranium, neptunium, plutonium, americium, and curium from a simulated dissolved used fuel simulant adjusted to 1.0 M nitric acid is investigated using a mixture of the soft donor bis(bis-3,5-trifluoromethyl)phenyl) dithiophosphinic acid (“0”) and the hard donor synergist trioctylphosphine oxide (TOPO) dissolved in toluene. The results reported in this work are compared to our recent demonstration of a complete actinide recovery from a simulated dissolved fuel solution using a synergistic combination of bis(o-trifluoromethylphenyl)dithiophosphinic acid (“1”) and TOPO dissolved in either toluene or trifluoromethylphenyl sulfone. While the extraction efficiency of americium was enhanced for the liquid-liquidmore » system containing “0”, enabling to accomplish a trivalent An/Ln separation at 1.0 M HNO3, the extraction of neptunium was drastically diminished, relative to “1”. The partitioning behavior of curium was also negatively impacted, introducing an effective opportunity for americium/curium separation. Radiometric and spectrophotometric studies demonstrate that the complete actinide recovery using the solvent based upon “0” and TOPO is not feasible. Additionally, the importance of radiolytic degradation processes is discussed through the comparisons of extraction properties of liquid-liquid systems based on both soft donor reagents.« less

Biological production of acetic acid from waste gases with Clostridium ljungdahlii

DOEpatents

Gaddy, James L.

1998-01-01

A method and apparatus for converting waste gases from industrial processes such as oil refining, carbon black, coke, ammonia, and methanol production, into useful products. The method includes introducing the waste gases into a bioreactor where they are fermented to various organic acids or alcohols by anaerobic bacteria within the bioreactor. These valuable end products are then recovered, separated and purified. In an exemplary recovery process, the bioreactor raffinate is passed through an extraction chamber into which one or more non-inhibitory solvents are simultaneously introduced to extract the product. Then, the product is separated from the solvent by distillation. Gas conversion rates can be maximized by use of centrifuges, hollow fiber membranes, or other means of ultrafiltration to return entrained anaerobic bacteria from the bioreactor raffinate to the bioreactor itself, thus insuring the highest possible cell concentration.

Clostridium stain which produces acetic acid from waste gases

DOEpatents

Gaddy, James L.

1997-01-01

A method and apparatus for converting waste gases from industrial processes such as oil refining, carbon black, coke, ammonia, and methanol production, into useful products. The method includes introducing the waste gases into a bioreactor where they are fermented to various organic acids or alcohols by anaerobic bacteria within the bioreactor. These valuable end products are then recovered, separated and purified. In an exemplary recovery process, the bioreactor raffinate is passed through an extraction chamber into which one or more non-inhibitory solvents are simultaneously introduced to extract the product. Then, the product is separated from the solvent by distillation. Gas conversion rates can be maximized by use of centrifuges, hollow fiber membranes, or other means of ultrafiltration to return entrained anaerobic bacteria from the bioreactor raffinate to the bioreactor itself, thus insuring the highest possible cell concentration.

Clostridium strain which produces acetic acid from waste gases

DOEpatents

Gaddy, J.L.

1997-01-14

A method and apparatus are disclosed for converting waste gases from industrial processes such as oil refining, carbon black, coke, ammonia, and methanol production, into useful products. The method includes introducing the waste gases into a bioreactor where they are fermented to various organic acids or alcohols by anaerobic bacteria within the bioreactor. These valuable end products are then recovered, separated and purified. In an exemplary recovery process, the bioreactor raffinate is passed through an extraction chamber into which one or more non-inhibitory solvents are simultaneously introduced to extract the product. Then, the product is separated from the solvent by distillation. Gas conversion rates can be maximized by use of centrifuges, hollow fiber membranes, or other means of ultrafiltration to return entrained anaerobic bacteria from the bioreactor raffinate to the bioreactor itself, thus insuring the highest possible cell concentration. 4 figs.

Simultaneous qualification and quantification of baccharane glycosides in Impatientis Semen by HPLC-ESI-MSD and HPLC-ELSD.

PubMed

Li, Hui-Jun; Yu, Jun-Jie; Li, Ping

2011-03-25

This study presents a high performance liquid chromatography (HPLC) with electrospray ionization mass spectrometric detection (ESI-MSD) and evaporative light scattering detection (ELSD) method for the simultaneous qualification and quantification of eight major baccharane glycosides, namely hosenlosides A, B, C, F, G, K, L, and M in Impatientis Semen, a Chinese herbal medicine derived from the seeds of Impatiens balsamina L. In order to achieve optimum performance, several extraction parameters (including extraction solvent, extraction mode, extraction time) were optimized. The baccharane glycosides were separated on a Shim-pack CLC-ODS column with gradient elution of water and methanol. Temperature for the ELSD drift tube was set at 98°C and the nitrogen flow rate was 2.7l/min. The unambiguous identities of the analytes were realized by comparing retention times and mass data with those of reference compounds. The developed method was fully validated in terms of linearity, sensitivity, precision, repeatability, recovery as well as robustness, and subsequently applied to evaluate the quality of 14 batches of Impatientis Semen commercial samples from different collections. Copyright © 2010 Elsevier B.V. All rights reserved.

A novel approach to the simultaneous extraction and non-targeted analysis of the small molecules metabolome and lipidome using 96-well solid phase extraction plates with column-switching technology.

PubMed

Li, Yubo; Zhang, Zhenzhu; Liu, Xinyu; Li, Aizhu; Hou, Zhiguo; Wang, Yuming; Zhang, Yanjun

2015-08-28

This study combines solid phase extraction (SPE) using 96-well plates with column-switching technology to construct a rapid and high-throughput method for the simultaneous extraction and non-targeted analysis of small molecules metabolome and lipidome based on ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry. This study first investigated the columns and analytical conditions for small molecules metabolome and lipidome, separated by an HSS T3 and BEH C18 columns, respectively. Next, the loading capacity and actuation duration of SPE were further optimized. Subsequently, SPE and column switching were used together to rapidly and comprehensively analyze the biological samples. The experimental results showed that the new analytical procedure had good precision and maintained sample stability (RSD<15%). The method was then satisfactorily applied to more widely analyze the small molecules metabolome and lipidome to test the throughput. The resulting method represents a new analytical approach for biological samples, and a highly useful tool for researches in metabolomics and lipidomics. Copyright © 2015 Elsevier B.V. All rights reserved.

Microwave-Assisted Simplified Simultaneous Distillation Coupled with Ionic Liquid Pretreatment for the Analysis of Essential Oil in Schisandra sphenanthera.

PubMed

Yu, Guo-Wei; Nie, Jing; Song, Zhi-Yu; Li, Zu-Guang; Lee, Maw-Rong; Wang, Shen-Peng

2017-11-01

Simultaneous distillation extraction (SDE) is quite useful for the separation of volatile compounds from an analyte when their contents are quite low. In this study, a simplified SDE approach is applied for the extraction of essential oil from Schisandra sphenanthera, with microwave as heating source, [Bmim][Cl] as the medium for pretreatment, and gas chromatography-mass spectrometry as the analytical approach. Consequently, the improvement resulted from [Bmim][Cl] pretreatment is demonstrated by taking comparison with blank experiments. Totally 61 compounds have been detected in the essential oil obtained by using [Bmim][Cl] pretreatment, while without [Bmim][Cl] pretreatment, only 53 compounds can be detected. Moreover, [Bmim][Cl] pretreatment can also resulted in a higher yield of essential oil. The experimental results demonstrate that the simplified SDE coupled with ionic liquid pretreatment is a feasible approach for the extraction of essential oil from S. sphenanthera with high efficiency as 0.85% of essential oil yield has been obtained, and can be potentially extended to the extraction of essential oil or other target volatile compounds with low content. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

RP-HPTLC densitometric determination and validation of vanillin and related phenolic compounds in accelerated solvent extract of Vanilla planifolia*.

PubMed

Sharma, Upendra Kumar; Sharma, Nandini; Gupta, Ajai Prakash; Kumar, Vinod; Sinha, Arun Kumar

2007-12-01

A simple, fast and sensitive RP-HPTLC method is developed for simultaneous quantitative determination of vanillin and related phenolic compounds in ethanolic extracts of Vanilla planifolia pods. In addition to this, the applicability of accelerated solvent extraction (ASE) as an alternative to microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE) and Soxhlet extraction was also explored for the rapid extraction of phenolic compounds in vanilla pods. Good separation was achieved on aluminium plates precoated with silica gel RP-18 F(254S) in the mobile phase of methanol/water/isopropanol/acetic acid (30:65:2:3, by volume). The method showed good linearity, high precision and good recovery of compounds of interest. ASE showed good extraction efficiency in less time as compared to other techniques for all the phenolic compounds. The present method would be useful for analytical research and for routine analysis of vanilla extracts for their quality control.

Combination of in situ metathesis reaction with a novel "magnetic effervescent tablet-assisted ionic liquid dispersive microextraction" for the determination of endogenous steroids in human fluids.

PubMed

Wu, Jia; Xu, Zilin; Pan, Yixuan; Shi, Yi; Bao, Xiujie; Li, Jun; Tong, Yu; Tang, Han; Ma, Shuyan; Wang, Xuedong; Lyu, Jianxin

2018-05-01

Herein, a novel magnetic effervescence tablet-assisted microextraction coupled to in situ metathesis reaction of ionic liquid (IS-META-ILDM) is presented for the determination of four endogenous steroids in human urine, pregnant women's blood, and fetal umbilical cord blood. The magnetic effervescent tablets, which were composed of Fe 3 O 4 nanoparticles, sodium carbonate (alkaline source), and tartaric acid (acidic source), were used to disperse the extractant and for convenient magnetic separation. After the effervescent reaction, in situ reaction between NH 4 PF 6 and [C 6 MIM]BF 4 was adopted to change hydrophilic ionic liquid to hydrophobic liquid, which could be separated from the aqueous phase. The newly developed method has three obvious advantages: (1) combination of effervescent dispersion and magnetic nanoparticles' retrieval is cost-effective and the dispersion and collection of the extractant can be completed almost simultaneously; (2) as compared to temperature-controlled ionic liquid dispersive microextraction and cold-induced solidified microextraction, this method avoids a heating and cooling process which significantly reduces the extraction time and energy cost; and (3) the combination of adsorption by magnetic nanoparticles with extraction by in situ metathesis reaction easily produces high recoveries for target analytes. The optimized composition of effervescent tablet and experimental parameters are as follows: 0.64 g mixture of sodium carbonate and tartaric acid, 7 mg of Fe 3 O 4 (20 nm) as magnetic sorbents, 40 μL of [C 6 MIM]BF 4 as the extraction solvent, 0.15 g NH 4 PF 6 , and 300 μL of elution solvent. Under the optimized conditions, the newly developed method provided high extraction recoveries (90.0-118.5%) and low LODs (0.14-0.17 μg L -1 ) in urine and blood samples. In total, this IS-META-ILDM method provided high extraction efficiency, fast and convenient separation, and underutilization of any organic solvent, and thus it has great potential for the determination of trace endogenous steroids in complex human fluids. Graphical abstract The newly developed method has three obvious advantages: combination of effervescent dispersion and magnetic nanoparticles' retrieval is cost-effective and the dispersion and collection of the extractant can be completed almost simultaneously. It avoids a heating and cooling process which significantly reduces the extraction time and energy cost and easily produces high recoveries for target analytes.

New fluorescence spectroscopic method for the simultaneous determination of alkaloids in aqueous extract of green coffee beans.

PubMed

Yisak, Hagos; Redi-Abshiro, Mesfin; Chandravanshi, Bhagwan Singh

2018-05-11

There is no fluorescence spectroscopic method for the determination of trigonelline and theobromine in green coffee beans. Therefore, the objective of this study was to develop a new fluorescence spectroscopic method to determine the alkaloids simultaneously in the aqueous extract of green coffee beans. The calibration curves were linear in the range 2-6, 1-6, 1-5 mg/L for caffeine, theobromine and trigonelline, respectively, with R 2  ≥ 0.9987. The limit of detection and limit of quantification were 2, 6 and 7 µg/L and 40, 20 and 20 µg/L for caffeine, theobromine and trigonelline, respectively. Caffeine and trigonelline exhibited well separated fluorescence excitation spectra and therefore the two alkaloids were selectively quantified in the aqueous extract of green coffee. While theobromine showed overlapping fluorescence excitation spectra with caffeine and hence theobromine could not be determined in the aqueous extract of green coffee beans. The amount of caffeine and trigonelline in the three samples of green coffee beans were found to be 0.95-1.10 and 1.00-1.10% (w/w), respectively. The relative standard deviations (RSD ≤ 4%) of the method for the three compounds of interest were of very good. The accuracy of the developed analytical method was evaluated by spiking standard caffeine and trigonelline to green coffee beans and the average recoveries were 99 ± 2% for both the alkaloids. A fast, sensitive and reliable fluorescence method for the simultaneous determination of caffeine and trigonelline in the aqueous extract of green coffee beans was developed and validated. The developed method reflected an effective performance to the direct determination of the two alkaloids in the aqueous extract of green coffee beans.

[Simultaneous determination of 22 typical pharmaceuticals and personal care products in environmental water using ultra performance liquid chromatography- triple quadrupole mass spectrometry].

PubMed

Wu, Chunying; Gu, Feng; Bai, Lu; Lu, Wenlong

2015-08-01

An analytical method for simultaneous determination of 22 typical pharmaceuticals and personal care products (PPCPs) in environmental water samples was developed by ultra performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS/MS). An Oasis HLB solid phase extraction cartridge, methanol as washing solution, water containing 0. 1% formic acid-methanol (7:3, v/v) as the mobile phases were selected for sample pretreatment and chromatographic separation. Based on the optimized sample pretreatment procedures and separation condition, the target recoveries ranged from 73% to 125% in water with the relative standard deviations ( RSDs) from 8.8% to 17.5%, and the linear ranges were from 2 to 2 000 µg/L with correlation coefficients (R2) not less than 0.997. The method can be applied to simultaneous determination of the 22 typical PPCPs in environmental water samples because of its low detection limits and high recoveries. It can provide support and help for the related research on water environmental risk assessment and control of the micro-organic pollutants.

One-enzyme catalyzed simultaneous plant cell disruption and conversion of released glycoside to aglycone combined with in situ product separation as green one-pot production of genipin from gardenia fruit.

PubMed

Winotapun, Weerapath; Opanasopit, Praneet; Ngawhirunpat, Tanasait; Rojanarata, Theerasak

2013-07-10

A direct one-pot production of genipin, an iridoid aglycone, from crude gardenia fruit was developed. The method relied on the use of single cellulase to disrupt plant cells and to cleave off sugar molecules simultaneously, thereby enhancing the release of intracellular iridoids and converting geniposide to genipin. During the biocatalysis, eco-friendly ethyl acetate was used to extract the product, providing the partial purification and the minimization of genipin degradation. By using 10 mg/mL cellulase and 24 h-incubation at 50 °C, pH 4, combined with in situ extraction, genipin with good purity was yielded at 58.83 mg/g, which increased 12.38 and 1.72 times compared with those obtained from the procedures without either the aid of enzyme or in situ extraction, respectively. Therefore, this integrated approach is promising for the production of genipin and should be potentially applied to the preparation of other plant aglycones. Copyright © 2013 Elsevier Inc. All rights reserved.

A single extraction and HPLC procedure for simultaneous analysis of phytosterols, tocopherols and lutein in soybeans.

PubMed

Slavin, Margaret; Yu, Liangli Lucy

2012-12-15

A saponification/extraction procedure and high performance liquid chromatography (HPLC) analysis method were developed and validated for simultaneous analysis of phytosterols, tocopherols and lutein (a carotenoid) in soybeans. Separation was achieved on a phenyl column with a ternary, isocratic solvent system of acetonitrile, methanol and water (48:22.5:29.5, v/v/v). Evaporative light scattering detection (ELSD) was used to quantify β-sitosterol, stigmasterol, campesterol, and α-, δ- and γ-tocopherols, while lutein was quantified with visible light absorption at 450 nm. Peak identification was verified by retention times and spikes with external standards. Standard curves were constructed (R(2)>0.99) to allow for sample quantification. Recovery of the saponification and extraction was demonstrated via analysis of spiked samples. Also, the accuracy of results of four soybeans using the described saponification and HPLC analytical method was validated against existing methods. This method offers a more efficient alternative to individual methods for quantifying lutein, tocopherols and sterols in soybeans. Copyright © 2012 Elsevier Ltd. All rights reserved.

Development of a sensitive high-performance liquid chromatographic method with simple extraction for simultaneous determination of huperzine A and huperzine B in the species containing lycopodium alkaloids.

PubMed

Zhang, Yanqing; Xie, Junbo; Chen, Wen-Qian; Zhou, Tian-Yan; Lu, Wei

2009-01-01

A sensitive HPLC method with simple extraction was developed for simultaneous determination of huperzine A (HupA) and huperzine B (HupB) in Huperzia serrata, H. crispata, H. miyoshiana, and Lycopodiastrum casuarinoides. In order to avoid conventional multiple-step and time-consuming sample preparation methods, direct reflux extraction with alkaline chloroform was adopted. The quantitative determination was conducted by reversed-phase HPLC with a photodiode array detector set at 308 nm. Separation was performed on a Luna C18 column (250 x 4.6 mm id, 5 microm) with methanol-0.2% aqueous acetic acid (18 + 82, v/v) mobile phase. The method was validated for accuracy, reproducibility, precision, and limits of detection and quantification. Quantification of the two active compounds in the samples was performed by this newly developed method, and the content of HupA and HupB varied substantially among four different species. The satisfactory results indicated that the developed method can readily be utilized for quality control of the species of Huperziaceae and Lycopodiaceae containing the two compounds.

Simultaneous preparation of naturally abundant and rare catechins by tannase-mediated biotransformation combining high speed counter current chromatography.

PubMed

Xia, Guobin; Hong, Shan; Liu, Songbai

2014-05-15

Simultaneous preparation of naturally rare catechins, EGC and EC, has been realized by tannase-mediated biotransformation combining high speed counter current chromatography. In addition, simultaneous preparation of the four catechins, EGCG, ECG, EGC, and EC in green tea extract has also been achieved by HSCCC under the normal phase and the reversed phase modes. The identity of the catechins was determined by HPLC-DAD-ESI-MS and quantification of the catechins was performed by HPLC-DAD. In a typical HSCCC separation, 27.2 mg 98.8% EGCG, 14.1 mg 94.7% EGC, and 9.3 mg 97.5% EC were obtained. This new method is efficient, time-saving and valuable for biological studies. Copyright © 2013 Elsevier Ltd. All rights reserved.

Simultaneous extraction of acetylsalicylic acid and salicylic acid from human plasma and simultaneous estimation by liquid chromatography and atmospheric pressure chemical ionization/tandem mass spectrometry detection. Application to a pharmacokinetic study.

PubMed

Nirogi, Ramakrishna; Kandikere, Vishwottam; Mudigonda, Koteshwara; Ajjala, Devender; Suraneni, Ramakrishna; Thoddi, Parthasarathi

2011-01-01

A simple analytical method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in atmospheric chemical ionization mode (APCI) for the simultaneous estimation of acetylsalicylic acid (ASA, CAS 50-78-2) and its active metabolite salicylic acid (SA, CAS 69-72-7) in human plasma has been developed and validated. ASA and SA were analyzed simultaneously despite differences in plasma concentration ranges of ASA and SA after oral administration of ASA. In spite of having different chemical, ionization and chromatographic properties, ASA and SA were extracted simultaneously from the plasma sample using acetonitrile protein precipitation followed by liquid-liquid extraction. The analytes were separated on a reversed phase column with rapid gradient program using mobile phase consisting of ammonium acetate buffer and methanol. The structural analogue diclofenac was used as an internal standard. The multiple reaction monitoring (MRM) transitions m/z 179 --> 137 for ASA, m/z 137 --> 65 for SA and m/z 294 --> 250 for IS were used. The assay exhibited a linear dynamic range of 0.02-10 microg/mL for ASA and 0.1-50 microg/mL for SA. The between-batch precision (%CV) ranged from 2.1 to 7.9% for ASA and from 0.2 to 5.2% for SA. The between-batch accuracy ranged from 95.4 to 96.7% for ASA and from 94.6 to 111.3% for SA. The validated method was successfully applied for the evaluation of pharmacokinetics of ASA after single oral administration of 650 mg test formulation versus two 325 mg reference formulations of ASA in human subjects.

Sensitive and simultaneous determination of HIV protease inhibitors in rat biological samples by liquid chromatography-mass spectrometry.

PubMed

Gao, Weihua; Kishida, Tomoyuki; Kimura, Keisuke; Kageyama, Michiharu; Sumi, Masaki; Yoshikawa, Yukako; Shibata, Nobuhito; Takada, Kanji

2002-06-01

A sensitive and simultaneous liquid chromatographic-mass spectrometric (LC/MS) method for the determination of current four HIV protease inhibitors (PIs), indinavir (IDV), saquinavir (SQV), nelfinavir (NFV) and amprenavir (APV) in rat plasma and liver dialysate by a microdialysis method was described. An isocratic LC/MS method in combination with atmospheric pressure chemical ionization was developed for the determination of these four PIs in biological samples in the same run. The analytes including an internal standard were extracted from 100 microL of plasma or 150 microL of liver dialysate samples by salting-out with 100 microL of ice-cold 2 M K(3)PO(4) followed by ether extraction. The separation of analytes was carried out on a reversed-phase semi-micro column using 50% of acetonitrile containing 1% acetic acid as mobile phase at a flow rate of 0.2mL/min(-1). The separation was completed within 5 min. Precision, recovery and limits of detection indicated that the method was suitable for the quantitative determination of these PIs in rat plasma or liver dialysate. This simple, sensitive and highly specific LC/MS method is suitable for pharmacokinetic studies and therapeutic drug monitoring in AIDS patients who receive double protease therapy. Copyright 2002 John Wiley & Sons, Ltd.

Simultaneous analysis of hydrochlorothiazide, triamterene and reserpine in rat plasma by high performance liquid chromatography and tandem solid-phase extraction.

PubMed

Li, Hang; He, Junting; Liu, Qin; Huo, Zhaohui; Liang, Si; Liang, Yong

2011-03-01

A tandem solid-phase extraction method (SPE) of connecting two different cartridges (C(18) and MCX) in series was developed as the extraction procedure in this article, which provided better extraction yields (>86%) for all analytes and more appropriate sample purification from endogenous interference materials compared with a single cartridge. Analyte separation was achieved on a C(18) reversed-phase column at the wavelength of 265 nm by high-performance liquid chromatography (HPLC). The method was validated in terms of extraction yield, precision and accuracy. These assays gave mean accuracy values higher than 89% with RSD values that were always less than 3.8%. The method has been successfully applied to plasma samples from rats after oral administration of target compounds. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rapid and sensitive analytical method for monitoring of 12 organotin compounds in natural waters.

PubMed

Vahčič, Mitja; Milačič, Radmila; Sčančar, Janez

2011-03-01

A rapid analytical method for the simultaneous determination of 12 different organotin compounds (OTC): methyl-, butyl-, phenyl- and octyl-tins in natural water samples was developed. It comprises of in situ derivatisation (by using NaBEt4) of OTC in salty or fresh water sample matrix adjusted to pH 6 with Tris-citrate buffer, extraction of ethylated OTC into hexane, separation of OTC in organic phase on 15 m GC column and subsequent quantitative determination of separated OTC by ICP-MS. To optimise the pH of ethylation, phosphate, carbonate and Tris-citrate buffer were investigated alternatively to commonly applied sodium acetate - acetic acid buffer. The ethylation yields in Tris-citrate buffer were found to be better for TBT, MOcT and DOcT in comparison to commonly used acetate buffer. Iso-octane and hexane were examined as organic phase for extraction of ethylated OTC. The advantage of hexane was in its ability for quantitative determination of TMeT. GC column of 15 m in length was used for separation of studied OTC under the optimised separation conditions and its performances compared to 30 m column. The analytical method developed enables sensitive simultaneous determination of 12 different OTC and appreciably shortened analysis time in larger series of water samples. LOD's obtained for the newly developed method ranged from 0.05-0.06 ng Sn L-1 for methyl-, 0.11-0.45 ng Sn L-1 for butyl-, 0.11-0.16 ng Sn L-1 for phenyl-, and 0.07-0.10 ng Sn L-1 for octyl-tins. By applying the developed analytical method, marine water samples from the Northern Adriatic Sea containing mainly butyl- and methyl-tin species were analysed to confirm the proposed method's applicability.

Pressurized liquid extraction coupled with countercurrent chromatography for systematic isolation of chemical constituents by preprogrammed automatic control.

PubMed

Zhang, Yuchi; Guo, Liping; Liu, Chunming; Fu, Zi' ao; Cong, Lei; Qi, Yanjuan; Li, Dongping; Li, Sainan; Wang, Jing

2013-09-15

Pressurized liquid extraction (PLE) coupled with high-speed countercurrent chromatography (HSCCC) via an automated procedure was firstly developed to extract and isolate ginsenosides from Panax quinquefolium. The experiments were designed under the guidance of mathematical model. The partition coefficient (K) values of the target compounds and resolutions of peak profiles were employed as the research indicators, and exponential function and binomial formulas were used to optimizing the solvent systems and flow rates of the mobile phases in a three-stage separation. In the first stage, ethyl acetate, n-butanol, and water were simultaneously pumped into the solvent separator at the flow rates 11.0, 10.0, and 23.0mL/min, respectively. The upper phase of the solvent system in the solvent separator was used as both the PLE solvent and the HSCCC stationary phase, followed by elution with the lower phase of the corresponding solvent system to separate the common ginsenosides. In the second and third stages, rare ginsenosides were first separated by elution with ethyl acetate, n-butanol, methanol, and water (flow rates: 20.0, 3.0, 5.0, and 11.0mL/min, respectively), then with n-heptane, n-butanol, methanol, and water (flow rates: 17.5, 6.0, 5.0, and 22.5mL/min, respectively). Nine target compounds, with purities exceeding 95.0%, and three non-target compounds, with purities above 84.48%, were successfully separated at the semipreparative scale in 450min. The separation results prove that the PLE/HSCCC parameters calculated via mathematical model and formulas were accurately and scientifically. This research has opened up great prospects for industrial automation application. Copyright © 2013 Elsevier B.V. All rights reserved.

Biological production of acetic acid from waste gases with Clostridium ljungdahlii

DOEpatents

Gaddy, J.L.

1998-09-15

A method and apparatus are disclosed for converting waste gases from industrial processes such as oil refining, carbon black, coke, ammonia, and methanol production, into useful products. The method includes introducing the waste gases into a bioreactor where they are fermented to various organic acids or alcohols by anaerobic bacteria within the bioreactor. These valuable end products are then recovered, separated and purified. In an exemplary recovery process, the bioreactor raffinate is passed through an extraction chamber into which one or more non-inhibitory solvents are simultaneously introduced to extract the product. Then, the product is separated from the solvent by distillation. Gas conversion rates can be maximized by use of centrifuges, hollow fiber membranes, or other means of ultrafiltration to return entrained anaerobic bacteria from the bioreactor raffinate to the bioreactor itself, thus insuring the highest possible cell concentration. 5 figs.

Development and Validation of a Liquid Chromatography-Tandem Mass Spectrometry Method Coupled with Dispersive Solid-Phase Extraction for Simultaneous Quantification of Eight Paralytic Shellfish Poisoning Toxins in Shellfish.

PubMed

Yang, Xianli; Zhou, Lei; Tan, Yanglan; Shi, Xizhi; Zhao, Zhiyong; Nie, Dongxia; Zhou, Changyan; Liu, Hong

2017-06-29

In this study, a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for simultaneous determination of eight paralytic shellfish poisoning (PSP) toxins, including saxitoxin (STX), neosaxitoxin (NEO), gonyautoxins (GTX1-4) and the N -sulfo carbamoyl toxins C1 and C2, in sea shellfish. The samples were extracted by acetonitrile/water (80:20, v / v ) with 0.1% formic and purified by dispersive solid-phase extraction (dSPE) with C18 silica and acidic alumina. Qualitative and quantitative detection for the target toxins were conducted under the multiple reaction monitoring (MRM) mode by using the positive electrospray ionization (ESI) mode after chromatographic separation on a TSK-gel Amide-80 HILIC column with water and acetonitrile. Matrix-matched calibration was used to compensate for matrix effects. The established method was further validated by determining the linearity ( R ² ≥ 0.9900), average recovery (81.52-116.50%), sensitivity (limits of detection (LODs): 0.33-5.52 μg·kg -1 ; limits of quantitation (LOQs): 1.32-11.29 μg·kg -1 ) and precision (relative standard deviation (RSD) ≤ 19.10%). The application of this proposed approach to thirty shellfish samples proved its desirable performance and sufficient capability for simultaneous determination of multiclass PSP toxins in sea foods.

[Simultaneous determination of the migrations of bisphenol A and phenol in polycarbonate bottles based on subcritical water extraction and high performance liquid chromatography].

PubMed

Bai, Weiwei; Liu, Shuhui; Cao, Jiangping; Fan, Yingying; Xie, Qilong

2013-03-01

A new method was established for the simultaneous determination of the migration amounts of bisphenol A (BPA) and phenol from polycarbonate (PC) bottles based on subcritical water extraction (SWE) and high performance liquid chromatography. The optimum extraction conditions included an extraction temperature of 120 degree C, a pressure of 6.89 MPa (1000 psi), a static extraction time of 1 h and one cycle. Under the conditions, the migration amounts of the BPA ranged from 6.81 to 1116 micro g/g in 11 samples. Phenol was not detectable in 5 samples, and in other ones the migration amounts of phenol varied in the range of 3.25 -6. 08 micro g/g. The traditional soaking extraction experiments showed that PC was subjected to weak hydrolysis after long-time leaching. The BPA and phenol were separated in 8 min. Good linearities were obtained in the range of 0. 05 - 20 mg/L for BPA and 0.02 - 20 mg/L for phenol ( r > 0.999 7). The limits of detection were 7.6 micro g/L for BPA and 2.0 micro g/L for phenol. Intra-day and inter-day repeatabilities (expressed as RSD) were less than 5.21% and 11.63%, respectively. Compared with traditional water soaking extraction, the extraction efficiencies increased 49 - 106 times using this developed SWE method. The procedure is simple, rapid and environment friendly, and can be utilized to determine the migration amounts of BPA and phenol in PC bottles.

Simultaneous extraction and determination of phthalate esters in aqueous solution by yolk-shell magnetic mesoporous carbon-molecularly imprinted composites based on solid-phase extraction coupled with gas chromatography-mass spectrometry.

PubMed

Yang, Rui; Liu, Yuxin; Yan, Xiangyang; Liu, Shaomin

2016-12-01

A rapid, sensitive and accurate method for the simultaneous extraction and determination of five types of trace phthalate esters (PAEs) in environmental water and beverage samples using magnetic molecularly imprinted solid-phase extraction (MMIP-SPE) coupled with gas chromatography-mass spectrometry (GC-MS) was developed. A novel type of molecularly imprinted polymers on the surface of yolk-shell magnetic mesoporous carbon (Fe 3 O 4 @void@C-MIPs) was used as an efficient adsorbent for selective adsorption of phthalate esters based on magnetic solid-phase extraction (MSPE). The real samples were first preconcentrated by Fe 3 O 4 @void@C-MIPs, subsequently extracted by eluent and finally determined by GC-MS after magnetic separation. Several variables affecting the extraction efficiency of the analytes, including the type and volume of the elution solvent, amount of adsorbent, extraction time, desorption time and pH of the sample solution, were investigated and optimized. Validation experiments indicated that the developed method presented good linearity (R 2 >0.9961), satisfactory precision (RSD<6.7%), and high recovery (86.1-103.1%). The limits of detection ranged from 1.6ng/L to 5.2ng/L and the enrichment factor was in the range of 822-1423. The results indicated that the novel method had the advantages of convenience, good sensitivity, and high efficiency, and it could also be successfully applied to the analysis of PAEs in real samples. Copyright © 2016. Published by Elsevier B.V.

Development of a Method for Detection of Giardia duodenalis Cysts on Lettuce and for Simultaneous Analysis of Salad Products for the Presence of Giardia Cysts and Cryptosporidium Oocysts▿

PubMed Central

Cook, N.; Nichols, R. A. B.; Wilkinson, N.; Paton, C. A.; Barker, K.; Smith, H. V.

2007-01-01

We report a method for detecting Giardia duodenalis cysts on lettuce, which we subsequently use to examine salad products for the presence of Giardia cysts and Cryptosporidium oocysts. The method is based on four basic steps: extraction of cysts from the foodstuffs, concentration of the extract and separation of the cysts from food materials, staining of the cysts to allow their visualization, and identification of cysts by microscopy. The concentration and separation steps are performed by centrifugation, followed by immunomagnetic separation using proprietary kits. Cyst staining is also performed using proprietary reagents. The method recovered 46.0% ± 19.0% (n = 30) of artificially contaminating cysts in 30 g of lettuce. We tested the method on a variety of commercially available natural foods, which we also seeded with a commercially available internal control, immediately prior to concentration of the extract. Recoveries of the Texas Red-stained Giardia cyst and Cryptosporidium oocyst internal controls were 36.5% ± 14.3% and 36.2% ± 19.7% (n = 20), respectively. One natural food sample of organic watercress, spinach, and rocket salad contained one Giardia cyst 50 g−1 of sample as an indigenous surface contaminant. PMID:17890337

Investigation of six bioactive anthraquinones in slimming tea by accelerated solvent extraction and high performance capillary electrophoresis with diode-array detection.

PubMed

Wang, Ning; Su, Ming; Liang, Shuxuan; Sun, Hanwen

2016-05-15

A rapid and effective method for effective separation and rapid simultaneous determination of six bioactive anthraquinones by capillary zone electrophoresis was developed. An accelerated solvent extraction procedure was used for the extraction of anthraquinones from slimming tea. Under the optimized conditions, the effective separation of six anthraquinones was achieved within 8 min. Good linearity was achieved, with a correlation coefficient (r) of ⩾ 0.999. The limit of detection ranged from 0.33 to 1.40 μg mL(-1). The intra- and inter-day relative standard deviation (RSD) of the six analytes was in the range of 2.3-3.9% and 3.2-4.9%, respectively. The average recovery of the six analytes from real tea samples was in the range of 86.15-98.30% with the RSD of 1.04-4.99%. The developed and validated method has speediness, high sensitivity, recovery and precision, and can be applied for the quality control of slimming tea. Copyright © 2015 Elsevier Ltd. All rights reserved.

Simultaneous analysis of nine aromatic amines in mainstream cigarette smoke using online solid-phase extraction combined with liquid chromatography-tandem mass spectrometry.

PubMed

Zhang, Jie; Bai, Ruoshi; Zhou, Zhaojuan; Liu, Xingyu; Zhou, Jun

2017-04-01

A fully automated analytical method was developed and validated by this present study. The method was based on two-dimensional (2D) online solid-phase extraction liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) to determine nine aromatic amines (AAs) in mainstream smoke (MSS) simultaneously. As a part of validation process, AAs yields for 16 top-selling commercial cigarettes from China market were evaluated by the developed method under both Health Canada Intensive (HCI) and ISO machine smoking regimes. The gas phase of MSS was trapped by 25 mL 0.6 M hydrochloric acid solution, while the particulate phase was collected on a glass fiber filter. Then, the glass fiber pad was extracted with hydrochloric acid solution in an ultrasonic bath. The extract was analyzed with 2D online SPE-LC-MS/MS. In order to minimize the matrix effects of sample on each analyte, two cartridges with different extraction mechanisms were utilized to cleanup disturbances of different polarity, which were performed by the 2D SPE. A phenyl-hexyl analytical column was used to achieve a chromatographic separation. Under the optimized conditions, the isomers of p-toluidine, m-toluidine and o-toluidine, 3-aminobiphenyl and 4-aminobiphenyl, and 1-naphthylamine and 2-naphthylamine were baseline separated with good peak shapes for the first time. The limits of detection for nine AAs ranged from 0.03 to 0.24 ng cig -1 . The recovery of the measurement of nine AAs was from 84.82 to 118.47%. The intra-day and inter-day precisions of nine AAs were less than 10 and 16%, respectively. Compared with ISO machine smoking regime, the AAs yields in MSS were 1.17 to 3.41 times higher under HCI machine smoking regime. Graphical abstract New method using online SPE-LC/MS/MS for analysis of aromatic amines in mainstream cigarette smoke.

[An ultrafast liquid chromatography-tandem mass spectrometric method for simultaneous determination of common artificial synthetic pigments in cooked meat products].

PubMed

Chen, Xiaohong; Li, Xiaoping; Zhao, Yonggang; Pan, Shengdong; Jin, Micong

2015-07-01

A method based on ultrafast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) has been developed for the simultaneous determination of seven synthetic pigments in cooked meat product. After the cooked meat products were extracted by mixed extraction agent, purified by WAX column, the UFLC separation was performed on a Shim-pack XR-ODS II column (75 mm x 2.0 mm, 2.2 µm) with a linear gradient elution program of acetonitrile and ammonium acetate (AmAc, 5 mmol/L) as the mobile phase. Electrospray ionization was applied and operated in the negative ion mode. The limits of quantitation (LOQs) for the seven synthetic pigments were in the range of 0.7-5.0 µg/kg. The calibration curves showed good linearities for the seven analytes in their detection ranges, and the correlative coefficients (r) were more than 0.999. The recoveries were between 88.2%-106.5% with the RSDs in the range of 1.2%-5.0%. The method is sensitive, reproducible, quick and adapts to the simultaneous determination of the seven synthetic pigments in cooked meat product.

Modifying a standard method allows simultaneous extraction of RNA and protein, enabling detection of enzymes in the rat retina with low expressions and protein levels.

PubMed

Agardh, Elisabet; Gustavsson, Carin; Hagert, Per; Nilsson, Marie; Agardh, Carl-David

2006-02-01

The aim of the study was to evaluate messenger RNA and protein expression in limited amounts of tissue with low protein content. The Chomczynski method was used for simultaneous extraction of RNA, and protein was modified in the protein isolation step. Template mass and cycling time for the complementary DNA synthesis step of real-time reverse transcription-polymerase chain reaction (RT-PCR) for analysis of catalase, copper/zinc superoxide dismutase, manganese superoxide dismutase, the catalytic subunit of glutamylcysteine ligase, glutathione peroxidase 1, and the endogenous control cyclophilin B (CypB) were optimized before PCR. Polymerase chain reaction accuracy and efficacy were demonstrated by calculating the regression (R2) values of the separate amplification curves. Appropriate antibodies, blocking buffers, and running conditions were established for Western blot, and protein detection and multiplex assays with CypB were performed for each target. During the extraction procedure, the protein phase was dissolved in a modified washing buffer containing 0.1% sodium dodecyl sulfate, followed by ultrafiltration. Enzyme expression on real-time RT-PCR was accomplished with high reliability and reproducibility (R2, 0.990-0.999), and all enzymes except for glutathione peroxidase 1 were detectable in individual retinas on Western blot. Western blot multiplexing with CypB was possible for all targets. In conclusion, connecting gene expression directly to protein levels in the individual rat retina was possible by simultaneous extraction of RNA and protein. Real-time RT-PCR and Western blot allowed accurate detection of retinal protein expressions and levels.

Simultaneous detection of ultraviolet B-induced DNA damage using capillary electrophoresis with laser-induced fluorescence.

PubMed

Guthrie, Jeffrey W; Limmer, Robert T; Brooks, Eric A; Wisnewski, Chelsea C; Loggins-Davis, Nnekia D; Bouzid, Abderraouf

2015-01-01

An immunoassay based on CE-LIF was developed for the simultaneous detection of cyclobutane pyrimidine dimers (CPDs) and pyrimidine 6-4 pyrimidone photoproducts (6-4PPs) in genomic DNA irradiated with UVB or natural sunlight. Human cells were first exposed to varying amounts of UVB or natural sunlight to induce DNA damage. Genomic DNA was extracted and incubated with anti-CPD and anti-6-4PP primary antibodies attached to secondary antibodies with a fluorescent quantum dot (QD) reporter that emitted either red or yellow fluorescence. CE was used to separate the unbound antibodies from those bound to the photoproducts, and LIF with appropriate optical filters was used to separate the fluorescence signals from each QD to individual photomultiplier tubes for simultaneous photoproduct detection. Using this strategy, photoproducts were detected from ∼6 ng (200 ng μL(-1)) of DNA under a low UVB fluence of 65 J m(-2) for CPDs or 195 J m(-2) for 6-4PPs. This assay was also the first to demonstrate the detection of CPDs in human cells after only 15 min of irradiation under natural sunlight. Copyright © 2014 Elsevier B.V. All rights reserved.

Rapid extraction and determination of 25 bioactive constituents in Alpinia oxyphylla using microwave extraction with ultra high performance liquid chromatography with tandem mass spectrometry.

PubMed

Sun, Zhi; Kong, Xiangzhen; Zuo, Lihua; Kang, Jian; Hou, Lei; Zhang, Xiaojian

2016-02-01

A novel and rapid microwave extraction and ultra high performance liquid chromatography with tandem mass spectrometry method was developed and validated for the simultaneous determination of 25 bioactive constituents (including two new constituents) in Fructus Alpinia oxyphylla. The optimized conditions of the microwave extraction was a microwave power of 300 W, extraction temperature of 80°C, solvent-to-solid ratio of 30 mL/g and extraction time of 8 min. Separation was achieved on a Waters ACQUITY UPLC(®) HSS C18 column (2.1 mm× 50 mm, 1.8 μm) using gradient elution with a mobile phase consisting of acetonitrile and 1 mM ammonium acetate at a flow rate of 0.2 mL/min. This is the first report of the simultaneous determination of 25 bioactive constituents in Fructus Alpinia oxyphylla by ultra high performance liquid chromatography with tandem mass spectrometry. The method was validated with good linearity, acceptable precision and accuracy. The validated method was successfully applied to determine the contents of 25 bioactive constituents in Fructus Alpinia oxyphylla from different sources and the analysis results were classified by hierarchical cluster analysis, which indicated the effect of different cultivation regions on the contents of constituents. This study provides powerful and practical guidance in the quality control of Alpinia oxyphylla and lays the foundation for further research of Alpinia oxyphylla. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous determination and pharmacokinetic study of Atractylenolide I, II and III in rat plasma after intragastric administration of Baizhufuling extract and Atractylodis extract by UPLC-MS/MS.

PubMed

Yan, Han; Sun, Yuanyuan; Zhang, Qili; Yang, Mingjing; Wang, Xiaorui; Wang, Yang; Yu, Zhiguo; Zhao, Yunli

2015-07-01

A simple and rapid ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for the simultaneous determination of Atractylenolide I, II and III in rat plasma. Plasma samples were processed by liquid-liquid extraction with ethyl acetate, using schisandrin as internal standard (IS). Chromatographic separation was accomplished on a Thermo Hypersil GOLD C18 column (2.1mm×50mm, 1.9μm) with mobile phase consisting of acetonitrile and 0.1% formic acid-water (50:50, v/v). The detection was carried out by ESI-MS (positive ionization mode) and low-energy collision dissociation tandem mass spectrometric analyses using the multiple-reaction monitoring (MRM) scan mode. The quantification was performed using the transitions of the protonated molecule→product ion at m/z 231.0→185.1 for Atractylenolide I, at m/z 233.1→187.1 for Atractylenolide II and at m/z 249.1→231.1 for Atractylenolide III, respectively. Method validation revealed excellent linearity over investigated range together with satisfactory intra- and inter-day precision, accuracy, matrix effects and extraction recoveries. This method was successfully applied to the comparative pharmacokinetic study of Atractylenolide I, II and III in rat plasma after intragastric administration of Baizhufuling extract and Atractylodis extract. Copyright © 2015 Elsevier B.V. All rights reserved.

Ultra-fast LC-ESI-MS/MS method for the simultaneous determination of six highly toxic Aconitum alkaloids from Aconiti kusnezoffii radix in rat plasma and its application to a pharmacokinetic study.

PubMed

Liu, Jingjing; Li, Qing; Yin, Yidi; Liu, Ran; Xu, Huarong; Bi, Kaishun

2014-01-01

A fast, sensitive, and efficient ultra-fast LC-ESI-MS/MS method was developed for the simultaneous quantitation of six highly toxic Aconitum alkaloids, that is, aconitine, mesaconitine, hypaconitine, benzoylaconine, benzoylmesaconine, and benzoylhypaconine, in rat plasma after oral administration of crude ethanol extracts from Aconiti kusnezoffii radix by ultrasonic extraction, reflux extraction for 1 h, and reflux extraction for 3 h, respectively. The separation of six Aconitum alkaloids and aminopyrine (internal standard) was performed on an InertSustain® C18 column, and the quantification of the analytes was performed on a 4000Q ultra-fast LC-MS/MS system with turbo ion spray source in the positive ion and multiple-reaction monitoring mode. Absolute recoveries ranged within 65.06-85.1% for plasma samples. The intra- and interday precision and accuracy of analytes were satisfactory. The methods were validated with sensitivity reaching the lower LOQ for aconitine, mesaconitine, hypaconitine, benzoylaconine, benzoylmesaconine, and benzoylhypaconine, which were 0.025, 0.025, 0.050, 0.025, 0.025, and 0.100 ng/mL, respectively. The method was successfully applied to a pharmacokinetic study of six Aconitum alkaloids in rat plasma after oral administration of crude ethanol extracts from the raw root of Aconitum kusnezoffii Reichb. by three different extraction processes. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous quantification of the major bile acids in artificial Calculus bovis by high-performance liquid chromatography with precolumn derivatization and its application in quality control.

PubMed

Shi, Yan; Xiong, Jing; Sun, Dongmei; Liu, Wei; Wei, Feng; Ma, Shuangcheng; Lin, Ruichao

2015-08-01

An accurate and sensitive high-performance liquid chromatography method coupled with ultralviolet detection and precolumn derivatization was developed for the simultaneous quantification of the major bile acids in Artificial Calculus bovis, including cholic acid, hyodeoxycholic acid, chenodeoxycholic acid, and deoxycholic acid. The extraction, derivatization, chromatographic separation, and detection parameters were fully optimized. The samples were extracted with methanol by ultrasonic extraction. Then, 2-bromine-4'-nitroacetophenone and 18-crown ether-6 were used for derivatization. The chromatographic separation was performed on an Agilent SB-C18 column (250 × 4.6 mm id, 5 μm) at a column temperature of 30°C and liquid flow rate of 1.0 mL/min using water and methanol as the mobile phase with a gradient elution. The detection wavelength was 263 nm. The method was extensively validated by evaluating the linearity (r(2) ≥ 0.9980), recovery (94.24-98.91%), limits of detection (0.25-0.31 ng) and limits of quantification (0.83-1.02 ng). Seventeen samples were analyzed using the developed and validated method. Then, the amounts of bile acids were analyzed by hierarchical agglomerative clustering analysis and principal component analysis. The results of the chemometric analysis showed that the contents of these compounds reflect the intrinsic quality of artificial Calculus bovis, and two compounds (hyodeoxycholic acid and chenodeoxycholic acid) were the most important markers for quality evaluating. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination and validation of a simple high-performance liquid chromatographic method for simultaneous assay of iprodione and vinclozolin in human urine.

PubMed

Carlucci, Giuseppe; Pasquale, Dorina Di; Ruggieri, Fabrizio; Mazzeo, Pietro

2005-12-15

A method based on solid-phase extraction (SPE) and high-performance liquid chromatography (HPLC) was developed for the simultaneous determination of 3-(3,5-diclorophenyl)-5-ethenyl-5-methyl-2,4-oxazolidinedione (vinclozolin) and 3-(3,5-diclorophenyl)-N-(1-methylethyl)-2,4-dioxo-1-imidazolidinecarboxamide (iprodione) in human urine. Urine samples containing vinclozolin and iprodione were collected by solid phase extraction using C(18) cartridges. The chromatographic separation was achieved on a Spherisorb ODS2 (250 mm x 4.6 mm, 5 microm) column with an isocratic mobile phase of acetonitrile-water (60:40, v/v). Detection was UV absorbance at 220 nm. The calibration graphs were linear from 30 to 1000 ng/mL for the two fungicides. Intra- and inter-day R.S.D. did not exceed 2.9%. The quantitation limit was 50 ng/mL for vinclozolin and 30 ng/mL for iprodione, respectively.

Simultaneous UHPLC-UV analysis of hydroxychloroquine, minocycline and doxycycline from serum samples for the therapeutic drug monitoring of Q fever and Whipple's disease.

PubMed

Armstrong, Nicholas; Richez, Magali; Raoult, Didier; Chabriere, Eric

2017-08-15

A fast UHPLC-UV method was developed for the simultaneous analysis of Hydroxychloroquine, Minocycline and Doxycycline drugs from 100μL of human serum samples. Serum samples were extracted by liquid-liquid extraction and injected into a phenyl hexyl reverse phase column. Compounds were separated using a mobile phase linear gradient and monitored by UV detection at 343nm. Chloroquine and Oxytetracycline were used as internal standards. Lower and upper limits of quantifications, as well as the other levels of calibration, were validated with acceptable accuracy (<15% deviation) and precision (<15% coefficient of variation) according to the European Medicines Agency guidelines. This new method enables cost and time reduction and was considered suitable for the clinical laboratory. It is the first published assay for the therapeutic drug monitoring of patients diagnosed with Q fever or Whipple's disease. Copyright © 2017 Elsevier B.V. All rights reserved.

Development and validation of an analytical method for the separation and determination of major bioactive curcuminoids in Curcuma longa rhizomes and herbal products using non-aqueous capillary electrophoresis.

PubMed

Anubala, S; Sekar, R; Nagaiah, K

2014-06-01

A simple, fast and efficient non-aqueous capillary electrophoresis method (NACE) was developed for the simultaneous determination of three major bioactive curcuminoids (CMNs) in Curcuma longa rhizomes and its herbal products. Good separation, resolution and reproducibility were achieved with the background electrolyte (BGE) consisting a mixture of 15.0 mM sodium tetraborate and 7.4 mM sodium hydroxide (NaOH) in 2:10:15 (v/v/v) of water, 1-propanol, and methanol. The influences of background electrolyte, sodium hydroxide, water, sodium dodecyl sulfate and hydroxylpropyl-β-cyclodextrin on separations were investigated. The separation was carried out in a fused-silica capillary tube with reverse polarity. Hydrodynamic injection of 25mbar for 12s was used for injecting samples and a voltage of 28 kV was applied for separation. The ultrasonication method was used for the extraction of CMNs from the turmeric herbal products and the extract was filtered and directly injected without any further treatments. The limits of detection and quantification were less than 5.0 and 14.6 µg/ml respectively for all CMNs. The percentage recoveries for CMNs were >97.2% (%RSD, <2.62). The results obtained by the method were compared with existing spectrophotometric and HPLC methods. The related compounds in the extract did not interfere in the determination of CMNs. The proposed NACE method is better than existing chromatographic and electrophoretic methods in terms of simple electrophoretic medium, fast analysis and good resolution. Copyright © 2014 Elsevier B.V. All rights reserved.

Surface area generation and droplet size control in solvent extraction systems utilizing high intensity electric fields

DOEpatents

Scott, Timothy C.; Wham, Robert M.

1988-01-01

A method and system for solvent extraction where droplets are shattered by a high intensity electric field. These shattered droplets form a plurality of smaller droplets which have a greater combined surface area than the original droplet. Dispersion, coalescence and phase separation are accomplished in one vessel through the use of the single pulsing high intensity electric field. Electric field conditions are chosen so that simultaneous dispersion and coalescence are taking place in the emulsion formed in the electric field. The electric field creates a large amount of interfacial surface area for solvent extraction when the droplet is disintegrated and is capable of controlling droplet size and thus droplet stability. These operations take place in the presence of a counter current flow of the continuous phase.

Simultaneous and rapid determination of deoxynivalenol and its acetylate derivatives in wheat flour and rice by ultra high performance liquid chromatography with photo diode array detection.

PubMed

Xu, Jiao-Jiao; Zhou, Jian; Huang, Bai-Fen; Cai, Zeng-Xuan; Xu, Xiao-Min; Ren, Yi-Ping

2016-06-01

A simple and reliable method of ultra high performance liquid chromatography coupled with photo-diode array detection has been proposed for the simultaneous determination of deoxynivalenol and its acetylated derivatives in wheat flour and rice, especially focusing on the optimization of sample extraction, cleanup, and chromatographic separation conditions. Sample pretreatment consisted of a first step using a quick, easy, cheap, effective, rugged, and safe based extraction procedure and a subsequent cleanup step based on solid-phase extraction. The method was extensively validated in wheat flour and rice, obtaining satisfactory analytical performance with good linearity (R(2) ≥ 0.999), acceptable recoveries (80.0-104.4%), and repeatability (RSDs 1.3-10.7%). The limits of detection (21.7-57.4 μg/kg) and quantitation (72.3-191.4 μg/kg) for deoxynivalenols were lower than those usually permitted by various countries' legislation in these food matrices. The method was applied to 34 wheat and rice samples. The results were further compared with results of ultra high performance liquid chromatography with electrospray ionization tandem mass spectrometry. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous determination of 117 pesticides and 30 mycotoxins in raw coffee, without clean-up, by LC-ESI-MS/MS analysis.

PubMed

Reichert, Bárbara; de Kok, André; Pizzutti, Ionara Regina; Scholten, Jos; Cardoso, Carmem Dickow; Spanjer, Martien

2018-04-03

This paper describes the optimization and validation of an acetonitrile based method for simultaneous extraction of multiple pesticides and mycotoxins from raw coffee beans followed by LC-ESI-MS/MS determination. Before extraction, the raw coffee samples were milled and then slurried with water. The slurried samples were spiked with two separate standard solutions, one containing 131 pesticides and a second with 35 mycotoxins, which were divided into 3 groups of different relative concentration levels. Optimization of the QuEChERS approach included performance tests with acetonitrile acidified with acetic acid or formic acid, with or without buffer and with or without clean-up of the extracts before LC-ESI-MS/MS analysis. For the clean-up step, seven d-SPE sorbents and their various mixtures were evaluated. After method optimization a complete validation study was carried out to ensure adequate performance of the extraction and chromatographic methods. The samples were spiked at 3 concentrations levels with both mycotoxins and pesticides (with 6 replicates at each level, n = 6) and then submitted to the extraction procedure. Before LC-ESI-MS/MS analysis, the acetonitrile extracts were diluted 2-fold with methanol, in order to improve the chromatographic performance of the early-eluting polar analytes. Calibration standard solutions were prepared in organic solvent and in blank coffee extract at 7 concentration levels and analyzed 6 times each. The method was assessed for accuracy (recovery %), precision (RSD%), selectivity, linearity (r 2 ), limit of quantification (LOQ) and matrix effects (%). Copyright © 2017 Elsevier B.V. All rights reserved.

The selective cleanup of complex matrices and simultaneous separation of benzo[a]pyrene by solid-phase extraction with MgO microspheres as sorbents.

PubMed

Jin, Jing; Li, Yun; Zhang, Zhiping; Su, Fan; Qi, Peipei; Lu, Xianbo; Chen, Jiping

2011-12-23

A new method for the selective cleanup of complex matrices and simultaneous separation of benzo[a]pyrene (BaP) was developed in this study. This method was based on solid-phase extraction (SPE) using magnesium oxide microspheres as sorbents, and it eliminated interferences from various impurities, such as lipids, sulphur, pigments, halobenzenes, polychlorodibenzo-p-dioxins and polychlorodibenzofurans. Several parameters, including the volume of rinsing and eluting solvents, the type of loading solvents and SPE sorbents, were optimized systematically. The capability for impurity removal was verified by gel permeation chromatography, gas chromatography, and liquid chromatography. Compared to commercial sorbents (silica gel, florisil and alumina), MgO microspheres exhibited excellent performance in the selective isolation of BaP and removal of impurities. The proposed method was applied to detect BaP in complex samples (sediments, soils, fish, and porcine liver). The limit of quantification (LOQ) was 1.04 ngL(-1), and the resulting regression coefficient (r(2)) was greater than 0.999 over a broad concentration range (9.5-7600 ngL(-1)). In contrast to traditional methods, the proposed method can give rise to higher recovery (85.1-100.8%) and better selectivity with simpler operation and less consumption of organic solvents (20-40 mL). Copyright © 2011 Elsevier B.V. All rights reserved.

Simultaneous determination of five coumarins in Angelicae dahuricae Radix by HPLC/UV and LC-ESI-MS/MS.

PubMed

Park, Ah Yeon; Park, So-Young; Lee, Jaehyun; Jung, Mihye; Kim, Jinwoong; Kang, Sam Sik; Youm, Jeong-Rok; Han, Sang Beom

2009-10-01

Rapid, simple and reliable HPLC/UV and LC-ESI-MS/MS methods for the simultaneous determination of five active coumarins of Angelicae dahuricae Radix, byakangelicol (1), oxypeucedanin (2), imperatorin (3), phellopterin (4) and isoimperatorin (5) were developed and validated. The separation condition for HPLC/UV was optimized using a Develosil RPAQUEOUS C(30) column using 70% acetonitrile in water as the mobile phase. This HPLC/UV method was successful for providing the baseline separation of the five coumarins with no interfering peaks detected in the 70% ethanol extract of Angelicae dahuricae Radix. The specific determination of the five coumarins was also accomplished by a triple quadrupole tandem mass spectrometer equipped with an electrospray ionization source (LC-ESI-MS/MS). Multiple reaction monitoring (MRM) in the positive mode was used to enhance the selectivity of detection. The LC-ESI-MS/MS methods were successfully applied for the determination of the five major coumarins in Angelicae dahuricae Radix. These HPLC/UV and LC-ESI-MS/MS methods were validated in terms of recovery, linearity, accuracy and precision (intra- and inter-day validation). Taken together, the shorter analysis time involved makes these HPLC/UV and LC-ESI-MS/MS methods valuable for the commercial quality control of Angelicae dahuricae Radix extracts and its pharmaceutical preparations. Copyright (c) 2009 John Wiley & Sons, Ltd.

Simultaneous determination of 11 fluorescent whitening agents in food-contact paper and board by ion-pairing high-performance liquid chromatography with fluorescence detection.

PubMed

Jiang, Dingguo; Chen, Lisong; Fu, Wusheng; Qiu, Hanquan

2015-02-01

4,4'-Diaminostilbene-2,2'-disulfonic acid based fluorescent whitening agents (DSD-FWAs) are prohibited in food-contact paper and board in many countries. In this work, a reliable high-performance liquid chromatography method was developed for the simultaneous determination of 11 common DSD-FWAs in paper material. Sample preparation and extraction as well as chromatographic separation of multicomponent DSD-FWAs were successfully optimized. DSD-FWAs in prepared samples were ultrasonically extracted with acetonitrile/water/triethylamine (40:60:1, v/v/v), separated on the C(18) column with the mobile phase containing tetrabutylammonium bromide, and then detected by a fluorescence detector. The limits of detection were 0.12-0.24 mg/kg, and the calibration curves showed the linear correlation (R(2) ≥ 0.9994) within the range of 8.0-100 ng/mL, which was equivalent to the range of 0.80-10 mg/kg in the sample. The average recoveries and the RSDs were 81-106% and 2-9% at two fortification levels (1.0 and 5.0 mg/kg) in paper bowls, respectively. The successful determination of 11 DSD-FWAs in food-contact paper and board obtained from local markets indicated that the newly developed method was rapid, accurate, and highly selective. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous quantification of cardiovascular disease related metabolic risk factors using liquid chromatography tandem mass spectrometry in human serum.

PubMed

Wang, Mo; Yang, Ruiyue; Dong, Jun; Zhang, Tianjiao; Wang, Siming; Zhou, Weiyan; Li, Hongxia; Zhao, Haijian; Zhang, Lijiao; Wang, Shu; Zhang, Chuanbao; Chen, Wenxiang

2016-01-15

Recent observations from metabonomic studies have consistently found that branched-chain amino acids (BCAAs), aromatic amino acids (AAAs), glutamine (Gln), glutamic acid (Glu), Gln/Glu ratio, carnitine, and several species of acylcarnitines and lysophosphatidylcholines (LPCs) are possible risk factors for metabolic diseases such as diabetes mellitus (DM) and cardiovascular diseases (CVD). We described here a simple and reliable method for simultaneous quantification of these metabolic risk factors by liquid chromatography tandem mass spectrometry (LC-MS/MS). Serum samples were extracted with isopropanol, and the extracted metabolites were separated by hydrophilic interaction liquid chromatography (HILIC) and detected with electrospary ionization (ESI) inpositive ion mode with multiple reaction monitor (MRM) mode. All the metabolites were effectively separated within 5.5min. Analytical recoveries were in the range of 92.8-106.9%, with an average of 100.6%. The intra- run and total imprecisions for the measurement of these metabolites were 1.2-3.8% and 1.5-7.4%, respectively. Serum concentrations of the metabolites were analyzed in 123 apparently healthy volunteers. Significant associations between the metabolites and traditional CVD risk factors were observed. The newly developed LC-MS/MS method was simple, precise, and accurate and can be used as an efficient tool in CVD research and studies. Copyright © 2015 Elsevier B.V. All rights reserved.

Simultaneous determination of a variety of endocrine disrupting compounds in carrot, lettuce and amended soil by means of focused ultrasonic solid-liquid extraction and dispersive solid-phase extraction as simplified clean-up strategy.

PubMed

Mijangos, L; Bizkarguenaga, E; Prieto, A; Fernández, L A; Zuloaga, O

2015-04-10

The present study is focused on the development of an analytical method based on focused ultrasonic solid-liquid extraction (FUSLE) followed by dispersive solid-phase extraction (dSPE) clean-up and liquid chromatography-triple quadrupole tandem mass spectrometry (LC-MS/MS) optimised for the simultaneous analysis of certain endocrine disrupting compounds (EDCs), including alkylphenols (APs), bisphenol A (BPA), triclosan (TCS) and several hormones and sterols in vegetables (lettuce and carrot) and amended soil samples. Different variables affecting the chromatographic separation, the electrospray ionisation and mass spectrometric detection were optimised in order to improve the sensitivity of the separation and detection steps. Under the optimised extraction conditions (sonication of 5min at 33% of power with pulse times on of 0.8s and pulse times off of 0.2s in 10mL of n-hexane:acetone (30:70, v:v) mixture using an ice bath), different dSPE clean-up sorbents, such as Florisil, Envi-Carb, primary-secondary amine bonded silica (PSA) and C18, or combinations of them were evaluated for FUSLE extracts before LC-MS/MS. Apparent recoveries and precision in terms of relative standard deviation (RSDs %) of the method were determined at two different fortification levels (according to the matrix and the analyte) and values in the 70-130% and 2-27% ranges, respectively, were obtained for most of the target analytes and matrices. Matrix-matched calibration approach and the use of labelled standards as surrogates were needed for the properly quantification of most analytes and matrices. Method detection limits (MDLs), estimated with fortified samples, in the ranges of 0.1-100ng/g for carrot, 0.2-152ng/g for lettuce and 0.9-31ng/g for amended soil were obtained. The developed methodology was applied to the analysis of 11 EDCs in both real vegetable bought in a local market and in compost (from a local wastewater treatment plant, WWTP) amended soil samples. Copyright © 2015 Elsevier B.V. All rights reserved.

A hollow-fiber membrane extraction process for recovery and separation of lactic acid from aqueous solution.

PubMed

Huang, Hanjing; Yang, Shang-Tian; Ramey, David E

2004-01-01

An energy-efficient hollow-fiber membrane extraction process was successfully developed to separate and recover lactic acid produced in fermentation. Although many fermentation processes have been developed for lactic acid production, an economical method for lactic acid recovery from the fermentation broth is still needed. Continuous extraction of lactic acid from a simulated aqueous stream was achieved by using Alamine 336 in 2-octanol contained in a hollow-fiber membrane extractor. In this process, the extractant was simultaneously regenerated by stripping with NaOH in a second membrane extractor, and the final product is a concentrated lactate salt solution. The extraction rate increased linearly with an increase in the Alamine 336 content in the solvent (from 5 to 40%). Increasing the concentration of the undissociated lactic acid in the feed solution by either increasing the lactate concentration (from 5 to 40 g/L) or decreasing the solution pH (from 5.0 to 4.0) also increased the extraction rate. Based on these observations, a reactive extraction model with a first-order reaction mechanism for both lactic acid and amine concentrations was proposed. The extraction rate also increased with an increase in the feed flow rate, but not the flow rates of solvent and the stripping solution, suggesting that the process was not limited by diffusion in the liquid films or membrane pores. A mathematical model considering both diffusion and chemical reaction in the extractor and back extractor was developed to simulate the process. The model fits the experimental data well and can be used in scale up design of the process.

Rapid simultaneous determination of marmelosin, umbelliferone and scopoletin from Aegle marmelos fruit by RP-HPLC.

PubMed

Shinde, P B; Katekhaye, S D; Mulik, M B; Laddha, K S

2014-09-01

The surge of interest in naturally occurring phytochemicals with high therapeutic potential has led to the discovery of many molecules, out of which naturally occuring coumarins such as marmelosin, umbelliferone and scopoletin present in Aegle marmelos (Bael) fruit shows good therapeutic potential. The aim of the present work is to develop and validate Reverse Phase-High Performance Liquid Chromatography (RP-HPLC) method for simultaneous determination of marmelosin, umbelliferone and scopoletin in A. marmelos fruit extracts. The chromatographic separation was performed with isocratic elution of 55:45 (%, v/v) methanol-water containing 0.1 % acetic acid as mobile phase. The method used to analyse the extract of A. marmelos showed good resolution with retention time within 12 min. The relative concentrations of above phytoconstituent were determined in A. marmelos fruits. The method was found to give compact peaks for scopoletin, umbelliferone and marmelosin (Rt of 4.6, 6.5 and 11.3 min respectively) and were linear over the range 5-30 μg ml(-1) (R(2) = 0.9655), 2-10 μg ml(-1) (R(2) = 0.9964) and 2-10 μg ml(-1) (R(2) = 0.9862) respectively. The mean recoveries for marmelosin, umbelliferone and scopoletin at three concentrations were in the range of 98.8-102.9, 98.8-101.1 and 94.2-98.3 % respectively. The relative standard deviation of accuracy, precision and repeatability were within 2 %, indicating the method produced highly reproducible results. Therefore this simple, precise and accurate method enables simultaneous separation of this phytoconstituent and hence can be successfully applied in analysis and routine quality control of herbal material and formulation containing A. marmelos.

[Simultaneous determination of ten benzotriazole ultraviolet stabilizers in food contact plastic materials by solid phase extraction and ultra performance liquid chromatography with tandem mass spectrometry].

PubMed

Gou, Xinlei; Zhao, Xinying; Chi, Haitao; Gao, Xia; Zhou, Mingqiang; Liu, Weili

2015-06-01

A sensitive method was developed for the simultaneous determination of ten benzotriazole ultraviolet stabilizers in food contact plastic materials by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The sample was extracted by methanol-dichloromethane, and purified by a C18 solid-phase extraction (SPE) column. The separation was performed by using water containing 0. 1% (v/v) formic acid and methanol as the mobile phases with gradient elution at a flow rate of 0. 3 mL/min. The electrospray ionization (ESI) source in positive ion mode was used for the analysis of the ten benzotriazole ultraviolet stabilizers in multiple reaction monitoring (MRM) mode. The results showed that the standard curves were obtained with good correlation coefficients (r2 > 0.996) in their linear concentration ranges. The limits of detection (LODs, S/N = 3) for the ten benzotriazole ultraviolet stabilizers were in the range of 0.6-1.6 µg/kg. The mean recoveries for the ten benzotriazole ultraviolet stabilizers at three spiked levels (low, medium and high) were 75.2%-85.3% with relative standard deviations of 1.0%-5.7%. Ten kinds of food contact plastic materials were tested, and 2,2'-methylenebis (6-(benzotriazol-2-yl)-4-tert-octylphenol) (UV-360) was found in a sample of polyethylene (PE) material. The method is accurate, simple, rapid and feasible for the simultaneous determination of benzotriazole ultraviolet stabilizers in food plastic materials.

Development and Validation of a Liquid Chromatography-Tandem Mass Spectrometry Method Coupled with Dispersive Solid-Phase Extraction for Simultaneous Quantification of Eight Paralytic Shellfish Poisoning Toxins in Shellfish

PubMed Central

Yang, Xianli; Zhou, Lei; Tan, Yanglan; Shi, Xizhi; Zhao, Zhiyong; Nie, Dongxia; Zhou, Changyan; Liu, Hong

2017-01-01

In this study, a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for simultaneous determination of eight paralytic shellfish poisoning (PSP) toxins, including saxitoxin (STX), neosaxitoxin (NEO), gonyautoxins (GTX1–4) and the N-sulfo carbamoyl toxins C1 and C2, in sea shellfish. The samples were extracted by acetonitrile/water (80:20, v/v) with 0.1% formic and purified by dispersive solid-phase extraction (dSPE) with C18 silica and acidic alumina. Qualitative and quantitative detection for the target toxins were conducted under the multiple reaction monitoring (MRM) mode by using the positive electrospray ionization (ESI) mode after chromatographic separation on a TSK-gel Amide-80 HILIC column with water and acetonitrile. Matrix-matched calibration was used to compensate for matrix effects. The established method was further validated by determining the linearity (R2 ≥ 0.9900), average recovery (81.52–116.50%), sensitivity (limits of detection (LODs): 0.33–5.52 μg·kg−1; limits of quantitation (LOQs): 1.32–11.29 μg·kg−1) and precision (relative standard deviation (RSD) ≤ 19.10%). The application of this proposed approach to thirty shellfish samples proved its desirable performance and sufficient capability for simultaneous determination of multiclass PSP toxins in sea foods. PMID:28661471

Feature extraction based on semi-supervised kernel Marginal Fisher analysis and its application in bearing fault diagnosis

NASA Astrophysics Data System (ADS)

Jiang, Li; Xuan, Jianping; Shi, Tielin

2013-12-01

Generally, the vibration signals of faulty machinery are non-stationary and nonlinear under complicated operating conditions. Therefore, it is a big challenge for machinery fault diagnosis to extract optimal features for improving classification accuracy. This paper proposes semi-supervised kernel Marginal Fisher analysis (SSKMFA) for feature extraction, which can discover the intrinsic manifold structure of dataset, and simultaneously consider the intra-class compactness and the inter-class separability. Based on SSKMFA, a novel approach to fault diagnosis is put forward and applied to fault recognition of rolling bearings. SSKMFA directly extracts the low-dimensional characteristics from the raw high-dimensional vibration signals, by exploiting the inherent manifold structure of both labeled and unlabeled samples. Subsequently, the optimal low-dimensional features are fed into the simplest K-nearest neighbor (KNN) classifier to recognize different fault categories and severities of bearings. The experimental results demonstrate that the proposed approach improves the fault recognition performance and outperforms the other four feature extraction methods.

RAPID DETERMINATION OF ACTINIDES IN URINE BY INDUCTIVELY-COUPLED PLASMA MASS SPECTROMETRY AND ALPHA SPECTROMETRY: A HYBRID APPROACH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maxwell, S.; Jones, V.

2009-05-27

A new rapid separation method that allows separation and preconcentration of actinides in urine samples was developed for the measurement of longer lived actinides by inductively coupled plasma mass spectrometry (ICP-MS) and short-lived actinides by alpha spectrometry; a hybrid approach. This method uses stacked extraction chromatography cartridges and vacuum box technology to facilitate rapid separations. Preconcentration, if required, is performed using a streamlined calcium phosphate precipitation. Similar technology has been applied to separate actinides prior to measurement by alpha spectrometry, but this new method has been developed with elution reagents now compatible with ICP-MS as well. Purified solutions are splitmore » between ICP-MS and alpha spectrometry so that long- and short-lived actinide isotopes can be measured successfully. The method allows for simultaneous extraction of 24 samples (including QC samples) in less than 3 h. Simultaneous sample preparation can offer significant time savings over sequential sample preparation. For example, sequential sample preparation of 24 samples taking just 15 min each requires 6 h to complete. The simplicity and speed of this new method makes it attractive for radiological emergency response. If preconcentration is applied, the method is applicable to larger sample aliquots for occupational exposures as well. The chemical recoveries are typically greater than 90%, in contrast to other reported methods using flow injection separation techniques for urine samples where plutonium yields were 70-80%. This method allows measurement of both long-lived and short-lived actinide isotopes. 239Pu, 242Pu, 237Np, 243Am, 234U, 235U and 238U were measured by ICP-MS, while 236Pu, 238Pu, 239Pu, 241Am, 243Am and 244Cm were measured by alpha spectrometry. The method can also be adapted so that the separation of uranium isotopes for assay is not required, if uranium assay by direct dilution of the urine sample is preferred instead. Multiple vacuum box locations may be set-up to supply several ICP-MS units with purified sample fractions such that a high sample throughput may be achieved, while still allowing for rapid measurement of short-lived actinides by alpha spectrometry.« less

Extraction and characterization of polysaccharides from Semen Cassiae by microwave-assisted aqueous two-phase extraction coupled with spectroscopy and HPLC.

PubMed

Chen, Zhi; Zhang, Wei; Tang, Xunyou; Fan, Huajun; Xie, Xiujuan; Wan, Qiang; Wu, Xuehao; Tang, James Z

2016-06-25

A novel and rapid method for simultaneous extraction and separation of the different polysaccharides from Semen Cassiae (SC) was developed by microwave-assisted aqueous two-phase extraction (MAATPE) in a one-step procedure. Using ethanol/ammonium sulfate system as a multiphase solvent, the effects of MAATPE on the extraction of polysaccharides from SC such as the composition of the ATPS, extraction time, temperature and solvent-to-material ratio were investigated by UV-vis analysis. Under the optimum conditions, the yields of polysaccharides were 4.49% for the top phase, 8.80% for the bottom phase and 13.29% for total polysaccharides, respectively. Compared with heating solvent extraction and ultrasonic assisted extraction, MAATPE exhibited the higher extraction yields in shorter time. Fourier-transform infrared spectra showed that two polysaccharides extracted from SC to the top and bottom phases by MAATPE were different from each other in their chemical structures. Through acid hydrolysis and PMP derivatization prior to HPLC, analytical results by indicated that a polysaccharide of the top phases was a relatively homogeneous homepolysaccharide composed of dominant gucose glucose while that of the bottom phase was a water-soluble heteropolysaccharide with multiple components of glucose, xylose, arabinose, galactose, mannose and glucuronic acid. Molar ratios of monosaccharides were 95.13:4.27:0.60 of glucose: arabinose: galactose for the polysaccharide from the top phase and 62.96:14.07:6.67: 6.67:5.19:4.44 of glucose: xylose: arabinose: galactose: mannose: glucuronic acid for that from the bottom phase, respectively. The mechanism for MAATPE process was also discussed in detail. MAATPE with the aid of microwave and the selectivity of the ATPS not only improved yields of the extraction, but also obtained a variety of polysaccharides. Hence, it was proved as a green, efficient and promising alternative to simultaneous extraction of polysaccharides from SC. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Simultaneous determination of nine estrogens in eel by ultrafast liquid chromatography-tandem mass spectrometry with isotope dilution technique and solid-phase extraction].

PubMed

Chen, Xiaohong; Yao, Shanshan; Li, Xiaoping; Zhao, Yonggang; Jin, Micong

2012-11-01

Developing a rapid and sensitive analytical method based on ultrafast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) with solid-phase extraction (SPE) for the simultaneous determination of nine estrogens (dienestrol, diethylstilbestrol, estrone, hexestrol, 17-alpha-estradiol, 17-beta-estradiol, estriol, 17alpha-ethinylestradiol and estradiol valerate) in eel. After the sample was extracted by acetonitrile and cleaned by Waters Oasis HLB solid-phase extraction cartridge, the UFLC separation was performed on a Shim-pack XR-ODS II column (100 mm x 2.0 mm, 2.2 microm) with a linear gradient elution program of methanol solution containing 0.04% ammonia (v/v) and 0.04% ammonia aqueous solution (v/v) as the mobile phase. Electrospray ionization was applied and operated in the negative multiple reaction monitoring (MRM) mode. The quantitation was used by isotope internal standard dilution technique. The results showed that the limits of quantitation (LOQs, S/N(10) were in the range of 0.07-0.4 microg/kg, the calibration curves were in good linearities for the nine analytes in the range of 0.5-50.0 microg/L with the correlative coefficients (r2) more than 0.998, the recoveries were between 81.0% and 110.0% with the relative standard deviations (RSDs) of 1.92%-8.24%. Additional, the mass spectra characterization of the nine estrogens was discussed and the fragmentation pathways were speculated. The developed method is rapid, sensitive, specific and reproducible, and adapts not only to the simultaneous determination of the nine trace estrogens including the epimer of 17-alpha-estradiol and 17-beta-estradiol but also to the identified detection in other fish tissues.

HPTLC method for the simultaneous determination of four indole alkaloids in Rauwolfia tetraphylla: a study of organic/green solvent and continuous/pulse sonication.

PubMed

Gupta, Shikha; Shanker, Karuna; Srivastava, Santosh K

2012-07-01

A new validated high-performance thin-layer chromatographic (HPTLC) method has been developed for the simultaneous quantitation of four antipsychotic indole alkaloids (IAs), reserpiline (RP, 1), α-yohimbine (YH, 2), isoreserpiline (IRP, 3) and 10-methoxy tetrahydroalstonine (MTHA, 4) as markers in the leaves of Rauwolfia tetraphylla. Extraction efficiency of the targeted IAs from the leaf matrix with organic and ecofriendly (green) solvents using percolation, ultrasonication and microwave techniques were studied. Non-ionic surfactants, viz. Triton X-100, Triton X-114 and Genapol X-80 were used for extraction and no back-extraction or liquid chromatographic steps were used to remove the targeted IAs from the surfactant-rich extractant phase. The optimized cloud point extraction was found a potentially useful methodology for the preconcentration of the targeted IAs. The separation was achieved on silica gel 60F(254) HPTLC plates using hexane-ethylacetate-methanol (5:4:1, v/v/v) as mobile phase. The quantitation of IAs (1-4) was carried out using the densitometric reflection/absorption mode at 520 nm after post chromatographic derivatization using Dragendorff's reagent. The method was validated for peak purity, precision, accuracy, robustness, limit of detection (LOD) and quantitation (LOQ). Method specificity was confirmed using retention factor (R(f)) and visible spectral (post chromatographic scan) correlation of marker compounds in the samples and standard tracks. Copyright © 2012 Elsevier B.V. All rights reserved.

Speciation of organotin compounds in urine by GC-MIP-AED and GC-MS after ethylation and liquid-liquid extraction.

PubMed

Zachariadis, G A; Rosenberg, E

2009-04-15

A method for the determination of organotin compounds in urine samples based on liquid-liquid extraction (LLE) in hexane and gas chromatographic separation was developed and optimized. Seven organotin species, namely monobutyltin (MBT), dibutyltin (DBT), tributyltin (TBT), tetrabutyltin (TeBT), monophenyltin (MPhT), diphenyltin (DPhT) and triphenyltin (TPhT), were in situ derivatized by sodium tetraethylborate (NaBEt(4)) to form ethylated less polar derivatives directly in the urine matrix. The critical parameters which have a significant effect on the yield of the successive liquid-liquid extraction procedure were examined, by using standard solutions of tetrabutyltin in hexane. The method was optimized for use in direct analysis of undiluted human urine samples and ways to overcome practical problems such as foam formation during extraction, due to various constituents of urine are discussed. After thorough optimization of the extraction procedure, all examined species could be determined after 3 min of simultaneous derivatization and extraction at room temperature and 5 min phase separation by centrifugation. Gas chromatography with a microwave-induced plasma atomic emission detector (MIP-AED) as element specific detector was employed for quantitative measurements, while a quadrupole mass spectrometric detector (MS) was used as molecular specific detector. The detection limits were between 0.42 and 0.67 microg L(-1) (as Sn) for the quantitative LLE-GC-MIP-AED method and the precision between 4.2% and 11.7%, respectively.

Simultaneous determination of celecoxib, hydroxycelecoxib, and carboxycelecoxib in human plasma using gradient reversed-phase liquid chromatography with ultraviolet absorbance detection.

PubMed

Störmer, Elke; Bauer, Steffen; Kirchheiner, Julia; Brockmöller, Jürgen; Roots, Ivar

2003-01-05

A new HPLC method for the simultaneous determination of celecoxib, carboxycelecoxib and hydroxycelecoxib in human plasma samples has been developed. Following a solid-phase extraction procedure, the samples were separated by gradient reversed-phase HLPC (C(18)) and quantified using UV detection at 254 nm. The method was linear over the concentration range 10-500 ng/ml. The intra-assay variability for the three analytes ranged from 4.0 to 12.6% and the inter-assay variability from 4.9 to 14.2%. The achieved limits of quantitation (LOQ) of 10 ng/ml for each analyte allowed the determination of the pharmacokinetic parameters of the analytes after administration of 100 mg celecoxib.

Complete recovery of actinides from UREX-like raffinates using a combination of hard and soft donor ligands. II. soft donor structure variation

DOE PAGES

Zalupski, Peter R.; Klaehn, John R.; Peterman, Dean R.

2015-07-30

The feasibility of simultaneous separation of uranium, neptunium, plutonium, americium, and curium from a simulated dissolved used fuel simulant adjusted to 1.0 M nitric acid is investigated using a mixture of the soft donor bis(bis-3,5-trifluoromethyl)phenyl) dithiophosphinic acid (“0”) and the hard donor synergist trioctylphosphine oxide (TOPO) dissolved in toluene. The results reported in this work are compared to our recent demonstration of a complete actinide recovery from a simulated dissolved fuel solution using a synergistic combination of bis(o-trifluoromethylphenyl)dithiophosphinic acid (“1”) and TOPO dissolved in either toluene or trifluoromethylphenyl sulfone. While the extraction efficiency of americium was enhanced for the liquid-liquidmore » system containing “0”, enabling to accomplish a trivalent An/Ln separation at 1.0 M HNO3, the extraction of neptunium was drastically diminished, relative to “1”. The partitioning behavior of curium was also negatively impacted, introducing an effective opportunity for americium/curium separation. Radiometric and spectrophotometric studies demonstrate that the complete actinide recovery using the solvent based upon “0” and TOPO is not feasible. Additionally, the importance of radiolytic degradation processes is discussed through the comparisons of extraction properties of liquid-liquid systems based on both soft donor reagents.« less

Information extraction during simultaneous motion processing.

PubMed

Rideaux, Reuben; Edwards, Mark

2014-02-01

When confronted with multiple moving objects the visual system can process them in two stages: an initial stage in which a limited number of signals are processed in parallel (i.e. simultaneously) followed by a sequential stage. We previously demonstrated that during the simultaneous stage, observers could discriminate between presentations containing up to 5 vs. 6 spatially localized motion signals (Edwards & Rideaux, 2013). Here we investigate what information is actually extracted during the simultaneous stage and whether the simultaneous limit varies with the detail of information extracted. This was achieved by measuring the ability of observers to extract varied information from low detail, i.e. the number of signals presented, to high detail, i.e. the actual directions present and the direction of a specific element, during the simultaneous stage. The results indicate that the resolution of simultaneous processing varies as a function of the information which is extracted, i.e. as the information extraction becomes more detailed, from the number of moving elements to the direction of a specific element, the capacity to process multiple signals is reduced. Thus, when assigning a capacity to simultaneous motion processing, this must be qualified by designating the degree of information extraction. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Nitrate and Nitrite Determination in Gunshot Residue Samples by Capillary Electrophoresis in Acidic Run Buffer.

PubMed

Erol, Özge Ö; Erdoğan, Behice Y; Onar, Atiye N

2017-03-01

Simultaneous determination of nitrate and nitrite in gunshot residue has been conducted by capillary electrophoresis using an acidic run buffer (pH 3.5). In previously developed capillary electrophoretic methods, alkaline pH separation buffers were used where nitrite and nitrate possess similar electrophoretic mobility. In this study, the electroosmotic flow has been reversed by using low pH running buffer without any additives. As a result of reversing the electroosmotic flow, very fast analysis has been actualized, well-defined and separated ion peaks emerge in less than 4 min. Besides, the limit of detection was improved by employing large volume sample stacking. Limit of detection values were 6.7 and 4.3 μM for nitrate and nitrite, respectively. In traditional procedure, mechanical agitation is employed for extraction, while in this work the extraction efficiency of ultrasound mixing for 30 min was found sufficient. The proposed method was successfully applied to authentic gunshot residue samples. © 2016 American Academy of Forensic Sciences.

Rapid identification and simultaneous analysis of multiple constituents from Rheum tanguticum Maxim. ex Balf. by UPLC/Q-TOF-MS.

PubMed

Gao, Liang-Liang; Guo, Tao; Xu, Xu-Dong; Yang, Jun-Shan

2017-07-01

Rhubarb contains biologically active compounds such as anthraquinones, anthrones, stilbenes and tannins. A rapid and efficient UPLC/Q-TOF-MS/MS method was developed and applied towards identifying the constituents of Rheum tanguticum Maxim. ex Balf. for the first time. Chemical constituents were separated and investigated by UPLC/Q-TOF-MS/MS in the negative ion mode. The ESI-MS 2 fragmentation pathways of four types of compounds were interpreted, providing a very useful guidance for the characterisation of different types of compounds. Based on the exact mass information, fragmentation characteristic and LC retention time of 7 reference standards, 30 constituents were tentatively identified from the methanol extract of R. tanguticum. Among them, seven compounds were described for the first time from R. tanguticum and two from the genus Rheum were described for the first time. The analytical tool used here is valuable for the rapid separation and identification of multiple and minor constituents in methanol extracts of R. tanguticum.

Simultaneous column chromatographic extraction and purification of abscisic acid in peanut plants for direct HPLC analysis.

PubMed

Zhang, Ya-Wen; Fan, Wei-Wei; Li, Hui; Ni, He; Han, Han-Bing; Li, Hai-Hang

2015-10-01

Abscisic acid (ABA), a universal signaling molecule, plays important roles in regulating plant growth, development and stress responses. The low contents and complex components in plants make it difficult to be accurately analyzed. A novel one-step sample preparation method for ABA in plants was developed. Fresh peanut (Arachis hypogaea) plant materials were fixed by oven-drying, microwave drying, boiling or Carnoy's fixative, and loaded onto a mini-preparing column. After washed the impurities, ABA was eluted with a small amount of solvent. ABA in plant materials was completely extracted and purified in 2mL solution and directly analyzed by HPLC, with a 99.3% recovery rate. Multiple samples can be simultaneously prepared. Analyses using this method indicated that the endogenous ABA in oven-dried peanut leaves increased 20.2-fold from 1.01 to 20.37μgg(-1) dry weight within 12h and then decreased in 30% polyethylene glycol 6000 treated plants, and increased 3.34-fold from 0.85 to 2.84μgg(-1) dry weight in 5 days and then decreased in soil drought treated plants. The method combined the column chromatographic extraction and solid-phase separation technologies in one step and can completely extracted plant endogenous ABA in a purified and highly concentrated form for direct HPLC analysis. Copyright © 2015 Elsevier B.V. All rights reserved.

Chemically-modified activated carbon with ethylenediamine for selective solid-phase extraction and preconcentration of metal ions.

PubMed

Li, Zhenhua; Chang, Xijun; Zou, Xiaojun; Zhu, Xiangbing; Nie, Rong; Hu, Zheng; Li, Ruijun

2009-01-26

A new method that utilizes ethylenediamine-modified activated carbon (AC-EDA) as a solid-phase extractant has been developed for simultaneous preconcentration of trace Cr(III), Fe(III), Hg(II) and Pb(II) prior to the measurement by inductively coupled plasma optical emission spectrometry (ICP-OES). The new sorbent was prepared by oxidative surface modification. Experimental conditions for effective adsorption of trace levels of Cr(III), Fe(III), Hg(II) and Pb(II) were optimized with respect to different experimental parameters using batch and column procedures in detail. The optimum pH value for the separation of metal ions simultaneously on the new sorbent was 4.0. Complete elution of absorbed metal ions from the sorbent surface was carried out using 3.0 mL of 2% (%w/w) thiourea and 0.5 mol L(-1) HCl solution. Common coexisting ions did not interfere with the separation and determination of target metal ions. The maximum static adsorption capacity of the sorbent at optimum conditions was found to be 39.4, 28.9, 60.5 and 49.9 mg g(-1) for Cr(III), Fe(III), Hg(II) and Pb(II), respectively. The time for 94% adsorption of target metal ions was less than 2 min. The detection limits of the method was found to be 0.28, 0.22, 0.09 and 0.17 ng mL(-1) for Cr(III), Fe(III), Hg(II) and Pb(II), respectively. The precision (R.S.D.) of the method was lower 4.0% (n=8). The prepared sorbent as solid-phase extractant was successfully applied for the preconcentration of trace Cr(III), Fe(III), Hg(II) and Pb(II) in natural and certified samples with satisfactory results.

[Simultaneous determination of 6 neonicotinoid residues in soil using DLLME-HPLC and UV].

PubMed

Sun, Bao-li; Shan, Hong; Li, Yan-hua; Zeng, Ya-ling; Shen, Xiu-li; Tong, Cheng-feng

2013-09-01

A simple, cheap and rugged method was developed for simultaneous deter mination of 6 neonicotinoid residues in soil, including imidacloprid, acetamiprid, thiamethoxam, thiacloprid, clothianidin and nitenpyram. The soil sample was produced by dispersive liquid-liquid micro-extraction (DLLME) after extracted by the mixed solution of acetonitrile and CH2Cl2 (2:1, phi). The analytes were separated by HPLC with Alltima C18 column (4.6 mm x 250 mm, 5 microm) and detected by PDA at 260 nm. External standard method was used for quantification. The results showed that good linearity was obtained with correlation coefficients between 0.9982 and 0.9999 in the range of 0.5-200 microg x L(-1). The limits of detection (LODs) were in the range between 0.0005 and 0.003 microg x mL(-1) (S/N = 3). The method was validated with five soil samples spiked at three fortification levels (0.05, 0.1, 1.0 mg x kg(-1)) and recoveries were in the range of 55.3%-95.6% with RSD of 1.4%-7.0%. The effect of clean-up was evaluated by UV spectra and demonstrated that the method established is effective. In conclusion, this method is competent for the simultaneous analysis of 6 neonicotinoid residues in soil.

Separation and concentration of lower alcohols from dilute aqueous solutions

DOEpatents

Moore, Raymond H.; Eakin, David E.; Baker, Eddie G.; Hallen, Richard T.

1991-01-01

A process for producing, from a dilute aqueous solution of a lower (C.sub.1 -C.sub.5) alcohol, a concentrated liquid solution of the alcohol in an aromatic organic solvent is disclosed. Most of the water is removed from the dilute aqueous solution of alcohol by chilling sufficiently to form ice crystals. Simultaneously, the remaining liquid is extracted at substantially the same low temperature with a liquid organic solvent that is substantially immiscible in aqueous liquids and has an affinity for the alcohol at that temperature, causing the alcohol to transfer to the organic phase. After separating the organic liquid from the ice crystals, the organic liquid can be distilled to enrich the concentration of alcohol therein. Ethanol so separated from water and concentrated in an organic solvent such as toluene is useful as an anti-knock additive for gasoline.

Optimized extraction by cetyl trimethyl ammonium bromide reversed micelles of xylose reductase and xylitol dehydrogenase from Candida guilliermondii homogenate.

PubMed

Cortez, Ely Vieira; Pessoa, Adalberto; das Graças de Almeida Felipe, Maria; Roberto, Inês Conceição; Vitolo, Michele

2004-07-25

The intracellular enzymes xylose reductase (XR, EC 1.1.1.21) and xylitol dehydrogenase (XD, EC 1.1.1.9) from Candida guilliermondii, grown in sugar cane bagasse hydrolysate, were separated by reversed micelles of cetyl trimethyl ammonium bromide (CTAB) cationic surfactant. An experimental design was employed to optimize the extraction conditions of both enzymes. Under these conditions (temperature = 5 degree C, hexanol: isooctane proportion = 5% (v/v), 22 %, surfactant concentration = 0.15M, pH = 7.0 and electrical conductivity = 14 mScm(-1)) recovery values of about 100 and 80% were achieved for the enzymes XR and XD, respectively. The purity of XR and XD increased 5.6- and 1.8-fold, respectively. The extraction process caused some structural modifications in the enzymes molecules, as evidenced by the alteration of K(M) values determined before and after extraction, either in regard to the substrate (up 35% for XR and down 48% for XD) or cofactor (down 29% for XR and up 11% for XD). However, the average variation of V(max) values for both enzymes was not higher than 7%, indicating that the modified affinity of enzymes for their respective substrates and cofactors, as consequence of structural modifications suffered by them during the extraction, are compensated in some extension. This study demonstrated that liquid-liquid extraction by CTAB reversed micelles is an efficient process to separate the enzymes XR and XD present in the cell extract, and simultaneously increase the enzymatic activity and the purity of both enzymes produced by C. guilliermondii.

The production of chemicals from food processing wastes using a novel fermenter separator. Annual progress report, January 1993--March 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dale, M.C.; Venkatesh, K.V.; Choi, H.

The basic objective of this project is to convert waste streams from the food processing industry to usable fuels and chemicals using novel bioreactors. These bioreactors should allow economical utilization of waste (whey, waste sugars, waste starch, bottling wastes, candy wastes, molasses, and cellulosic wastes) by the production of ethanol, acetone/butanol, organic acids (acetic, lactic, and gluconic), yeast diacetyl flavor, and antifungal compounds. Continuous processes incorporating various processing improvements such as simultaneous product separation and immobilized cells are being developed to allow commercial scale utilization of waste stream. The production of ethanol by a continuous reactor-separator is the process closestmore » to commercialization with a 7,500 liter pilot plant presently sited at an Iowa site to convert whey lactose to ethanol. Accomplishments during 1993 include installation and start-up of a 7,500 liter ICRS for ethanol production at an industry site in Iowa; Donation and installation of a 200 liter yeast pilot Plant to the project from Kenyon Enterprises; Modeling and testing of a low energy system for recovery of ethanol from vapor is using a solvent absorption/extractive distillation system; Simultaneous saccharification/fermentation of raw corn grits and starch in a stirred reactor/separator; Testing of the ability of `koji` process to ferment raw corn grits in a `no-cook` process.« less

[Simultaneous determination of 5 compounds in Tripterygium hypoglaucum based on ultrasound-assisted ionic liquid coupled with HPLC].

PubMed

Zhang, Xiao-Mei; Chen, Yi-Long; Yao, Yuan-Yuan; Li, Na; Liu, You-Ping; Liang, Xu-Ming

2016-03-01

Using six kinds of ionic liquids as extractants, ultrasonic-assisted extraction coupled with HPLC method was developed for the simultaneous determination of wilforgine, wiforizine, triptophenolide, wilforine and triptoquinone A in Tripterygium hypoglaucum. The separation was performed on an Inertsil ODS-4 column with the mobile phase of acetonitrile-0.1% phosphoric acid in gradient elution at a flow rate of 0.75 mL•min⁻¹. Detection wavelength was 220 nm and the column temperature was 30℃. Under the optimal extractions, the results showed that triptophenolide and triptoquinone A had the highest extraction yield by using 0.6 mol•L⁻¹ [BMIm]PF6 methanol solution as extraction solvent with the solid-liquid ratio of 1∶10. The calibration curves of triptophenolide and triptoquinone A showed a good linearity in the range of 0.000 65-0.026, 0.066 55-2.662 μg (r=0.999 9)respectively. The average recovery was 102.4% and 97.90% with RSD of 2.5% and 1.5%, respectively. Wilforgine, wiforizine and wilforine had the highest extraction yield when using 0.6 mol• L⁻¹ [BMIm]PF6absolute ethanol solution as extraction solvent with the solid-liquid ratio of 1∶10. The content of wilforgine, wiforizine and wilforine from 0.023 9-0.956, 0.002 7-0.108, 0.006 4-0.256 μg showed a good linearity (r=0.999 9), and the average recovery was 100.6%,99.50% and 98.70% with RSD of 2.1%,1.9% and 2.7%, respectively. The results indicated that this method is convenient, reliable and green, and can be used as a reliableanalytical method for the quality control of T.hypoglaucum. Copyright© by the Chinese Pharmaceutical Association.

Simultaneous determination of secondary metabolites from Vinca rosea plant extractives by reverse phase high performance liquid chromatography

PubMed Central

Siddiqui, Mohammad Jamshed Ahmad; Ismail, Zhari; Saidan, Noor Hafizoh

2011-01-01

Background: Vinca rosea (Apocynaceae) is one of the most important and high value medicinal plants known for its anticancer alkaloids. It is the iota of the isolated secondary metabolites used in chemotherapy to treat diverse cancers. Several high performance liquid chromatography (HPLC) methods have been developed to quantify the active alkaloids in the plant. However, this method may serve the purpose in quantification of V. rosea plant extracts in totality. Objective: To develop and validate the reverse phase (RP)-HPLC method for simultaneous determination of secondary metabolites, namely alkaloids from V. rosea plant extracts. Materials and Methods: The quantitative determination was conducted by RP-HPLC equipped with ultraviolet detector. Optimal separation was achieved by isocratic elution with mobile phase consisting of methanol:acetonitrile:ammonium acetate buffer (25 mM) with 0.1% triethylamine (15:45:40 v/v) on a column (Zorbax Eclipse plus C18, 250 mm % 4.6 mm; 5 μm). The standard markers (vindoline, vincristine, catharanthine, and vinblastine) were identified by retention time and co-injected with reference standard and quantified by external standard method at 297 nm. Results: The precision of the method was confirmed by the relative standard deviation (R.S.D.), which was lower than 2.68%. The recoveries were in the range of 98.09%-108%. The limits of detection (LOD) for each marker alkaloids were lower than 0.20 μg. Different parts of the V. rosea extracts shows different concentrations of markers, flower samples were high in vinblastine content, while methanol extract from the leaves contains all the four alkaloids in good yield, and there is no significant presence of markers in water extracts. Conclusion: HPLC method established is appropriate for the standardization and quality assurance of V. rosea plant extracts. PMID:21716929

Liquefaction of ground tire rubber at low temperature.

PubMed

Cheng, Xiangyun; Song, Pan; Zhao, Xinyu; Peng, Zonglin; Wang, Shifeng

2018-01-01

Low-temperature liquefaction has been investigated as a novel method for recycling ground tire rubber (GTR) into liquid using an environmentally benign process. The liquefaction was carried out at different temperatures (140, 160 and 180 °C) over variable time ranges (2-24 h) by blending the GTR with aromatic oil in a range from 0 to 100 parts per hundred rubber (phr). The liquefied GTR was separated into sol (the soluble fraction of rubber which can be extracted with toluene) and gel fractions (the solid fraction obtained after extraction) to evaluate the reclaiming efficiency. It was discovered that the percentage of the sol fraction increased with time, swelling ratio and temperature. Liquefied rubber was obtained with a high sol fraction (68.34 wt%) at 140 °C. Simultaneously, separation of nano-sized carbon black from the rubber networks occurred. The separation of carbon black from the network is the result of significant damage to the cross-linked-network that occurs throughout the liquefaction process. During liquefaction, a competitive reaction between main chain scission and cross-link bond breakage takes place. Copyright © 2017 Elsevier Ltd. All rights reserved.

Magnetic nanoparticles and high-speed countercurrent chromatography coupled in-line and using the same solvent system for separation of quercetin-3-O-rutinoside, luteoloside and astragalin from a Mikania micrantha extract.

PubMed

Wang, Juanqiang; Geng, Shan; Wang, Binghai; Shao, Qian; Fang, Yingtong; Wei, Yun

2017-07-28

A new in-line method of magnetic nanoparticles (MNPs) coupled with high-speed countercurrent chromatography (HSCCC) using a same solvent system during the whole separation process was established to achieve the rapid separation of flavonoids from Mikania micrantha. The adsorption and desorption capacities of five different MNPs for flavonoid standards and Mikania micrantha crude extract were compared and the most suitable magnetic nanoparticle Fe 3 O 4 @SiO 2 @DIH@EMIMLpro was selected as the in-line MNP column. An in-line separation system was established by combining this MNP column with HSCCC through a six-way valve. The comparison between two solvent systems n-hexane-ethyl acetate-methanol-water (3:5:3:5, v/v) and ethyl acetate-methanol-water (25:1:25, v/v) showed that the latter solvent system was more suitable for simultaneously in-line separating three flavonoids quercetin-3-O-rutinoside, luteoloside and astragalin from Mikania micrantha. The purities of these three compounds with the ethyl acetate-methanol-water solvent system were 95.13%, 98.54% and 98.19% respectively. Results showed the established in-line separation system of MNP-HSCCC was efficient, recyclable and served to isolate potential flavonoids with similar polarities from natural complex mixtures. The in-line combination of magnetic nanoparticles with high-speed countercurrent chromatography eluting with the same solvent system during the whole separation process was established for the first time. Copyright © 2017 Elsevier B.V. All rights reserved.

Bilateral cataract extraction with posterior chamber intraocular lens implantation simultaneous in pediatric cataracts.

PubMed

Caça, Ihsan; Sakalar, Yildirim Bayezit; Ari, Seyhmus; Alakus, Fuat; Dogan, Eyüp

2008-01-01

We evaluated the results of simultaneous bilateral cataract extraction with intraocular lens (IOL) inplantation 32 pediatric cataract patients. Simultaneous cataract extraction and posterior capsulotomy with anterior vitrectomy and IOL implantation is an effective and safe procedure in bilateral pediatric cataracts treatment.

Optimization of the Ultrasonic-Assisted Extraction of Bioactive Flavonoids from Ampelopsis grossedentata and Subsequent Separation and Purification of Two Flavonoid Aglycones by High-Speed Counter-Current Chromatography.

PubMed

Zhang, Hongbing; Xie, Guoyong; Tian, Mei; Pu, Qian; Qin, Minjian

2016-08-20

The fermented leaf of Ampelopsis grossedentata has been used as a beverage and folk medicine called "vine tea" in the southern region of China. In this paper, the optimum extraction conditions for the maximum recovery amounts of total flavonoids (TF), dihydromyricetin (DMY), myricitrin (MYG) and myricetin (MY) from natural Ampelopsis grossedentata leaves subjected to ultrasonic-assisted extraction (UAE) were determined and optimized by using response surface methodology. The method was employed by the Box-Behnken design (BBD) and Derringer's desirability function using methanol concentration, extraction time, liquid/solid ratio as factors and the contents of TF, DMY, MYG and MY as responses. The obtained optimum UAE conditions were as follows: a solvent of 80.87% methanol, an extraction time of 31.98 min and a liquid/solid ratio of 41.64:1 mL/g. Through analysis of the response surface, it implied that methanol concentration and the liquid/solid ratio had significant effects on TF, DMY, MYG and MY yields, whereas extraction time had relatively little effects. The established extraction and analytical methods were successfully applied to determine the contents of the total flavonoids and three individual flavonoids in 10 batches of the leaf samples of A. grossedentata from three counties in Fujian Province, China. The results suggested the variability in the quality of A. grossedentata leaves from different origins. In addition, high purities of dihydromyricetin and myricetin were simultaneously separated and purified from the extract subjected to optimized UAE, by high-speed counter-current chromatography using a solvent system of N-hexane-ethyl acetate-methanol-water (1:3:2:4; v/v/v/v). In a single operation, 200 mg of the extract were separated to yield 86.46 mg of dihydromyricetin and 3.61 mg of myricetin with the purity of 95.03% and 99.21%, respectively. The results would be beneficial for further exploiting the herbal products and controlling the quality of the herb and its derived products.

Simultaneous extraction of proteins and metabolites from cells in culture

PubMed Central

Sapcariu, Sean C.; Kanashova, Tamara; Weindl, Daniel; Ghelfi, Jenny; Dittmar, Gunnar; Hiller, Karsten

2014-01-01

Proper sample preparation is an integral part of all omics approaches, and can drastically impact the results of a wide number of analyses. As metabolomics and proteomics research approaches often yield complementary information, it is desirable to have a sample preparation procedure which can yield information for both types of analyses from the same cell population. This protocol explains a method for the separation and isolation of metabolites and proteins from the same biological sample, in order for downstream use in metabolomics and proteomics analyses simultaneously. In this way, two different levels of biological regulation can be studied in a single sample, minimizing the variance that would result from multiple experiments. This protocol can be used with both adherent and suspension cell cultures, and the extraction of metabolites from cellular medium is also detailed, so that cellular uptake and secretion of metabolites can be quantified. Advantages of this technique includes:1.Inexpensive and quick to perform; this method does not require any kits.2.Can be used on any cells in culture, including cell lines and primary cells extracted from living organisms.3.A wide variety of different analysis techniques can be used, adding additional value to metabolomics data analyzed from a sample; this is of high value in experimental systems biology. PMID:26150938

Simultaneous LC-MS/MS quantitation of acetaminophen and its glucuronide and sulfate metabolites in human dried blood spot samples collected by subjects in a pilot clinical study.

PubMed

Li, Wenkui; Doherty, John P; Kulmatycki, Kenneth; Smith, Harold T; Tse, Francis Ls

2012-06-01

In support of a pilot clinical trial using acetaminophen as the model compound to assess dried blood spot (DBS) sampling as the method for clinical pharmacokinetic sample collection, a novel sensitive LC-MS/MS method was developed and validated for the simultaneous determination of acetaminophen and its major metabolites, acetaminophen glucuronide and sulfate, in human DBS samples collected by subjects via fingerprick. The validated assay dynamic range was from 50.0 to 5000 ng/ml for each compound using a 1/8´´ (3-mm) disc punched from a DBS sample. Baseline separation of the three analytes was achieved to eliminate the possible impact of insource fragmentation of the conjugated metabolites on the analysis of the parent. The overall extraction efficiency was from 61.3 to 78.8% for the three analytes by direct extraction using methanol. The validated method was successfully implemented in the pilot clinical study with the obtained pharmacokinetic parameters in agreement with the values reported in literature.

[Simultaneous isolation and purification of gallic acid and brevifolincarboxylic acid from Polygonum capitatum by high-speed counter-current chromatography].

PubMed

Chen, Xinxia; Zhang, Liyan; Wan, Jinzhi; Liang, Bin; Xie, Yu

2010-08-01

To isolate and purify gallic acid and brevifolincarboxylic acid simultaneously by high-speed counter-current chromatography (HSCCC) from a crude extract of Polygonum capitatum. The biphasic solvent system composed of ethyl acetate-n-butanol-0.44% acetic acid (3:1:5) was used at a flow rate of 2.0 mL x min(-1), while the aqueous phase was selected as the mobile phase and the apparatus was rotated at 860 r x min(-1). The effluent was detected at 272 nm. 51.5 mg of gallic acid and 5.9 mg of brevifolincarboxylic acid were separated from 1.07 g of the crude extract with the purities of 99.7% and 97.5%, respectively, while brevifolincarboxylic acid was obtained firstly from the genus Polygonum. The structures of the compounds were identified by ultraviolet spectrometry (UV), infra-red spectrometry (IR), liquid chromatography/mass spectrometry (LC/MS), time-of-flight mass spectrometry( TOF-MS), 1H-nuclear magnetic resonance (NMR) and 13C-NMR. This method is feasible and rapid for isolation and purification of gallice acid and brevifolincarboxylil acid.

Simultaneous determination of quinolones for veterinary use by high-performance liquid chromatography with electrochemical detection.

PubMed

Rodríguez Cáceres, M I; Guiberteau Cabanillas, A; Galeano Díaz, T; Martínez Cañas, M A

2010-02-01

A selective method based on high-performance liquid chromatography with electrochemical detection (HPLC-ECD) has been developed to enable simultaneous determination of three fluoroquinolones (FQs), namely danofloxacin (DANO), difloxacin (DIFLO) and sarafloxacin (SARA). The fluoroquinolones are separated on a Novapack C-18 column and detected in a high sensitivity amperometric cell at a potential of +0.8 V. Solid-phase extraction was used for the extraction of the analytes in real samples. The range of concentration examined varied from 10 to 150 ng g(-1) for danofloxacin, from 25 to 100 ng g(-1) for sarafloxacin and from 50 to 315 ng g(-1) for difloxacin, respectively. The method presents detection limits under 10 ng g(-1) and recoveries around 90% for the three analytes have been obtained in the experiments with fortified samples. This HPLC-ECD approach can be useful in the routine analysis of antibacterial residues being less expensive and less complicated than other more powerful tools as hyphenated techniques. 2009 Elsevier B.V. All rights reserved.

A PLS-based extractive spectrophotometric method for simultaneous determination of carbamazepine and carbamazepine-10,11-epoxide in plasma and comparison with HPLC

NASA Astrophysics Data System (ADS)

Hemmateenejad, Bahram; Rezaei, Zahra; Khabnadideh, Soghra; Saffari, Maryam

2007-11-01

Carbamazepine (CBZ) undergoes enzyme biotransformation through epoxidation with the formation of its metabolite, carbamazepine-10,11-epoxide (CBZE). A simple chemometrics-assisted spectrophotometric method has been proposed for simultaneous determination of CBZ and CBZE in plasma. A liquid extraction procedure was operated to separate the analytes from plasma, and the UV absorbance spectra of the resultant solutions were subjected to partial least squares (PLS) regression. The optimum number of PLS latent variables was selected according to the PRESS values of leave-one-out cross-validation. A HPLC method was also employed for comparison. The respective mean recoveries for analysis of CBZ and CBZE in synthetic mixtures were 102.57 (±0.25)% and 103.00 (±0.09)% for PLS and 99.40 (±0.15)% and 102.20 (±0.02)%. The concentrations of CBZ and CBZE were also determined in five patients using the PLS and HPLC methods. The results showed that the data obtained by PLS were comparable with those obtained by HPLC method.

Protein extraction from biomass in a bioethanol refinery--possible dietary applications: Use as animal feed and potential extension to human consumption.

PubMed

Chiesa, Simone; Gnansounou, Edgard

2011-01-01

The economy of the production of lignocellulosic ethanol could be supported by the simultaneous use of different components of the biomass other than sugars. Among these, protein is present at high concentration in leaves and is a candidate for different possible utilizations. Among dietary applications, plant protein may be used as animal feed and possibly extended to human consumption, in close similarity to leaf protein concentrates already proposed in the past. This would be especially beneficial for developing countries. For this aim, protein quality plays a crucial role: separating only the noble fraction of protein in biomass and preserving its nutritional value, while simultaneously obtaining good yields and limiting drawbacks on other steps of the production chain is particularly challenging from a technical viewpoint. In this review, we compare the possible extraction of protein from dry biomass with the more commonly studied situation in which freshly harvested material is used, with special focus on dietary implications. Copyright © 2010 Elsevier Ltd. All rights reserved.

A low-power current-reuse dual-band analog front-end for multi-channel neural signal recording.

PubMed

Sepehrian, H; Gosselin, B

2014-01-01

Thoroughly studying the brain activity of freely moving subjects requires miniature data acquisition systems to measure and wirelessly transmit neural signals in real time. In this application, it is mandatory to simultaneously record the bioelectrical activity of a large number of neurons to gain a better knowledge of brain functions. However, due to limitations in transferring the entire raw data to a remote base station, employing dedicated data reduction techniques to extract the relevant part of neural signals is critical to decrease the amount of data to transfer. In this work, we present a new dual-band neural amplifier to separate the neuronal spike signals (SPK) and the local field potential (LFP) simultaneously in the analog domain, immediately after the pre-amplification stage. By separating these two bands right after the pre-amplification stage, it is possible to process LFP and SPK separately. As a result, the required dynamic range of the entire channel, which is determined by the signal-to-noise ratio of the SPK signal of larger bandwidth, can be relaxed. In this design, a new current-reuse low-power low-noise amplifier and a new dual-band filter that separates SPK and LFP while saving capacitors and pseudo resistors. A four-channel dual-band (SPK, LFP) analog front-end capable of simultaneously separating SPK and LFP is implemented in a TSMC 0.18 μm technology. Simulation results present a total power consumption per channel of 3.1 μw for an input referred noise of 3.28 μV and a NEF for 2.07. The cutoff frequency of the LFP band is fc=280 Hz, and fL=725 Hz and fL=11.2 KHz for SPK, with 36 dB gain for LFP band 46 dB gain for SPK band.

Determination of macrolide antibiotics in chicken tissues by liquid chromatography-electrospray mass spectrometry

NASA Astrophysics Data System (ADS)

Salikin, Jamilah; Abdullah, Aminah

2013-11-01

A methodusingliquid chromatography-electrospray mass spectrometry (LC-(ESI)MS) for the simultaneous determination of three macrolides (tylosin, spiramycin and tilmicosin) in poultry muscle has been developed. The drugs were extracted with EDTA McIlvaine buffer, filter through celite 545 and the extracts were cleaned up by SPE Oasis HLB cartridge. Separation was carried out in end-capped silica-based C18 column and mobile phases containing trifluoroacetic acid-acetonitrile with a binary gradient system at a flow rate 0.5 ml/min. Detection was performed by single mass spectrometry with electrospray ionization in the positive mode. Several parameters affecting the mass spectra were studied. Chicken samples from the market were analyzed to check the residue of macrolide antibiotics.

On-Demand Single Photons with High Extraction Efficiency and Near-Unity Indistinguishability from a Resonantly Driven Quantum Dot in a Micropillar.

PubMed

Ding, Xing; He, Yu; Duan, Z-C; Gregersen, Niels; Chen, M-C; Unsleber, S; Maier, S; Schneider, Christian; Kamp, Martin; Höfling, Sven; Lu, Chao-Yang; Pan, Jian-Wei

2016-01-15

Scalable photonic quantum technologies require on-demand single-photon sources with simultaneously high levels of purity, indistinguishability, and efficiency. These key features, however, have only been demonstrated separately in previous experiments. Here, by s-shell pulsed resonant excitation of a Purcell-enhanced quantum dot-micropillar system, we deterministically generate resonance fluorescence single photons which, at π pulse excitation, have an extraction efficiency of 66%, single-photon purity of 99.1%, and photon indistinguishability of 98.5%. Such a single-photon source for the first time combines the features of high efficiency and near-perfect levels of purity and indistinguishabilty, and thus opens the way to multiphoton experiments with semiconductor quantum dots.

Fifteen terawatt picosecond CO2 laser system.

PubMed

Haberberger, D; Tochitsky, S; Joshi, C

2010-08-16

The generation of a record peak-power of 15 TW (45 J, 3 ps) in a single CO(2) laser beam is reported. Using a master oscillator-power amplifier laser system, it is shown that up to 100 J of energy can be extracted in a train of 3 ps laser pulses separated by 18 ps, a characteristic time of the CO(2) molecule. The bandwidth required for amplifying the short injected laser pulse train in a 2.5 atm final CO(2) amplifier is provided by field broadening of the medium at intensities of up to 140 GW/cm(2). The measured saturation energy for 3 ps pulses is 120 mJ/cm(2) which confirms that energy is simultaneously extracted from six rovibrational lines.

Quantification of the level of fat-soluble vitamins in feed based on the novel microemulsion electrokinetic chromatography (MEEKC) method.

PubMed

Olędzka, Ilona; Kowalski, Piotr; Bałuch, Alicja; Bączek, Tomasz; Paradziej-Łukowicz, Jolanta; Taciak, Marcin; Pastuszewska, Barbara

2014-02-01

Simultaneous quantification of liposoluble vitamins is not a new area of interest, since these compounds co-determine the nutritional quality of food and feed, a field widely explored in the human and animal diet. However, the development of appropriate methods is still a matter of concern, especially when the vitamin composition is highly complex, as is the case with feed designated for laboratory animals, representing a higher health and microbiological status. A method combining microemulsion electrokinetic chromatography (MEEKC) with liquid-liquid extraction was developed for the determination of four fat-soluble vitamins in animal feed. A separation medium consisting of 25 mmol L⁻¹ phosphate buffer (pH 2.5), 2-propanol, 1-butanol, sodium dodecyl sulfate and octane allowed the simultaneous determination of vitamins A, D, E and K within a reasonable time of 25 min. The polarity of the separation voltage was reversed in view of the strongly suppressed electro-osmotic flow, and the applied voltage was set at 12 kV. The fat-soluble vitamins were separated in the order of decreasing hydrophobicity. It was proved that the proposed MEEKC method was sufficiently specific and sensitive for screening fat-soluble vitamins in animal feed samples after their sterilization. © 2013 Society of Chemical Industry.

Development and validation of simple spectrophotometric and chemometric methods for simultaneous determination of empagliflozin and metformin: Applied to recently approved pharmaceutical formulation

NASA Astrophysics Data System (ADS)

Ayoub, Bassam M.

2016-11-01

New univariate spectrophotometric method and multivariate chemometric approach were developed and compared for simultaneous determination of empagliflozin and metformin manipulating their zero order absorption spectra with application on their pharmaceutical preparation. Sample enrichment technique was used to increase concentration of empagliflozin after extraction from tablets to allow its simultaneous determination with metformin without prior separation. Validation parameters according to ICH guidelines were satisfactory over the concentration range of 2-12 μg mL- 1 for both drugs using simultaneous equation with LOD values equal to 0.20 μg mL- 1 and 0.19 μg mL- 1, LOQ values equal to 0.59 μg mL- 1 and 0.58 μg mL- 1 for empagliflozin and metformin, respectively. While the optimum results for the chemometric approach using partial least squares method (PLS-2) were obtained using concentration range of 2-10 μg mL- 1. The optimized validated methods are suitable for quality control laboratories enable fast and economic determination of the recently approved pharmaceutical combination Synjardy® tablets.

Simultaneous densitometric determination of anthelmintic drug albendazole and its metabolite albendazole sulfoxide by HPTLC in human plasma and pharmaceutical formulations.

PubMed

Pandya, Jui J; Sanyal, Mallika; Shrivastav, Pranav S

2017-09-01

A new, simple, accurate and precise high-performance thin-layer chromatographic method has been developed and validated for simultaneous determination of an anthelmintic drug, albendazole, and its active metabolite albendazole, sulfoxide. Planar chromatographic separation was performed on aluminum-backed layer of silica gel 60G F 254 using a mixture of toluene-acetonitrile-glacial acetic acid (7.0:2.9:0.1, v/v/v) as the mobile phase. For quantitation, the separated spots were scanned densitometrically at 225 nm. The retention factors (R f ) obtained under the established conditions were 0.76 ± 0.01 and 0.50 ± 0.01 and the regression plots were linear (r 2  ≥ 0.9997) in the concentration ranges 50-350 and 100-700 ng/band for albendazole and albendazole sulfoxide, respectively. The method was validated for linearity, specificity, accuracy (recovery) and precision, repeatability, stability and robustness. The limit of detection and limit of quantitation found were 9.84 and 29.81 ng/band for albendazole and 21.60 and 65.45 ng/band for albendazole sulfoxide, respectively. For plasma samples, solid-phase extraction of analytes yielded mean extraction recoveries of 87.59 and 87.13% for albendazole and albendazole sulfoxide, respectively. The method was successfully applied for the analysis of albendazole in pharmaceutical formulations with accuracy ≥99.32%. Copyright © 2017 John Wiley & Sons, Ltd.

Simultaneous extraction and depolymerization of fucoidan from Sargassum muticum in aqueous media.

PubMed

Balboa, Elena M; Rivas, Sandra; Moure, Andrés; Domínguez, Herminia; Parajó, Juan Carlos

2013-11-21

The biomass components of the invasive seaweed Sargassum muticum were fractionated to allow their separate valorization. S. muticum (Sm) and the solid residue remaining after alginate extraction of this seaweed (AESm) were processed with hot, compressed water (hydrothermal processing) to assess the effects of temperature on fucoidan solubilization. Fucose-containing oligosaccharides were identified as reaction products. Operating under optimal conditions (170 °C), up to 62 and 85 wt% of the dry mass of Sm and AESm were solubilized, respectively. The reaction media were subjected to precipitation, nanofiltration and freeze-drying. The dried products contained 50% and 85% of the fucoidan present in Sm and AESm, respectively; together with other components such as phenolics and inorganic components. The saccharidic fraction, accounting for up to 35% of the dried extracts, contained fucose as the main sugar, and also galactose, xylose, glucose and mannose. The concentrates were characterized for antioxidant activity using the TEAC assay.

Determination of emamectin benzoate in medicated fish feed.

PubMed

Farer, L J; Hayes, J; Rosen, J; Knight, P

1999-01-01

A method was developed to quantitate emamectin benzoate in fish feed at levels between 5 and 15 ppm. The active ingredient is extracted from 20 g medicated feed into aqueous-methanolic solvent by overnight shaking. A solid-phase extraction procedure using a 2 g C18 cartridge is then used to concentrate the active residue and remove interfering matrix components. The extracted drug and internal standard are eluted from the cartridge, evaporated to dryness, and reconstituted in methanol. A control feed sample and fortified control working standard are simultaneously prepared. Remaining interferences and sample analysis are further separated on a gradient liquid chromatographic system. Recovery of emamectin benzoate from fortified feeds ranged from 97 to 100%, with a coefficient of variation (CV) of 1.2%. Determination of emamectin benzoate in medicated feeds resulted in CVs ranging from 2.3 to 4.2% and recoveries of 88 to 98% of label claim.

Simultaneous Extraction and Depolymerization of Fucoidan from Sargassum muticum in Aqueous Media

PubMed Central

Balboa, Elena M.; Rivas, Sandra; Moure, Andrés; Domínguez, Herminia; Parajó, Juan Carlos

2013-01-01

The biomass components of the invasive seaweed Sargassum muticum were fractionated to allow their separate valorization. S. muticum (Sm) and the solid residue remaining after alginate extraction of this seaweed (AESm) were processed with hot, compressed water (hydrothermal processing) to assess the effects of temperature on fucoidan solubilization. Fucose-containing oligosaccharides were identified as reaction products. Operating under optimal conditions (170 °C), up to 62 and 85 wt% of the dry mass of Sm and AESm were solubilized, respectively. The reaction media were subjected to precipitation, nanofiltration and freeze-drying. The dried products contained 50% and 85% of the fucoidan present in Sm and AESm, respectively; together with other components such as phenolics and inorganic components. The saccharidic fraction, accounting for up to 35% of the dried extracts, contained fucose as the main sugar, and also galactose, xylose, glucose and mannose. The concentrates were characterized for antioxidant activity using the TEAC assay. PMID:24284426

Development and validation of a method for the simultaneous extraction and separate measurement of oxytetracycline, florfenicol, oxolinic acid and flumequine from marine sediments.

PubMed

Norambuena, Luis; Gras, Nuri; Contreras, Sergio

2013-08-15

A simple and rapid method for the detection and extraction of oxolinic acid, flumequine, florfenicol and oxytetracycline from marine sediments was developed and validated. The analytes were extracted from the marine sediment using a solution of oxalic acid diluted in methanol with sonication before detection by HPLC using a diode-array detector (florfenicol and oxytetracycline) and fluorescence (oxolinic acid and flumequine). The quantification limits (QL) were 100 ng/g for oxytetracycline and florfenicol and 5 ng/g for oxolinic acid and flumequine. The coefficients of variation of the repeatability and intermediate precision were less than 10% in all of the analytes. The calibration curves were linear between 50 and 500 ng/ml for oxytetracycline and florfenicol and 1 and 20 ng/ml for oxolinic acid and flumequine. The recuperation rate for the analytes was above 86%. Copyright © 2013 Elsevier Ltd. All rights reserved.

Feasibility of Surfactant-Free Supported Emulsion Liquid Membrane Extraction

NASA Technical Reports Server (NTRS)

Hu, Shih-Yao B.; Li, Jin; Wiencek, John M.

2001-01-01

Supported emulsion liquid membrane (SELM) is an effective means to conduct liquid-liquid extraction. SELM extraction is particularly attractive for separation tasks in the microgravity environment where density difference between the solvent and the internal phase of the emulsion is inconsequential and a stable dispersion can be maintained without surfactant. In this research, dispersed two-phase flow in SELM extraction is modeled using the Lagrangian method. The results show that SELM extraction process in the microgravity environment can be simulated on earth by matching the density of the solvent and the stripping phase. Feasibility of surfactant-free SELM (SFSELM) extraction is assessed by studying the coalescence behavior of the internal phase in the absence of the surfactant. Although the contacting area between the solvent and the internal phase in SFSELM extraction is significantly less than the area provided by regular emulsion due to drop coalescence, it is comparable to the area provided by a typical hollow-fiber membrane. Thus, the stripping process is highly unlikely to become the rate-limiting step in SFSELM extraction. SFSELM remains an effective way to achieve simultaneous extraction and stripping and is able to eliminate the equilibrium limitation in the typical solvent extraction processes. The SFSELM design is similar to the supported liquid membrane design in some aspects.

Validation of lipolysis product extraction from aqueous/biological samples, separation and quantification by thin-layer chromatography with flame ionization detection analysis using O-cholesteryl ethylene glycol as a new internal standard.

PubMed

Cavalier, Jean-François; Lafont, Dominique; Boullanger, Paul; Houisse, David; Giallo, Jacqueline; Ballester, Jean-Michel; Carrière, Frédéric

2009-09-11

A general and easily accessible method for the extraction followed by the simultaneous separation and quantitative determination of triacylglycerols, diacylglycerols, monoacylglycerols and free fatty acids has been improved and optimized based on existing protocols using liquid-phase extraction and thin-layer chromatography coupled to flame ionization detection (TLC/FID Iatroscan). After lipid extraction in the presence of a suitable new synthetic internal standard, namely CholE1, a single elution step using n-heptane/diethyl ether/formic acid (55:45:1, v/v/v) was applied. This method was validated in line with international bioanalytical method validation guidelines using two different matrix systems: purified water and human gastro-intestinal fluid. Overall, the assay was found to have high levels of precision with coefficients of variation ranging from 1.48% to 11.0% and accuracy ranging from -13.3% to +5.79% RE. The confidence limits of the lipid mean recovery rates varied between 89.9% and 104%. This method is therefore highly suitable for quantifying the lipolysis products generated in vitro during the hydrolysis of various fats and oils by digestive lipases, as well as those collected from the gastro-intestinal tract in the course of human clinical studies on lipid digestion.

Simultaneous determination of four trace estrogens in feces, leachate, tap and groundwater using solid-liquid extraction/auto solid-phase extraction and high-performance liquid chromatography with fluorescence detection.

PubMed

Liu, Na; Shi, Yue-e; Li, Mengyan; Zhang, Ting-di; Gao, Song

2015-10-01

A simple and selective high-performance liquid chromatography method coupled with fluorescence detection was developed for the simultaneous measurement of trace levels of four estrogens (estrone, estradiol, estriol and 17α-ethynyl estradiol) in environmental matrices. For feces samples, solid-liquid extraction was applied with a 1:1 v/v mixture of acetonitrile and ethyl acetate as the extraction solvent. For liquid samples (e.g., leachate and groundwater), hydrophobic/lipophilic balanced automated solid-phase extraction disks were selected due to their high recoveries compared to conventional C18 disks. Chromatographic separations were performed on a reversed-phase C18 column gradient-eluted with a 45:55 v/v mixture of acetonitrile and water. The detection limits were down to 1.1 × 10(-2) (estrone), 4.11 × 10(-4) (estradiol), 5.2 × 10(-3) (estriol) and 7.18 × 10(-3) μg/L (17α-ethynyl estradiol) at excitation/emission wavelengths of 288/310 nm, with recoveries in the range of 96.9 ± 3.2-105.4 ± 3.2% (n = 3). The method was successfully applied to determine estrogens in feces and water samples collected at livestock farms and a major river in Northeast China. We observed relatively high abundance and widespread distribution of all four estrogens in our sample collections, implying the urgency for a comprehensive and intricate investigation of estrogenic fate and contamination in our researched area. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Re-manufacture of cobalt-manganese-bromide as a liquid catalyst from spent catalyst containing cobalt generated from petrochemical processes via hydrometallurgy.

PubMed

Joo, Sung-Ho; Shin, Dong Ju; Oh, Chang Hyun; Wang, Jei-Pil; Shin, Shun Myung

2016-11-15

Cobalt and manganese have been the subject of individual separation studies because their fields of application are different. However, this study shows that high-value products can be manufactured in the form of a cobalt-manganese-bromide (CMB) liquid catalyst by simultaneously recovering cobalt and manganese. Na-bis-(2,4,4-tri-methyl-pentyl)phosphinic acid was employed in order to manufacture the CMB liquid catalyst from the spent catalyst generated from petroleum chemistry processes. The pH-isotherm, degree of saponification of solvent and separation factor values were investigated. ΔpH50 and separation factor values show that Co and Mn can be separated from impurities such as Mg and Ca. Further, the extraction stages and organic/aqueous ratio isotherms were investigated using counter-current simulation extraction batch tests. To prepare CMB from a loaded organic phase obtained in a stripping study using hydrogen bromide, the Co and Mn were completely stripped and concentrated by a factor of 6 using a 2M hydrogen bromide solution. When compared with manufactured and commercial CMB, the CMB liquid catalyst could be produced by supplying a shortage of Mn in the form of manganese bromide. Finally, the method of manufacture of CMB was subjected to a real pilot plant test. Copyright © 2016. Published by Elsevier B.V.

Detection of monohydroxylated polycyclic aromatic hydrocarbons in urine and particulate matter using LC separations coupled with integrated SPE and fluorescence detection or coupled with high-resolution time-of-flight mass spectrometry.

PubMed

Lintelmann, Jutta; Wu, Xiao; Kuhn, Evelyn; Ritter, Sebastian; Schmidt, Claudia; Zimmermann, Ralf

2018-05-01

A high-performance liquid chromatographic (HPLC) method with integrated solid-phase extraction for the determination of 1-hydroxypyrene and 1-, 2-, 3-, 4- and 9-hydroxyphenanthrene in urine was developed and validated. After enzymatic treatment and centrifugation of 500 μL urine, 100 μL of the sample was directly injected into the HPLC system. Integrated solid-phase extraction was performed on a selective, copper phthalocyanine modified packing material. Subsequent chromatographic separation was achieved on a pentafluorophenyl core-shell column using a methanol gradient. For quantification, time-programmed fluorescence detection was used. Matrix-dependent recoveries were between 94.8 and 102.4%, repeatability and reproducibility ranged from 2.2 to 17.9% and detection limits lay between 2.6 and 13.6 ng/L urine. A set of 16 samples from normally exposed adults was analyzed using this HPLC-fluorescence detection method. Results were comparable with those reported in other studies. The chromatographic separation of the method was transferred to an ultra-high-performance liquid chromatography pentafluorophenyl core-shell column and coupled to a high-resolution time-of-flight mass spectrometer (HR-TOF-MS). The resulting method was used to demonstrate the applicability of LC-HR-TOF-MS for simultaneous target and suspect screening of monohydroxylated polycyclic aromatic hydrocarbons in extracts of urine and particulate matter. Copyright © 2018 John Wiley & Sons, Ltd.

A confirmatory method for the simultaneous extraction, separation, identification and quantification of Tetracycline, Sulphonamide, Trimethoprim and Dapsone residues in muscle by ultra-high-performance liquid chromatography-tandem mass spectrometry according to Commission Decision 2002/657/EC.

PubMed

McDonald, Mark; Mannion, Celine; Rafter, Paul

2009-11-13

A rapid confirmatory multi-residue method for the analysis of tetracyclines, sulphonamides, trimethoprim and dapsone by UPLC-MS/MS is described. The method is able to quantify and confirm the following 19 compounds, oxytetracycline, tetracycline, chlortetracycline, doxycycline, sulfadiazine, sulfathiazole, sulfapyridine, trimethoprim, sulfamerazine, sulfamethizole, sulfamethazine, sulfamethoxypyridazine, sulfamonomethoxine, sulfachlorpyridazine, dapsone, sulfamethoxazole, sulfisoxazole, sulfaquinoxaline and sulfadimethoxine. Samples are extracted with 0.1M EDTA and acetonitrile, which is then evaporated under a stream of nitrogen and reconstituted in water. Following centrifugation and filtering, an aliquot is analysed by UPLC-MS/MS using positive electrospray ionisation and multiple reaction monitoring. The method is deemed rapid as all analytes are extracted by a single extraction technique, with no solid-phase extraction clean up required. Validation is according to Commission Decision 2002/657/EC and was carried out for bovine, porcine, ovine and poultry species. Specificity, recovery, repeatability, reproducibility, CCalpha and CCbeta data is presented.

Miniaturized sample preparation needle: a versatile design for the rapid analysis of smoking-related compounds in hair and air samples.

PubMed

Saito, Yoshihiro; Ueta, Ikuo; Ogawa, Mitsuhiro; Hayashida, Makiko; Jinno, Kiyokatsu

2007-05-09

Miniaturized needle extraction device has been developed as a versatile sample preparation device designed for the rapid and simple analysis of smoking-related compounds in smokers' hair samples and environmental tobacco smoke. Packed with polymeric particle, the resulting particle-packed needle was employed as a miniaturized sample preparation device for the analysis of typical volatile organic compounds in tobacco smoke. Introducing a bundle of polymer-coated filaments as the extraction medium, the needle was further applied as a novel sample preparation device containing simultaneous derivatization/extraction process of volatile aldehydes. Formaldehyde (FA) and acetaldehyde (AA) in smoker's breath during the smoking were successfully derivatized with two derivatization reagents in the polymer-coated fiber-packed needle device followed by the separation and determination in gas chromatography (GC). Smokers' hair samples were also packed into the needle, allowing the direct extraction of nicotine from the hair sample in a conventional GC injector. Optimizing the main experimental parameters for each technique, successful determination of several smoking-related compounds with these needle extraction methods has been demonstrated.

Simultaneous quantitation of 14 active components in Yinchenhao decoction by using ultra high performance liquid chromatography with diode array detection: Method development and ingredient analysis of different commonly prepared samples.

PubMed

Yi, YaXiong; Zhang, Yong; Ding, Yue; Lu, Lu; Zhang, Tong; Zhao, Yuan; Xu, XiaoJun; Zhang, YuXin

2016-11-01

We developed a novel quantitative analysis method based on ultra high performance liquid chromatography coupled with diode array detection for the simultaneous determination of the 14 main active components in Yinchenhao decoction. All components were separated on an Agilent SB-C18 column by using a gradient solvent system of acetonitrile/0.1% phosphoric acid solution at a flow rate of 0.4 mL/min for 35 min. Subsequently, linearity, precision, repeatability, and accuracy tests were implemented to validate the method. Furthermore, the method has been applied for compositional difference analysis of 14 components in eight normal-extraction Yinchenhao decoction samples, accompanied by hierarchical clustering analysis and similarity analysis. The result that all samples were divided into three groups based on different contents of components demonstrated that extraction methods of decocting, refluxing, ultrasonication and extraction solvents of water or ethanol affected component differentiation, and should be related to its clinical applications. The results also indicated that the sample prepared by patients in the family by using water extraction employing a casserole was almost same to that prepared using a stainless-steel kettle, which is mostly used in pharmaceutical factories. This research would help patients to select the best and most convenient method for preparing Yinchenhao decoction. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous determination of limonin, dictamnine, obacunone and fraxinellone in rat plasma by a validated UHPLC-MS/MS and its application to a pharmacokinetic study after oral administration of Cortex Dictamni extract.

PubMed

Wang, Pei; Sun, Jianbo; Gao, Enze; Zhao, Yunli; Qu, Wei; Yu, Zhiguo

2013-06-01

A rapid and selective ultra high performance liquid chromatography-tandem mass spectrometry method was developed for the simultaneous determination of four major ingredients in Cortex Dictamni extract, including limonin, dictamnine, obacunone and fraxinellone in rats plasma. Nimodipine was used as the internal standard. Following extraction by methyl tert-butyl ether, the analytes were separated on a Thermo Syncronis C18 column by a gradient elution within a runtime of 9min. The mobile phase consisted of A (methanol) and B (2mmol/L ammonium acetate in water). The detection was accomplished by using positive ion electrospray ionization in multiple reaction monitoring mode. The method was linear for all analytes over investigated range with all correlation coefficients greater than 0.998. The lower limits of quantification were 9.18ng/mL for limonin, 12.0ng/mL for dictamnine, 16.05ng/mL for obacunone and 4.59ng/mL for fraxinellone. The intra- and inter-day precision (RSD%) was within 10% and the accuracy (RE%) ranged from -12.9% to 9.7%. This rapid and sensitive method was fully validated and successfully applied to the pharmacokinetic study of limonin, dictamnine, obacunone and fraxinellone in the rat plasma after oral administration of Cortex Dictamni extract. Copyright © 2013 Elsevier B.V. All rights reserved.

Simultaneous determination of all polyphenols in vegetables, fruits, and teas.

PubMed

Sakakibara, Hiroyuki; Honda, Yoshinori; Nakagawa, Satoshi; Ashida, Hitoshi; Kanazawa, Kazuki

2003-01-29

Polyphenols, which have beneficial effects on health and occur ubiquitously in plant foods, are extremely diverse. We developed a method for simultaneously determining all the polyphenols in foodstuffs, using HPLC and a photodiode array to construct a library comprising retention times, spectra of aglycons, and respective calibration curves for 100 standard chemicals. The food was homogenized in liquid nitrogen, lyophilized, extracted with 90% methanol, and subjected to HPLC without hydrolysis. The recovery was 68-92%, and the variation in reproducibility ranged between 1 and 9%. The HPLC eluted polyphenols with good resolution within 95 min in the following order: simple polyphenols, catechins, anthocyanins, glycosides of flavones, flavonols, isoflavones and flavanones, their aglycons, anthraquinones, chalcones, and theaflavins. All the polyphenols in 63 vegetables, fruits, and teas were then examined in terms of content and class. The present method offers accuracy by avoiding the decomposition of polyphenols during hydrolysis, the ability to determine aglycons separately from glycosides, and information on simple polyphenol levels simultaneously.

A new method for quantifying the performance of EEG blind source separation algorithms by referencing a simultaneously recorded ECoG signal.

PubMed

Oosugi, Naoya; Kitajo, Keiichi; Hasegawa, Naomi; Nagasaka, Yasuo; Okanoya, Kazuo; Fujii, Naotaka

2017-09-01

Blind source separation (BSS) algorithms extract neural signals from electroencephalography (EEG) data. However, it is difficult to quantify source separation performance because there is no criterion to dissociate neural signals and noise in EEG signals. This study develops a method for evaluating BSS performance. The idea is neural signals in EEG can be estimated by comparison with simultaneously measured electrocorticography (ECoG). Because the ECoG electrodes cover the majority of the lateral cortical surface and should capture most of the original neural sources in the EEG signals. We measured real EEG and ECoG data and developed an algorithm for evaluating BSS performance. First, EEG signals are separated into EEG components using the BSS algorithm. Second, the EEG components are ranked using the correlation coefficients of the ECoG regression and the components are grouped into subsets based on their ranks. Third, canonical correlation analysis estimates how much information is shared between the subsets of the EEG components and the ECoG signals. We used our algorithm to compare the performance of BSS algorithms (PCA, AMUSE, SOBI, JADE, fastICA) via the EEG and ECoG data of anesthetized nonhuman primates. The results (Best case >JADE = fastICA >AMUSE = SOBI ≥ PCA >random separation) were common to the two subjects. To encourage the further development of better BSS algorithms, our EEG and ECoG data are available on our Web site (http://neurotycho.org/) as a common testing platform. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Steam distillation/drop-by-drop extraction with gas chromatography-mass spectrometry for fast determination of volatile components in jujube (Ziziphus jujuba Mill.) extract.

PubMed

Sun, Shi-Hao; Chai, Guo-Bi; Li, Peng; Xie, Jian-Ping; Su, Yue

2017-10-13

Jujube extract is commonly used as a food additive and flavoring. The unique jujube aroma and the mild sweet aroma of the extract are critical factors that determine product quality and affect consumer acceptability. The aroma changes with changes in the extraction condition, which is typically dependent on the characteristics of volatile oils in the extract. Despite their importance, the volatile oils of jujube extract have received less attention compared with the soluble components. So, an appropriate qualitative and quantitative method for determination of the volatile oils is vitally important for quality control of the product. A method coupling steam distillation/drop-by-drop extraction with gas chromatography-mass spectrometry (S3DE/GC-MS) was developed to determine the volatile components of jujube extract. Steam distillation was coupled with solvent extraction; the resulting condensate containing volatile components from jujube extract was drop-by-drop extracted using 2 mL of methyl tertiary butyl ether. The solvent served two purposes. First, the solvent extracted the volatile components from the condensate. Second, the volatile components were pre-concentrated by drop-by-drop accumulation in the solvent. As a result, the extraction, separation, and concentration of analytes in the sample were simultaneously completed in one step. The main parameters affecting the S3DE procedure, such as the water steam bubbling rate, extraction solvent volume, sample weight and S3DE time, were optimized. The standard addition approach was essential to obtain accurate measurements by minimizing matrix effects. Good linearity (R 2  ≥ 0.9887) and good repeatability (RSDs ≤ 10.35%, n = 5) for 16 analytes in spiked standard analyte samples were achieved. With the S3DE/GC-MS method, seventy-six volatile compounds from jujube extract were identified and the content of 16 compounds was measured. The results were similar to those from simultaneous distillation extraction. The developed method was simple, fast, effective, sensitive, and provided an overall profile of the volatile components in jujube extract. Thus, this method can be used to determine the volatile components of extracts. Graphical abstract The diagram of steam distillation/drop-by-drop extraction device.

Tannase-mediated biotransformation assisted separation and purification of theaflavin and epigallocatechin by high speed counter current chromatography and preparative high performance liquid chromatography: A comparative study.

PubMed

Xia, Guobin; Lin, Chunfang; Liu, Songbai

2016-09-01

A large scale isolation and purification of theaflavin (TF) and epigallocatechin (EGC) has been successfully developed by tannase-mediated biotransformation combining high-speed countercurrent chromatography. After tannase hydrolysis of a commercially available theaflavins extract (TE), the content of TF and EGC in tannase-mediated biotransformation product (TBP) achieved approximately 3 times enrichment. SEM studies revealed smooth tannase biotransformation and the possibility of recovery of the tannase. A single 1.5 hours' HSCCC separation for TF and EGC employing a two-phase solvent system could simultaneously produce 180.8 mg of 97.3% purity TF and 87.5 mg of 97.3% purity EGC. However, a preparative HPLC separation of maximum injection volume containing 120 mg TBP prepared 11.2 mg TF of 94.9% purity and 7.7 mg EGC of 89.9% purity. HSCCC separation demonstrated significant advantages over Prep HPLC in terms of sample loading size, separation time, environmental friendly solvent systems, and the production. © 2016 Wiley Periodicals, Inc.

Design for simultaneous acceleration of stable and unstable beams in a superconducting heavy-ion linear accelerator for RISP

NASA Astrophysics Data System (ADS)

Kim, Jongwon; Son, Hyock-Jun; Park, Young-Ho

2017-11-01

The post-accelerator of isotope separation on-line (ISOL) system for rare isotope science project (RISP) is a superconducting linear accelerator (SC-linac) with a DC equivalent voltage of around 160 MV. An isotope beam extracted from the ISOL is in a charge state of 1+ and its charge state is increased to n+ by charge breeding with an electron beam ion source (EBIS). The charge breeding takes tens of ms and the pulse width of extracted beam from the EBIS is tens of μs, which operates at up to 30 Hz. Consequently a large portion of radio frequency (rf) time of the post SC-linac is unused. The post-linac is equipped also with an electron cyclotron resonance (ECR) ion source for stable ion acceleration. Thanks to the large phase acceptance of SC-linac, it is possible to accelerate simultaneously both stable and radioisotope ions with a similar charge to mass ratio by sharing rf time. This operation scheme is implemented for RISP with the addition of an electric chopper and magnetic kickers. The facility will be capable of providing the users of the ISOL and in-flight fragmentation (IF) systems with different beams simultaneously, which would help nuclear science users in obtaining a beam time as high-precision measurements often need long hours.

Rapid simultaneous determination of amines and organic acids in citrus using high-performance liquid chromatography.

PubMed

Uckoo, Ram M; Jayaprakasha, Guddadarangavvanahally K; Nelson, Shad D; Patil, Bhimanagouda S

2011-01-15

Rapid analytical method for the simultaneous separation and determination of amines and organic acids is a vital interest for quality control of citrus and their products. In the present study, a simultaneous high performance liquid chromatography (HPLC) method for the rapid separation of three amines and two organic acids was developed. Chromatographic separation of compounds was achieved using Xbridge C(18) column at ambient temperature, with an isocratic mobile phase of 3mM phosphoric acid at a flow rate of 1.0 mL min(-1). A photodiode array (PDA) detector was used to monitor the eluent at 223 nm and 254 nm with a total analysis time of 10 min. Extraction of amines and organic acids from citrus juice was optimized. The method was validated by tests of linearity, recovery, precision and ruggedness. The limit of detection (LOD) and limit of quantification (LOQ) for amines and ascorbic acid were determined to be 5 ng and 9.8 ng, respectively. All calibration curves showed good linearity (R(2) ≥ 0.9999) within the test ranges. The recoveries of the amines and organic acids ranged between 84% and 117%. The identity of each peak was confirmed by mass spectral (MS) analysis. The developed method was successfully applied to analyze the content of amines and organic acids in six different species and two varieties of citrus. Results indicate that mandarin and Marrs sweet orange contain high level of amines, while pummelo and Rio Red grapefruit had high content of ascorbic acid (137-251 μg mL(-1)) and citric acid (5-22 mg mL(-1)). Synephrine was the major amine present in Clementine (114 μg mL(-1)) and Marrs sweet orange (85 μg mL(-1)). To the best of our knowledge, this is the first report on simultaneous separation and quantification of amines and organic acids in Marrs sweet orange, Meyer lemon, Nova tangerine, Clementine, Ugli tangelo and Wekiwa tangelo. Copyright © 2010 Elsevier B.V. All rights reserved.

Quantitative analysis of the major constituents of St John's wort with HPLC-ESI-MS.

PubMed

Chandrasekera, Dhammitha H; Welham, Kevin J; Ashton, David; Middleton, Richard; Heinrich, Michael

2005-12-01

A method was developed to profile the major constituents of St John's wort extracts using high-performance liquid chromatography-electrospray mass spectrometry (HPLC-ESI-MS). The objective was to simultaneously separate, identify and quantify hyperforin, hypericin, pseudohypericin, rutin, hyperoside, isoquercetrin, quercitrin and chlorogenic acid using HPLC-MS. Quantification was performed using an external standardisation method with reference standards. The method consisted of two protocols: one for the analysis of flavonoids and glycosides and the other for the analysis of the more lipophilic hypericins and hyperforin. Both protocols used a reverse phase Luna phenyl hexyl column. The separation of the flavonoids and glycosides was achieved within 35 min and that of the hypericins and hyperforin within 9 min. The linear response range in ESI-MS was established for each compound and all had linear regression coefficient values greater than 0.97. Both protocols proved to be very specific for the constituents analysed. MS analysis showed no other signals within the analyte peaks. The method was robust and applicable to alcoholic tinctures, tablet/capsule extracts in various solvents and herb extracts. The method was applied to evaluate the phytopharmaceutical quality of St John's wort preparations available in the UK in order to test the method and investigate if they contain at least the main constituents and at what concentrations.

Study on Dicarboxylic Acids in Aerosol Samples with Capillary Electrophoresis

PubMed Central

Adler, Heidi; Sirén, Heli

2014-01-01

The research was performed to study the simultaneous detection of a homologous series of α, ω-dicarboxylic acids (C2–C10), oxalic, malonic, succinic, glutaric, adipic, pimelic, suberic, azelaic, and sebacic acids, with capillary electrophoresis using indirect UV detection. Good separation efficiency in 2,6-pyridinedicarboxylic acid as background electrolyte modified with myristyl trimethyl ammonium bromide was obtained. The dicarboxylic acids were ionised and separated within five minutes. For the study, authentic samples were collected onto dry cellulose membrane filters of a cascade impactor (12 stages) from outdoor spring aerosols in an urban area. Hot water and ultrasonication extraction methods were used to isolate the acids from membrane filters. Due to the low concentrations of acids in the aerosols, the extracts were concentrated with solid-phase extraction (SPE) before determination. The enrichment of the carboxylic acids was between 86 and 134% with sample pretreatment followed by 100-time increase by preparation of the sample to 50 μL. Inaccuracy was optimised for all the sample processing steps. The aerosols contained dicarboxylic acids C2–C10. Then, mostly they contained C2, C5, and C10. Only one sample contained succinic acid. In the study, the concentrations of the acids in aerosols were lower than 10 ng/m3. PMID:24729915

Simultaneous quantitation and identification of organic and inorganic selenium in diet supplements by liquid chromatography with tandem mass spectrometry.

PubMed

Zembrzuska, Joanna; Matusiewicz, Henryk; Polkowska-Motrenko, Halina; Chajduk, Ewelina

2014-01-01

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for selenium speciation in dietary supplements. Chromatographic separation was performed on a TSK-Gel ODS-100V column using a mixture of 5mM ammonium acetate water solution and methanol as a mobile phase. Conditions chosen for this process allowed to separate all investigated chemical compounds of selenium: seleno-l-methionine, methyl-seleno-l-cysteine, l-selenocystine, methaneseleninic acid, selenite and selenate. A tandem mass spectrometer with an ion trap operating in negative or positive ion mode according to the selenium form being determined was used as a detector. Three extraction procedures: water extraction, enzymatic hydrolysis and sequential extraction were used for preparation of samples for the determination of the actual forms of selenium in diet supplements. The developed method was used for analysis of six dietary supplements containing selenium bought in a pharmacy and supermarket. Apart from speciation analysis of selenium content in supplements total selenium content was determined using instrumental neutron activation analysis (INAA). All expected forms of selenium except for selenite were determined using LC-MS/MS technique. It should be stressed that amounts of selenate were smaller than expected. Copyright © 2013 Elsevier Ltd. All rights reserved.

Pressurized liquid extraction combined with capillary electrophoresis-mass spectrometry as an improved methodology for the determination of sulfonamide residues in meat.

PubMed

Font, Guillermina; Juan-García, Ana; Picó, Yolanda

2007-08-03

A new analytical method, based on capillary electrophoresis and tandem mass spectrometry (CE-MS2), is proposed and validated for the identification and simultaneous quantification of 12 sulfonamides (SAs) in pork meat. The studied SAs include sulfathiazole, sulfadiazine, sulfamethoxypyridazine, sulfaguanidine, sulfanilamide, sulfadimethoxyne, sulfapyridine, sulfachloropyridazine, sulfisoxazole, sulfasalazine, sulfabenzamide and sulfadimidine. Different parameters (i.e. separation buffer, sheath liquid, electrospray conditions) were optimized to obtain an adequate CE separation and high MS sensitivity. MS2 experiments using an ion trap as analyzer, operating in the selected reaction monitoring (SRM) mode, were carried out to achieve the required number of identification points according to the 2002/657/EC European Decision. For the quantification in pork tissue samples, a pressurized liquid extraction (PLE) procedure, using hot water as extractant followed by an Oasis HLB cleanup, was developed. Linearity (r between 0.996 and 0.997), precision (RSD<14 %) and recoveries (from 76 to 98%) were satisfactory. The limits of detection and quantification (below 12.5 and 46.5 microg kg(-1), respectively) were in all cases lower than the maximum residue limits (MRLs), indicating the potential of CE-MS2 for the analysis of SAs, in the food quality and safety control areas.

Simultaneous determination of gaseous and particulate carbonyls in air by coupling micellar electrokinetic capillary chromatography with molecular imprinting solid-phase extraction.

PubMed

Sun, Hui; Lai, Jia-Ping; Fung, Ying Sing

2014-09-05

A novel method coupling molecular imprinting solid-phase extraction (MISPE) and micellar electrokinetic capillary chromatography (MEKC) was developed to enable the hourly determination of low level of ambient carbonyls, and study their partition between gaseous phase and particulate phase. With 2,4-dinitroaniline (DNAN) as dummy imprinting template, the unreacted 2,4-Dinitrophenylhydrazine (DNPH) in sampling solution could be removed effectively using MISPE, and an average recovery of 97±5.3% (n=5) for the carbonyl-DNPH derivatives was achieved. Owing to the high enrichment due to sample clean-up, and the improvement of MEKC separation efficiency, many low abundant carbonyls could be detected by hourly in the field study. Copyright © 2014 Elsevier B.V. All rights reserved.

Simultaneous quantification of four native estrogen hormones at trace levels in human cerebrospinal fluid using liquid chromatography-tandem mass spectrometry.

PubMed

Nguyen, Hien P; Li, Li; Gatson, Joshua W; Maass, David; Wigginton, Jane G; Simpkins, James W; Schug, Kevin A

2011-03-25

Estrogens are known to exhibit neuroprotective effects on the brain. Their importance in this regard and in others has been emphasized in many recent studies, which increases the need to develop reliable analytical methods for the measurement of estrogen hormones. A heart-cutting two-dimensional liquid chromatography separation method coupled with electrospray ionization-tandem mass spectrometry (ESI-MS/MS) has been developed for simultaneous measurement of four estrogens, including estriol (E3), estrone (E1), 17β-estradiol (17β-E2), and 17α-estradiol (17α-E2), in human cerebrospinal fluid (CSF). The method was based on liquid-liquid extraction and derivatization of estrogens with dansyl chloride to enhance the sensitivity of ESI-based detection in conjunction with tandem mass spectrometry. Dansylated estriol and estrone were separated in the first dimension by an amide-C18 column, while dansylated 17β- and 17α-estradiol were resolved on the second dimension by two C18 columns (175 mm total length) connected in series. This is the first report of a method for simultaneous quantification of all four endogenous estrogen compounds in their dansylated form. The detection limits for E1, 17α-E2, 17β-E2, and E3 were 19, 35, 26, and 61pg/mL, respectively. Due to matrix effects, validation and calibration was carried out in charcoal-stripped CSF. The precision and accuracy were more than 86% for the two E2 compounds and 79% for E1 and E3 while the extraction recovery ranged from 91% to 104%. The method was applied to measure estrogens obtained in a clinical setting, from the CSF of ischemic trauma patients. While 17β-estradiol was present at a significant level in the CSF of some samples, other estrogens were present at lower levels or were undetectable. Copyright © 2010 Elsevier B.V. All rights reserved.

High-performance liquid chromatography coupled with post-column dual-bioactivity assay for simultaneous screening of xanthine oxidase inhibitors and free radical scavengers from complex mixture.

PubMed

Li, D Q; Zhao, J; Li, S P

2014-06-06

Xanthine oxidase (XO) can catalyze hypoxanthine and xanthine to generate uric acid and reactive oxygen species (ROS), including superoxide anion radical (O₂(•-)) and hydrogen peroxide. XO inhibitors and free radical scavengers are beneficial to the treatment of gout and many related diseases. In the present study, an on-line high-performance liquid chromatography (HPLC) coupled with post-column dual-bioactivity assay was established and successfully applied to simultaneously screening of XO inhibitors and free radical scavengers from a complex mixture, Oroxylum indicum extract. The integrated system of HPLC separation, bioactivity screening and mass spectrometry identification was proved to be simple and effective for rapid and sensitive screening of individual bioactive compounds in complex mixtures. Copyright © 2014 Elsevier B.V. All rights reserved.

Simultaneous determination of ornidazole and its main metabolites in human plasma by LC-MS/MS: application to a pharmacokinetic study.

PubMed

Du, Jiangbo; Ma, Zhiyu; Zhang, Yifan; Wang, Ting; Chen, Xiaoyan; Zhong, Dafang

2014-09-01

Ornidazole is a 5-nitroimidazole antimicrobial agent used for almost 40 years. A novel LC-MS/MS assay was developed and validated for the simultaneous determination of ornidazole and its main metabolites (M3, M6, M16-1, and M16-2) in human plasma. After extraction from 100 μl of plasma by protein precipitation with acetonitrile, all the analytes were separated on a Capcell PAK MG C18 column (100 × 4.6 mm, 5 μm) within 5.0 min and detected by ESI-MS/MS in the positive mode. The validation results met the acceptance criteria as per the US FDA and EMA guidelines. The validated method was successfully applied to a pharmacokinetic study after oral administration of 1000 mg ornidazole to six healthy Chinese volunteers.

Optimization of Microwave-Assisted Extraction Conditions for Five Major Bioactive Compounds from Flos Sophorae Immaturus (Cultivars of Sophora japonica L.) Using Response Surface Methodology.

PubMed

Liu, Jin-Liang; Li, Long-Yun; He, Guang-Hua

2016-03-02

Microwave-assisted extraction was applied to extract rutin; quercetin; genistein; kaempferol; and isorhamnetin from Flos Sophorae Immaturus. Six independent variables; namely; solvent type; particle size; extraction frequency; liquid-to-solid ratio; microwave power; and extraction time were examined. Response surface methodology using a central composite design was employed to optimize experimental conditions (liquid-to-solid ratio; microwave power; and extraction time) based on the results of single factor tests to extract the five major components in Flos Sophorae Immaturus. Experimental data were fitted to a second-order polynomial equation using multiple regression analysis. Data were also analyzed using appropriate statistical methods. Optimal extraction conditions were as follows: extraction solvent; 100% methanol; particle size; 100 mesh; extraction frequency; 1; liquid-to-solid ratio; 50:1; microwave power; 287 W; and extraction time; 80 s. A rapid and sensitive ultra-high performance liquid chromatography method coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (EIS-Q-TOF MS/MS) was developed and validated for the simultaneous determination of rutin; quercetin; genistein; kaempferol; and isorhamnetin in Flos Sophorae Immaturus. Chromatographic separation was accomplished on a Kinetex C18 column (100 mm × 2.1 mm; 2.6 μm) at 40 °C within 5 min. The mobile phase consisted of 0.1% aqueous formic acid and acetonitrile (71:29; v/v). Isocratic elution was carried out at a flow rate of 0.35 mL/min. The constituents of Flos Sophorae Immaturus were simultaneously identified by EIS-Q-TOF MS/MS in multiple reaction monitoring mode. During quantitative analysis; all of the calibration curves showed good linear relationships (R² > 0.999) within the tested ranges; and mean recoveries ranged from 96.0216% to 101.0601%. The precision determined through intra- and inter-day studies showed an RSD% of <2.833%. These results demonstrate that the developed method is accurate and effective and could be readily utilized for the comprehensive quality control of Flos Sophorae Immaturus.

Simultaneous determination of free and total glycerol in biodiesel by capillary electrophoresis using multiple short-end injection.

PubMed

Spudeit, Daniel Alfonso; Piovezan, Marcel; Dolzan, Maressa D; Vistuba, Jacqueline Pereira; Azevedo, Mônia Stremel; Vitali, Luciano; Leal Oliveira, Marcone Augusto; Oliveira Costa, Ana Carolina; Micke, Gustavo Amadeu

2013-12-01

A rapid method for the simultaneous determination of free glycerol (FG) and total glycerol (TG) in biodiesel by CE using a short-end multiple injection (SE/MI) configuration system is described. The sample preparation for FG involves the extraction of glycerol with water and for TG a saponification reaction is carried out followed by extraction as in the case of FG. The glycerol extracted in both cases is submitted to periodate oxidation and the iodate ions formed are measured on a CE-SE/MI system. The relevance of this study lies in the fact that no analytical procedure has been previously reported for the determination of TG (or of FG and TG simultaneously) by CE. The optimum conditions for the saponification/extraction process were 1.25% KOH and 25°C, with a time of only 5 min, and biodiesel mass in the range of 50.0-200.0 mg can be used. Multiple injections were performed hydrodynamically with negative pressure as follows: 50 mbar/3s (FG sample); 50 mbar/6s (electrolyte spacer); 50 mbar/3s (TG sample). The linear range obtained was 1.55-46.5 mg/L with R(2) > 0.99. The LOD and LOQ were 0.16 mg/L and 0.47 mg/L, respectively for TG. The method provides acceptable throughput for application in quality control and monitoring biodiesel synthesis process. In addition, it offers simple sample preparation (saponification process), it can be applied to a variety biodiesel samples (soybean, castor, and waste cooking oils) and it can be used for the determination of two key parameters related to the biodiesel quality with a fast separation (less than 30 s) using an optimized CE-SE/MI system. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous quantification of 25 active constituents in the total flavonoids extract from Herba Desmodii Styracifolii by high-performance liquid chromatography with electrospray ionization tandem mass spectrometry.

PubMed

Guo, Panpan; Yan, Wenying; Han, Qingjie; Wang, Chunying; Zhang, Zijian

2015-04-01

A sensitive and selective high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry method has been developed and validated for the simultaneous determination of 25 active constituents, including 21 flavonoids and four phenolic acids in the total flavonoids extract from Herba Desmodii Styracifolii for the first time. Among the 25 compounds, seven compounds including caffeic acid, acacetin, genistein, genistin, diosmetin, diosmin and hesperidin were identified and quantified for the first time in Herba Desmodii Styracifolii. Chromatographic separation was accomplished on a ZORBAX SB-C18 (250 mm×4.6 mm, 5.0 μm) column using gradient elution of methanol and 0.1‰ acetic acid v/v at a flow rate of 1.0 mL/min. The identification and quantification of the analytes were achieved using negative electrospray ionization mass spectrometry in multiple-reaction monitoring mode. The method was fully validated in terms of limits of detection and quantification, linearity, precision and accuracy. The results indicated that the developed method is simple, rapid, specific and reliable. Furthermore, the developed method was successfully applied to quantify the 25 active components in six batches of total flavonoids extract from Herba Desmodii Styracifolii. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rapid determination of anti-estrogens by gas chromatography/mass spectrometry in urine: Method validation and application to real samples.

PubMed

Gerace, E; Salomone, A; Abbadessa, G; Racca, S; Vincenti, M

2012-02-01

A fast screening protocol was developed for the simultaneous determination of nine anti-estrogenic agents (aminoglutethimide, anastrozole, clomiphene, drostanolone, formestane, letrozole, mesterolone, tamoxifen, testolactone) plus five of their metabolites in human urine. After an enzymatic hydrolysis, these compounds can be extracted simultaneously from urine with a simple liquid-liquid extraction at alkaline conditions. The analytes were subsequently analyzed by fast-gas chromatography/mass spectrometry (fast-GC/MS) after derivatization. The use of a short column, high-flow carrier gas velocity and fast temperature ramping produced an efficient separation of all analytes in about 4 min, allowing a processing rate of 10 samples/h. The present analytical method was validated according to UNI EN ISO/IEC 17025 guidelines for qualitative methods. The range of investigated parameters included the limit of detection, selectivity, linearity, repeatability, robustness and extraction efficiency. High MS-sampling rate, using a benchtop quadrupole mass analyzer, resulted in accurate peak shape definition under both scan and selected ion monitoring modes, and high sensitivity in the latter mode. Therefore, the performances of the method are comparable to the ones obtainable from traditional GC/MS analysis. The method was successfully tested on real samples arising from clinical treatments of hospitalized patients and could profitably be used for clinical studies on anti-estrogenic drug administration.

Rapid determination of anti-estrogens by gas chromatography/mass spectrometry in urine: Method validation and application to real samples

PubMed Central

Gerace, E.; Salomone, A.; Abbadessa, G.; Racca, S.; Vincenti, M.

2011-01-01

A fast screening protocol was developed for the simultaneous determination of nine anti-estrogenic agents (aminoglutethimide, anastrozole, clomiphene, drostanolone, formestane, letrozole, mesterolone, tamoxifen, testolactone) plus five of their metabolites in human urine. After an enzymatic hydrolysis, these compounds can be extracted simultaneously from urine with a simple liquid–liquid extraction at alkaline conditions. The analytes were subsequently analyzed by fast-gas chromatography/mass spectrometry (fast-GC/MS) after derivatization. The use of a short column, high-flow carrier gas velocity and fast temperature ramping produced an efficient separation of all analytes in about 4 min, allowing a processing rate of 10 samples/h. The present analytical method was validated according to UNI EN ISO/IEC 17025 guidelines for qualitative methods. The range of investigated parameters included the limit of detection, selectivity, linearity, repeatability, robustness and extraction efficiency. High MS-sampling rate, using a benchtop quadrupole mass analyzer, resulted in accurate peak shape definition under both scan and selected ion monitoring modes, and high sensitivity in the latter mode. Therefore, the performances of the method are comparable to the ones obtainable from traditional GC/MS analysis. The method was successfully tested on real samples arising from clinical treatments of hospitalized patients and could profitably be used for clinical studies on anti-estrogenic drug administration. PMID:29403714

A quantitative LC-MS/MS method for simultaneous determination of cocaine and its metabolites in whole blood

PubMed Central

Chen, Xiabin; Zheng, Xirong; Ding, Kai; Zhou, Ziyuan; Zhan, Chang-Guo; Zheng, Fang

2016-01-01

As new metabolic pathways of cocaine were recently identified, a high performance liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed to simultaneously determine cocaine and nine cocaine-related metabolites in whole blood samples. One-step solid phase extraction was used to extract all of the ten compounds and corresponding internal standards from blood samples. All compounds and internal standards extracted were separated on an Atlantis T3 (100Å, 3 µm, 2.1 mm × 150 mm I.D) column and detected in positive ion and high sensitivity mode with multiple reaction monitoring. This method was validated for its sensitivity, linearity, specificity, accuracy, precision, recovery, and stability. All of the ten compounds were quantifiable ranging from the lower limit of quantification (LLOQs) of ~10 nM (1.9–3.2 ng/ml) to ~1000 nM (190–320 ng/ml) without any interfering substance. Accuracy and precision were determined, and both of them were within the acceptance criteria of the United States (US) Food and Drug Administration (FDA) and European Medicines Agency (EMA) guidelines. The recovery was above 66.7% for all compounds. Stability tests demonstrated the stability of compounds under different storage conditions in whole blood samples. The method was successfully applied to a pharmacokinetic study with co-administration of cocaine and alcohol in rats. PMID:27923200

Validated high-performance liquid chromatographic method utilizing solid-phase extraction for the simultaneous determination of naringenin and hesperetin in human plasma.

PubMed

Kanaze, Feras Imad; Kokkalou, Eugene; Georgarakis, Manolis; Niopas, Ioannis

2004-03-05

Naringenin and hesperetin, the aglycones of the flavanone glucosides naringin and hesperidin occur naturally in citrus fruits. They exert a variety of pharmacological effects such as antioxidant, blood lipid-lowering, anticarcinogenic and inhibit selected cytochrome P-450 enzymes resulting in drug interactions. A specific, sensitive, precise, and accurate solid-phase extraction high-performance liquid chromatographic (HPLC) assay for the simultaneous determination of naringenin and hesperetin in human plasma was developed and validated. After addition of 7-ethoxycoumarin as internal standard, plasma samples were incubated with beta-glucuronidase/sulphatase, and the analytes were isolated from plasma by solid-phase extraction using C(18) cartridges and separated on a C(8) reversed phase column with methanol/water/acetic acid (40:58:2, v/v/v) as the eluent at 45 degrees C. The method was linear in the 10-300 ng/ml concentration range for both naringenin and hesperetin (r>0.999). Recovery for naringenin, hesperetin and internal standard was greater than 76.7%. Intra- and inter-day precision for naringenin ranged from 1.4 to 4.2% and from 1.9 to 5.2%, respectively, and for hesperetin ranged from 1.3 to 4.1% and from 1.7 to 5.1%, respectively. Accuracy was better than 91.5 and 91.3% for naringenin and hesperetin, respectively.

A novel ultra high-performance liquid chromatography-tandem mass spectrometry method for the simultaneous determination of xanthones and steroidal saponins in crude and salt-processed Anemarrhenae Rhizoma aqueous extracts.

PubMed

Ji, De; Su, Xiaonan; Huang, Ziyan; Wang, Qiaohan; Lu, Tulin

2018-06-01

We established a rapid and sensitive ultra high-performance liquid chromatography tandem mass spectrometry method for the simultaneous quantification of xanthones and steroidal saponins in rat plasma. Chromatographic separation was achieved on a C 18 column with a mobile phase comprising acetonitrile and 0.1% formic acid. The detection was performed by negative electrospray ionization in multiple reaction monitoring mode. The validated method showed good linearity within the tested range (r > 0.9945). The intra- and interday precision at high, medium, and low concentrations was less than 7.96%. The bias of accuracies ranged from -1.92 to 9.62%. The extraction recoveries of the compounds ranged from 84.78 to 88.69%, and the matrix effects ranged from 96.76 to 108.59%. This method was successfully applied to a pharmacokinetic comparison of crude and salt-processed Anemarrhenae Rhizoma aqueous extracts after oral administration in rats. The maximum plasma concentration and area under concentration-time curve of timosaponin BIII and timosaponin AIII increased significantly (P < 0.05 or 0.01) and those of timosaponin BII decreased significantly (P < 0.05) after processing. These results could contribute to the clinical application of crude and salt-processed Anemarrhenae Rhizoma and reveal the processing mechanism. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous determination of 3-monochloropropane-1,2-diol and acrylamide in food by gas chromatography-triple quadrupole mass spectrometry with coupled column separation.

PubMed

Xu, Xiao-min; He, Hua-li; Zhu, Yan; Feng, Liang; Ying, Ying; Huang, Bai-fen; Shen, Hai-tao; Han, Jian-long; Ren, Yi-ping

2013-01-14

Both 3-monochloropropane-1,2-diol (3-MCPD) and acrylamide are contaminants found in heat-processed foods and their related products. A quantitative method was developed for the simultaneous determination of both contaminants in food by gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS). The analytes were purified and extracted by the matrix solid-phase dispersion extraction (MSPDE) technique with Extrelut NT. A coupled column (a 3 m Innowax combined with a 30 m DB-5 ms) was developed to separate both compounds efficiently without derivatization. Triple quadrupole mass spectrometry in multiple reaction monitoring mode (MRM) was applied to suppress matrix interference and obtain good sensitivity in the determination of both analytes. The limit of detection (LOD) in the sample matrix was 5 μg kg(-1) for 3-MCPD or acrylamide. The average recoveries for 3-MCPD and acrylamide in different food matrices were 90.5-107% and 81.9-95.7%, respectively, with the intraday relative standard deviations (RSDs) of 5.6-13.5% and 5.3-13.4%, respectively. The interday RSDs were 6.1-12.6% for 3-MCPD and were 5.0-12.8% for acrylamide. Both contaminants were found in samples of bread, fried chips, fried instant noodles, soy sauce, and instant noodle flavoring. Neither 3-MCPD nor acrylamide was detected in the samples of dairy products (solid or liquid samples) and non-fried instant noodles. Copyright © 2012 Elsevier B.V. All rights reserved.

1-(2-Formamidoethyl)-3-phenylurea functionalized activated carbon for selective solid-phase extraction and preconcentration of metal ions.

PubMed

Tu, Zhifeng; He, Qun; Chang, Xijun; Hu, Zheng; Gao, Ru; Zhang, Lina; Li, Zhenhua

2009-09-07

A novel method that utilizes 1-(2-formamidoethyl)-3-phenylurea-modified activated carbon (AC-1-(2-formamidoethyl)-3-phenylurea) as a solid-phase extractant has been developed for simultaneous preconcentration of trace Cr(III), Cu(II), Fe(III) and Pb(II) prior to the measurement by inductively coupled plasma atomic emission spectrometry (ICP-AES). Experimental conditions for effective adsorption of trace levels of Cr(III), Cu(II), Fe(III) and Pb(II) were optimized using batch and column procedures in detail. The optimum pH value for the separation of metal ions simultaneously on the new sorbent was 4. And the adsorbed metal ions could be completely eluted by using 2.0 mL 2.0 mol L(-1) HCl solution. Common coexisting ions did not interfere with the separation and determination of target metal ions. The maximum static adsorption capacity of the sorbent at optimum conditions was found to be 39.8, 39.9, 77.8 and 17.3 mg g(-1) for Cr(III), Cu(II), Fe(III) and Pb(II), respectively. The detection limits of the method were found to be 0.15, 0.41, 0.27 and 0.36 ng mL(-1) for Cr(III), Cu(II), Fe(III) and Pb(II), respectively. The relative standard deviation (RSD) of the method was lower than 4.0% (n=8). The method was successfully applied for the preconcentration of trace Cr(III), Cu(II), Fe(III) and Pb(II) in natural and certified samples with satisfactory results.

Analysis of Free Amino Acids in Different Extracts of Orthosiphon stamineus Leaves by High-Performance Liquid Chromatography Combined with Solid-Phase Extraction.

PubMed

Shafaei, Armaghan; Halim, Nor Hidayah Ab; Zakaria, Norhidayah; Ismail, Zhari

2017-10-01

Orthosiphon stamineus (OS) Benth is a medicinal plant and native in Southeast Asia. Previous studies have shown that OS leaves possess antioxidant, cytotoxic, diuretic, antihypertensive, and uricosuric effects. These beneficial effects have been attributed to the presence of primary and secondary metabolites such as polyphenols, amino acids, and flavonoids. To develop and validate an high-performance liquid chromatography (HPLC)-diode array detector (DAD) method combined with solid-phase extraction that involves precolumn derivatization with O -phthaladehyde for simultaneous analysis of free amino acids in OS leaves extracts. OS leaves were extracted with water (OS-W), ethanol (OS-E), methanol (OS-M), 50% ethanol (OS-EW), and 50% methanol (OS-MW). The extracts were treated by C18 cartridge before derivatization, resulting in great improvement of separation by Zorbox Eclipse XDB-C 18 column. The HPLC-DAD method was successfully developed and validated for analyzing the contents of free amino acids in OS extracts. The results showed that l-aspartic acid with 0.93 ± 0.01 nmol/mg was the major free amino acid in OS-W extract. However, in OS-E, OS-M, OS-EW, and OS-MW, l-glutamic acid with 3.53 ± 0.16, 2.17 ± 0.10, 4.01 ± 0.12, and 2.49 ± 0.12 nmol/mg, respectively, was the major free amino acid. Subsequently, l-serine, which was detected in OS-W, OS-E, and OS-M, was the minor free amino acid with 0.33 ± 0.02, 0.12 ± 0.01, and 0.06 ± 0.01 nmol/mg, respectively. However, l-threonine with 0.26 ± 0.02 and 0.19 ± 0.08 nmol/mL in OS-EW and OS-MW, respectively, had the lowest concentration compared with other amino acid components. All validation parameters of the developed method indicate that the method is reliable and efficient to simultaneously determine the free amino acids content for routine analysis of OS extracts. The HPLC-DAD method combined with solid phase extraction was successfully developed and validated for simultaneous determination and quantification of 17 free amino acids in Orthosiphon stamineus (OS) Benth extractsOS extracts were found to be rich in free amino acid contentL-aspartic acid was the major free amino acid in OS water extract while, in OS ethanol, methanol, 50% ethanol and 50% methanol extracts, L-glutamic acid was the major free amino acidL-serine was the minor free amino acid in OS water, ethanol and methanol extracts while, in OS 50% ethanol and 50% methanol extracts, L-threonine had the lowest concentration compared to other amino acid components. Abbreviations used: HPLC-DAD: High-Performance Liquid Chromatography with Diode-Array Detection, OS: Orthosiphon stamineus , OS-W: Orthosiphon stamineus water extract, OS-E: Orthosiphon stamineus ethanol extract, OS-M: Orthosiphon stamineus methanol extract, OS-EW: Orthosiphon stamineus 50% ethanol extract, OS-MW: Orthosiphon stamineus 50% methanol extract, OPA: O-phthaladehyde , SPE: Solid Phase Extraction, UV: Ultraviolet, LOD: Limit of Detection, LOQ: Limit of Quantification, RSD: Relative Standard Deviation.

Simultaneous determination of seven coumarins by UPLC-MS/MS: Application to a comparative pharmacokinetic study in normal and arthritic rats after oral administration of Huo Luo Xiao Ling Dan or single-herb extract.

PubMed

Wu, Yun; Wang, Fenrong; Ai, Yu; Ma, Wen; Bian, Qiaoxia; Lee, David Y-W; Dai, Ronghua

2015-06-01

A simple, sensitive and reliable ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method has been developed and validated for simultaneous quantitation of seven coumarins, the bio-active ingredients of Huo Luo Xiao Ling Dan (HLXLD), in rat plasma. The liquid-liquid extraction method with ether-dichloromethane (2:1, v/v) was used to prepare the plasma samples. Analytes and internal standard (IS) of bifendate were separated on a Shim-pack XR-ODS column (75mm×3.0mm, 2.2μm particles) using gradient elution with the mobile phase consisting of methanol and 0.05% formic acid in water at a flow rate of 0.4mL/min. Detection was performed on a triple quadrupole (TQ) tandem mass spectrometry equipped with an electrospray ionization source in the positive ionization and multiple reaction monitoring (MRM) mode. The lower limits of quantitation (LLOQ) were 0.03-0.25ng/mL for all the analytes. Intra- and inter-day precision and accuracy of the seven analytes were well within acceptance criteria (15%). The matrix effect and the mean extraction recoveries of the analytes and IS from rat plasma were all within satisfaction. The validated method has been successfully applied to compare pharmacokinetic profiles of the seven active ingredients in rat plasma between normal and arthritic rats after oral administration of HLXLD, Angelica pubescens extract and Notopterygium incisum extract, respectively. Results showed that there were remarkable differences in pharmacokinetic properties of the analytes among the different groups. Copyright © 2015. Published by Elsevier B.V.

[Analysis of sulfonamids and their metabolites in drinking water by high Performance liquid chromatography tandem mass spectrometry].

PubMed

Wang, Shuo; Li, Shuming; Zhang, Xiangming; Wei, Yunfang; Zhang, Meiyun; Zhang, Jing

2015-07-01

To develop a comprehensive method for simultaneous analysis of sulfonamides and their metabolites in drinking water by high performance liquid chromatography tandem mass spectrometry (LC-MS/MS). Different solid-phase extraction columns were compared with respect to the recovery of target drugs from drinking water. The drinking water samples were adjusted to 3 by HCl and purified by a mix mode cation-ion exchange solid-phase extraction (SPE), following determination using LG-MS/MS. A total of 21 sulfonamides were separated by a C15 column (2.1 mm x 100 mm, 1.7 µm) and analyzed under positive ion mode with multi-reaction monitoring. The matrix-matched external standard calibration was used for quantification. The method quantification limits for 21 analytes were 0.03-0.63 ng/L with overall recoveries of 50.1%-114.9%, and the relative standard deviations less than 20%. The method was finally used to analyze sulfonamides in drinking water in Beijing, and 5 target compounds (sulfadiazine, sulfathiazole, sulfapyridine, trimethoprim and sulfamethazine) were detected at a concentration range of 0.08-32.54 ng/L. This method could be applied in simultaneous analysis of sulfonamides and their metabolites in drinking water samples.

An efficient method for the simultaneous determination of furan, 2-methylfuran and 2-pentylfuran in fruit juices by headspace solid phase microextraction and gas chromatography-flame ionisation detector.

PubMed

Hu, Gaofei; Zhu, Yan; Hernandez, Marta; Koutchma, Tatiana; Shao, Suqin

2016-02-01

A headspace solid phase microextraction (HS-SPME) procedure followed by gas chromatography-flame ionisation detector (GC-FID) analysis was developed and validated for the simultaneous analysis of furan, 2-methylfuran and 2-pentylfuran from juice samples. Extraction at 32 °C for 20 min with stirring at 600 rpm and NaCl concentration 15% (W/V) was the optimal HS-SPME condition for all the three compounds by using a carboxen/polydimethylsiloxane fused silica fibre (75 μm). The extracted compounds were base line separated on a SPB-1 GC column within 12 min. The relative standard deviations of all analytes were less than 6.7%. The recovery rates were between 90.2% and 110.1%. The limits of detection and limits of quantification were 0.056-0.23 ng/mL and 0.14-0.76 ng/mL, respectively. The results showed that the developed method was sensitive, precise, accurate and robust for the determination of furan, 2-methylfuran and 2-pentylfuran in complex matrices without interferences from other components. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Simultaneous determination of quinolones in fish by liquid chromatography coupled with fluorescence detection: comparison of sub-2 microm particles and conventional C18 columns.

PubMed

Zhang, Hong; Chen, Si; Lu, Yanbin; Dai, Zhiyuan

2010-07-01

A simple and effective multi-residue analysis method is presented for the extraction and determination of eleven quinolones (pipemidic acid, enoxacin, norfloxacin, ciprofloxacin, lomefloxacin, enrofloxacin, gatifloxacin, difloxacin, oxolinic acid, nalidixic acid and flumequine) in fish tissues. In this study, multi-residue separations on four columns packed with 5 microm or sub-2 microm particles were simultaneously developed for the purpose of comparison. Various gradients were optimized and best resolutions were achieved on each column. A short and sub-2 microm particle-sized HPLC column was chosen for its advantages in analysis time and column performance. Additionally, considering the matrix effect of the complex crude fish tissue, an effective extraction protocol was also established for sample pre-treatment procedure. Good recoveries (71-98%) were obtained from samples fortified with a mix of eleven quinolones at three levels, with satisfactory relative standard deviations and limits of detection. As a result, the sub-2 microm HPLC column and proposed analytical procedures have been evaluated and applied to the analysis of different fish tissues. Detectable residues were observed in 8 of 30 samples, at concentrations ranging from 4.74 to 23.27 microg/kg.

Chromatographic methods for determination of S-substituted cysteine derivatives--a comparative study.

PubMed

Kubec, Roman; Dadáková, Eva

2009-10-09

A novel HPLC method for determination of a wide variety of S-substituted cysteine derivatives in Allium species has been developed and validated. This method allows simultaneous separation and quantification of S-alk(en)ylcysteine S-oxides, gamma-glutamyl-S-alk(en)ylcysteines and gamma-glutamyl-S-alk(en)ylcysteine S-oxides in a single run. The procedure is based on extraction of these amino acids and dipeptides by methanol, their derivatization by dansyl chloride and subsequent separation by reversed phase HPLC. The main advantages of the new method are simplicity, excellent stability of derivatives, high sensitivity, specificity and the ability to simultaneously analyze the whole range of S-substituted cysteine derivatives. This method was critically compared with other chromatographic procedures used for quantification of S-substituted cysteine derivatives, namely with two other HPLC methods (derivatization by o-phthaldialdehyde/tert-butylthiol and fluorenylmethyl chloroformate), and with determination by gas chromatography or capillary electrophoresis. Major advantages and drawbacks of these analytical procedures are discussed. Employing these various chromatographic methods, the content and relative proportions of individual S-substituted cysteine derivatives were determined in four most frequently consumed alliaceous vegetables (garlic, onion, shallot, and leek).

Fast Simultaneous Determination of 13 Nucleosides and Nucleobases in Cordyceps sinensis by UHPLC-ESI-MS/MS.

PubMed

Zong, Shi-Yu; Han, Han; Wang, Bing; Li, Ning; Dong, Tina Ting-Xia; Zhang, Tong; Tsim, Karl W K

2015-12-04

A reliable ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS) method for the fast simultaneous determination of 13 nucleosides and nucleobases in Cordyceps sinensis (C. sinensis) with 2-chloroadenosine as internal standard was developed and validated. Samples were ultrasonically extracted in an ice bath thrice, and the optimum analyte separation was performed on an ACQUITY UPLC(TM) HSS C18 column (100 mm × 2.1 mm, 1.8 μm) with gradient elution. All targeted analytes were separated in 5.5 min. Furthermore, all calibration curves showed good linear regression (r > 0.9970) within the test ranges, and the limits of quantitation and detection of the 13 analytes were less than 150 and 75 ng/mL, respectively. The relative standard deviations (RSDs) of intra- and inter-day precisions were <6.23%. Recoveries of the quantified analytes ranged within 85.3%-117.3%, with RSD < 6.18%. The developed UHPLC-ESI-MS/MS method was successfully applied to determine nucleosides and nucleobases in 11 batches of C. sinensis samples from different regions in China. The range for the total content in the analyzed samples was 1329-2057 µg/g.

Multiplexed Colorimetric Solid-Phase Extraction

NASA Technical Reports Server (NTRS)

Gazda, Daniel B.; Fritz, James S.; Porter, Marc D.

2009-01-01

Multiplexed colorimetric solid-phase extraction (MC-SPE) is an extension of colorimetric solid-phase extraction (C-SPE) an analytical platform that combines colorimetric reagents, solid phase extraction, and diffuse reflectance spectroscopy to quantify trace analytes in water. In CSPE, analytes are extracted and complexed on the surface of an extraction membrane impregnated with a colorimetric reagent. The analytes are then quantified directly on the membrane surface using a handheld diffuse reflectance spectrophotometer. Importantly, the use of solid-phase extraction membranes as the matrix for impregnation of the colorimetric reagents creates a concentration factor that enables the detection of low concentrations of analytes in small sample volumes. In extending C-SPE to a multiplexed format, a filter holder that incorporates discrete analysis channels and a jig that facilitates the concurrent operation of multiple sample syringes have been designed, enabling the simultaneous determination of multiple analytes. Separate, single analyte membranes, placed in a readout cartridge create unique, analyte-specific addresses at the exit of each channel. Following sample exposure, the diffuse reflectance spectrum of each address is collected serially and the Kubelka-Munk function is used to quantify each water quality parameter via calibration curves. In a demonstration, MC-SPE was used to measure the pH of a sample and quantitate Ag(I) and Ni(II).

[Simultaneous extraction of tea-polyphenols and caffeine from green tea].

PubMed

Hai, L; Sun, H; Li, Z

1998-05-01

Tea-polyphenols and caffeine were extracted simultaneously from green tea. The factors influencing on the process of impregnation and extraction were studied. The result indicated that the content of tea-polyphenols and caffeine in tea was increased with the duration of extraction and decreased with the frequency of extraction. The authors discuss the effect of pH on the precipition of calcium-tea-polyphenols.

An ammonium sulfate/ethanol aqueous two-phase system combined with ultrasonication for the separation and purification of lithospermic acid B from Salvia miltiorrhiza Bunge.

PubMed

Guo, Y X; Han, J; Zhang, D Y; Wang, L H; Zhou, L L

2012-07-01

We studied the effect of ultrasonication extraction technology combined with ammonium sulfate/ethanol aqueous two-phase system (ATPS) for the separation of lithospermic acid B (LAB) from Salvia miltiorrhiza Bunge. According to the literature and preliminary studies, ammonium sulfate concentration, ethanol concentration, pH, ultrasonication power, ultrasonication time and the ratio of solvent-to-solid were investigated using a single factor design to identify the factors affecting separation. Taking into consideration a simultaneous increase in LAB recovery (R (%)) and partition coefficient (K), the best performance of the ATPS was obtained at 25°C and pH 2 using ammonium sulfate 22% (w/w) and ethanol 30% (w/w). To keep the solvent-to-solid ratio at 10, response surface methodology was used to find the optimal ultrasonication power and ultrasonication time. Quadratic models were predicted for LAB yield in the upper phase. Optimal conditions of 572.1 W ultrasonication power and 42.2 min produced a maximum yield of LAB of 42.16 mg g(-1) sample. There was no obvious degradation of LAB with ultrasound under the applied conditions, and the experimental yield of LAB was 42.49 mg g(-1) sample and the purity was 55.28% (w/w), which was much higher than that obtained using conventional extraction. The present study demonstrated that ultrasound coupled with aqueous two-phase systems is very efficient tool for the extraction and purification of LAB from Salvia miltiorrhiza Bunge. Copyright © 2011 Elsevier B.V. All rights reserved.

Simultaneous Determination of 11 Aminoglycoside Residues in Honey, Milk, and Pork by Liquid Chromatography with Tandem Mass Spectrometry and Molecularly Imprinted Polymer Solid Phase Extraction.

PubMed

Yang, Bixia; Wang, Lian; Luo, Chunying; Wang, Xixi; Sun, Chengjun

2017-11-01

An analytical method was developed for the simultaneous determination of 11 aminoglycoside (AG) antibiotics, including amikacin, paromomycin, dihydrostreptomycin, gentamicin C1a, hygromycin, kanamycin, netilmicin, spectinomycin, sisomicin, streptomycin, and tobramycin in honey, milk, and pork samples by LC with tandem MS and molecularly imprinted polymer (MIP) SPE. The AG antibiotics in milk and homogenated meat samples were extracted with a solution composed of 10 mmol/L potassium dihydrogen phosphate, 0.4 mmol/L EDTA-Na2, and 2% trichloroacetic acid. For honey samples, the extractant was 50 mmol/L potassium dihydrogen phosphate. The extracts were cleaned up with MIP SPE cartridges. The separation was performed on a zwitter ionic-HILIC column (50 × 2.1 mm, 3.5 μm), with the mobile phase consisting of methanol, 0.3% formic acid, and 175 mmol/L ammonium formate at 0.50 mL/min in gradient elution. A triple-quadrupole mass spectrometer equipped with an electrospray ionization source, which was operated in positive mode, was used for detection. The quantification was based on matrix-matched calibration curves. The method was applied to real samples with three different matrixes. The LODs of the method were 2-30 μg/kg and the LOQs were 7-100 μg/kg; the average recovery ranged from 78.2 to 94.8%; intraday RSDs and interday RSDs were ≤15 and ≤18%, respectively; and the absolute values of matrix effect for all AGs were RSDs ≤23%.

Neuro-genetic multioptimization of the determination of polychlorinated biphenyl congeners in human milk by headspace solid phase microextraction coupled to gas chromatography with electron capture detection.

PubMed

Kowalski, Cláudia Hoffmann; da Silva, Gilmare Antônia; Poppi, Ronei Jesus; Godoy, Helena Teixeira; Augusto, Fabio

2007-02-28

Polychlorinated biphenyls (PCB) can eventually contaminate breast milk, which is a serious issue to the newborn due to their high vulnerability. Solid phase microextraction (SPME) can be a very convenient technique for their isolation and pre-concentration prior chromatographic analysis. Here, a simultaneous multioptimization strategy based on a neuro-genetic approach was applied to a headspace SPME method for determination of 12 PCB in human milk. Gas chromatography with electron capture detection (ECD) was adopted for the separation and detection of the analytes. Experiments according to a Doehlert design were carried out with varied extraction time and temperature, media ionic strength and concentration of the methanol (co-solvent). To find the best model that simultaneously correlate all PCB peak areas and SPME extraction conditions, a multivariate calibration method based on a Bayesian Neural Network (BNN) was applied. The net output from the neural network was used as input in a genetic algorithm (GA) optimization operation (neuro-genetic approach). The GA pointed out that the best values of the overall SPME operational conditions were the saturation of the media with NaCl, extraction temperature of 95 degrees C, extraction time of 60 min and addition of 5% (v/v) methanol to the media. These optimized parameters resulted in the decrease of the detection limits and increase on the sensitivity for all tested analytes, showing that the use of neuro-genetic approach can be a promising way for optimization of SPME methods.

Simultaneous determination of eight metabolites of organophosphate and pyrethroid pesticides in urine.

PubMed

Guo, Xin Y; Sun, Li S; Huang, Meng Y; Xu, Wei L; Wang, Ying; Wang, Na

2017-01-02

A simultaneous method for quantifying eight metabolites of organophosphate pesticides and pyrethroid pesticides in urine samples has been established. The analytes were extracted using liquid-liquid extraction coupled with WCX solid phase extraction (SPE) cartridges. Eight metabolites were chemically derivatized before analysis using gas chromatography-tandem mass spectrometry (GC-MS-MS). The separation was performed on a HP-5MS capillary column (30 m × 0.25 mm × 0.25 µm) with temperature programming. The detection was performed under electro-spray ionization (ESI) in multiple reaction monitoring (MRM) mode. An internal standard method was used. The extraction solvent, types of SPE cartridges and eluents were optimized by comparing the sample recoveries under different conditions. The results showed that the calibration curves of the five organophosphorus pesticides metabolites were linear in the range of 0.2-200 μg/L (r 2 ≥ 0.992) and that of the three pyrethroid pesticides metabolites were linear in the range of 0.025-250 μg/L (r 2 ≥ 0.991). The limits of detection (LODs, S/N ≥ 3) and the limits of quantification (LOQs, S/N ≥ 10) of the eight metabolites were 0.008-0.833 μg/L and 0.25-2.5 μg/L, respectively. The recoveries of the eight metabolites ranged from 54.08% to 82.49%. This efficient, stable, and cost-effective method is adequate to handle the large number of samples required for surveying the exposure level of organophosphorus and pyrethroid pesticides in the general population.

Simultaneous determination of vitexin-2"-O-glucoside, vitexin-2"-O-rhamnoside, rutin, and hyperoside in the extract of hawthorn (Crataegus pinnatifida Bge.) leaves by RP-HPLC with ultraviolet photodiode array detection.

PubMed

Cheng, Shan; Qiu, Feng; Huang, Jia; He, Junqi

2007-03-01

RP-HPLC with UV photodiode array detection (UV-DAD) was developed and validated for the simultaneous determination of vitexin-2"-O-glucoside, vitexin-2"-O-rhamnoside, rutin, and hyperoside in the extract of hawthorn (Crataegus pinnatifida Bge.) leaves. The analytes of interest were separated on a Diamonsil C18 column (250 x 4.6 mm id, 5 microm) with the mobile phase consisting of THF/ACN/methanol/ 0.05% phosphoric acid solution (pH 5.0) (18:1:1:80 v/vl/v). The flow rate was set at 1.0 mL/min and the eluent was detected at 340 nm for the four flavonoids. The method was linear over the studied range of 1.00-100 microg/mL for the four analytes of interest with the correlation coefficient for each analyte greater than 0.999. The LOD and LOQwere 0.03 and 0.10 microg/mL, 0.03 and 0.10 microg/mL, 0.05 and 0.15 pg/mL, 0.10 and 0.30 microg/mL for vitexin-2"-O-glucoside, vitexin-2"-0-rhamnoside, rutin, and hyperoside, respectively. The optimized method was successfully applied to the analysis of four important flavonoids in the extract of hawthorn leaves. The total amounts of the four flavonoids were 22.2, 62.3, 4.27, and 8.24 mg/g dry weight for vitexin-2"-O-glucoside, vitexin-2"-O-rhamnoside, rutin, and hyperoside in the extract of hawthorn leaves, respectively.

Simultaneous determination of calycosin-7-O-β-D-glucoside, ononin, calycosin, formononetin, astragaloside IV, and astragaloside II in rat plasma after oral administration of Radix Astragali extraction for their pharmacokinetic studies by ultra-pressure liquid chromatography with tandem mass spectrometry.

PubMed

Liu, Xiao-hua; Zhao, Jian-bang; Guo, Long; Yang, Ying-lai; Hu, Fang; Zhu, Rui-juan; Feng, Shi-lan

2014-09-01

A sensitive and reliable ultra-pressure liquid chromatography with tandem mass spectrometry (UPLC-MS) was developed and validated for simultaneous quantification of six main bioactive components, i.e., calycosin-7-O-β-D-glucoside, ononin, calycosin, formononetin, astragaloside IV, and astragaloside II in rat plasma after oral administration of the 95 % ethanol extraction from Radix Astragali. Plasma samples were extracted with Waters Oasis(TM) HLB 1 cc (30 mg) Extraction Cartridges (SPE) separated on an UPLC™ BEH C18 column and detected by MS with electro spray ionization interface in positive selective ion monitoring mode. Calibration curves offered linear ranges of two orders of magnitude with r (2) > 0.99. The method had the lower limit quantification of 1.30, 0.73, 1.17, 2.33, 0.63, and 0.83 ng/mL for ononin, calycosin, calycosin-7-O-β-D-glucoside, formononetin, astragaloside IV, and astragaloside II, respectively, with precision less than 10 %. The RSD of intra- and inter-day variations ranged from 1.66 to 6.46 and 3.39 to 6.58 %. This developed method was applied subsequently to pharmacokinetic studies of the six compounds in rats successfully. The proposed method was for the first time to compare the pharmacokinetic difference between calycosin-7-O-β-D-glucoside and calycosin in rat plasma, so as between ononin and formononetin, and studied to the astragaloside II pharmacokinetics in rat plasma.

Application of an online post-column derivatization HPLC-DPPH assay to detect compounds responsible for antioxidant activity in Sonchus oleraceus L. leaf extracts.

PubMed

Ou, Zong-Quan; Schmierer, David M; Rades, Thomas; Larsen, Lesley; McDowell, Arlene

2013-02-01

To use an online assay to identify key antioxidants in Sonchus oleraceus leaf extracts and to investigate the effect of leaf position and extraction conditions on antioxidant concentration and activity. Separation of phytochemicals and simultaneous assessment of antioxidant activity were performed online using HPLC and post-column reaction with a free-radical reagent (2, 2-diphenylpicrylhydrazyl, DPPH). Active compounds were identified using nuclear magnetic resonance spectroscopy and mass spectrometry. We applied the online HPLC-DPPH radical assay to evaluate antioxidants in leaves from different positions on the plant and to assess the effect of pre-treatment of leaves with liquid N(2) before grinding, extraction time, extraction temperature and method of concentrating extracts. Key antioxidants identified in S. oleraceus leaf extracts were caftaric acid, chlorogenic acid and chicoric acid. Middle leaves contained the highest total amount of the three key antioxidant compounds, consisting mainly of chicoric acid. Pre-treatment with liquid N(2), increasing the extraction temperature and time and freeze-drying the extract did not enhance the yield of the key antioxidants. The online HPLC-DPPH radical assay was validated as a useful screening tool for investigating individual antioxidants in leaf extracts. Optimized extraction conditions were middle leaves pre-treated with liquid N(2), extraction at 25°C for 0.5 h and solvent removal by rotary evaporation. © 2012 The Authors. JPP © 2012. Royal Pharmaceutical Society.

An effective biometric discretization approach to extract highly discriminative, informative, and privacy-protective binary representation

NASA Astrophysics Data System (ADS)

Lim, Meng-Hui; Teoh, Andrew Beng Jin

2011-12-01

Biometric discretization derives a binary string for each user based on an ordered set of biometric features. This representative string ought to be discriminative, informative, and privacy protective when it is employed as a cryptographic key in various security applications upon error correction. However, it is commonly believed that satisfying the first and the second criteria simultaneously is not feasible, and a tradeoff between them is always definite. In this article, we propose an effective fixed bit allocation-based discretization approach which involves discriminative feature extraction, discriminative feature selection, unsupervised quantization (quantization that does not utilize class information), and linearly separable subcode (LSSC)-based encoding to fulfill all the ideal properties of a binary representation extracted for cryptographic applications. In addition, we examine a number of discriminative feature-selection measures for discretization and identify the proper way of setting an important feature-selection parameter. Encouraging experimental results vindicate the feasibility of our approach.

Comparative pharmacokinetics study of three anthraquinones in rat plasma after oral administration of Radix et Rhei Rhizoma extract and Dahuang Fuzi Tang by high performance liquid chromatography-mass spectrometry.

PubMed

Li, Huan; Guo, Hui; Wu, Li; Zhang, Yongxin; Chen, Juan; Liu, Xiao; Cai, Hao; Zhang, Kewei; Cai, Baochang

2013-03-25

A specific and sensitive high performance liquid chromatography-mass spectrometric (HPLC-MS) method has been developed and validated for simultaneous determination of three anthraquinones of rhein, aloe-emodin and emodin in rat plasma after oral administration of Radix et Rhei Rhizoma extract and Dahuang Fuzi Tang. The analytes were separated on a Kromaisl(®) C(18) column within a total running time of 12min with a mobile phase of methanol:ammonium acetate (3mM) (75:25, v/v). The calibration curves for all the anthraquinones showed good linearity in the measured range with correlation coefficient (r) higher than 0.9978. The precision, accuracy, recovery and stability were deemed acceptable. The method was successfully applied to the comparative pharmacokinetics study of the anthraquinones in rat plasma after oral administration of Radix et Rhei Rhizoma extract and Dahuang Fuzi Tang. Copyright © 2012 Elsevier B.V. All rights reserved.

Joint Feature Extraction and Classifier Design for ECG-Based Biometric Recognition.

PubMed

Gutta, Sandeep; Cheng, Qi

2016-03-01

Traditional biometric recognition systems often utilize physiological traits such as fingerprint, face, iris, etc. Recent years have seen a growing interest in electrocardiogram (ECG)-based biometric recognition techniques, especially in the field of clinical medicine. In existing ECG-based biometric recognition methods, feature extraction and classifier design are usually performed separately. In this paper, a multitask learning approach is proposed, in which feature extraction and classifier design are carried out simultaneously. Weights are assigned to the features within the kernel of each task. We decompose the matrix consisting of all the feature weights into sparse and low-rank components. The sparse component determines the features that are relevant to identify each individual, and the low-rank component determines the common feature subspace that is relevant to identify all the subjects. A fast optimization algorithm is developed, which requires only the first-order information. The performance of the proposed approach is demonstrated through experiments using the MIT-BIH Normal Sinus Rhythm database.

Development of a rapid LC-DAD/FLD method for the simultaneous determination of auxins and abscisic acid in plant extracts.

PubMed

Bosco, Renato; Caser, Matteo; Vanara, Francesca; Scariot, Valentina

2013-11-20

Plant hormones play a crucial role in controlling plant growth and development. These groups of naturally occurring substances trigger physiological processes at very low concentrations, which mandate sensitive techniques for their quantitation. This paper describes a method to quantify endogenous (±)-2-cis-4-trans-abscisic acid, indole-3-acetic acid, indole-3-propionic acid, and indole-3-butyric acid. The method combines high-performance liquid chromatography (HPLC) with diode array and fluorescence detection in a single run. Hybrid tea rose 'Monferrato' matrices (leaves, petals, roots, seeds, androecium, gynoecium, and pollen) were used as references. Rose samples were separated and suspended in extracting methanol, after which (±)-2-cis-4-trans-abscisic acid and auxins were extracted by solvent extraction. Sample solutions were added first to cation solid phase extraction (SPE) cartridges and the eluates to anion SPE cartridges. The acidic hormones were bound to the last column and eluted with 5% phosphoric acid in methanol. Experimental results showed that this approach can be successfully applied to real samples and that sample preparation and total time for routine analysis can be greatly reduced.

Thin-layer chromatography with stationary phase gradient as a method for separation of water-soluble vitamins.

PubMed

Cimpoiu, Claudia; Hosu, Anamaria; Puscas, Anitta

2012-02-03

The group of hydrophilic vitamins play an important role in human health, and their lack or excess produces specific diseases. Therefore, the analysis of these compounds is indispensable for monitoring their content in pharmaceuticals and food in order to prevent some human diseases. TLC was successfully applied in the analysis of hydrophilic vitamins, but the most difficult problem in the simultaneous analysis of all these compounds is to find an optimum stationary phase-mobile phase system due to different chemical characteristics of analytes. Unfortunately structural analogues are difficult to separate in one chromatographic run, and this is the case in hydrophilic vitamins investigations. TLC gives the possibility to perform two-dimensional separations by using stationary phase gradient achieving the highest resolution by combining two systems with different selectivity. The goal of this work was to develop a method of analysis enabling separation of hydrophilic vitamins using TLC with adsorbent gradient. The developed method was used for identifying the water-soluble vitamins in alcoholic extracts of Hippophae rhamnoides and of Ribes nigrum. Copyright © 2011 Elsevier B.V. All rights reserved.

Crisis route to chaos in semiconductor lasers subjected to external optical feedback

NASA Astrophysics Data System (ADS)

Wishon, Michael J.; Locquet, Alexandre; Chang, C. Y.; Choi, D.; Citrin, D. S.

2018-03-01

Semiconductor lasers subjected to optical feedback have been intensively used as archetypical testbeds for high-speed (sub-ns) and high-dimensional nonlinear dynamics. By simultaneously extracting all the dynamical variables, we demonstrate that for larger current, the commonly named "quasiperiodic" route is in fact based on mixed external-cavity solutions that lock the oscillation frequency of the intensity, voltage, and separation in optical frequency through a mechanism involving successive rejections along the unstable manifold of an antimode. We show that chaos emerges from a crisis resulting from the inability to maintain locking as the unstable manifold becomes inaccessible.

Determination of tocopherols and sitosterols in seeds and nuts by QuEChERS-liquid chromatography.

PubMed

Delgado-Zamarreño, M Milagros; Fernández-Prieto, Cristina; Bustamante-Rangel, Myriam; Pérez-Martín, Lara

2016-02-01

In the present work a simple, reliable and affordable sample treatment method for the simultaneous analysis of tocopherols and free phytosterols in nuts was developed. Analyte extraction was carried out using the QuEChERS methodology and analyte separation and detection were accomplished using HPLC-DAD. The use of this methodology for the extraction of natural occurring substances provides advantages such as speed, simplicity and ease of use. The parameters evaluated for the validation of the method developed included the linearity of the calibration plots, the detection and quantification limits, repeatability, reproducibility and recovery. The proposed method was successfully applied to the analysis of tocopherols and free phytosterols in samples of almonds, cashew nuts, hazelnuts, peanuts, tiger nuts, sun flower seeds and pistachios. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cooperative dynamics in auditory brain response

NASA Astrophysics Data System (ADS)

Kwapień, J.; DrożdŻ, S.; Liu, L. C.; Ioannides, A. A.

1998-11-01

Simultaneous estimates of activity in the left and right auditory cortex of five normal human subjects were extracted from multichannel magnetoencephalography recordings. Left, right, and binaural stimulations were used, in separate runs, for each subject. The resulting time series of left and right auditory cortex activity were analyzed using the concept of mutual information. The analysis constitutes an objective method to address the nature of interhemispheric correlations in response to auditory stimulations. The results provide clear evidence of the occurrence of such correlations mediated by a direct information transport, with clear laterality effects: as a rule, the contralateral hemisphere leads by 10-20 ms, as can be seen in the average signal. The strength of the interhemispheric coupling, which cannot be extracted from the average data, is found to be highly variable from subject to subject, but remarkably stable for each subject.

Simultaneous determination of active ingredients in Erigeron breviscapus (Vant.) Hand-Mazz. by capillary electrophoresis with electrochemical detection.

PubMed

Chu, Qingcui; Wu, Ting; Fu, Liang; Ye, Jiannong

2005-03-09

A high-performance capillary electrophoresis (CE) with electrochemical detection (ED) method was developed for the determination of the pharmacologically active ingredients in Erigeron breviscapus (Vant.) Hand-Mazz. and its extract phytopharmaceuticals in this work. Under the optimum conditions, nine analytes, baicalein, naringenin, scopoletin, kaempferol, apigenin, scutellarin, luteolin, caffeic acid and protocatechuic acid were separated within 24 min in a borax buffer (pH 8.7). Notably, excellent linearity was obtained over two orders of magnitude with detection limits (S/N=3) ranged from 1.0 x 10(-7) g/mL to 5.6 x 10(-7) g/mL for all nine analytes. This method was successfully used in the analysis of E. breviscapus (Vant.) Hand-Mazz. and its phytopharmaceuticals with a relatively simple extraction procedure, and the assay results were satisfactory.

Simultaneous and rapid determination of gefitinib, erlotinib and afatinib plasma levels using liquid chromatography/tandem mass spectrometry in patients with non-small-cell lung cancer.

PubMed

Hayashi, Hideki; Kita, Yutaro; Iihara, Hirotoshi; Yanase, Koumei; Ohno, Yasushi; Hirose, Chiemi; Yamada, Maya; Todoroki, Kenichiro; Kitaichi, Kiyoyuki; Minatoguchi, Shinya; Itoh, Yoshinori; Sugiyama, Tadashi

2016-07-01

A simultaneous, selective, sensitive and rapid liquid chromatography/tandem mass spectrometry method was developed and validated for the quantification of gefitinib, erlotinib and afatinib in 250 μL samples of human blood plasma. Diluted plasma samples were extracted using a liquid-phase extraction procedure with tert-butyl methyl ether. The three drugs were separated by high-performance liquid chromatography using a C18 column and an isocratic mobile phase running at a flow rate of 0.2 mL/min for 5 min. The drugs were detected using a tandem mass spectrometer with electrospray ionization using imatinib as an internal standard. Calibration curves were generated over the linear concentration range of 0.05-100 nm in plasma with a lower limit of quantification of 0.01 or 0.05 nm for all compounds. Finally, the validated method was applied to a clinical pharmacokinetic study in patients with nonsmall-cell lung cancer (NSCLC) following the oral administration of afatinib. These results indicate that this method is suitable for assessing the risks and benefits of chemotherapy in patients with NSCLC and is useful for therapeutic drug monitoring for NSCLC treatment. As far as we know, this is the first report on LC-MS/MS method for the simultaneous quantification of NSCLC tyrosine kinase inhibitor plasma concentrations including afatinib. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Brain activity during bilateral rapid alternate finger tapping measured with magnetoencephalography

NASA Astrophysics Data System (ADS)

Fukuda, Hiroshi; Odagaki, Masato; Hiwaki, Osamu; Kodabashi, Atsushi; Fujimoto, Toshiro

2009-04-01

Using magnetoencephalography (MEG), brain regions involved in an alternate bimanual tapping task by index fingers triggered with spontaneous timing were investigated. The tapping mode in which both index fingers moved simultaneously was interlaced during the task. The groups of the alternate tapping (AL mode) and the simultaneous tapping (SI mode) were extracted from the successive alternating taps with a histogram of intervals between the right and left index fingers. MEG signals in each mode were averaged separately before and after the tapping initiation of the dominant index finger. The activities of the contralateral sensorimotor cortex before and after the tapping initiation in the AL mode were larger than that in the SI mode. The result indicates that the activity of the contralateral sensorimotor cortex depends on the degree of achievement in the difficult motor task such as the voluntary alternate tapping movements.

Particle image velocimetry based on wavelength division multiplexing

NASA Astrophysics Data System (ADS)

Tang, Chunxiao; Li, Enbang; Li, Hongqiang

2018-01-01

This paper introduces a technical approach of wavelength division multiplexing (WDM) based particle image velocimetry (PIV). It is designed to measure transient flows with different scales of velocity by capturing multiple particle images in one exposure. These images are separated by different wavelengths, and thus the pulse separation time is not influenced by the frame rate of the camera. A triple-pulsed PIV system has been created in order to prove the feasibility of WDM-PIV. This is demonstrated in a sieve plate extraction column model by simultaneously measuring the fast flow in the downcomer and the slow vortices inside the plates. A simple displacement/velocity field combination method has also been developed. The constraints imposed by WDM-PIV are limited wavelength choices of available light sources and cameras. The usage of WDM technique represents a feasible way to realize multiple-pulsed PIV.

[Simultaneous determination of 7 arsenic species in chicken muscle and chicken liver with high performance liquid chromatography-inductively coupled plasma mass spectrometry].

PubMed

Yang, Lijun; Hu, Qiaoru; Guo, Wei; Liu, Yumin; Song, Xiaohua; Zhang, Pengcheng

2011-05-01

A method for the simultaneous determination of 7 arsenic species was developed with high performance liquid chromatography and inductively coupled plasma mass spectrometry (HPLC-ICP-MS). The sample was extracted with artificial gastric juice. The HPLC separation was performed on an anion analytical column utilizing a gradient elution program of ammonium carbonate and water as the mobile phase. Identification and quantification were achieved by ICP-MS. Good linearities of 7 arsenic species were observed in the range from 1 microg/kg to 50 microg/kg with the correlation coefficients greater than 0.999. The average recoveries of 7 arsenic species spiked at the three levels of 1, 2 and 10 microg/kg ranged from 84.3% to 106.6% with the relative standard deviations of 1.4%-4.2%. The quantification limits of 7 arsenic species were 1 microg/kg. The method was proved to be good reproducibility, high sensitivity and simple preprocessing. This method is suitable for the simultaneous determination of 7 arsenic species in chicken muscle and chicken liver.

Sensitive liquid chromatography-tandem mass spectrometry method for the simultaneous determination of paracetamol and guaifenesin in human plasma.

PubMed

Chen, Xiaoyan; Huang, Jia; Kong, Zhang; Zhong, Dafang

2005-03-25

A rapid and sensitive method for the simultaneous determination of paracetamol and guaifenesin in human plasma was developed and validated, using high-performance liquid chromatographic separation with tandem mass spectrometric detection. After extracted from plasma samples by diethyl ether-dichloromethane (3:2, v/v), the analytes and internal standard osalmide were chromatographed on a C18 column. Detection was performed on a triple quadrupole tandem mass spectrometer by selected reaction monitoring (SRM) mode via atmospheric pressure chemical ionization (APCI). The method was linear in the concentration range of 0.05-20.0 microg/ml for paracetamol and 5.0-2000.0 ng/ml for guaifenesin. The intra- and inter-day precision was within 14% for both paracetamol and guaifenesin. The assay accuracy was within +/-2.4% for the analytes. This is the first assay method described for the simultaneous determination of paracetamol and guaifenesin in plasma using one chromatographic run. The method was successfully employed in a pharmacokinetic study after an oral administration of a multicomponent formulation, containing 650 mg paracetamol, 200 mg guaifenesin, 60 mg pseudoephedrine and 20 mg dextrorphan.

Determination of 15 polycyclic aromatic hydrocarbons in aquatic products by solid-phase extraction and GC-MS.

PubMed

Liu, Qiying; Guo, Yuanming; Sun, Xiumei; Hao, Qing; Cheng, Xin; Zhang, Lu

2018-02-22

We propose a method for the simultaneous determination of 15 kinds of polycyclic aromatic hydrocarbons in marine samples (muscle) employing gas chromatography with mass spectrometry after saponification with ultrasound-assisted extraction and solid-phase extraction. The experimental conditions were optimized by the response surface method. In addition, the effects of different lyes and extractants on polycyclic aromatic hydrocarbons extraction were discussed, and saturated sodium carbonate was first used as the primary saponification reaction and extracted with 10 mL of ethyl acetate and secondly 1 mol/L of sodium hydroxide and 10 mL of n-hexane were used to achieve better results. The average recovery was 67-112%. Satisfactory data showed that the method has good reproducibility with a relative standard deviation of <13%. The detection limits of polycyclic aromatic hydrocarbons were 0.02-0.13 ng/g. Compared with other methods, this method has the advantages of simple pretreatment, low solvent consumption, maximum polycyclic aromatic hydrocarbons extraction, the fast separation speed, and the high extraction efficiency. It is concluded that this method meets the batch processing requirements of the sample and can also be used to determine polycyclic aromatic hydrocarbons in other high-fat (fish, shrimp, crab, shellfish) biological samples. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous quantification of four metabolites of sulfur mustard in urine samples by ultra-high performance liquid chromatography-tandem mass spectrometry after solid phase extraction.

PubMed

Liu, Chang-Cai; Liu, Shi-Lei; Xi, Hai-Ling; Yu, Hui-Lan; Zhou, Shi-Kun; Huang, Gui-Lan; Liang, Long-Hui; Liu, Jing-Quan

2017-04-07

Four HD urinary metabolites including hydrolysis metabolite thiodiglycol (TDG), glutathione-derived metabolite 1,1'-sulfonylbis[2-S-(N-acetylcysteinyl)ethane] (SBSNAE), as well as the β-lyase metabolites 1,1'-sulfonylbis[2-(methylsulfinyl)ethane] (SBMSE) and 1-methylsulfinyl-2-[2-(methylthio) ethylsulfonyl]ethane (MSMTESE) are considered as important biomarkers for short-term retrospective detection of HD exposure. In this study, a single method for simultaneous quantification of the four HD metabolites in urine samples was developed using ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The four urinary metabolites were simultaneously extracted from urinary samples using a solid phase extraction (SPE) method with high extraction recoveries for all four metabolites varied in the range of 71.1-103% followed by UHPLC-MS/MS analysis. The SPE is simple and high effective only requiring 0.1mL of urinary samples and 0.5h time consuming. The problem of previous co-elution of TDG and SBSNAE in UHPLC was well solved, and complete separation of TDG, SBSNAE, SBMSE and MSMTESE from SPE-processed urine matrix was obtained to increase specificity and sensitivity. A full method validation was performed for each analyte in urine matrix. The linear range of calibration curves for the four analytes were respectively from 0.50-500ngmL -1 for TDG and SBSNAE, 0.05-500ngmL -1 for SBMSE and MSMTESE with coefficient of determination value (R 2 ) ≥0.990. The limit of detection was 0.25ngmL -1 for TDG and SBSNAE, 0.01ngmL -1 for SBMSE and MSMTESE spiked in normal urine. The intra/inter-day precision for each analyte at three QC levels had relative standard deviation (%RSD) of ≤10.3%, and the intra/inter-day accuracy ranged between 88.0-108%. This developed method allows for simultaneous and trace measurement of four HD urinary metabolites within one single determination with the lowest usage amount of urine samples over all previous methods This study provides a useful tool for early diagnosis and monitoring of HD poisoning for medical treatment with high confidence, avoiding the need for application of several analysis methods. Copyright © 2017 Elsevier B.V. All rights reserved.

Single-step preparation of selected biological fluids for the high performance liquid chromatographic analysis of fat-soluble vitamins and antioxidants.

PubMed

Lazzarino, Giacomo; Longo, Salvatore; Amorini, Angela Maria; Di Pietro, Valentina; D'Urso, Serafina; Lazzarino, Giuseppe; Belli, Antonio; Tavazzi, Barbara

2017-12-08

Fat-soluble vitamins and antioxidants are of relevance in health and disease. Current methods to extract these compounds from biological fluids mainly need use of multi-steps and multi organic solvents. They are time-consuming and difficult to apply to treat simultaneously large sample number. We here describe a single-step, one solvent extraction of fat-soluble vitamins and antioxidants from biological fluids, and the chromatographic separation of all-trans-retinoic acid, 25-hydroxycholecalciferol, all-trans-retinol, astaxanthin, lutein, zeaxanthin, trans-β-apo-8'-carotenal, γ-tocopherol, β-cryptoxanthin, α-tocopherol, phylloquinone, lycopene, α-carotene, β-carotene and coenzyme Q 10 . Extraction is obtained by adding one volume of biological fluid to two acetonitrile volumes, vortexing for 60s and incubating for 60min at 37°C under agitation. HPLC separation occurs in 30min using Hypersil C18, 100×4.6mm, 5μm particle size column, gradient from 70% methanol+30% H 2 O to 100% acetonitrile, flow rate of 1.0ml/min and 37°C column temperature. Compounds are revealed using highly sensitive UV-VIS diode array detector. The HPLC method suitability was assessed in terms of sensitivity, reproducibility and recovery. Using the present extraction and chromatographic conditions we obtained values of the fat-soluble vitamins and antioxidants in serum from 50 healthy controls similar to those found in literature. Additionally, the profile of these compounds was also measured in seminal plasma from 20 healthy fertile donors. Results indicate that this simple, rapid and low cost sample processing is suitable to extract fat-soluble vitamins and antioxidants from biological fluids and can be applied in clinical and nutritional studies. Copyright © 2017 Elsevier B.V. All rights reserved.

Analysis of Free Amino Acids in Different Extracts of Orthosiphon stamineus Leaves by High-Performance Liquid Chromatography Combined with Solid-Phase Extraction

PubMed Central

Shafaei, Armaghan; Halim, Nor Hidayah Ab; Zakaria, Norhidayah; Ismail, Zhari

2017-01-01

Background: Orthosiphon stamineus (OS) Benth is a medicinal plant and native in Southeast Asia. Previous studies have shown that OS leaves possess antioxidant, cytotoxic, diuretic, antihypertensive, and uricosuric effects. These beneficial effects have been attributed to the presence of primary and secondary metabolites such as polyphenols, amino acids, and flavonoids. Objective: To develop and validate an high-performance liquid chromatography (HPLC)-diode array detector (DAD) method combined with solid-phase extraction that involves precolumn derivatization with O-phthaladehyde for simultaneous analysis of free amino acids in OS leaves extracts. Materials and Methods: OS leaves were extracted with water (OS-W), ethanol (OS-E), methanol (OS-M), 50% ethanol (OS-EW), and 50% methanol (OS-MW). The extracts were treated by C18 cartridge before derivatization, resulting in great improvement of separation by Zorbox Eclipse XDB-C18 column. Results: The HPLC–DAD method was successfully developed and validated for analyzing the contents of free amino acids in OS extracts. The results showed that l-aspartic acid with 0.93 ± 0.01 nmol/mg was the major free amino acid in OS-W extract. However, in OS-E, OS-M, OS-EW, and OS-MW, l-glutamic acid with 3.53 ± 0.16, 2.17 ± 0.10, 4.01 ± 0.12, and 2.49 ± 0.12 nmol/mg, respectively, was the major free amino acid. Subsequently, l-serine, which was detected in OS-W, OS-E, and OS-M, was the minor free amino acid with 0.33 ± 0.02, 0.12 ± 0.01, and 0.06 ± 0.01 nmol/mg, respectively. However, l-threonine with 0.26 ± 0.02 and 0.19 ± 0.08 nmol/mL in OS-EW and OS-MW, respectively, had the lowest concentration compared with other amino acid components. Conclusion: All validation parameters of the developed method indicate that the method is reliable and efficient to simultaneously determine the free amino acids content for routine analysis of OS extracts. SUMMARY The HPLC-DAD method combined with solid phase extraction was successfully developed and validated for simultaneous determination and quantification of 17 free amino acids in Orthosiphon stamineus (OS) Benth extractsOS extracts were found to be rich in free amino acid contentL-aspartic acid was the major free amino acid in OS water extract while, in OS ethanol, methanol, 50% ethanol and 50% methanol extracts, L-glutamic acid was the major free amino acidL-serine was the minor free amino acid in OS water, ethanol and methanol extracts while, in OS 50% ethanol and 50% methanol extracts, L-threonine had the lowest concentration compared to other amino acid components. Abbreviations used: HPLC-DAD: High-Performance Liquid Chromatography with Diode-Array Detection, OS: Orthosiphon stamineus, OS-W: Orthosiphon stamineus water extract, OS-E: Orthosiphon stamineus ethanol extract, OS-M: Orthosiphon stamineus methanol extract, OS-EW: Orthosiphon stamineus 50% ethanol extract, OS-MW: Orthosiphon stamineus 50% methanol extract, OPA: O-phthaladehyde, SPE: Solid Phase Extraction, UV: Ultraviolet, LOD: Limit of Detection, LOQ: Limit of Quantification, RSD: Relative Standard Deviation. PMID:29142388

Extracting archaeal populations from iron oxidizing systems

NASA Astrophysics Data System (ADS)

Whitmore, L. M.; Hutchison, J.; Chrisler, W.; Jay, Z.; Moran, J.; Inskeep, W.; Kreuzer, H.

2013-12-01

Unique environments in Yellowstone National Park offer exceptional conditions for studying microorganisms in extreme and constrained systems. However, samples from some extreme systems often contain inorganic components that pose complications during microbial and molecular analysis. Several archaeal species are found in acidic, geothermal ferric-oxyhydroxide mats; these species have been shown to adhere to mineral surfaces in flocculated colonies. For optimal microbial analysis, (microscopy, flow cytometry, genomic extractions, proteomic analysis, stable isotope analysis, and others), improved techniques are needed to better facilitate cell detachment and separation from mineral surfaces. As a requirement, these techniques must preserve cell structure while simultaneously minimizing organic carryover to downstream analysis. Several methods have been developed for removing sediments from mixed prokaryotic populations, including ultra-centrifugation, nycodenz gradient, sucrose cushions, and cell straining. In this study we conduct a comparative analysis of mechanisms used to detach archaeal cell populations from the mineral interface. Specifically, we evaluated mechanical and chemical approaches for cell separation and homogenization. Methods were compared using confocal microscopy, flow cytometry analyses, and real-time PCR detection. The methodology and approaches identified will be used to optimize biomass collection from environmental specimens or isolates grown with solid phases.

Zincon-modified activated carbon for solid-phase extraction and preconcentration of trace lead and chromium from environmental samples.

PubMed

Li, Zhenhua; Chang, Xijun; Hu, Zheng; Huang, Xinping; Zou, Xiaojun; Wu, Qiong; Nie, Rong

2009-07-15

A new method that utilizes zincon-modified activated carbon (AC-ZCN) as a solid-phase extractant has been developed for simultaneous preconcentration of trace Cr(III) and Pb(II) prior to the measurement by inductively coupled plasma optical emission spectrometry (ICP-OES). The separation/preconcentration conditions of analytes were investigated, including effects of pH, the shaking time, the sample flow rate and volume, the elution condition and the interfering ions. At pH 4, the maximum adsorption capacity of Cr(III) and Pb(II) onto the AC-ZCN were 17.9 and 26.7 mg g(-1), respectively. The adsorbed metal ions were quantitatively eluted by 1 mL of 0.1 mol L(-1) HCl. Common coexisting ions did not interfere with the separation. According to the definition of IUPAC, the detection limits (3 sigma) of this method for Cr(III) and Pb(II) were 0.91 and 0.65 ng mL(-1), respectively. The relative standard deviation under optimum condition is less than 3.5% (n=8). The method has been applied for the determination of Cr(III) and Pb(II) in biological materials and water samples with satisfactory results.

Relationship Between Ktrans and K1 with Simultaneous Versus Separate MR/PET in Rabbits with VX2 Tumors.

PubMed

Lee, Kyung Hee; Kang, Seung Kwan; Goo, Jin Mo; Lee, Jae Sung; Cheon, Gi Jeong; Seo, Seongho; Hwang, Eui Jin

2017-03-01

To compare the relationship between K trans from DCE-MRI and K 1 from dynamic 13 N-NH 3 -PET, with simultaneous and separate MR/PET in the VX-2 rabbit carcinoma model. MR/PET was performed simultaneously and separately, 14 and 15 days after VX-2 tumor implantation at the paravertebral muscle. The K trans and K 1 values were estimated using an in-house software program. The relationships between K trans and K 1 were analyzed using Pearson's correlation coefficients and linear/non-linear regression function. Assuming a linear relationship, K trans and K 1 exhibited a moderate positive correlations with both simultaneous (r=0.54-0.57) and separate (r=0.53-0.69) imaging. However, while the K trans and K 1 from separate imaging were linearly correlated, those from simultaneous imaging exhibited a non-linear relationship. The amount of change in K 1 associated with a unit increase in K trans varied depending on K trans values. The relationship between K trans and K 1 may be mis-interpreted with separate MR and PET acquisition. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Active Sampling Device for Determining Pollutants in Surface and Pore Water - the In Situ Sampler for Biphasic Water Monitoring

NASA Astrophysics Data System (ADS)

Supowit, Samuel D.; Roll, Isaac B.; Dang, Viet D.; Kroll, Kevin J.; Denslow, Nancy D.; Halden, Rolf U.

2016-02-01

We designed and evaluated an active sampling device, using as analytical targets a family of pesticides purported to contribute to honeybee colony collapse disorder. Simultaneous sampling of bulk water and pore water was accomplished using a low-flow, multi-channel pump to deliver water to an array of solid-phase extraction cartridges. Analytes were separated using either liquid or gas chromatography, and analysis was performed using tandem mass spectrometry (MS/MS). Achieved recoveries of fipronil and degradates in water spiked to nominal concentrations of 0.1, 1, and 10 ng/L ranged from 77 ± 12 to 110 ± 18%. Method detection limits (MDLs) were as low as 0.040-0.8 ng/L. Extraction and quantitation of total fiproles at a wastewater-receiving wetland yielded concentrations in surface water and pore water ranging from 9.9 ± 4.6 to 18.1 ± 4.6 ng/L and 9.1 ± 3.0 to 12.6 ± 2.1 ng/L, respectively. Detected concentrations were statistically indistinguishable from those determined by conventional, more laborious techniques (p > 0.2 for the three most abundant fiproles). Aside from offering time-averaged sampling capabilities for two phases simultaneously with picogram-per-liter MDLs, the novel methodology eliminates the need for water and sediment transport via in situ solid phase extraction.

Recent advances in simultaneous analysis of bisphenol A and its conjugates in human matrices: Exposure biomarker perspectives.

PubMed

Andra, Syam S; Austin, Christine; Yang, Juan; Patel, Dhavalkumar; Arora, Manish

2016-12-01

Human exposures to bisphenol A (BPA) has attained considerable global health attention and represents one of the leading environmental contaminants with potential adverse health effects including endocrine disruption. Current practice of measuring of exposure to BPA includes the measurement of unconjugated BPA (aglycone) and total (both conjugated and unconjugated) BPA; the difference between the two measurements leads to estimation of conjugated forms. However, the measurement of BPA as the end analyte leads to inaccurate estimates from potential interferences from background sources during sample collection and analysis. BPA glucuronides (BPAG) and sulfates (BPAS) represent better candidates for biomarkers of BPA exposure, since they require in vivo metabolism and are not prone to external contamination. In this work, the primary focus was to review the current state of the art in analytical methods available to quantitate BPA conjugates. The entire analytical procedure for the simultaneous extraction and detection of aglycone BPA and conjugates is covered, from sample pre-treatment, extraction, separation, ionization, and detection. Solid phase extraction coupled with liquid chromatograph and tandem mass spectrometer analysis provides the most sensitive detection and quantification of BPA conjugates. Discussed herein are the applications of BPA conjugates analysis in human exposure assessment studies. Measuring these potential biomarkers of BPA exposure has only recently become analytically feasible and there are limitations and challenges to overcome in biomonitoring studies. Copyright © 2016 Elsevier B.V. All rights reserved.

Simultaneous determination of tetrahydropalmatine, protopine, and palmatine in rat plasma by LC-ESI-MS and its application to a pharmacokinetic study.

PubMed

Ma, Hongda; Wang, Yongjun; Guo, Tao; He, Zhonggui; Chang, Xinyu; Pu, Xiaohui

2009-02-20

A sensitive and specific liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) method has been developed and validated for the simultaneous quantification of tetrahydropalmatine, protopine and palmatine in rat plasma using phenacetin as the internal standard (IS). Two hundred microliters plasma samples were extracted by dichloromethane under a strong basic condition. The analytes were separated by a C18 column and detected with a single quadrupole mass spectrometer. The used mobile phase was acetonitrile-water (40:60, v/v) containing 5mM ammonium acetate and 0.2% glacial acetic acid. Detection was carried out by positive electrospray ionization in selected ion reaction (SIR) mode at m/z 356.6 for tetrahydropalmatine, 354.6 for protopine, 352.6 for palmatine and 180.4 for the IS, respectively. The method was validated over the concentration range of 1.00-500ngmL(-1) and the lower limit of quantification (LLOQ) was 1.00ngmL(-1) for all three analytes. The intra- and inter-day precision values were less than 9% relative standard deviation (R.S.D.), and the relative error ranged from -7.4 to 4.8%. The extraction recoveries were on average 91.42% for tetrahydropalmatine, 84.75% for protopine, 57.26% for palmatine, and 83.18% for IS. The validated method was successfully applied to a pharmacokinetic study of tetrahydropalmatine, protopine and palmatine in rats after oral administration of Rhizoma Corydalis Decumbentis extract.

Influence of pomegranate seed oil and bitter melon aqueous extract on polyunsaturated fatty acids and their lipoxygenase metabolites concentration in serum of rats.

PubMed

Białek, Agnieszka; Jelińska, Małgorzata; Tokarz, Andrzej; Pergół, Aleksandra; Pinkiewicz, Katarzyna

2016-11-01

Competition with polyunsaturated fatty acids (PUFA) and an impact on eicosanoid biosynthesis may be one of mechanisms of conjugated linolenic acids (CLnA) action. The aim of this study was to investigate the influence of diet supplementation with pomegranate seed oil, containing punicic acid (PA)-one of CLnA isomers, and an aqueous extract of dried bitter melon fruits, administered separately or together, on PUFA and their lipoxygenase metabolites' concentration in serum of rats. Percentage share of fatty acids was diversified in relation to applied supplementation. PA was only detected in serum of pomegranate seed oil supplemented group, where it was about 1%. Cis-9, trans-11 conjugated linoleic acid (rumenic acid, RA) level tended to increase in group supplemented simultaneously with both dietary supplements whereas its highest share in total fatty acids pool was detected in group receiving solely bitter melon dried fruits aqueous extract. This indicates that consumption of bitter melon tea significantly increased RA content in fatty acids pool in serum. However, pomegranate seed oil elevated procarcinogenic 12-hydroxyeicosatetraenoic acid concentration. Taking into account that pomegranate seed oil and bitter melon dried fruits are dietary supplements accessible worldwide and willingly consumed, the biological significance of this phenomenon should be further investigated. We presume, that there may be a need for some precautions concerning the simultaneous use of these products. Copyright © 2016 Elsevier Inc. All rights reserved.

Developing a system for blind acoustic source localization and separation

NASA Astrophysics Data System (ADS)

Kulkarni, Raghavendra

This dissertation presents innovate methodologies for locating, extracting, and separating multiple incoherent sound sources in three-dimensional (3D) space; and applications of the time reversal (TR) algorithm to pinpoint the hyper active neural activities inside the brain auditory structure that are correlated to the tinnitus pathology. Specifically, an acoustic modeling based method is developed for locating arbitrary and incoherent sound sources in 3D space in real time by using a minimal number of microphones, and the Point Source Separation (PSS) method is developed for extracting target signals from directly measured mixed signals. Combining these two approaches leads to a novel technology known as Blind Sources Localization and Separation (BSLS) that enables one to locate multiple incoherent sound signals in 3D space and separate original individual sources simultaneously, based on the directly measured mixed signals. These technologies have been validated through numerical simulations and experiments conducted in various non-ideal environments where there are non-negligible, unspecified sound reflections and reverberation as well as interferences from random background noise. Another innovation presented in this dissertation is concerned with applications of the TR algorithm to pinpoint the exact locations of hyper-active neurons in the brain auditory structure that are directly correlated to the tinnitus perception. Benchmark tests conducted on normal rats have confirmed the localization results provided by the TR algorithm. Results demonstrate that the spatial resolution of this source localization can be as high as the micrometer level. This high precision localization may lead to a paradigm shift in tinnitus diagnosis, which may in turn produce a more cost-effective treatment for tinnitus than any of the existing ones.

Simultaneous determination of eight flavonoids in propolis using chemometrics-assisted high performance liquid chromatography-diode array detection.

PubMed

Sun, Yan-Mei; Wu, Hai-Long; Wang, Jian-Yao; Liu, Zhi; Zhai, Min; Yu, Ru-Qin

2014-07-01

A fast analytical strategy of second-order calibration method based on the alternating trilinear decomposition algorithm (ATLD)-assisted high performance liquid chromatography coupled with a diode array detector (HPLC-DAD) was established for the simultaneous determination of eight flavonoids (rutin, quercetin, luteolin, kaempferol, isorhamnetin, apigenin, galangin and chrysin) in propolis capsules samples. The chromatographic separation was implemented on a Wondasil™ C18 column (250mm×4.6mm, 5μm) within 13min with a binary mobile phase composed of water with 1% formic acid and methanol at a flow rate of 1.0mLmin(-1) after flavonoids were only extracted with methanol by ultrasound extraction for 15min. The baseline problem was overcome by considering background drift as additional compositions or factors as well as the target analytes, and ATLD was employed to handle the overlapping peaks from analytes of interest or from analytes and co-eluting matrix compounds. The linearity was good with the correlation coefficients no less than 0.9947; the limit of detections (LODs) within the range of 3.39-33.05ngmL(-1) were low enough; the accuracy was confirmed by the recoveries ranged from 91.9% to 110.2% and the root-mean-square-error of predictions (RMSEPs) less than 1.1μg/mL. The results indicated that the chromatographic method with the aid of ATLD is efficient, sensitive and cost-effective and can realize the resolution and accurate quantification of flavonoids even in the presence of interferences, thus providing an alternative method for accurate quantification of analytes especially when the complete separation is not easily accomplished. The method was successfully applied to propolis capsules samples and the satisfactory results were obtained. Copyright © 2014 Elsevier B.V. All rights reserved.

Offline solid-phase extraction for preconcentration of pharmaceuticals and personal care products in environmental water and their simultaneous determination using the reversed phase high-performance liquid chromatography method.

PubMed

G Archana; Dhodapkar, Rita; Kumar, Anupama

2016-09-01

The present study reports a precise and simple offline solid-phase extraction (SPE) coupled with reversed-phase high-performance liquid chromatography (RP-HPLC) method for the simultaneous determination of five representative and commonly present pharmaceuticals and personal care products (PPCPs), a new class of emerging pollutants in the aquatic environment. The target list of analytes including ciprofloxacin, acetaminophen, caffeine benzophenone and irgasan were separated by a simple HPLC method. The column used was a reversed-phase C18 column, and the mobile phase was 1 % acetic acid and methanol (20:80 v/v) under isocratic conditions, at a flow rate of 1 mL min(-1). The analytes were separated and detected within 15 min using the photodiode array detector (PDA). The linearity of the calibration curves were obtained with correlation coefficients 0.98-0.99.The limit of detection (LOD), limit of quantification (LOQ), precision, accuracy and ruggedness demonstrated the reproducibility, specificity and sensitivity of the developed method. Prior to the analysis, the SPE was performed using a C18 cartridge to preconcentrate the targeted analytes from the environmental water samples. The developed method was applied to evaluate and fingerprint PPCPs in sewage collected from a residential engineering college campus, polluted water bodies such as Nag river and Pili river and the influent and effluent samples from a sewage treatment plant (STP) situated at Nagpur city, in the peak summer season. This method is useful for estimation of pollutants present in microquantities in the surface water bodies and treated sewage as compared to nanolevel pollutants detected by mass spectrometry (MS) detectors.

An efficient and target-oriented sample enrichment method for preparative separation of minor alkaloids by pH-zone-refining counter-current chromatography.

PubMed

Feng, Rui-Hong; Hou, Jin-Jun; Zhang, Yi-Bei; Pan, Hui-Qin; Yang, Wenzhi; Qi, Peng; Yao, Shuai; Cai, Lu-Ying; Yang, Min; Jiang, Bao-Hong; Liu, Xuan; Wu, Wan-Ying; Guo, De-An

2015-08-28

An efficient and target-oriented sample enrichment method was established to increase the content of the minor alkaloids in crude extract by using the corresponding two-phase solvent system applied in pH-zone-refining counter-current chromatography. The enrichment and separation of seven minor indole alkaloids from Uncaria rhynchophylla (Miq.) Miq. ex Havil(UR) were selected as an example to show the advantage of this method. An optimized two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (3:7:1:9, v/v) was used in this study, where triethylamine (TEA) as the retainer and hydrochloric acid (HCl) as the eluter were added at the equimolar of 10mM. Crude alkaloids of UR dissolved in the corresponding upper phase (containing 10mM TEA) were extracted twice with lower phase (containing 10mM TEA) and lower phase (containing 10mM HCl), respectively, the second lower phase extract was subjected to pH-zone-refining CCC separation after alkalization and desalination. Finally, from 10g of crude alkaloids, 4g of refined alkaloids was obtained and the total content of seven target indole alkaloids was increased from 4.64% to 15.78%. Seven indole alkaloids, including 54mg isocorynoxeine, 21mg corynoxeine, 46mg isorhynchophylline, 35mg rhynchophylline, 65mg hirsutine, 51mg hirsuteine and 27mg geissoschizine methylether were all simultaneously separated from 2.5g of refined alkaloids, with the purity of 86.4%, 97.5%, 90.3%, 92.1%, 98.5%, 92.3%, and 92.8%, respectively. The total content and purities of the seven minor indole alkaloids were tested by HPLC and their chemical structures were elucidated by ESI-HRMS and (1)H NMR. Copyright © 2015 Elsevier B.V. All rights reserved.

Simultaneous determination and pharmacokinetic study of three flavonoid glycosides in rat plasma by LC-MS/MS after oral administration of Rubus chingii Hu extract.

PubMed

Zan, Tao; Piao, Li; Wei, Yuntao; Gu, Yue; Liu, Baohua; Jiang, Daqing

2018-03-01

A simple and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of isoquercitrin, kaempferol-3-O-rutinoside and tiliroside in rat plasma. Plasma samples were deproteinized with methanol and separated on a Hypersil Gold C 18 column (2.1 × 50 mm, i.d., 3.0 μm) using gradient elution with the mobile phase of water and methanol at a flow rate of 0.4 mL/min. Mass spectrometric detection was performed with negative ion electrospray ionization in selected reaction monitoring mode. All analytes showed good linearity over their investigated concentration ranges (r 2  > 0.99). The lower limit of quantification was 1.0 ng/mL for isoquercitrin and 2.0 ng/mL for kaempferol-3-O-rutinoside and tiliroside, respectively. Intra- and inter-day precisions were <8.2% and accuracy ranged from -11.5 to 9.7%. The mean extraction recoveries of analytes and IS from rat plasma were >80.4%. The assay was successfully applied to investigate the pharmacokinetic study of the three ingredients after oral administration of Rubus chingii Hu to rats. Copyright © 2017 John Wiley & Sons, Ltd.

Simultaneous quantification of multiple components in rat plasma by UPLC-MS/MS and pharmacokinetic study after oral administration of Huangqi decoction.

PubMed

Zeng, Jia-Kai; Li, Yuan-Yuan; Wang, Tian-Ming; Zhong, Jie; Wu, Jia-Sheng; Liu, Ping; Zhang, Hua; Ma, Yue-Ming

2018-05-01

A rapid, sensitive and accurate UPLC-MS/MS method was developed for the simultaneous quantification of components of Huangqi decoction (HQD), such as calycosin-7-O-β-d-glucoside, calycosin-glucuronide, liquiritin, formononetin-glucuronide, isoliquiritin, liquiritigenin, ononin, calycosin, isoliquiritigenin, formononetin, glycyrrhizic acid, astragaloside IV, cycloastragenol, and glycyrrhetinic acid, in rat plasma. After plasma samples were extracted by protein precipitation, chromatographic separation was performed with a C 18 column, using a gradient of methanol and 0.05% acetic acid containing 4mm ammonium acetate as the mobile phase. Multiple reaction monitoring scanning was performed to quantify the analytes, and the electrospray ion source polarity was switched between positive and negative modes in a single run of 10 min. Method validation showed that specificity, linearity, accuracy, precision, extraction recovery, matrix effect and stability for 14 components met the requirements for their quantitation in biological samples. The established method was successfully applied to the pharmacokinetic study of multiple components in rats after intragastric administration of HQD. The results clarified the pharmacokinetic characteristics of multiple components found in HQD. This research provides useful information for understanding the relation between the chemical components of HQD and their therapeutic effects. Copyright © 2017 John Wiley & Sons, Ltd.

[Determination of 25 quinolones in cosmetics by liquid chromatography-tandem mass spectrometry].

PubMed

Lin, Li; Zhang, Yi; Tu, Xiaoke; Xie, Liqi; Yue, Zhenfeng; Kang, Haining; Wu, Weidong; Luo, Yao

2015-03-01

An analytical method was developed for the simultaneous determination of 25 quinolones, including danofloxacin mesylate, enrofloxacin, flumequine, oxloinic acid, ciprofloxacin, sarafloxacin, nalidixic acid, norfloxacin, and ofloxacin etc in cosmetics using direct extraction and liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Cosmetic sample was extracted by acidified acetonitrile, defatted by n-hexane and separated on Poroshell EC-C18 column with gradient elution program using acetonitrile and water (both containing 0. 1% formic acid) as the mobile phases and analyzed by LC-ESI-MS/MS under the positive mode using multiple reaction monitoring (MRM). The interference of matrix was reduced by the matrix-matched calibration standard curve. The method showed good linearities over the range of 1-200 mg/kg for the 25 quinolones with good linear correlation coefficients (r ≥ 0.999). The method detection limit of the 25 quinolones was 1.0 mg/kg, and the recoveries of all analytes in lotion, milky and cream cosmetics matrices ranged from 87.4% to 105% at the spiked levels of 1, 5 and 10 mg/kg with the relative standard deviations (RSD) of 4.54%-19.7% (n = 6). The results indicated that this method is simple, fast and credible, and suitable for the simultaneous determination of the quinolones in the above three types of cosmetics.

Simultaneous determination of twelve tea catechins by high-performance liquid chromatography with electrochemical detection.

PubMed

Sano, M; Tabata, M; Suzuki, M; Degawa, M; Miyase, T; Maeda-Yamamoto, M

2001-06-01

A high-performance liquid chromatographic method with electrochemical detection was developed for the determination of twelve tea catechins including four major catechins: epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG) and epigallocatechin gallate (EGCG); four of their epimers at the C-2 position, C, GC, CG and GCG; and four methylated catechin derivatives, epigallocatechin-3-O-(3-O-methyl)gallate, gallocatechin-3-O-(3-O-methyl)gallate, epigallocatechin-3-O-(4-O-methyl)gallate and epicatechin-3-O-(3-O-methyl)gallate. These catechins were separated on an ODS C18 reversed-phase column by isocratic elution with 0.1 M NaH2PO4 buffer (pH 2.5)-acetonitrile (87:13) containing 0.1 mM EDTA.2Na. The detection limits (S/N = 3) of these catechins were approximately 10-40 pmol ml-1 at an applied voltage of 600 mV. Extracting these catechins from tea leaf powder with H2O-acetonitrile (1:1) at 30 degrees C for 40 min inhibited the epimerization at C-2 significantly from these epicatechins compared to extraction with hot water at 90 degrees C. This analytical method is sensitive to and appropriate for the simultaneous determination of various biologically active catechins in green tea.

[Simultaneous determination of six fluorescent whitening agents in plastic and paper packaging materials by high performance liquid chromatography].

PubMed

Zhang, Juzhou; Ji, Shuilin; Cai, Huimei; Li, Jing; Wang, Yongxin; Wang, Jingqiu

2017-11-08

A novel analytical method was developed for the simultaneous determination of six fluorescent whitening agents (FWAs:FWA 135, FWA 184, FWA 185, FWA 199, FWA 378 and FWA 393) in paper and plastic food packaging materials by high performance liquid chromatography with fluorescence detection (HPLC-FLD). The sample was extracted with mixed solution of chloroform and acetonitrile (3:7, v/v), then cleaned up by HLB solid phase extraction column. Qualitative and quantitative analyses were carried out by HPLC. The sample was separated on a Phenomenex C18 column using acetonitrile and 5 mmol/L ammonium acetate aqueous solution as mobile phases. The results indicated that the linear range of FWA393 was 15-1500 μg/L and the linear ranges of the other five FWAs were 5-500 μg/L with correlation coefficients greater than 0.999. The recoveries in spiked samples were between 80.4% and 125.0% with RSDs ( n =6) of 1%-13%. Furthermore, this method was applied to analyze 12 samples in the market to verify the practicality of the method. The method showed the advantages of simplicity, high recovery and good precision, and is suitable for the detection of the six fluorescent whitening agents in food packaging materials.

Simultaneous determination of calycosin-7-O-β-d-glucoside, calycosin, formononetin, astragaloside IV and schisandrin in rat plasma by LC-MS/MS: application to a pharmacokinetic study after oral administration of Shenqi Wuwei chewable tablets.

PubMed

Sun, Xuehui; Zhang, Pingping; Wu, Xiujun; Wu, Qiong; Zhang, Mengmeng; An, Ye; Shi, Guobing

2014-08-01

A rapid, sensitive and reliable high-performance liquid chromatography-mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous quantification of the five main bioactive components, calycosin, calycosin-7-O-β-d-glucoside, formononetin, astragaloside IV and schisandrin in rat plasma after oral administration of Shenqi Wuwei chewable tablets. Plasma samples were extracted using solid-phase extraction separated on a CEC18 column and detected by MS with an electrospray ionization interface in multiple-reaction monitoring mode. Calibration curves offered linear ranges of two orders of magnitude with r > 0.995. The method had a lower limit of quantitation of 0.1, 0.02, 0.1, 1 and 0.1 ng/mL for calycosin, calycosin-7-O-β-d-glucoside, formononetin, astragaloside IV and schisandrin, respectively. Intra- and inter-day precisions (relative standard deviation) for all analytes ranged from 0.97 to 7.63% and from 3.45 to 10.89%, respectively. This method was successfully applied to the pharmacokinetic study of the five compounds in rats after oral administration of Shenqi Wuwei chewable tablets. Copyright © 2014 John Wiley & Sons, Ltd.

HPLC-ESI-MS/MS validated method for simultaneous quantification of zopiclone and its metabolites, N-desmethyl zopiclone and zopiclone-N-oxide in human plasma.

PubMed

Mistri, Hiren N; Jangid, Arvind G; Pudage, Ashutosh; Shrivastav, Pranav

2008-03-15

A simple, selective and sensitive isocratic HPLC method with triple quadrupole mass spectrometry detection has been developed and validated for simultaneous quantification of zopiclone and its metabolites in human plasma. The analytes were extracted using solid phase extraction, separated on Symmetry shield RP8 column (150 mm x 4.6 mm i.d., 3.5 microm particle size) and detected by tandem mass spectrometry with a turbo ion spray interface. Metaxalone was used as an internal standard. The method had a chromatographic run time of 4.5 min and linear calibration curves over the concentration range of 0.5-150 ng/mL for both zopiclone and N-desmethyl zopiclone and 1-150 ng/mL for zopiclone-N-oxide. The intra-batch and inter-batch accuracy and precision evaluated at lower limit of quantification and quality control levels were within 89.5-109.1% and 3.0-14.7%, respectively, for all the analytes. The recoveries calculated for the analytes and internal standard were > or = 90% from spiked plasma samples. The validated method was successfully employed for a comparative bioavailability study after oral administration of 7.5 mg zopiclone (test and reference) to 16 healthy volunteers under fasted condition.

Investigation of high duty factor ISR RFQ-1000

NASA Astrophysics Data System (ADS)

Lu, Y. R.; Chen, C. E.; Fang, J. X.; Gao, S. L.; Guo, J. F.; Guo, Z. Y.; Li, D. S.; Li, W. G.; Pan, O. J.; Ren, X. T.; Wu, Y.; Yan, X. Q.; Yu, J. X.; Yu, M. L.; Ratzinger, U.; Deitinghoff, H.; Klein, H.; Schempp, A.

2003-12-01

Two Integral Split Ring (ISR) RFQs with high duty factor of 16.7% have been designed for the application of heavy ion implantation and built in the past several years at Institute of Heavy Ion Physics (IHIP) in Peking University. Two kinds of PIG ion sources with permanent magnets and LEBT were installed and optimized for the injection into these two RFQs. The positive O+ and negative O- ions were extracted and accelerated separately as well as simultaneously. The output macro pulse O- beam current reached 660 μA at a transmission efficiency of more than 82%. The N+ beam was also accelerated with similar transmission efficiency, but the output current intensity for positive ions were lower than the negative ions because of the extracted current limitation of ion sources. The improvements, especially for high duty factor and experimental results with the 1 MeV ISR RFQ will be presented in this paper.

[Simultaneous determination of six synthetic sweeteners in food by high performance liquid chromatography-tandem mass spectrometry].

PubMed

Liu, Xiaoxi; Ding, Li; Liu, Jinxia; Zhang, Ying; Huang, Zhiqiang; Wang, Libing; Chen, Bo

2010-11-01

A simple and sensitive method for the determination of six synthetic sweeteners (sodium cyclamate, saccharin sodium, acesulfame-K, aspartame, alitame and neotame) in food was developed. The synthetic sweeteners were extracted by methanol-water (1 : 1, v/v). The extract was separated on a C18 column using 0.1% (v/v) formic acid-5 mmol/L ammonium formate/acetonitrile as mobile phase, and then detected by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) using multiple reaction monitoring (MRM) mode. The good linearities (r > 0.998) were achieved for all the analytes over the range of 20-500 microg/L. The recoveries obtained ranged from 81.3% to 106.0% at three spiked concentrations, with the relative standard deviations lower than 11%. The established method has been successfully applied to the determination of synthetic sweeteners in food.

[Determination of four bisphenolic compounds in drinking water by liquid chromatography-tandem mass spectrometry].

PubMed

Hu, Xiaojian; Zhang, Haijing; Wang, Xiaohong; Ding, Changming; Lin, Shaobin

2015-05-01

To simultaneously determine the four bisphenolic compounds (bisphenol F, bisphenol A, tetrachlorobisphenol A and tetrabromobisphenol A) in drinking water by liquid chromatography tandem mass spectrometry. 200 ml water sample was extracted by solid-phase extraction, eluted with methanol and analyzed by liquid chromatography tandem mass spectrometry under the MRM mode. The separation was carried out on a T3 column (2.1 mm x 150 mm, 3 μm). The limits of detection for the four bisphenolic compounds were in the range of 0.20 - 5.5 ng/L. The mean recoveries at the two spiked levels were 87.1% - 109.0% with the intra-day precision between 6.3% - 12.4% and inter-day precision between 4.5% - 15.4%. The method was applied for determination of 15 water samples. The method was sensitive, precise and accurate.

Oil shale retorting and combustion system

DOEpatents

Pitrolo, Augustine A.; Mei, Joseph S.; Shang, Jerry Y.

1983-01-01

The present invention is directed to the extraction of energy values from l shale containing considerable concentrations of calcium carbonate in an efficient manner. The volatiles are separated from the oil shale in a retorting zone of a fluidized bed where the temperature and the concentration of oxygen are maintained at sufficiently low levels so that the volatiles are extracted from the oil shale with minimal combustion of the volatiles and with minimal calcination of the calcium carbonate. These gaseous volatiles and the calcium carbonate flow from the retorting zone into a freeboard combustion zone where the volatiles are burned in the presence of excess air. In this zone the calcination of the calcium carbonate occurs but at the expense of less BTU's than would be required by the calcination reaction in the event both the retorting and combustion steps took place simultaneously. The heat values in the products of combustion are satisfactorily recovered in a suitable heat exchange system.

Capillary electrophoresis method for the analysis of organic acids and amino acids in the presence of strongly alternating concentrations of aqueous lactic acid.

PubMed

Laube, Hendrik; Boden, Jana; Schneider, Roland

2017-07-01

During the production of bio-based bulk chemicals, such as lactic acid (LA), organic impurities have to be removed to produce a ready-to-market product. A capillary electrophoresis method for the simultaneous detection of LA and organic impurities in less than 10 min was developed. LA and organic impurities were detected using a direct UV detection method with micellar background electrolyte, which consisted of borate and sodium dodecyl sulfate. We investigated the effects of electrolyte composition and temperature on the speed, sensitivity, and robustness of the separation. A few validation parameters, such as linearity, limit of detection, and internal and external standards, were evaluated under optimized conditions. The method was applied for the detection of LA and organic impurities, including tyrosine, phenylalanine, and pyroglutamic acid, in samples from a continuous LA fermentation process from post-extraction tapioca starch and yeast extract.

A comparison of solid-phase microextraction (SPME) with simultaneous distillation-extraction (SDE) for the analysis of volatile compounds in heated beef and sheep fats.

PubMed

Watkins, P J; Rose, G; Warner, R D; Dunshea, F R; Pethick, D W

2012-06-01

A comparison has been made on the application of SPME and SDE for the extraction of volatile compounds from heated beef and sheep fats with separation and measurement by gas chromatography-mass spectrometry. As far as we know, this report represents the first time that such a comparison has been made for the measurement of volatile compounds in heated sheep fat. Approximately 100 compounds (in relatively high abundance) were characterised in the volatile profiles of heated beef and sheep fats using both techniques. Differences were observed in the volatile profiles obtained from each technique, independent of compound class. Rather than rate one technique as superior to another, the techniques can be regarded as complementary to each other. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Simple and sensitive analysis of long-chain free fatty acids in milk by fluorogenic derivatization and high-performance liquid chromatography.

PubMed

Lu, Chi-Yu; Wu, Hsin-Lung; Chen, Su-Hwei; Kou, Hwang-Shang; Wu, Shou-Mei

2002-01-02

A highly sensitive high-performance liquid chromatography (HPLC) method is described for the simultaneous determination of some important saturated and unsaturated fatty acids in milk, including lauric (dodecanoic), myristic (tetradecanoic), palmitic (hexadecanoic), stearic (octadecanoic), palmitoleic (hexadecenoic), oleic (octadecenoic), and linoleic acids (octadecadienoic acids). The fatty acids were fluorogenically derivatized with 2-(2-naphthoxy)ethyl 2-(piperidino)ethanesulfonate (NOEPES) as their naphthoxyethyl derivatives. The resulting derivatives were separated by isocratic HPLC and monitored with a fluorometric detector (lambdaex = 235 nm, lambdaem = 350 nm). The fatty acids in milk were extracted with toluene, and the extract with the fatty acids was directly derivatized with NOEPES without solvent replacement. Determination of long-chain free fatty acids in milk is feasible by a standard addition method. A small amount of milk product, 10 microL, is sufficient for the analysis.

Development of a chiral micellar electrokinetic chromatography-tandem mass spectrometry assay for simultaneous analysis of warfarin and hydroxywarfarin metabolites: application to the analysis of patients serum samples.

PubMed

Wang, Xiaochun; Hou, Jingguo; Jann, Michael; Hon, Yuen Yi; Shamsi, Shahab A

2013-01-04

The enantioseparation of warfarin (WAR) along with the five positional and optical isomers is challenging because of the difficulty to simultaneously separate and quantitate these chiral compounds. Currently, no effective chiral CE-MS methods exist for the simultaneous enantioseparation of WAR and all its hydroxylated metabolites in a single run. Polymeric surfactants (aka. molecular micelles) are particularly compatible with micellar electrokinetic chromatography-mass spectrometry (MEKC-MS) because they have a wider elution window for enantioseparation and do not interfere with the MS detection of chiral drugs. Using polysodium N-undecenoyl-L,L-leucylvalinate (poly-L,L-SULV) as a chiral pseudophase in MEKC-MS baseline separation of WAR, its five metabolites along with the internal standard was obtained in 45 min. This is in comparison to 100 min required for separation of the same mixture with packed column CEC-MS using a vancomycin chiral stationary phase. Serum samples were extracted with mixed-mode anion-exchange (MAX) cartridge with recoveries of greater than 85.2% for all WAR and hydroxywarfarin (OH-WAR) metabolites. Utilizing the tandem MS and multiple reaction monitoring mode, the MEKC-MS/MS method was used to simultaneously generate calibration curves over a concentration range from 2 to 5000 ng/mL for R- and S-warfarin, 5 to 1000 ng/mL for R- and S-6-, 7-, 8- and 10-OH-WAR and 10 to 1000 ng/mL for R and S-4'-OH-WAR. For the first time, the limits of detection and quantitation for most WAR metabolites by MEKC-MS/MS were found to be at levels of 2 and 5 ng/mL, respectively. The method was successfully applied for the first time to analyze WAR and its metabolites in plasma samples of 55 patients undergoing WAR therapy, demonstrating the potential of chiral MEKC-MS/MS method to accurately quantitate with high sensitivity. Copyright © 2012 Elsevier B.V. All rights reserved.

Simultaneous analysis of tert-butylhydroquinone, tert-butylquinone, butylated hydroxytoluene, 2-tert-butyl-4-hydroxyanisole, 3-tert-butyl-4-hydroxyanisole, α-tocopherol, γ-tocopherol, and δ-tocopherol in edible oils by normal-phase high performance liquid chromatography.

PubMed

Li, Jun; Bi, Yanlan; Sun, Shangde; Peng, Dan

2017-11-01

A normal-phase high performance liquid chromatography method for the simultaneous determination of tert-butylhydroquinone, tert-butylquinone, butylated hydroxytoluene, 2-tert-butyl-4-hydroxyanisole, 3-tert-butyl-4-hydroxyanisole, α-tocopherol, γ-tocopherol, and δ-tocopherol in edible oils was investigated. A silica column was used to separate the analytes with the gradient elution. An ultraviolet-visible detector was set at dual wavelengths mode (280 and 310nm). The column temperature was 30°C. The analytes were directly extracted with methanol. Results showed that the normal-phase high performance liquid chromatography method performed well with wide liner ranges (0.10∼500.00μg/mL, R 2 >0.9998), low limits of detection and quantitation (below 0.40 and 1.21μg/mL, respectively), and good recoveries (81.38∼102.34% in soybean oils and 83.03∼100.79% in lard, respectively). The reduction of tert-butylquinone caused by the reverse-phase high performance liquid chromatography during the injection was avoided with the current normal-phase method. The two isomers of butylated hydroxyanisole can also be separated with good resolution. Copyright © 2017 Elsevier Ltd. All rights reserved.

Simultaneous analysis of Cr(III), Cr(VI), and chromium picolinate in foods using capillary electrophoresis-inductively coupled plasma mass spectrometry.

PubMed

Chen, YiQuan; Chen, JinFa; Xi, Zhiming; Yang, Guidi; Wu, Zujian; Li, JianRong; Fu, FengFu

2015-05-01

We herein reported a method for the simultaneous detection of trace Cr(VI), Cr(III), and chromium(III) picolinate (CrPic) in foods using CE-ICP-MS together with ultrasonic-assisted extraction. The Cr(III) (Cr(3+) ) was chelated with trans-1,2-diaminocyclohexane-N,N,N´,N´-tetraacetic acid (DCTA) to form a single charged Cr-DCTA(-) complex. Then, Cr(VI) (CrO4 (2-) ), Cr-DCTA(-) , and CrPic were separated by CE within 8 min under a separation voltage of -13 KV followed by their monitoring with ICP mass spectrometer (ICP-MS). The proposed method is simple, effective, and sensitive. It has an instrument detection limit of 0.10, 0.18, and 0.20 ngCr/mL for Cr(VI), Cr(III), and CrPic, respectively. With the help of the methods, we have successfully determined Cr(VI), Cr(III), and CrPic in nutritional supplement (CrPic yeast tablet) with an RSD (n = 5) <6% and a recovery of 93-103%. The experimental results showed that CrPic was the main speciation of chromium in the nutritional supplement, with a concentration of 1514.6 μg Cr/g. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous quantification of acetanilide herbicides and their oxanilic and sulfonic acid metabolites in natural waters.

PubMed

Heberle, S A; Aga, D S; Hany, R; Müller, S R

2000-02-15

This paper describes a procedure for simultaneous enrichment, separation, and quantification of acetanilide herbicides and their major ionic oxanilic acid (OXA) and ethanesulfonic acid (ESA) metabolites in groundwater and surface water using Carbopack B as a solid-phase extraction (SPE) material. The analytes adsorbed on Carbopack B were eluted selectively from the solid phase in three fractions containing the parent compounds (PCs), their OXA metabolites, and their ESA metabolites, respectively. The complete separation of the three compound classes allowed the analysis of the neutral PCs (acetochlor, alachlor, and metolachlor) and their methylated OXA metabolites by gas chromatography/mass spectrometry. The ESA compounds were analyzed by high-performance liquid chromatography with UV detection. The use of Carbopack B resulted in good recoveries of the polar metabolites even from large sample volumes (1 L). Absolute recoveries from spiked surface and groundwater samples ranged between 76 and 100% for the PCs, between 41 and 91% for the OXAs, and between 47 and 96% for the ESAs. The maximum standard deviation of the absolute recoveries was 12%. The method detection limits are between 1 and 8 ng/L for the PCs, between 1 and 7 ng/L for the OXAs, and between 10 and 90 ng/L for the ESAs.

Multispectral computational ghost imaging with multiplexed illumination

NASA Astrophysics Data System (ADS)

Huang, Jian; Shi, Dongfeng

2017-07-01

Computational ghost imaging has attracted wide attention from researchers in many fields over the last two decades. Multispectral imaging as one application of computational ghost imaging possesses spatial and spectral resolving abilities, and is very useful for surveying scenes and extracting detailed information. Existing multispectral imagers mostly utilize narrow band filters or dispersive optical devices to separate light of different wavelengths, and then use multiple bucket detectors or an array detector to record them separately. Here, we propose a novel multispectral ghost imaging method that uses one single bucket detector with multiplexed illumination to produce a colored image. The multiplexed illumination patterns are produced by three binary encoded matrices (corresponding to the red, green and blue colored information, respectively) and random patterns. The results of the simulation and experiment have verified that our method can be effective in recovering the colored object. Multispectral images are produced simultaneously by one single-pixel detector, which significantly reduces the amount of data acquisition.

A nonradioactive high-performance liquid chromatographic microassay for uridine 5'-monophosphate synthase, orotate phosphoribosyltransferase, and orotidine 5'-monophosphate decarboxylase.

PubMed

Krungkrai, J; Wutipraditkul, N; Prapunwattana, P; Krungkrai, S R; Rochanakij, S

2001-12-15

A novel nonradioactive, microassay method has been developed to determine simultaneously the two enzymatic activities of orotate phosphoribosyltransferase (OPRTase) and orotidine 5'-monophosphate decarboxylase (ODCase), either as a bifunctional protein (uridine 5'-monophosphate synthase, UMPS) or as separate enzymes. Substrates (orotate for OPRTase or orotidine 5'-monophosphate for ODCase) and a product (UMP) of the enzymatic assay were separated by high-performance liquid chromatography (HPLC) using a reversed-phase column and an ion-pairing system; the amount of UMP was quantified by dual-wavelength uv detection at 260 and 278 nm. This HPLC assay can easily detect picomole levels of UMP in enzymatic reactions using low specific activity UMPS of mammalian cell extracts, which is difficult to do with the other nonradioactive assays that have been described. The HPLC assay is suitable for use in protein purification and for kinetic study of these enzymes. (c)2001 Elsevier Science.

308-nm excimer laser in endodontics

NASA Astrophysics Data System (ADS)

Liesenhoff, Tim

1992-06-01

Root canal preparation was performed on 20 extracted human teeth. After opening the coronal pulp, the root canals were prepared by 308 nm excimer laser only. All root canals were investigated under SEM after separation in the axial direction. By sagittal separation of the mandibles of freshly slaughtered cows, it was possible to get access to the tissues and irradiate under optical control. Under irradiation of excimer laser light, tissue starts to fluoresce. It was possible to demonstrate that each tissue (dentin, enamel, bone, pulpal, and connective tissue) has a characteristic spectral pattern. The SEM analyses showed that it is well possible to prepare root canals safely. All organic soft tissue has been removed by excimer laser irradiation. There was no case of via falsa. The simultaneous spectroscopic identification of the irradiated tissue provides a safe protection from overinstrumentation. First clinical trials on 20 patients suffering of chronical apical parodontitis have been carried out successfully.

Separation of two major chalcones from Angelica keiskei by high-speed counter-current chromatography.

PubMed

Kil, Yun-Seo; Nam, Joo-Won; Lee, Jun; Seo, Eun Kyoung

2015-08-01

Angelica keiskei (Shin-sun cho) is an edible higher plant with the beneficial preventive effects on cancer, hypertension, and coronary heart disease. Two bioactive chalcones of Shin-sun cho, xanthoangelol (1) and 4-hydroxyderricin (2), were separated simultaneously by using high-speed counter-current chromatography with a two-phase solvent system composed of n-hexane-EtOAc-MeOH-H2O (9:5:9:4). Only nonconsuming processes, solvent fractionations and Sephadex LH-20 column chromatography, were conducted as presteps. Xanthoangelol (1, 35.9 mg, 99.9 % purity at 254 and 365 nm) and 4-hydroxyderricin (2, 4.4 mg, 98.7 % purity at 254 nm and 98.8 % purity at 365 nm) were successfully purified from 70 mg of the processed extract from A. keiskei. The structures of two compounds were confirmed by (1)H- and (13)C-NMR analysis.

Fingerprinting postblast explosive residues by portable capillary electrophoresis with contactless conductivity detection.

PubMed

Kobrin, Eeva-Gerda; Lees, Heidi; Fomitšenko, Maria; Kubáň, Petr; Kaljurand, Mihkel

2014-04-01

A portable capillary electrophoretic system with contactless conductivity detection was used for fingerprint analysis of postblast explosive residues from commercial organic and improvised inorganic explosives on various surfaces (sand, concrete, metal witness plates). Simple extraction methods were developed for each of the surfaces for subsequent simultaneous capillary electrophoretic analysis of anions and cations. Dual-opposite end injection principle was used for fast (<4 min) separation of 10 common anions and cations from postblast residues using an optimized separation electrolyte composed of 20 mM MES, 20 mM l-histidine, 30 μM CTAB and 2 mM 18-crown-6. The concentrations of all ions obtained from the electropherograms were subjected to principal component analysis to classify the tested explosives on all tested surfaces, resulting in distinct cluster formations that could be used to verify (each) type of the explosive. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Online combination of reversed-phase/reversed-phase and porous graphitic carbon liquid chromatography for multicomponent separation of proteomics and glycoproteomics samples.

PubMed

Lam, Maggie P Y; Lau, Edward; Siu, S O; Ng, Dominic C M; Kong, Ricky P W; Chiu, Philip C N; Yeung, William S B; Lo, Clive; Chu, Ivan K

2011-11-01

In this paper, we describe an online combination of reversed-phase/reversed-phase (RP-RP) and porous graphitic carbon (PGC) liquid chromatography (LC) for multicomponent analysis of proteomics and glycoproteomics samples. The online RP-RP portion of this system provides comprehensive 2-D peptide separation based on sequence hydrophobicity at pH 2 and 10. Hydrophilic components (e.g. glycans, glycopeptides) that are not retained by RP are automatically diverted downstream to a PGC column for further trapping and separation. Furthermore, the RP-RP/PGC system can provide simultaneous extension of the hydropathy range and peak capacity for analysis. Using an 11-protein mixture, we found that the system could efficiently separate native peptides and released N-glycans from a single sample. We evaluated the applicability of the system to the analysis of complex biological samples using 25 μg of the lysate of a human choriocarcinoma cell line (BeWo), confidently identifying a total of 1449 proteins from a single experiment and up to 1909 distinct proteins from technical triplicates. The PGC fraction increased the sequence coverage through the inclusion of additional hydrophilic sequences that accounted for up to 6.9% of the total identified peptides from the BeWo lysate, with apparent preference for the detection of hydrophilic motifs and proteins. In addition, RP-RP/PGC is applicable to the analysis of complex glycomics samples, as demonstrated by our analysis of a concanavalin A-extracted glycoproteome from human serum; in total, 134 potentially N-glycosylated serum proteins, 151 possible N-glycosylation sites, and more than 40 possible N-glycan structures recognized by concanavalin A were simultaneously detected. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Method of simultaneous stir bar sorptive extraction of phenethylamines and THC metabolite from urine.

PubMed

Goto, Yoshiyuki; Takeda, Shiho; Araki, Toshinori; Fuchigami, Takayuki

2011-10-01

Stir bar sorptive extraction is a technique used for extracting target substances from various aqueous matrixes such as environmental water, food, and biological samples. This type of extraction is carried out by rotating a coated stir bar is rotated in the sample solution. In particular, Twister bar is a commercial stir bar that is coated with polydimethylsiloxane (PDMS) and used to perform sorptive extraction. In this study, we developed a method for simultaneous detection of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, and a Δ(9)-tetrahydrocannabiniol (THC) metabolite in human urine. For extracting the target analytes, the Twister bar was simply stirred in the sample in the presence of a derivatizing agent. Using this technique, phenethylamines and the acidic THC metabolite can be simultaneously extracted from human urine. This method also enables the extraction of trace amounts of these substances with good reproducibility and high selectivity. The proposed method offers many advantages over other extraction-based approaches and is therefore well suited for screening psychoactive substances in urine specimens.

Distortion product otoacoustic emissions: comparison of sequential vs. simultaneous presentation of primary tones.

PubMed

Kumar, U Ajith; Maruthy, Sandeep; Chandrakant, Vishwakarma

2009-03-01

Distortion product otoacoustic emissions are one form of evoked otoacoustic emissions. DPOAEs provide the frequency specific information about the hearing status in mid and high frequency regions. But in most screening protocols TEOAEs are preferred as it requires less time compared to DPOAE. This is because, in DPOAE each stimulus is presented one after the other and responses are analyzed. Grason and Stadler Incorporation 60 (GSI-60) offer simultaneous presentation of four sets of primary tones at a time and checks for the DPOAE. In this mode of presentation, all the pairs are presented at a time and following that response is extracted separately whereas, in sequential mode primaries are presented in orderly fashion one after the other. In this article simultaneous and sequential protocols were used to compare the Distortion product otoacoustic emission amplitude, noise floor and administration time in individuals with normal hearing and mild sensori-neural (SN) hearing loss. In simultaneous protocols four sets of primary tones (i.e. 8 tones) were presented together whereas, in sequential presentation mode one set of primary tones was presented each time. Simultaneous protocol was completed in less than half the time required for the completion of sequential protocol. Two techniques yielded similar results at frequencies above 1000 Hz only in normal hearing group. In SN hearing loss group simultaneous presentation yielded signifi cantly higher noise floors and distortion product amplitudes. This result challenges the use of simultaneous presentation technique in neonatal hearing screening programmes and on other pathologies. This discrepancy between two protocols may be due to some changes in biomechanical process in the cochlear and/or due to higher distortion/noise produced by the system during the simultaneous presentation mode.

Development and validation of a method using supported liquid extraction for the simultaneous determination of midazolam and 1'-hydroxy-midazolam in human plasma by liquid chromatography with tandem mass spectrometry detection.

PubMed

Svanström, Camilla; Hansson, Gunnar P; Svensson, Leif D; Sennbro, Carl Johan

2012-01-25

The metabolic conversion of midazolam (MDZ) to its main metabolite 1'-hydroxy-midazolam (1-OH-MDZ) can be used as a probe drug for cytochrome P450 3A (CYP3A) activity. A sensitive method for the simultaneous determination of MDZ and its metabolite 1-OH-MDZ in human plasma using supported liquid extraction (SLE) in combination with liquid chromatography-tandem mass spectrometry (LC-MS/MS) detection was developed and validated. Plasma samples (100 μL) were diluted with 0.5M NH(3) (aq) containing deuterated internal standards. The samples were extracted with ethyl acetate on a 96-well SLE-plate. Separation was performed on a Symmetry Shield RP18 column using an acidic gradient running from 2% to 95% methanol in 3 min. Detection was performed using a triple quadrupole mass spectrometer running in positive electrospray selected reaction monitoring (SRM) mode. The validated dynamic range was 0.2-100 nmol/L for both analytes. In the concentration range 0.6-75 nmol/L the extraction recoveries were in the ranges 91.2-98.6% and 94.5-98.3% for MDZ and 1-OH-MDZ, respectively. Matrix effects were more pronounced for MDZ than for 1-OH-MDZ but the response was still 75.4% or higher compared to a reference. The overall repeatability was within 2.2-7.6% for both analytes, the overall reproducibility was within 3.1-10.2% for both analytes and the overall accuracy bias was within -1.1 to 7.5% for both analytes. The method was successfully applied to determine the plasma concentrations of MDZ and 1-OH-MDZ in 14 healthy volunteers up to 24h after administration of a single oral dose of 2mg MDZ. The SLE technology was found to be convenient and suitable for sample preparation, and the developed method was found to be rapid, selective and reproducible for the simultaneous determination of MDZ and 1-OH-MDZ in human plasma. Copyright © 2011 Elsevier B.V. All rights reserved.

Spectroscopic methods of process monitoring for safeguards of used nuclear fuel separations

NASA Astrophysics Data System (ADS)

Warburton, Jamie Lee

To support the demonstration of a more proliferation-resistant nuclear fuel processing plant, techniques and instrumentation to allow the real-time, online determination of special nuclear material concentrations in-process must be developed. An ideal materials accountability technique for proliferation resistance should provide nondestructive, realtime, on-line information of metal and ligand concentrations in separations streams without perturbing the process. UV-Visible spectroscopy can be adapted for this precise purpose in solvent extraction-based separations. The primary goal of this project is to understand fundamental URanium EXtraction (UREX) and Plutonium-URanium EXtraction (PUREX) reprocessing chemistry and corresponding UV-Visible spectroscopy for application in process monitoring for safeguards. By evaluating the impact of process conditions, such as acid concentration, metal concentration and flow rate, on the sensitivity of the UV-Visible detection system, the process-monitoring concept is developed from an advanced application of fundamental spectroscopy. Systematic benchtop-scale studies investigated the system relevant to UREX or PUREX type reprocessing systems, encompassing 0.01-1.26 M U and 0.01-8 M HNO3. A laboratory-scale TRansUranic Extraction (TRUEX) demonstration was performed and used both to analyze for potential online monitoring opportunities in the TRUEX process, and to provide the foundation for building and demonstrating a laboratory-scale UREX demonstration. The secondary goal of the project is to simulate a diversion scenario in UREX and successfully detect changes in metal concentration and solution chemistry in a counter current contactor system with a UV-Visible spectroscopic process monitor. UREX uses the same basic solvent extraction flowsheet as PUREX, but has a lower acid concentration throughout and adds acetohydroxamic acid (AHA) as a complexant/reductant to the feed solution to prevent the extraction of Pu. By examining UV-Visible spectra gathered in real time, the objective is to detect the conversion from the UREX process, which does not separate Pu, to the PUREX process, which yields a purified Pu product. The change in process chemistry can be detected in the feed solution, aqueous product or in the raffinate stream by identifying the acid concentration, metal distribution and the presence or absence of AHA. A fiber optic dip probe for UV-Visible spectroscopy was integrated into a bank of three counter-current centrifugal contactors to demonstrate the online process monitoring concept. Nd, Fe and Zr were added to the uranyl nitrate system to explore spectroscopic interferences and identify additional species as candidates for online monitoring. This milestone is a demonstration of the potential of this technique, which lies in the ability to simultaneously and directly monitor the chemical process conditions in a reprocessing plant, providing inspectors with another tool to detect nuclear material diversion attempts. Lastly, dry processing of used nuclear fuel is often used as a head-end step before solvent extraction-based separations such as UREX or TRUEX. A non-aqueous process, used fuel treatment by dry processing generally includes chopping of used fuel rods followed by repeated oxidation-reduction cycles and physical separation of the used fuel from the cladding. Thus, dry processing techniques are investigated and opportunities for online monitoring are proposed for continuation of this work in future studies.

Effects of a standardized Panax ginseng extract on the skeletal muscle of the rat: a comparative study in animals at rest and under exercise.

PubMed

Ferrando, A; Vila, L; Voces, J A; Cabral, A C; Alvarez, A I; Prieto, J G

1999-04-01

The effect of standardized Panax ginseng extract G115 on enzymatic activities, myotypological composition, capillaries and mitochondrial content was studied in the skeletal muscle of male rats Wistar. Simultaneously to the G115 administration the rats performed exercise. The animals were divided into 4 groups. The dose of the ginseng extract G115 was 50 mg/kg. The length of the experimental period was 12 weeks. After 24 hours of inactivity the muscles of the hindlimb were extracted. With regard to the enzymatic activities of the citrate synthase (CS) and lactate dehydrogenase (LDH), CS increases with exercise, while the LDH undergoes no major variations, either due to the exercise or the treatment. Treatment with G115 increases the capillary density and the mitochondrial content of the red gastrocnemius muscle. The results suggest that prolonged treatment with G115 increases the capillary density and the oxidative capacity of the muscles with greater aerobic potential in a manner similar to the performance of physical exercise. When exercise and treatment are combined, the effects that are obtained separately are not potentiated.

Determination of preservatives in cosmetics, cleaning agents and pharmaceuticals using fast liquid chromatography.

PubMed

Baranowska, Irena; Wojciechowska, Iwona; Solarz, Natalia; Krutysza, Ewa

2014-01-01

This paper reports the development of a method for simultaneously determining five preservatives in cosmetics, cleaning agents and pharmaceuticals by fast liquid chromatography. Methylisothiazolinone, methylchloroisothiazolinone, benzyl alcohol, sodium benzoate and methylparaben were separated on a Chromolith Fast Gradient reversed-phase 18e column using gradient elution with acetonitrile and a 0.1% aqueous solution of formic acid, with a run time of 3 min. The preparation of solid and liquid samples included ultrasonic extraction with methanol with recoveries ranging from 69 to 119%. The developed method was used to analyze samples of cosmetics (66 samples), cleaning agents (five samples) and pharmaceutical industry products (17 samples).

Using tea stalk lignocellulose as an adsorbent for separating decaffeinated tea catechins.

PubMed

Ye, J H; Jin, J; Liang, H L; Lu, J L; Du, Y Y; Zheng, X Q; Liang, Y R

2009-01-01

Lignocelluloses prepared from woody tea stalk, pine sawdust and sugarcane bagasse were used as adsorbents to isolate decaffeinated catechins from tea extracts and compared with synthetic macroporous resin HPD 600. HPD 600 had the highest adsorption capacity to catechins, followed by tea stalk lignocellulose while lignocelluloses of pine sawdust and bagasse the least. Tea stalk lignocellulose absorbed preferentially tea catechins and showed a good selectivity. HPD 600 absorbed caffeine and tea catechins simultaneously. The kinetics data of tea stalk lignocellulose showed a good fit with the Langmuir isotherm model. It is considered that tea stalk lignocellulose is an alternative low-cost adsorbent for preparing decaffeinated tea catechins.

Simultaneous analysis and monitoring of 16 UV filters in cosmetics by high-performance liquid chromatography.

PubMed

Kim, Dojung; Kim, Sangseop; Kim, Seol-A; Choi, Myoengsin; Kwon, Kyoung-Jin; Kim, Mijeong; Kim, Dong-Sup; Kim, Seung-Hee; Choi, Bo-Kyung

2012-01-01

Sixteen UV filters were simultaneously analyzed using the high-performance liquid chromatographic method. They were drometrizole (USAN Drometrizole), 4-methylbenzylidene camphor (USAN Enzacamene), menthyl anthranilate (USAN Menthyl anthranilate), benzophenone-3 (USAN Oxybenzone), benzophenone-8 (USAN Dioxybenzone), butyl methoxydibenzoylmethane (USAN Avobenzone), ethylhexyl triazone (USAN Octyl triazone), octocrylene (USAN Octocrylene), ethylhexyl dimethyl p-aminobenzoic acid (USAN Padimate O), ethylhexyl methoxycinnamate (USAN Octinoxate), p-aminobenzoic acid (USAN Aminobenzoic acid), 2-phenylbenzimidazole-5-sulfonic acid (USAN Ensulizole), isoamyl p-methoxycinnamate (USAN Amiloxate), and recent UV filters such as diethylhexyl butamidotriazone (USAN Iscotrizinol), methylene bis-benzotriazolyl tetramethylbutylphenol (USAN Bisoctrizole), and terephthalylidene dicamphor sulfonic acid (USAN Ecamsule). Separation of the UV filters was carried out in a C(18) column with a gradient of methanol-phosphate buffer, and the UV detection was at 300, 320, or 360 nm without any interference. The limits of detection were between 0.08 and 1.94 μg/ml, and the limits of quantitation were between 0.24 and 5.89 μg/ml. The extracting solvent for the UV filters was methanol, except for ethylhexyl triazone and methylene bis-benzotriazolyl tetramethylbutylphenol, which were prepared with tetrahydrofuran. The recoveries from spiked samples were between 94.90% and 116.54%, depending on the matrixes used. The developed method was applied to 23 sunscreens obtained from local markets, and the results were acceptable to their own criteria and to maximum authorized concentrations. Consequently, these results would provide a simple extracting method and a simultaneous determination for various UV filters, which can improve the quality control process as well as the environmental monitoring of sunscreens.

Combining cationic and anionic mixed-mode sorbents in a single cartridge to extract basic and acidic pharmaceuticals simultaneously from environmental waters.

PubMed

Salas, Daniela; Borrull, Francesc; Fontanals, Núria; Marcé, Rosa Maria

2018-01-01

The aim of the present study is to broaden the applications of mixed-mode ion-exchange solid-phase extraction sorbents to extract both basic and acidic compounds simultaneously by combining the sorbents in a single cartridge and developing a simplified extraction procedure. Four different cartridges containing negative and positive charges in the same configuration were evaluated and compared to extract a group of basic, neutral, and acidic pharmaceuticals selected as model compounds. After a thorough optimization of the extraction conditions, the four different cartridges showed to be capable of retaining basic and acidic pharmaceuticals simultaneously through ionic interactions, allowing the introduction of a washing step with 15 mL methanol to eliminate interferences retained by hydrophobic interactions. Using the best combined cartridge, a method was developed, validated, and further applied to environmental waters to demonstrate that the method is promising for the extraction of basic and acidic compounds from very complex samples.

Simultaneous quantification of lenalidomide, ibrutinib and its active metabolite PCI-45227 in rat plasma by LC-MS/MS: application to a pharmacokinetic study.

PubMed

Veeraraghavan, Sridhar; Viswanadha, Srikant; Thappali, Satheeshmanikandan; Govindarajulu, Babu; Vakkalanka, Swaroopkumar; Rangasamy, Manivannan

2015-03-25

Efficacy assessments using a combination of ibrutinib and lenalidomide necessitate the development of an analytical method for determination of both drugs in plasma with precision. A high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of lenalidomide, ibrutinib, and its active metabolite PCI45227 in rat plasma. Extraction of lenalidomide, ibrutinib, PCI45227 and tolbutamide (internal standard; IS) from 50 μl rat plasma was carried out by liquid-liquid extraction with ethyl acetate:dichloromethane (90:10) ratio. Chromatographic separation of analytes was performed on YMC pack ODS AM (150 mm × 4.6 mm, 5 μm) column under gradient conditions with acetonitrile:0.1% formic acid buffer as the mobile phases at a flow rate of 1 ml/min. Precursor ion and product ion transition for analytes and IS were monitored on a triple quadrupole mass spectrometer, operated in the selective reaction monitoring with positive ionization mode. Method was validated over a concentration range of 0.72-183.20 ng/ml for ibrutinib, 0.76-194.33 ng/ml for PCI-45227 and 1.87-479.16 ng/ml for lenalidomide. Mean extraction recovery for ibrutinib, PCI-45227, lenalidomide and IS of 75.2%, 84.5%, 97.3% and 92.3% were consistent across low, medium, and high QC levels. Precision and accuracy at low, medium and high quality control levels were less than 15% across analytes. Bench top, wet, freeze-thaw and long term stability was evaluated for all the analytes. The analytical method was applied to support a pharmacokinetic study of simultaneous estimation of lenalidomide, ibrutinib, and its active metabolite PCI-45227 in Wistar rat. Assay reproducibility was demonstrated by re-analysis of 18 incurred samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Selective aqueous extraction of organics coupled with trapping by membrane separation

DOEpatents

van Eikeren, Paul; Brose, Daniel J.; Ray, Roderick J.

1991-01-01

An improvement to processes for the selective extractation of organic solutes from organic solvents by water-based extractants is disclosed, the improvement comprising coupling various membrane separation processes with the organic extraction process, the membrane separation process being utilized to continuously recycle the water-based extractant and at the same time selectively remove or concentrate organic solute from the water-based extractant.

Simultaneous Multiple-Location Separation Control

NASA Technical Reports Server (NTRS)

Greenblatt, David (Inventor)

2009-01-01

A method of controlling a shear layer for a fluid dynamic body introduces first periodic disturbances into the fluid medium at a first flow separation location. Simultaneously, second periodic disturbances are introduced into the fluid medium at a second flow separation location. A phase difference between the first and second periodic disturbances is adjusted to control flow separation of the shear layer as the fluid medium moves over the fluid dynamic body.

Development and Validation of a Rapid RP-UPLC Method for the Simultaneous Estimation of Bambuterol Hydrochloride and Montelukast Sodium from Tablets

PubMed Central

Yanamandra, R.; Vadla, C. S.; Puppala, U. M.; Patro, B.; Murthy, Y. L. N.; Parimi, A. R.

2012-01-01

A rapid, simple, sensitive and selective analytical method was developed by using reverse phase ultra performance liquid chromatographic technique for the simultaneous estimation of bambuterol hydrochloride and montelukast sodium in combined tablet dosage form. The developed method is superior in technology to conventional high performance liquid chromatography with respect to speed, resolution, solvent consumption, time, and cost of analysis. Elution time for the separation was 6 min and ultra violet detection was carried out at 210 nm. Efficient separation was achieved on BEH C18 sub-2-μm Acquity UPLC column using 0.025% (v/v) trifluoro acetic acid in water and acetonitrile as organic solvent in a linear gradient program. Resolutions between bambuterol hydrochloride and montelukast sodium were found to be more than 31. The active pharmaceutical ingredient was extracted from tablet dosage from using a mixture of methanol, acetonitrile and water as diluent. The calibration graphs were linear for bambuterol hydrochloride and montelukast sodium in the range of 6.25-37.5 μg/ml. The percentage recoveries for bambuterol hydrochloride and montelukast sodium were found to be in the range of 99.1-100.0% and 98.0-101.6%, respectively. The test solution was found to be stable for 7 days when stored in the refrigerator between 2-8°. Developed UPLC method was validated as per International Conference on Harmonization specifications for method validation. This method can be successfully employed for simultaneous estimation of bambuterol hydrochloride and montelukast sodium in bulk drugs and formulations. PMID:23325991

[Simultaneous determination of vitamins A, D3 and E in infant formula and adult nutritions by online two-dimensional liquid chromatography].

PubMed

Zhang, Yanhai; Qibule, Hasi; Jin, Yan; Wang, Jia; Ma, Wenli

2015-03-01

A rapid method for the simultaneous determination of vitamins A, D3 and E in infant formula and adult nutritions has been developed using online two-dimensional liquid chromatography (2D-LC). First of all, C8 and polar embedded C18 columns were chosen as the first and second dimensional column respectively according to hydrophobic-subtraction model, which constituted excellent orthogonal separation system. The detection wavelengths were set at 263 nm for vitamin D3, 296 nm for vitamin E and 325 nm for vitamin A. The purification of vitamin D3 and quantifications of vitamins A and E were completed simultaneously in the first dimensional separation using the left pump of Dual Gradient LC (DGLC) with methanol, acetonitrile and water as mobile phases. The heart-cutting time window of vitamin D3 was confirmed according to the retention time of vitamin D3 in the first dimensional separation. The elute from the first dimensional column (1-D column) which contained vitamin D3 was collected by a 500 µL sample loop and then taken into the second dimensional column (2-D column) by the right pump of DGLC with methanol, acetonitrile and water as mobile phases. The quantification of vitamin D3 was performed in the second dimensional separation with vitamin D2 as internal standard. At last, this method was applied for the analysis of the three vitamins in milk powder, cheese and yogurt. The injected sample solution with no further purification was pre-treated by hot-saponification using 1. 25 kg/L KOH solution and extracted by petroleum ether solvent. The recoveries of vitamin D3 spiked in all samples were 75.50%-85.00%. There was no statistically significant difference for the results between this method and standard method through t-test. The results indicate that vitamins A, D3 and E in infant formula and adult fortified dairy can be determined rapidly and accurately with this method.

Discrimination and chemical characterization of different Paeonia lactifloras (Radix Paeoniae Alba and Radix Paeoniae Rubra) by infrared macro-fingerprint analysis-through-separation

NASA Astrophysics Data System (ADS)

Wang, Yang; Wang, Ping; Xu, Changhua; Sun, Suqin; Zhou, Qun; Shi, Zhe; Li, Jin; Chen, Tao; Li, Zheng; Cui, Weili

2015-11-01

Paeonia lactiflora, a commonly used herbal medicine (HM) in Traditional Chinese Medicine (TCM), mainly has two species, Radix Paeoniae Alba (RPA) and Radix Paeoniae Rubra (RPR), for different clinical applications in TCM. For expounding the chemical profile of RPA and RPR and ensuring the clinical efficacy and safety, an infrared macro-fingerprint analysis-through-separation method integrated with statistical pattern recognition was developed to analyze and discriminate the two Paeonia lactifloras. In IR spectra, the major difference between the two was in the range of 1200-900 cm-1: the strongest peak of RPA was at 1024 cm-1, while that of RPR was 1049 cm-1. The difference was magnified in second derivative spectra. The findings were further verified by investigating the separation process of total glucosides, stepwisely monitored by both of IR and UPLC-MS/MS. Simultaneously, the aqueous extracts of RPA and RPR had been separated continuously to acquire the comprehensively hierarchical chemical characteristics for undoubtedly identification and subsequently discrimination of the two herbs. Moreover, 60 batches of the two HMs (30 for each) were objectively classified by principal component regression (PCR) model based on IR macro-fingerprints.

Mixed hemimicelles solid-phase extraction based on ionic liquid-coated Fe3O4/SiO2 nanoparticles for the determination of flavonoids in bio-matrix samples coupled with high performance liquid chromatography.

PubMed

He, Huan; Yuan, Danhua; Gao, Zhanqi; Xiao, Deli; He, Hua; Dai, Hao; Peng, Jun; Li, Nan

2014-01-10

A novel magnetic solid-phase extraction (MSPE) method based on mixed hemimicelles of room temperature ionic liquids (RTILs) coated Fe3O4/SiO2 nanoparticles (NPs) was developed for simultaneous extraction of trace amounts of flavonoids in bio-matrix samples. A comparative study on the use of RTILs (C16mimBr) and CTAB-coated Fe3O4/SiO2 NPs as sorbents was presented. Owing to bigger adsorption amounts for analytes, RTILs-coated Fe3O4/SiO2 NPs was selected as MSPE materials and three analytes luteolin, quercetin and kaempferol can be quantitatively extracted and simultaneously determined coupled with high performance liquid chromatography (HPLC) in urine samples. No interferences were caused by proteins or endogenous compounds. Good linearity (R(2)>0.9993) for all calibration curves was obtained, and the limits of detection (LOD) for luteolin, quercetin and kaempferol were 0.10 ng/mL, 0.50 ng/mL and 0.20 ng/mL in urine samples, respectively. Satisfactory recoveries (93.5-97.6%, 90.1-95.4% and 93.3-96.6% for luteolin, quercetin and kaempferol) in biological matrices were achieved. It was notable that while using a small amount of Fe3O4/SiO2 NPs (4.0 mg) and C16mimBr (1.0 mg), satisfactory preconcentration factors and extraction recoveries for the three flavonoids were obtained. To the best of our knowledge, this is the first time a mixed hemimicelles MSPE method based on RTILs and Fe3O4/SiO2 NPs magnetic separation has ever been used for pretreatment of complex biological samples. Copyright © 2013 Elsevier B.V. All rights reserved.

LC-MS/MS method for the simultaneous quantification of luteolin, wedelolactone and apigenin in mice plasma using hansen solubility parameters for liquid-liquid extraction: Application to pharmacokinetics of Eclipta alba chloroform fraction.

PubMed

Cheruvu, Hanumanth Srikanth; Yadav, Navneet K; Valicherla, Guru R; Arya, Rakesh K; Hussain, Zakir; Sharma, Chetan; Arya, Kamal R; Singh, Rama K; Datta, Dipak; Gayen, Jiaur R

2018-04-01

Eclipta alba (Bhringraj) in ayurveda has been widely used as a traditional medicine for its multi-therapeutic properties for ages. Luteolin (LTL), wedelolactone (WDL) and apigenin (APG) are the three main bioactive phytochemicals present in Eclipta alba extract. However there was a lack of sensitive bioanalytical method for the pharmacokinetics of these free compounds in plasma which majorly contributes for their activities after oral administration of Eclipta alba. The present study aims to develop a sensitive, rapid and reliable liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the simultaneous estimation of mice plasma concentrations of LTL, WDL and APG using quercetin as an internal standard for the pharmacokinetic analysis. Analytes were separated on Phenomenex Luna C18 (150 × 4.6 mm, 3.0 μm) column with mobile phase containing methanol: acetonitrile (90: 10, v/v) and 0.1% formic acid in 10 mM ammonium formate buffer in the ratio of 70: 30 (v/v) in isocratic mode. Liquid-liquid extraction was optimized using Hansen solubility parameters and diethyl ether finalized as an extraction solvent for the recovery ranging from 61 to 76% for all analytes in mice plasma. The validated method has an accuracy and precision over the linearity range of 0.1-200 ng/mL with a correlation coefficient (r 2 ) of ≥0.997. The intra and inter-day assay accuracy was between 98.17 and 107% and 95.83-107.89% respectively and the intra and inter day assay precision ranged from 0.37-6.05% and 1.85-10.76%, respectively for all the analytes. This validated method can be used for future clinical investigation studies of Eclipta alba extracts. Copyright © 2018 Elsevier B.V. All rights reserved.

Simultaneous serum nicotine, cotinine, and trans-3'-hydroxycotinine quantitation with minimal sample volume for tobacco exposure status of solid organ transplant patients.

PubMed

Shu, Irene; Wang, Ping

2013-06-01

Concentrations of nicotine and its metabolites in blood are indicative of patients' current tobacco exposure, and their quantifications have been clinically applied to multiple assessments including demonstration of abstinence prior to heart-lung transplantation. For the purpose of transplant evaluation, the laboratory work up is extensive; thereby an assay with minimal sample volume is preferred. We developed and validated a rapid LC-MS/MS assay to simultaneously quantitate nicotine and its major metabolites, Cotinine and trans-3'-OH-cotinine (3-OH-Cot), in serum. 100μL of serum was spiked with deuterated internal standards and extracted by Oasis HLB solid phase extraction cartridge. Nicotine and metabolites in the reconstituted serum extract were separated by Agilent Eclipse XDB-C8 3.5μm 2.1mm×50mm HPLC column within 4.7min, and quantified by MS/MS with positive mode electrospray ionization and multiple reaction monitoring. Ion suppression was insignificant, and extraction efficiency was 79-110% at 50ng/mL for all compounds. Limit of detection was 1.0ng/mL for nicotine and 3-OH-Cot, and <0.5ng/mL for Cotinine. Linearity ranges for nicotine, cotinine and 3-OH-Cot were 2-100, 2-1000, and 5-1000ng/mL with recoveries of 86-115%. Within-day and twenty-day imprecision at nicotine/cotinine/3-OH-Cot levels of 22/150/90, 37/250/150, and 50/800/500ng/mL were all 1.1-6.5%. The reconstituted serum extracts were stable for at least 7 days stored in the HPLC autosampler at 5°C. Our method correlates well with alternative LC-MS/MS methods. We successfully developed and validated an LC-MS/MS assay to quantitate concentrations of nicotine and its metabolites in serum with minimal sample volume to assess tobacco exposure of heart-lung transplant patients. Copyright © 2013 Elsevier B.V. All rights reserved.

[Determination of canthaxanthin and astaxanthin in egg yolks by reversed phase high performance liquid chromatography with diode array detection].

PubMed

He, Kang-Hao; Zou, Xiao-Li; Liu, Xiang; Zeng, Hong-Yan

2012-01-01

A method using reversed phase high performance liquid chromatography (RP-HPLC) coupled with diode array detector (DAD) was developed for the simultaneous determination of canthaxanthin and astaxanthin in egg yolks. Samples were extracted with acetonitrile in ultrasonic bath for 20 minutes and then purified by freezing-lipid filtration and solid phase extraction (SPE). After being vaporized to dryness by nitrogen blowing and made up to volume with methanol, the extract solution was chromatographically separated in C18 column with a unitary mobile phase consisting of acetonitrile. The proposed method was validated in terms of linearity, precision, accuracy, and limit of detection (LOD). Regression analysis revealed a good linearity between peak area of each analyte and its concentration (r > or = 0.998). The intra- and inter-day relative standard deviations (RSDs) were less than 3.6% and 5.2%, respectively. LODs of canthaxanthin and astaxanthin were 0.035 and 0.027 microg/mL (S/N = 3). The average recoveries of canthaxanthin and astaxanthin were 91.5% and 88.7%. The proposed method is simple, fast and easy to apply.

Assessment of different pre-treatment methods for the removal of limonene in citrus waste and their effect on methane potential and methane production rate.

PubMed

Ruiz, Begoña; de Benito, Amparo; Rivera, José Daniel; Flotats, Xavier

2016-12-01

The objective of this study was to assess the limonene removal efficiency of three pre-treatment methods when applied to citrus waste and to evaluate their effects on the biochemical methane potential and the methane production rate using batch anaerobic tests. The methods tested were based on removal (biological pretreatment by fungi) or recovery (steam distillation and ethanol extraction) of limonene. All the treatments decreased the concentration of limonene in orange peel, with average efficiencies of 22%, 44% and 100% for the biological treatment, steam distillation and ethanol extraction, respectively. By-products from limonene biodegradation by fungi exhibited an inhibitory effect also, not making interesting the biological pretreatment. The methane potential and production rate of the treated orange peel increased significantly after applying the recovery strategies, which separated and recovered simultaneously other inhibitory components of the citrus essential oil. Apart from the high recovery efficiency of the ethanol extraction process, it presented a favourable energy balance. © The Author(s) 2016.

Rapid and selective extraction of multiple macrolide antibiotics in foodstuff samples based on magnetic molecularly imprinted polymers.

PubMed

Zhou, Yusun; Zhou, Tingting; Jin, Hua; Jing, Tao; Song, Bin; Zhou, Yikai; Mei, Surong; Lee, Yong-Ill

2015-05-01

Magnetic molecularly imprinted polymers (MMIPs) were prepared based on surface molecular imprinting using erythromycin (ERY) as template molecule and Fe3O4 nanoparticles as support substrate. The MMIPs possessed high adsorption capacity of 94.1 mg/g for ERY and the imprinting factor was 11.9 indicating good imprinted effect for ERY. Selective evaluation demonstrated favorable selectivity of MMIPs for multiple macrolide antibiotics (MACs). Using MMIPs as adsorptive material, a rapid and convenient magnetic solid-phase extraction (MSPE) procedure was established for simultaneous and selective separation of six MACs in pork, fish and shrimp samples, then the MACs was subjected to high-performance liquid chromatography-ultraviolet (HPLC-UV) analysis. At different fortified concentrations, the extraction recoveries could reach 89.1% and the relative standard deviations were lower than 12.4%. Chromatogram revealed the response signals of MACs in spiked samples were greatly enhanced and matrix interferences were effectively eliminated after treatment with MSPE. The proposed MSPE procedure coupled with HPLC-UV realized selective and sensitive determination of multiple MACs in foodstuff samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Production of cellulosic ethanol from sugarcane bagasse by steam explosion: Effect of extractives content, acid catalysis and different fermentation technologies.

PubMed

Neves, P V; Pitarelo, A P; Ramos, L P

2016-05-01

The production of cellulosic ethanol was carried out using samples of native (NCB) and ethanol-extracted (EECB) sugarcane bagasse. Autohydrolysis (AH) exhibited the best glucose recovery from both samples, compared to the use of both H3PO4 and H2SO4 catalysis at the same pretreatment time and temperature. All water-insoluble steam-exploded materials (SEB-WI) resulted in high glucose yields by enzymatic hydrolysis. SHF (separate hydrolysis and fermentation) gave ethanol yields higher than those obtained by SSF (simultaneous hydrolysis and fermentation) and pSSF (pre-hydrolysis followed by SSF). For instance, AH gave 25, 18 and 16 g L(-1) of ethanol by SHF, SSF and pSSF, respectively. However, when the total processing time was taken into account, pSSF provided the best overall ethanol volumetric productivity of 0.58 g L(-1) h(-1). Also, the removal of ethanol-extractable materials from cane bagasse had no influence on the cellulosic ethanol production of SEB-WI, regardless of the fermentation strategy used for conversion. Copyright © 2016 Elsevier Ltd. All rights reserved.

A microextraction procedure based on a task-specific ionic liquid for the separation and preconcentration of lead ions from red lipstick and pine leaves.

PubMed

Saljooqi, Asma; Shamspur, Tayebeh; Mohamadi, Maryam; Afzali, Daryoush; Mostafavi, Ali

2015-05-01

First, the extraction and preconcentration of ultratrace amounts of lead(II) ions was performed using microliter volumes of a task-specific ionic liquid. The remarkable properties of ionic liquids were added to the advantages of microextraction procedure. The ionic liquid used was trioctylmethylammonium thiosalicylate, which formed a lead thiolate complex due to the chelating effect of the ortho-positioned carboxylate relative to thiol functionality. So, trioctylmethylammonium thiosalicylate played the roles of both chelating agent and extraction solvent simultaneously. Hence, there is no need to use a ligand. The main parameters affecting the efficiency of the method were investigated and optimized. Under optimized conditions, this approach showed a linear range of 2.0-24.0 ng/mL with a detection limit of 0.0010 ng/mL. The proposed method was applied to the extraction and preconcentration of lead from red lipstick and pine leaves samples prior to electrothermal atomic absorption spectroscopic determination. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multiresidue chromatographic method for the determination of macrolide residues in muscle by high-performance liquid chromatography with UV detection.

PubMed

Juhel-Gaugain, M; Anger, B; Laurentie, M

1999-01-01

A high-performance liquid chromatographic (HPLC) method for the simultaneous determination of tilmicosin, tylosin, spiramycin, and its major metabolite neospiramycin was developed that is suitable for porcine, bovine, and poultry muscles. Macrolide residues were extracted from muscle with acetonitrile, fat was removed by liquid-liquid extraction with isooctane, and the extract was then cleaned on Bond Elut C18 cartridges. The HPLC separation was performed on an Inertsil ODS3 C18 column (150 x 4 mm) with 0.05% trifluoroacetic acid-acetonitrile in a gradient mode. Two different chromatographic gradients were used for tilmicosin-tylosin and spiramycin-neospiramycin, and the detection wavelengths were 287 and 232 nm, respectively. The method was validated from 1/2 the maximum residue limit (MRL) to 4 times the MRL with pork muscle samples. Mean recoveries were 60, 63.5, 51, and 42% for tilmicosin, tylosin, spiramycin, and neospiramycin, respectively. The detection limits are 15 micrograms/kg for tilmicosin and tylosin, 30 micrograms/kg for spiramycin, and 25 micrograms/kg for neospiramycin. Linearity, precision, and accuracy of the method were also tested.

Oil-Water Flow Investigations using Planar-Laser Induced Fluorescence and Particle Velocimetry

NASA Astrophysics Data System (ADS)

Ibarra, Roberto; Matar, Omar K.; Markides, Christos N.

2017-11-01

The study of the complex behaviour of immiscible liquid-liquid flow in pipes requires the implementation of advanced measurement techniques in order to extract detailed in situ information. Laser-based diagnostic techniques allow the extraction of high-resolution space- and time resolve phase and velocity information, which aims to improve the fundamental understanding of these flows and to validate closure relations for advanced multiphase flow models. This work shows a novel simultaneous planar-laser induced fluorescence and particle velocimetry in stratified oil-water flows using two laser light sheets at two different wavelengths for fluids with different refractive indices at horizontal and upward pipe inclinations (<5°) in stratified flow conditions (i.e. separated layers). Complex flow structures are extracted from 2-D instantaneous velocity fields, which are strongly dependent on the pipe inclination at low velocities. The analysis of mean wall-normal velocity profiles and velocity fluctuations suggests the presence of single- and counter-rotating vortices in the azimuthal direction, especially in the oil layer, which can be attributed to the influence of the interfacial waves. Funding from BP, and the TMF Consortium is gratefully acknowledged.

Enhancement of simultaneous gold and copper extraction from computer printed circuit boards using Bacillus megaterium.

PubMed

Arshadi, M; Mousavi, S M

2015-01-01

In this research simultaneous gold and copper recovery from computer printed circuit boards (CPCBs) was evaluated using central composite design of response surface methodology (CCD-RSM). To maximize simultaneous metals' extraction from CPCB waste four factors which affected bioleaching were selected to be optimized. A pure culture of Bacillus megaterium, a cyanogenic bacterium, was used to produce cyanide as a leaching agent. Initial pH 10, pulp density 2g/l, particle mesh#100 and glycine concentration 0.5g/l were obtained as optimal conditions. Gold and copper were extracted simultaneously at about 36.81 and 13.26% under optimum conditions, respectively. To decrease the copper effect as an interference agent in the leaching solution, a pretreatment strategy was examined. For this purpose firstly using Acidithiobacillus ferrooxidans copper in the CPCB powder was totally extracted, then the residual sediment was subjected to further experiments for gold recovery by B. megaterium. Using pretreated sample under optimal conditions 63.8% gold was extracted. Copyright © 2014 Elsevier Ltd. All rights reserved.

Rapid determination of eight bioactive alkaloids in Portulaca oleracea L. by the optimal microwave extraction combined with positive-negative conversion multiple reaction monitor (+/-MRM) technology.

PubMed

Liang, Xiao; Tian, Jinlong; Li, Lingzhi; Gao, Jun; Zhang, Qingyi; Gao, Pinyi; Song, Shaojiang

2014-03-01

A rapid and reliable microwave extraction and the triple quadrupole-linear ion trap mass spectrometry method was developed and validated for the determination of eight alkaloids in Portulaca oleracea L. The optimal microwave extraction (MWE) condition was performed at 60 °C for 12 min with ethanol-water (70:30, v/v) as the extracting solvent, and the solvent to solid ratio was 30:1. The alkaloids were first detected simultaneously by electrospray ionization tandem mass spectrometry under positive-negative conversion multiple reaction monitor ((+/-)MRM) technique. With investigating three different columns, samples were separated in only 8 min on a Waters ACQUITY UPLC HSS T3 (50 × 2.1 mm(2), 1.8 μm) column using acetonitrile and formic acid-water solution as a mobile phase with a flow rate at 0.2 mL/min. All calibration curves showed good linearity (r>0.999) within the test ranges. The method developed was validated with acceptable sensitivity, intra- and inter-day precision, reproducibility, and extraction recoveries. It was successfully applied to the determination of eight alkaloids in Portulaca oleracea L. from different sources and different harvest periods. The method also provide a reference for extraction and determination of alkaloids in other complex systems. © 2013 Elsevier B.V. All rights reserved.

Extraction and preparation of high-aroma and low-caffeine instant green teas by the novel column chromatographic extraction method with gradient elution.

PubMed

Li, Qing-Rong; Wu, Min; Huang, Rui-Jie; Chen, Ya-Fei; Chen, Chan-Jian; Li, Hui; Ni, He; Li, Hai-Hang

2017-06-01

The lack of aroma and natural taste is a critical problem in production and consumption of instant green teas. A method to prepare instant green teas high in-natural-aroma and low-caffeine by the novel column chromatographic extraction with gradient elution is reported. This method simultaneously extracted aroma (or volatile) and non-aroma compounds from green tea. Green tea was loaded into columns with 2.0-fold of petroleum ether (PE): ethanol (8:2). After standing for 3 h until the aroma compounds dissolved, the column was sequentially eluted with 3.0-fold 40% ethanol and 3.5-fold water. The eluant was collected together and automatically separated into PE and ethanol aqueous phases. The aroma extracts was obtained by vacuum-evaporation of PE phase at 45 °C. The ethanol aqueous phase was vacuum-concentrated to aqueous and partially or fully decaffeinated with 4% or 9% charcoal at 70 °C. A regular instant green tea with epigallocatechin-3-gallate: caffeine of 3.5:1 and a low-caffeine instant green tea (less than 1% caffeine) with excellent aroma and taste were prepared, by combining the aroma and non-aroma extracts at a 1:10 ratio. This work provides a practical approach to solve the low-aroma and low-taste problems in the production of high quality instant green teas.

Simultaneous speciation analysis of chromate, molybdate, tungstate and vanadate in welding fume alkaline extracts by HPLC-ICP-MS.

PubMed

Ščančar, Janez; Berlinger, Balázs; Thomassen, Yngvar; Milačič, Radmila

2015-09-01

A novel analytical procedure was developed for the simultaneous speciation analysis of chromate, molybdate, tungstate and vanadate by anion-exchange high performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (HPLC-ICP-MS). Linear gradient elution from 100% water to 100% 0.7 M NaCl was applied for chromatographic separation of metal species. In standard aqueous solution at neutral pH molybdate, tungstate and vanadate exist in several aqueous species, while chromate is present as a single CrO4(2-) species. Consequently, only chromate can be separated from this solution in a sharp chromatographic peak. For obtaining sharp chromatographic peaks for molybdate, tungstate and vanadate, the pH of aqueous standard solutions was raised to 12. At highly alkaline conditions single CrO4(2-), MoO4(2-) and WO4(2-) are present and were eluted in sharp chromatographic peaks, while VO4(3-) species, which predominates at pH 12 was eluted in slightly broaden peak. In a mixture of aqueous standard solutions (pH 12) chromate, molybdate, tungstate and vanadate were eluted at retention times from 380 to 420 s, 320 to 370 s, 300 to 350 s and 240 to 360 s, respectively. Eluted species were simultaneously detected on-line by ICP-MS recording m/z 52, 95, 182 and 51. The developed procedure was successfully applied to the analysis of leachable concentrations of chromate, molybdate, tungstate and vanadate in alkaline extracts (2% NaOH+3% Na2CO3) of manual metal arc (MMA) welding fumes loaded on filters. Good repeatability and reproducibility of measurement (RSD±3.0%) for the investigated species were obtained in both aqueous standard solutions (pH 12) and in alkaline extracts of welding fumes. Low limits of detection (LODs) were found for chromate (0.02 ng Cr mL(-1)), molybdate (0.1 ng Mo mL(-1)), tungstate (0.1 ng W mL(-1)) and vanadate (0.2 ng V mL(-1)). The accuracy of analytical procedure for the determination of chromate was checked by analysis of CRM 545, Cr(VI) in welding dust loaded on a filter. Good agreement between determined and reported certified values was obtained. For molybdate, tungstate and vanadate the assessment of accuracy was performed by spiking welding fume filters. Good recoveries for all investigated species (98-101%) confirmed the accuracy of the analytical procedure. Copyright © 2015 Elsevier B.V. All rights reserved.

Separable spectro-temporal Gabor filter bank features: Reducing the complexity of robust features for automatic speech recognition.

PubMed

Schädler, Marc René; Kollmeier, Birger

2015-04-01

To test if simultaneous spectral and temporal processing is required to extract robust features for automatic speech recognition (ASR), the robust spectro-temporal two-dimensional-Gabor filter bank (GBFB) front-end from Schädler, Meyer, and Kollmeier [J. Acoust. Soc. Am. 131, 4134-4151 (2012)] was de-composed into a spectral one-dimensional-Gabor filter bank and a temporal one-dimensional-Gabor filter bank. A feature set that is extracted with these separate spectral and temporal modulation filter banks was introduced, the separate Gabor filter bank (SGBFB) features, and evaluated on the CHiME (Computational Hearing in Multisource Environments) keywords-in-noise recognition task. From the perspective of robust ASR, the results showed that spectral and temporal processing can be performed independently and are not required to interact with each other. Using SGBFB features permitted the signal-to-noise ratio (SNR) to be lowered by 1.2 dB while still performing as well as the GBFB-based reference system, which corresponds to a relative improvement of the word error rate by 12.8%. Additionally, the real time factor of the spectro-temporal processing could be reduced by more than an order of magnitude. Compared to human listeners, the SNR needed to be 13 dB higher when using Mel-frequency cepstral coefficient features, 11 dB higher when using GBFB features, and 9 dB higher when using SGBFB features to achieve the same recognition performance.

[Extraction of 10-Deacetyl Baccatin by Supercritical CO2 from Taxus yunnanensis Branches and Leaves].

PubMed

Tang, Yang-qin; Li, Hai-chi; Huang, Wen-jie; Xiong, Yan; Ge, Fa-huan

2015-04-01

To study the supercritical CO2 fluids extraction (SFE) method to extract the components from Taxus yunnanensis. Medicinal meterials were extracted by supercritical CO2, and then purified by industrial chromatography. Using the extraction yield of 10-DAB as the index,single factor test was carried out to investigate the effect of co-solvent, extraction time, extraction pressure, extraction temperature, pressure and temperature of separation kettle I. Then orthogonal experiment was used to optimize the best extraction condition. The suitable extraction condition was as follows: the ratio of co-solvent (80% ethanol) amount and the madicinal materials was 3: 1, Separation kettle I pressure was 14 MPa, separation kettle I temperature was 40 °C, extraction pressure was 25 MPa, extraction temperature was 60 T and extraction time was 90 min. The extract was separated by industrial chromatographic and then crystallized. The supercritical CO2 extraction and purification process of 10-DAB were simple and feasible.

Measurement of stable isotopic enrichment and concentration of long-chain fatty acyl-carnitines in tissue by HPLC-MS.

PubMed

Sun, Dayong; Cree, Melanie G; Zhang, Xiao-Jun; Bøersheim, Elisabet; Wolfe, Robert R

2006-02-01

We have developed a new method for the simultaneous measurements of stable isotopic tracer enrichments and concentrations of individual long-chain fatty acyl-carnitines in muscle tissue using ion-pairing high-performance liquid chromatography-electrospray ionization quadrupole mass spectrometry in the selected ion monitoring (SIM) mode. Long-chain fatty acyl-carnitines were extracted from frozen muscle tissue samples by acetonitrile/methanol. Baseline separation was achieved by reverse-phase HPLC in the presence of the volatile ion-pairing reagent heptafluorobutyric acid. The SIM capability of a single quadrupole mass analyzer allows further separation of the ions of interest from the sample matrixes, providing very clean total and selected ion chromatograms that can be used to calculate the stable isotopic tracer enrichment and concentration of long-chain fatty acyl-carnitines in a single analysis. The combination of these two separation techniques greatly simplifies the sample preparation procedure and increases the detection sensitivity. Applying this protocol to biological muscle samples proves it to be a very sensitive, accurate, and precise analytical tool.

Simultaneous determination of five free and total flavonoids in rat plasma by ultra HPLC-MS/MS and its application to a comparative pharmacokinetic study in normal and hyperlipidemic rats.

PubMed

Wang, Xiaofan; Zhao, Xu; Gu, Liqiang; Lv, Chunxiao; He, Bosai; Liu, Zhenzhen; Hou, Pengyi; Bi, Kaishun; Chen, Xiaohui

2014-03-15

A simple and rapid ultra-high performance liquid chromatography-tandem mass spectrometry (uHPLC-MS/MS) method has been developed for the simultaneous determination of five free flavonoids (amentoflavone, isorhamnetin, naringenin, kaempferol and quercetin) and their total (free and conjugated) forms, and to compare the pharmacokinetics of these active ingredients in normal and hyperlipidemic rats. The free and total forms of these flavonoids were extracted by liquid-liquid extraction with ethyl acetate. The conjugated flavonoids were deconjugated by the enzyme β-Glucuronidase and Sulfatase. Chromatographic separation was accomplished on a ZORBAX Eclipse XDB-C8 USP L7 column using gradient elution. Detection was performed on a 4000Q uHPLC-MS/MS system from AB Sciex using negative ion mode in the multiple reaction monitoring (MRM) mode. The lower limits of quantification were 2.0-5.0ng/mL for all the analytes. Intra-day and inter-day precision were less than 15% and accuracy ranged from -9.3% to 11.0%, and the mean extraction recoveries of analytes and internal standard (IS) from rat plasma were all more than 81.7%. The validated method was successfully applied to a comparative pharmacokinetic study of five free and total analytes in rat plasma. The results indicated that the absorption of five total flavonoids in hyperlipidemia group were significantly higher than those in normal group with similar concentration-time curves. Copyright © 2014 Elsevier B.V. All rights reserved.

An integrated platform for directly widely-targeted quantitative analysis of feces part I: Platform configuration and method validation.

PubMed

Song, Yuelin; Song, Qingqing; Li, Jun; Zheng, Jiao; Li, Chun; Zhang, Yuan; Zhang, Lingling; Jiang, Yong; Tu, Pengfei

2016-07-08

Direct analysis is of great importance to understand the real chemical profile of a given sample, notably biological materials, because either chemical degradation or diverse errors and uncertainties might be resulted from sophisticated protocols. In comparison with biofluids, it is still challenging for direct analysis of solid biological samples using high performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Herein, a new analytical platform was configured by online hyphenating pressurized liquid extraction (PLE), turbulent flow chromatography (TFC), and LC-MS/MS. A facile, but robust PLE module was constructed based on the phenomenon that noticeable back-pressure can be generated during rapid fluid passing through a narrow tube. TFC column that is advantageous at extracting low molecular analytes from rushing fluid was employed to link at the outlet of the PLE module to capture constituents-of-interest. An electronic 6-port/2-position valve was introduced between TFC column and LC-MS/MS to fragment each measurement into extraction and elution phases, whereas LC-MS/MS took the charge of analyte separation and monitoring. As a proof of concept, simultaneous determination of 24 endogenous substances including eighteen steroids, five eicosanoids, and one porphyrin in feces was carried out in this paper. Method validation assays demonstrated the analytical platform to be qualified for directly simultaneous measurement of diverse endogenous analytes in fecal matrices. Application of this integrated platform on homolog-focused profiling of feces is discussed in a companion paper. Copyright © 2016 Elsevier B.V. All rights reserved.

Polypyrrole/montmorillonite nanocomposite as a new solid phase microextraction fiber combined with gas chromatography-corona discharge ion mobility spectrometry for the simultaneous determination of diazinon and fenthion organophosphorus pesticides.

PubMed

Jafari, Mohammad T; Saraji, Mohammad; Sherafatmand, Hossein

2014-03-03

A novel solid phase microextraction (SPME) fiber was prepared and coupled with gas chromatography corona discharge ion mobility spectrometry (GC-CD-IMS) based on polypyrrole/montmorillonite nanocomposites for the simultaneous determination of diazinon and fenthion. The nanocomposite polymer was coated using a three-electrode electrochemical system and directly deposited on a Ni-Cr wire by applying a constant potential. The scanning electron microscopy images revealed that the new fiber exhibited a rather porous and homogenous surface. The thermal stability of the fabricated fiber was investigated by thermogravimetric analysis. The effects of different parameters influencing the extraction efficiency such as extraction temperature and time, salt addition, stirring rate, the amount of nanoclay, and desorption temperature were investigated and optimized. The method was exhaustively evaluated in terms of sensitivity, recovery, and reproducibility. The linearity ranges of 0.05-10 and 0.08-10 μg L(-1), and the detection limits of 0.020 and 0.035 μg L(-1) were obtained for diazinon and fenthion, respectively. The relative standard deviation values were calculated to be lower than 5% and 8% for intra-day and inter-day, respectively. Finally, the developed method was applied to determine the diazinon and fenthion (as model compounds) in cucumber, lettuce, apple, tap and river water samples. The satisfactory recoveries revealed the capability of the two-dimensional separation technique (retention time in GC and drift time in IMS) for the analysis of complex matrices extracted by SPME. Copyright © 2014 Elsevier B.V. All rights reserved.

Simultaneous determination of azilsartan and chlorthalidone in rat and human plasma by liquid chromatography-electrospray tandem mass spectrometry.

PubMed

Ramakrishna, Rachumallu; Puttrevu, Santosh Kumar; Bhateria, Manisha; Bala, Veenu; Sharma, Vishnu L; Bhatta, Rabi Sankar

2015-05-15

Azilsartan medoxomil (AZM), an ester prodrug of azilsartan (AZ), and chlorthalidone (CLT) have recently been approved as a combination therapy for the management of hypertension. This is the first report which described a selective and sensitive method for the simultaneous quantification of AZ and CLT in rat and human plasma using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). AZ and CLT were extracted from plasma by liquid-liquid extraction technique and separated on a C18 reverse phase column using ammonium acetate (10mM, pH 4)-mixture of methanol and acetonitrile (8:92, v/v) as a mobile phase at a flow rate of 0.7mL/min. Detection was performed by electrospray ionization (ESI) operated in negative multiple reaction monitoring (MRM) mode. The lower limit of quantitation (LLOQ) of this method was 1ng/mL and the calibration curves were linear (r(2)≥0.995) over the concentration range of 1-4000ng/mL for both the analytes. The intra- and inter-day precision and accuracy were well within the acceptable limits. The mean extraction recoveries were found to be about 80% and no matrix effect was observed. AZ and CLT were found to be stable under all relevant storage conditions. The method was successfully applied to the oral pharmacokinetic study of AZM and CLT in rats. Further, the sensitivity of the method enabled the determination of protein binding of AZ and CLT in human plasma. Copyright © 2015 Elsevier B.V. All rights reserved.

Simultaneous liquid chromatography/mass spectrometry determination of both polar and "multiresidue" pesticides in food using parallel hydrophilic interaction/reversed-phase liquid chromatography and a hybrid sample preparation approach.

PubMed

Robles-Molina, José; Gilbert-López, Bienvenida; García-Reyes, Juan F; Molina-Díaz, Antonio

2017-09-29

Pesticide testing of foodstuffs is usually accomplished with generic wide-scope multi-residue methods based on liquid chromatography tandem mass spectrometry (LC-MS/MS). However, this approach does not cover some special pesticides, the so called "single-residue method" compounds, that are hardly compatible with standard reversed-phase (RP) separations due to their specific properties. In this article, we propose a comprehensive strategy for the integration of single residue method compounds and standard multiresidue pesticides within a single run. It is based on the use of a parallel LC column assembly with two different LC gradients performing orthogonal hydrophilic interaction chromatography (HILIC) and reversed-phase (RPLC) chromatography within one analytical run. Two sample aliquots were simultaneously injected on each column, using different gradients, being the eluents merged post-column prior to mass spectrometry detection. The approach was tested with 41 multiclass pesticides covering a wide range of physicochemical properties across several orders of log K ow (from -4 to +5.5). With this assembly, distinct separation from the void was attained for all the pesticides studied, keeping similar performance in terms of sensitivity, peak area reproducibility (<6 RSD% in most cases) and retention time stability of standard single column approaches (better than±0.1min). The application of the proposed approach using parallel HILIC/RPLC and RPLC/aqueous normal phase (Obelisc) were assessed in leek using LC-MS/MS. For this purpose, a hybrid QuEChERS (Quick, easy, cheap, effective, rugged and safe)/QuPPe (quick method for polar pesticides) method was evaluated based on solvent extraction with MeOH and acetonitrile followed by dispersive solid-phase extraction, delivering appropriate recoveries for most of the pesticides included in the study within the log K ow in the range from -4 to +5.5. The proposed strategy may be extended to other fields such as sport drug testing or environmental analysis, where the same type of variety of analytes featuring poor retention within a single chromatographic separation occurs. Copyright © 2017 Elsevier B.V. All rights reserved.

Multielement extraction system for determining 19 trace elements in gold exploration samples

USGS Publications Warehouse

Clark, J. Robert; Viets, John G.; ,

1990-01-01

A multielement extraction system is being used successfully to provide essentially interference-free geochemical analyses to aid in gold exploration. The Methyl isobutyl ketone-Amine synerGistic Iodide Complex (MAGIC) extraction system separates Ag, As, Au, Bi, Cd, Cu, Ga, Hg, In, Mo, Pb, Pd, Pt, Sb, Se, Sn, Te, Tl, and Zn from interfering geological matrices. Quantitative extraction of these elements is accomplished over a broad range of acid normality making it possible to economically determine all 19 elements from a single digestion or leach solution. The resulting organic extracts are amenable to analysis by inductively coupled plasma atomic emission spectroscopy (ICP-AES) and flame atomic absorption spectroscopy (FAAS). For many years the principal shortcoming of ICP-AES was the complex spectral and stray-light interferences that were caused by the extreme variability of components such as Fe, Na, and Ca in common geological matrices. The MAGIC extraction allows determination of the extracted elements with enhanced sensitivity, from a virtually uniform matrix, by ICP-AES and FAAS. Because of its simultaneous multichannel capabilities, ICP-AES is the ideal instrumental technique for determining these 19 extracted elements. Ultratrace (sub-part-per-billion) determinations of Au and many of the other extracted elements can be made by graphite furnace atomic absorption spectroscopy (GFAAS), following back stripping of the extracts. The combination of the extraction followed by stripping of the organic phase eliminates 99.999% of potential interferences for Au. Gold determination by GFAAS from these extracts under the specified conditions yields a fourfold improvement in sensitivity over conventional GFAAS methods. This sensitivity enhancement and the interference-free matrix allow highly reliable determinations well into the parts-per-trillion range.

Simultaneous dispersive liquid-liquid microextraction derivatisation and gas chromatography mass spectrometry analysis of subcritical water extracts of sweet and sour cherry stems.

PubMed

Švarc-Gajić, Jaroslava; Clavijo, Sabrina; Suárez, Ruth; Cvetanović, Aleksandra; Cerdà, Víctor

2018-03-01

Cherry stems have been used in traditional medicine mostly for the treatment of urinary tract infections. Extraction with subcritical water, according to its selectivity, efficiency and other aspects, differs substantially from conventional extraction techniques. The complexity of plant subcritical water extracts is due to the ability of subcritical water to extract different chemical classes of different physico-chemical properties and polarities in a single run. In this paper, dispersive liquid-liquid microextraction (DLLME) with simultaneous derivatisation was optimised for the analysis of complex subcritical water extracts of cherry stems to allow simple and rapid preparation prior to gas chromatography-mass spectrometry (GC-MS). After defining optimal extracting and dispersive solvents, the optimised method was used for the identification of compounds belonging to different chemical classes in a single analytical run. The developed sample preparation protocol enabled simultaneous extraction and derivatisation, as well as convenient coupling with GC-MS analysis, reducing the analysis time and number of steps. The applied analytical protocol allowed simple and rapid chemical screening of subcritical water extracts and was used for the comparison of subcritical water extracts of sweet and sour cherry stems. Graphical abstract DLLME GC MS analysis of cherry stem extracts obtained by subcritical water.

Single sample extraction and HPLC processing for quantification of NAD and NADH levels in Saccharomyces cerevisiae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sporty, J; Kabir, M M; Turteltaub, K

A robust redox extraction protocol for quantitative and reproducible metabolite isolation and recovery has been developed for simultaneous measurement of nicotinamide adenine dinucleotide (NAD) and its reduced form, NADH, from Saccharomyces cerevisiae. Following culture in liquid media, approximately 10{sup 8} yeast cells were harvested by centrifugation and then lysed under non-oxidizing conditions by bead blasting in ice-cold, nitrogen-saturated 50-mM ammonium acetate. To enable protein denaturation, ice cold nitrogen-saturated CH{sub 3}CN + 50-mM ammonium acetate (3:1; v:v) was added to the cell lysates. After sample centrifugation to pellet precipitated proteins, organic solvent removal was performed on supernatants by chloroform extraction. Themore » remaining aqueous phase was dried and resuspended in 50-mM ammonium acetate. NAD and NADH were separated by HPLC and quantified using UV-VIS absorbance detection. Applicability of this procedure for quantifying NAD and NADH levels was evaluated by culturing yeast under normal (2% glucose) and calorie restricted (0.5% glucose) conditions. NAD and NADH contents are similar to previously reported levels in yeast obtained using enzymatic assays performed separately on acid (for NAD) and alkali (for NADH) extracts. Results demonstrate that it is possible to perform a single preparation to reliably and robustly quantitate both NAD and NADH contents in the same sample. Robustness of the protocol suggests it will be (1) applicable to quantification of these metabolites in mammalian and bacterial cell cultures; and (2) amenable to isotope labeling strategies to determine the relative contribution of specific metabolic pathways to total NAD and NADH levels in cell cultures.« less

Glycerol extracting dealcoholization for the biodiesel separation process.

PubMed

Ye, Jianchu; Sha, Yong; Zhang, Yun; Yuan, Yunlong; Wu, Housheng

2011-04-01

By means of utilizing sunflower oil and Jatropha oil as raw oil respectively, the biodiesel transesterification production and the multi-stage extracting separation were carried out experimentally. Results indicate that dealcoholized crude glycerol can be utilized as the extracting agent to achieve effective separation of methanol from the methyl ester phase, and the glycerol content in the dealcoholized methyl esters is as low as 0.02 wt.%. For the biodiesel separation process utilizing glycerol extracting dealcoholization, its technical and equipment information were acquired through the rigorous process simulation in contrast to the traditional biodiesel distillation separation process, and results show that its energy consumption decrease about 35% in contrast to that of the distillation separation process. The glycerol extracting dealcoholization has sufficient feasibility and superiority for the biodiesel separation process. Copyright © 2011 Elsevier Ltd. All rights reserved.

Simultaneous targeted analysis of trimethylamine-N-oxide, choline, betaine, and carnitine by high performance liquid chromatography tandem mass spectrometry.

PubMed

Liu, Jia; Zhao, Mingming; Zhou, Juntuo; Liu, Changjie; Zheng, Lemin; Yin, Yuxin

2016-11-01

Trimethylamine-N-oxide (TMAO) is a metabolite generated from choline, betaine and carnitine in a gut microbiota-dependent way. This molecule is associated with development of atherosclerosis and cardiovascular events. A sensitive liquid chromatographic electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) has been developed and validated for the simultaneous determination of TMAO related molecules including TMAO, betaine, choline, and carnitine in mouse plasma. Analytes are extracted after protein precipitation by methanol and subjected to LC-ESI-MS/MS without preliminary derivatization. Separation of analytes was achieved on an amide column with acetonitrile-water as the mobile phase. This method has been fully validated in this study in terms of selectivity, linearity, sensitivity, precision, accuracy, and carryover effect, and the stability of the analyte under various conditions has been confirmed. This developed method has successfully been applied to plasma samples of our mouse model. Copyright © 2016 Elsevier B.V. All rights reserved.

Decontamination of metals and polycyclic aromatic hydrocarbons from slag-polluted soil.

PubMed

Bisone, Sara; Mercier, Guy; Blais, Jean-François

2013-01-01

Metallurgy is an industrial activity that is one of the largest contributors to soil contamination by metals. This contamination is often associated with organic compound contamination; however, little research has been aimed at the development of simultaneous processes for decontamination as opposed to treatments to heavy metals or organic compounds alone. This paper presents an efficient process to decontaminate the soils polluted with smelting by-products rich in Cu, Zn and polycyclic aromatic hydrocarbons (PAHs). A simultaneous treatment for metals and PAHs was also tested. The process is mainly based on physical techniques, such as crushing, gravimetric separation and attrition. For the finest particle size fractions, an acid extraction with H2SO4 was used to remove metals. The PAH removal was enhanced by adding surfactant during attrition. The total metal removals varied from 49% to 73% for Cu and from 43% to 63% for Zn, whereas a removal yield of 92% was measured for total PAHs. Finally, a technical-economic evaluation was done for the two processes tested.

[Determination of phthalate plasticizers in foods by high performance liquid chromatography with gel permeation chromatographic clean-up].

PubMed

Zhang, Chunyu; Wang, Hui; Zhang, Xiaohui; Ma, Zhongqiang; Deng, Wanmei; Hu, Ke; Ding, Mingyu

2011-12-01

A method of gel permeation chromatography-high performance liquid chromatography (GPC-HPLC) was established for the simultaneous determination of 5 main phthalate plasticizers in foods (edible oil, instant noodles, fried pastries, Saqima, etc.). The samples were extracted with petroleum ether in an ultrasonator, purified by a GPC column, and analyzed by HPLC. The chromatographic separation was achieved on a Labtech-C18 column (250 mm x 4.6 mm, 5 microm) using acetonitrile and water mixture as the mobile phases in a gradient elution mode. The developed method exhibited a linear correlation coefficient of more than 0.997 and the detection limits of 3.25 - 13.4 microg/L. The spike recoveries were between 70.4% and 113.6% with the relative standard deviations (RSDs, n = 3) of 0.3% - 5.8% at the spiked level of 50 mg/L. This method is simple, rapid and practical, and can be used for the simultaneous determination of PAEs in grease food samples.

QuEChERS Purification Combined with Ultrahigh-Performance Liquid Chromatography Tandem Mass Spectrometry for Simultaneous Quantification of 25 Mycotoxins in Cereals.

PubMed

Sun, Juan; Li, Weixi; Zhang, Yan; Hu, Xuexu; Wu, Li; Wang, Bujun

2016-12-15

A method based on the QuEChERS (quick, easy, cheap, effective, rugged, and safe) purification combined with ultrahigh performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS), was optimized for the simultaneous quantification of 25 mycotoxins in cereals. Samples were extracted with a solution containing 80% acetonitrile and 0.1% formic acid, and purified with QuEChERS before being separated by a C18 column. The mass spectrometry was conducted by using positive electrospray ionization (ESI+) and multiple reaction monitoring (MRM) models. The method gave good linear relations with regression coefficients ranging from 0.9950 to 0.9999. The detection limits ranged from 0.03 to 15.0 µg·kg -1 , and the average recovery at three different concentrations ranged from 60.2% to 115.8%, with relative standard deviations (RSD%) varying from 0.7% to 19.6% for the 25 mycotoxins. The method is simple, rapid, accurate, and an improvement compared with the existing methods published so far.

Simultaneous spectrophotometric determination of trace amounts of uranium, thorium, and zirconium using the partial least squares method after their preconcentration by alpha-benzoin oxime modified Amberlite XAD-2000 resin.

PubMed

Ghasemi, Jahan B; Zolfonoun, E

2010-01-15

A new solid phase extraction method for separation and preconcentration of trace amounts of uranium, thorium, and zirconium in water samples is proposed. The procedure is based on the adsorption of U(VI), Th(IV) and Zr(IV) ions on a column of Amberlite XAD-2000 resin loaded with alpha-benzoin oxime prior to their simultaneous spectrophotometric determination with Arsenazo III using orthogonal signal correction partial least squares method. The enrichment factor for preconcentration of uranium, thorium, and zirconium was found to be 100. The detection limits for U(VI), Th(IV) and Zr(IV) were 0.50, 0.54, and 0.48microgL(-1), respectively. The precision of the method, evaluated as the relative standard deviation obtained by analyzing a series of 10 replicates, was below 4% for all elements. The practical applicability of the developed sorbent was examined using synthetic seawater, natural waters and ceramic samples.

Simultaneous determination of five systemic azoles in plasma by high-performance liquid chromatography with ultraviolet detection.

PubMed

Gordien, Jean-Baptiste; Pigneux, Arnaud; Vigouroux, Stephane; Tabrizi, Reza; Accoceberry, Isabelle; Bernadou, Jean-Marc; Rouault, Audrey; Saux, Marie-Claude; Breilh, Dominique

2009-12-05

A simple, specific and automatable HPLC assay was developed for a simultaneous determination of systemic azoles (fluconazole, posaconazole, voriconazole, itraconazole and its metabolite hydroxyl-itraconazole, and ketoconazole) in plasma. The major advantage of this assay was sample preparation by a fully automatable solid phase extraction with Varian Plexa cartridges. C6-phenyl column was used for chromatographic separation, and UV detection was set at a wavelength of 260 nm. Linezolid was used as an internal standard. The assay was specific and linear over the concentration range of 0.05 to 40 microg/ml excepted for fluconazole which was between 0.05 and 100 microg/ml, and itraconazole between 0.1 and 40 microg/ml. Validation data for accuracy and precision for intra- and inter-day were good and satisfied FDA's guidance: CV between 0.24% and 11.66% and accuracy between 93.8% and 108.7% for all molecules. This assay was applied to therapeutic drug monitoring on patients hospitalized in intensive care and onco-hematologic units.

[Simultaneous determination of ochratoxin A, B and citrinin in foods by HPLC-FL and LC/MS/MS].

PubMed

Tabata, Setsuko; Iida, Kenji; Kimura, Keisuke; Iwasaki, Yumiko; Nakazato, Mitsuo; Kamata, Kunihiro; Hirokado, Masako

2008-04-01

Methods using high-performance liquid chromatography with fluorescence detection (HPLC-FL) and using liquid chromatography with tandem mass spectrometry (LC/MS/MS) were developed for simultaneous determination of ochratoxin A (OTA), ochratoxin B (OTB) and citrinin (CIT) in cereal, fruit, and coffee products. The samples were extracted with ethyl acetate under an acidic condition, and then cleaned up with liquid-liquid separation. The test solutions were analyzed by reverse-phase HPLC-FL and LC/MS/MS. Mass spectral acquisition was performed in positive ion mode by applying multiple reaction monitoring. The performances of both detectors were almost equivalent. The recoveries of OTA and OTB were 87-111%, and that of CIT were 70-88%. The limits of quantification (S/N> or =10) of OTA, OTB and CIT was 0.1 mug/kg or less. These methods were considered to be useful for the determination of the three mycotoxins at low levels (0.1 microg/kg).

Simultaneous determination of eight water-soluble vitamins in supplemented foods by liquid chromatography.

PubMed

Zafra-Gómez, Alberto; Garballo, Antonio; Morales, Juan C; García-Ayuso, Luis E

2006-06-28

A fast, simple, and reliable method for the isolation and determination of the vitamins thiamin, riboflavin, niacin, pantothenic acid, pyridoxine, folic acid, cyanocobalamin, and ascorbic acid in food samples is proposed. The most relevant advantages of the proposed method are the simultaneous determination of the eight more common vitamins in enriched food products and a reduction of the time required for quantitative extraction, because the method consists merely of the addition of a precipitation solution and centrifugation of the sample. Furthermore, this method saves a substantial amount of reagents as compared with official methods, and minimal sample manipulation is achieved due to the few steps required. The chromatographic separation is carried out on a reverse phase C18 column, and the vitamins are detected at different wavelengths by either fluorescence or UV-visible detection. The proposed method was applied to the determination of water-soluble vitamins in supplemented milk, infant nutrition products, and milk powder certified reference material (CRM 421, BCR) with recoveries ranging from 90 to 100%.

Simultaneous determination of nine saponins from Panax notoginseng using HPLC and pressurized liquid extraction.

PubMed

Wan, J B; Lai, C M; Li, S P; Lee, M Y; Kong, L Y; Wang, Y T

2006-04-11

A HPLC and pressurized liquid extraction (PLE) method was developed for simultaneous determination of nine saponins, including notoginsenoside R1, ginsenoside Rg1, Re, Rf, Rb1, Rc, Rb2, Rb3 and Rd in Panax notoginseng. The analysis was performed on C18 column with water-acetonitrile gradient elution and the investigated saponins were authenticated by comparing retention time and mass spectra with their reference compounds. Several methods including PLE, ultrasonication, soxhlet extraction and immersion were used for sample preparation and their extraction efficiency was compared. The results showed that PLE has the highest extraction efficiency and repeatability, which would be valuable on standardization of sample preparation for quality control of Chinese medicines. The developed HPLC and PLE is an effective approach for simultaneously quantitative determination of sapoinins in P. notoginseng, which could be used for quality control of P. notoginseng and its preparations.

Single-exposure color digital holography

NASA Astrophysics Data System (ADS)

Feng, Shaotong; Wang, Yanhui; Zhu, Zhuqing; Nie, Shouping

2010-11-01

In this paper, we report a method for color image reconstruction by recording only one single multi-wavelength hologram. In the recording process, three lasers of different wavelengths emitting in the red, green and blue regions are used for illuminating on the object and the object diffraction fields will arrive at the hologram plane simultaneously. Three reference beams with different spatial angles will interfere with the corresponding object diffraction fields on the hologram plane, respectively. Finally, a series of sub-holograms incoherently overlapped on the CCD to be recorded as a multi-wavelength hologram. Angular division multiplexing is employed to reference beams so that the spatial spectra of the multiple recordings will be separated in the Fourier plane. In the reconstruction process, the multi-wavelength hologram will be Fourier transformed into its Fourier plane, where the spatial spectra of different wavelengths are separated and can be easily extracted by employing frequency filtering. The extracted spectra are used to reconstruct the corresponding monochromatic complex amplitudes, which will be synthesized to reconstruct the color image. For singleexposure recording technique, it is convenient for applications on the real-time image processing fields. However, the quality of the reconstructed images is affected by speckle noise. How to improve the quality of the images needs for further research.

Mycotoxin analysis: an update.

PubMed

Krska, Rudolf; Schubert-Ullrich, Patricia; Molinelli, Alexandra; Sulyok, Michael; MacDonald, Susan; Crews, Colin

2008-02-01

Mycotoxin contamination of cereals and related products used for feed can cause intoxication, especially in farm animals. Therefore, efficient analytical tools for the qualitative and quantitative analysis of toxic fungal metabolites in feed are required. Current methods usually include an extraction step, a clean-up step to reduce or eliminate unwanted co-extracted matrix components and a separation step with suitably specific detection ability. Quantitative methods of analysis for most mycotoxins use immunoaffinity clean-up with high-performance liquid chromatography (HPLC) separation in combination with UV and/or fluorescence detection. Screening of samples contaminated with mycotoxins is frequently performed by thin layer chromatography (TLC), which yields qualitative or semi-quantitative results. Nowadays, enzyme-linked immunosorbent assays (ELISA) are often used for rapid screening. A number of promising methods, such as fluorescence polarization immunoassays, dipsticks, and even newer methods such as biosensors and non-invasive techniques based on infrared spectroscopy, have shown great potential for mycotoxin analysis. Currently, there is a strong trend towards the use of multi-mycotoxin methods for the simultaneous analysis of several of the important Fusarium mycotoxins, which is best achieved by LC-MS/MS (liquid chromatography with tandem mass spectrometry). This review focuses on recent developments in the determination of mycotoxins with a special emphasis on LC-MS/MS and emerging rapid methods.

Development and validation of a solid-phase extraction method coupled with HPLC-UV detection for the determination of biogenic amines in Chinese rice wine.

PubMed

Zhang, Ying; Li, Yan; Zhu, Xiao-Juan; Li, Min; Chen, Hao-Yu; Lv, Xiao-Ling; Zhang, Jian

2017-07-01

A reliable and accurate method for the determination of seven biogenic amines (BAs) was developed and validated with Chinese rice wine samples. The BAs were derivatised with dansyl chloride, cleaned up using solid-phase extraction (SPE) and separated by high-performance liquid chromatography (HPLC) coupled with ultraviolet (UV) detection. The optimised derivatisation reaction, conducted at pH 9.6 and 60°C for 30 min, ensured baseline separation and peak symmetry for each BA. SPE clean-up using Oasis MCX cartridges yielded good recovery rates for all BAs and effectively reduced matrix effects. The developed method shows good linearity with determination coefficients of more than 0.9989 over a concentration range of 0.1-100 mg l -1 . The limits of detection (LODs) for the investigated BAs ranged from 2.07 to 5.56 µg l -1 . The intra- and inter-day relative standard deviations (RSDs) ranged from 0.86% to 3.81% and from 2.13% to 3.82%, respectively. Spiking experiments showed that the overall recovery rates ranged from 85% to 113%. Thus, the proposed method was demonstrated as being suitable for simultaneous detection, with accurate and precise quantification, of BAs in Chinese rice wine.

Simultaneous Determination and Pharmacokinetic Comparisons of Multi-Ingredients after Oral Administration of Radix Salviae Miltiorrhizae Extract, Hawthorn Extract, and a Combination of Both Extracts to Rats

PubMed Central

Liu, Yu-Qiang; Cai, Qian; Liu, Chang; Bao, Feng-Wei; Zhang, Zhen-Qiu

2014-01-01

A simple and sensitive HPLC method was developed for simultaneous determination of danshensu (DSS), rosmarinic acid (RA), lithospermic acid (LA), salvianolic acid B (SAB), and hyperoside (HP) in rat plasma. This method validated was successfully applied to the pharmacokinetic study of the main active ingredients after oral administration of Radix Salviae Miltiorrhizae extract (SME), hawthorn extract (HTE), and a combination of both extracts (2.5 : 1) to rats. The results indicated that there have been great differences in pharmacokinetics between a single extract and a combination of both extracts. A combination of both extracts can enhance their bioavailabilities and delay the elimination of SAB and DSS in rats. PMID:24660090

Molecularly imprinted polymers with synthetic dummy template for simultaneously selective removal and enrichment of ginkgolic acids from Ginkgo biloba L. leaves extracts.

PubMed

Ji, Wenhua; Ma, Xiuli; Xie, Hongkai; Chen, Lingxiao; Wang, Xiao; Zhao, Hengqiang; Huang, Luqi

2014-11-14

Dummy molecularly imprinted polymers (DMIPs) for simultaneously selective removal and enrichment of ginkgolic acids (GAs) during the processing of Ginkgo biloba leaves have been prepared. Two dummy template molecule with similar structural skeleton to GAs, 6-methoxysalicylic acid (MOSA, DT-1) and 6-hexadecyloxysalicylic acid (HOSA, DT-2), have been designed and synthesized. The performance of the DMIPs and NIPs were evaluated including selective recognition capacity, adsorption isotherm, and adsorption kinetics. The selective recognition capacity of the three GAs with four analogues on the sorbents illustrated that the DMIPs sorbents have high specificity for GAs. An efficient method based on DMIP-HOSA coupled with solid-phase extraction (SPE) was developed for simultaneously selective removal and enrichment of ginkgolic acids (GAs) during the processing of Ginkgo biloba leaves. The method showed excellent recoveries (82.5-88.7%) and precision (RSD 0.5-2.6%, n=5) for licorice extracts, Gastrodia elata extracts and pepper extracts spiked at three concentration levels each (50, 100, 200 μg mL(-1)). The results indicated that GAs and standardized Ginkgo biloba leaves extracts could be obtained simultaneously through the DMIP-SPE. Copyright © 2014 Elsevier B.V. All rights reserved.

Simultaneous extraction, identification and quantification of phenolic compounds in Eclipta prostrata using microwave-assisted extraction combined with HPLC-DAD-ESI-MS/MS.

PubMed

Fang, Xinsheng; Wang, Jianhua; Hao, Jifu; Li, Xueke; Guo, Ning

2015-12-01

A simple and rapid method was developed using microwave-assisted extraction (MAE) combined with HPLC-DAD-ESI-MS/MS for the simultaneous extraction, identification, and quantification of phenolic compounds in Eclipta prostrata, a common herb and vegetable in China. The optimized parameters of MAE were: employing 50% ethanol as solvent, microwave power 400 W, temperature 70 °C, ratio of liquid/solid 30 mL/g and extraction time 2 min. Compared to conventional extraction methods, the optimized MAE can avoid the degradation of the phenolic compounds and simultaneously obtained the highest yields of all components faster with less consumption of solvent and energy. Six phenolic acids, six flavonoid glycosides and one coumarin were firstly identified. The phenolic compounds were quantified by HPLC-DAD with good linearity, precision, and accuracy. The extract obtained by MAE showed significant antioxidant activity. The proposed method provides a valuable and green analytical methodology for the investigation of phenolic components in natural plants. Copyright © 2015 Elsevier Ltd. All rights reserved.

A Framework for Final Drive Simultaneous Failure Diagnosis Based on Fuzzy Entropy and Sparse Bayesian Extreme Learning Machine

PubMed Central

Ye, Qing; Pan, Hao; Liu, Changhua

2015-01-01

This research proposes a novel framework of final drive simultaneous failure diagnosis containing feature extraction, training paired diagnostic models, generating decision threshold, and recognizing simultaneous failure modes. In feature extraction module, adopt wavelet package transform and fuzzy entropy to reduce noise interference and extract representative features of failure mode. Use single failure sample to construct probability classifiers based on paired sparse Bayesian extreme learning machine which is trained only by single failure modes and have high generalization and sparsity of sparse Bayesian learning approach. To generate optimal decision threshold which can convert probability output obtained from classifiers into final simultaneous failure modes, this research proposes using samples containing both single and simultaneous failure modes and Grid search method which is superior to traditional techniques in global optimization. Compared with other frequently used diagnostic approaches based on support vector machine and probability neural networks, experiment results based on F 1-measure value verify that the diagnostic accuracy and efficiency of the proposed framework which are crucial for simultaneous failure diagnosis are superior to the existing approach. PMID:25722717

Development of "ultrasound-assisted dynamic extraction" and its combination with CCC and CPC for simultaneous extraction and isolation of phytochemicals.

PubMed

Zhang, Yuchi; Liu, Chunming; Li, Jing; Qi, Yanjuan; Li, Yuchun; Li, Sainan

2015-09-01

A new method for the extraction of medicinal herbs termed ultrasonic-assisted dynamic extraction (UADE) was designed and evaluated. This technique was coupled with counter-current chromatography (CCC) and centrifugal partition chromatography (CPC) and then applied to the continuous extraction and online isolation of chemical constituents from Paeonia lactiflora Pall (white peony) roots. The mechanical parameters, including the pitch and diameter of the shaft, were optimized by means of mathematical modeling. Furthermore, the configuration and mechanism of online UADE coupled with CCC and CPC were elaborated. The stationary phases of the two-phase solvent systems from CCC and CPC were utilized as the UADE solution. The extraction solution was pumped into the sample loop and then introduced into the CCC column; the target compounds were eluted with the lower aqueous phase of the two-phase solvent system. During the CCC separation, the extraction solution was continuously fed in the sample loop by turning the ten-port valve; the extraction solution was then pumped into the CPC column and eluted by the mobile phase of the two-phase solvent system mentioned above. When the first cycle of the UADE/CCC/CPC was completed, the second cycle experiment could be carried out, and so on. Four target compounds (albiflorin, benzoylpaeoniflorin, paeoniflorin, and galloylpaeoniflorin) with purities above 94.96% were successfully extracted and isolated online using the two-phase solvent system comprising ethyl acetate-n-butanol-ethanol-water (1:3.5:2:4.5, v/v/v/v). Compared with conventional extraction methods, the instrumental setup of the present method offers the advantages of automation and systematic extraction and isolation of natural products. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

System and method for conditioning a hardwood pulp liquid hydrolysate

DOEpatents

Waite, Darrell M; Arnold, Richard; St. Pierre, James; Pendse, Hemant P; Ceckler, William H

2013-12-17

A system and method for hardwood pulp liquid hydrolysate conditioning includes a first evaporator receives a hardwood mix extract and outputting a quantity of vapor and extract. A hydrolysis unit receives the extract, hyrolyzes and outputs to a lignin separation device, which separates and recovers a quantity of lignin. A neutralization device receives extract from the lignin separation device and a neutralizing agent, producing a mixture of solid precipitate and a fifth extract. The solid precipitate is removed from the fifth extract. A second evaporator removes a quantity of acid from the fifth extract in a vapor form. This vapor may be recycled to improve total acid recovery or discarded. A desalination device receives the diluted extract, separates out some of the acid and salt and outputs a desalinated solution.

Simultaneous quantification of 5 main components of Psoralea corylifolia L. in rats' plasma by utilizing ultra high pressure liquid chromatography tandem mass spectrometry.

PubMed

Gao, Qianqian; Xu, Zisheng; Zhao, Genhua; Wang, Heng; Weng, Zebin; Pei, Ke; Wu, Li; Cai, Baochang; Chen, Zhipeng; Li, Weidong

2016-02-01

Psoralea corylifolia L. has long been used in traditional Chinese medicine for treating and preventing many diseases. A group of flavonoid components are regarded as the active principals within the seeds. In this research, a rapid, accurate and sensitive ultra high pressure liquid chromatography tandem mass spectrometry (UHPLC/MS/MS) method has been established for simultaneous quantification of its 5 main components, namely, neobavaisoflavone, bavachin, isobavachalcone, bavachinin and corylifol A in rats' plasma after the rats were orally administrated with Buguzhi extract. Negative ion electrospray mode was applied in the detection process. Multiple reactions monitoring (MRM) mode was utilized for simultaneous quantitative analyzing of neobavaisoflavone (m/z 321.1→m/z 265.1), bavachin (m/z 323.1→m/z 119.0), isobavachalcone (m/z 323.2→m/z 119.0), bavachinin (m/z 337.2→m/z 119.0), corylifol A (m/z 389.2→m/z 277.0) and liquiritigenin (Internal Standard, m/z 255.1→m/z 119.0). Chromatographic separation of the above mentioned components was conducted on a Waters BEH-C18 column (100 mm×2.1mm, 1.7μm) with gradient elution system at flow rate of 0.3mL/min. The mobile phase was composed of acetonitrile and 0.1% formic acid solution. The lower limit of quantification (LLOQ) for each of the above analytes was 0.5ng/mL. Each of the analytes exhibited good linearity within the concentration range of 0.5-100ng/mL. The method was fully validated for its selectivity, accuracy, precision, stability, matrix effect and extraction recovery. The validated method has been successfully applied for simultaneous determination of the 5 flavonoids in rat plasma for the first time. Copyright © 2016 Elsevier B.V. All rights reserved.

Simultaneous spectrophotometric determination of synthetic dyes in food samples after cloud point extraction using multiple response optimizations.

PubMed

Heidarizadi, Elham; Tabaraki, Reza

2016-01-01

A sensitive cloud point extraction method for simultaneous determination of trace amounts of sunset yellow (SY), allura red (AR) and brilliant blue (BB) by spectrophotometry was developed. Experimental parameters such as Triton X-100 concentration, KCl concentration and initial pH on extraction efficiency of dyes were optimized using response surface methodology (RSM) with a Doehlert design. Experimental data were evaluated by applying RSM integrating a desirability function approach. The optimum condition for extraction efficiency of SY, AR and BB simultaneously were: Triton X-100 concentration 0.0635 mol L(-1), KCl concentration 0.11 mol L(-1) and pH 4 with maximum overall desirability D of 0.95. Correspondingly, the maximum extraction efficiency of SY, AR and BB were 100%, 92.23% and 95.69%, respectively. At optimal conditions, extraction efficiencies were 99.8%, 92.48% and 95.96% for SY, AR and BB, respectively. These values were only 0.2%, 0.25% and 0.27% different from the predicted values, suggesting that the desirability function approach with RSM was a useful technique for simultaneously dye extraction. Linear calibration curves were obtained in the range of 0.02-4 for SY, 0.025-2.5 for AR and 0.02-4 μg mL(-1) for BB under optimum condition. Detection limit based on three times the standard deviation of the blank (3Sb) was 0.009, 0.01 and 0.007 μg mL(-1) (n=10) for SY, AR and BB, respectively. The method was successfully used for the simultaneous determination of the dyes in different food samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Development of two step liquid-liquid extraction tandem UHPLC-MS/MS method for the simultaneous determination of Ginkgo flavonoids, terpene lactones and nimodipine in rat plasma: Application to the pharmacokinetic study of the combination of Ginkgo biloba dispersible tablets and Nimodipine tablets.

PubMed

Xiao, Jie; Wang, Tianyang; Li, Pei; Liu, Ran; Li, Qing; Bi, Kaishun

2016-08-15

A sensitive, reliable and accurate UHPLC-MS/MS method has been firstly established and validated for the simultaneous quantification of ginkgo flavonoids, terpene lactones and nimodipine in rat plasma after oral administration of Ginkgo biloba dispersible tablets, Nimodipine tablets and the combination of the both, respectively. The plasma samples were extracted by two step liquid-liquid extraction, nimodipine was extracted by hexane-ether (3:1, v/v) at the first step, after that ginkgo flavonoids and terpene lactones were extracted by ethyl acetate. Then the analytes were successfully separated by running gradient elution with the mobile phase consisting of 0.1% formic acid in water and methanol at a flow rate of 0.6mL/min. The detection of the analytes was performed on a UHPLC-MS/MS system with turbo ion spray source in the negative ion and multiple reaction monitoring (MRM) mode. The calibration curves for the determination of all the analytes showed good linearity (R(2)>0.99), and the lower limits of quantification were 0.50-4.00ng/mL. Intra-day and inter-day precisions were in the range of 3.6%-9.2% and 3.2%-13.1% for all the analytes. The mean extraction recoveries of the analytes were within 69.82%-103.5% and the matrix were within 82.8%-110.0%. The validated method had been successfully applied to compare the pharmacokinetic parameters of ginkgo flavonoids, terpene lactones and nimodipine in rat plasma after oral administration of Ginkgo biloba dispersible tablets, Nimodipine tablets with the combination of the both. There were no statistically significant differences on the pharmacokinetic behaviors of all the analytes between the combined and single administration groups. Results showed that the combination of the two agents may avoid dosage adjustments in clinic and the combination is more convenient as well as efficient on different pathogenesis of cerebral ischemia. Copyright © 2016 Elsevier B.V. All rights reserved.

Isolation, Separation, and Preconcentration of Biologically Active Compounds from Plant Matrices by Extraction Techniques.

PubMed

Raks, Victoria; Al-Suod, Hossam; Buszewski, Bogusław

2018-01-01

Development of efficient methods for isolation and separation of biologically active compounds remains an important challenge for researchers. Designing systems such as organomineral composite materials that allow extraction of a wide range of biologically active compounds, acting as broad-utility solid-phase extraction agents, remains an important and necessary task. Selective sorbents can be easily used for highly selective and reliable extraction of specific components present in complex matrices. Herein, state-of-the-art approaches for selective isolation, preconcentration, and separation of biologically active compounds from a range of matrices are discussed. Primary focus is given to novel extraction methods for some biologically active compounds including cyclic polyols, flavonoids, and oligosaccharides from plants. In addition, application of silica-, carbon-, and polymer-based solid-phase extraction adsorbents and membrane extraction for selective separation of these compounds is discussed. Potential separation process interactions are recommended; their understanding is of utmost importance for the creation of optimal conditions to extract biologically active compounds including those with estrogenic properties.

Simultaneous Determination of Oleanolic Acid and Ursolic Acid by in Vivo Microdialysis via UHPLC-MS/MS Using Magnetic Dispersive Solid Phase Extraction Coupling with Microwave-Assisted Derivatization and Its Application to a Pharmacokinetic Study of Arctiumlappa L. Root Extract in Rats.

PubMed

Zheng, Zhenjia; Zhao, Xian-En; Zhu, Shuyun; Dang, Jun; Qiao, Xuguang; Qiu, Zhichang; Tao, Yanduo

2018-04-18

Simultaneous detection of oleanolic acid and ursolic acid in rat blood by in vivo microdialysis can provide important pharmacokinetics information. Microwave-assisted derivatization coupled with magnetic dispersive solid phase extraction was established for the determination of oleanolic acid and ursolic acid by liquid chromatography tandem mass spectrometry. 2'-Carbonyl-piperazine rhodamine B was first designed and synthesized as the derivatization reagent, which was easily adsorbed onto the surface of Fe 3 O 4 /graphene oxide. Simultaneous derivatization and extraction of oleanolic acid and ursolic acid were performed on Fe 3 O 4 /graphene oxide. The permanent positive charge of the derivatization reagent significantly improved the ionization efficiencies. The limits of detection were 0.025 and 0.020 ng/mL for oleanolic acid and ursolic acid, respectively. The validated method was shown to be promising for sensitive, accurate, and simultaneous determination of oleanolic acid and ursolic acid. It was used for their pharmacokinetics study in rat blood after oral administration of Arctiumlappa L. root extract.

Simultaneous message framing and error detection

NASA Technical Reports Server (NTRS)

Frey, A. H., Jr.

1968-01-01

Circuitry simultaneously inserts message framing information and detects noise errors in binary code data transmissions. Separate message groups are framed without requiring both framing bits and error-checking bits, and predetermined message sequence are separated from other message sequences without being hampered by intervening noise.

Simultaneous enantioselective determination of phenylpyrazole insecticide flufiprole and its chiral metabolite in paddy field ecosystem by ultra-high performance liquid chromatography/tandem mass spectrometry.

PubMed

Li, Jing; Zhang, Yuting; Cheng, Youpu; Yuan, Shankui; Liu, Lei; Shao, Hui; Li, Hui; Li, Na; Zhao, Pengyue; Guo, Yongze

2016-03-20

A novel and sensitive ultra-high performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous enantioselective determination of flufiprole and its hydrolysis metabolite in paddy field ecosystem. The separation and determination were performed using reversed-phase chromatography on a novel cellulose chiral stationary phase, a Lux Cellulose-4 (150 mm × 2.0 mm) column, under isocratic conditions at 0.25 mL/min flow rate. The effects of other four different polysaccharide-based chiral stationary phases (CSPs) on the separation and simultaneous enantioseparation of the two target compounds were also evaluated. The elution orders of the eluting enantiomers were identified by an optical rotation detector. Modified QuEChERS (acronym for Quick, Easy, Cheap, Effective, Rugged and Safe) method and solid-phase extraction (SPE) were used for the enrichment and cleanup of paddy water, rice straw, brown rice and paddy soil samples, respectively. Parameters including the matrix effect, linearity, precision, accuracy and stability were evaluated. Under the optimal conditions, the mean recoveries for all enantiomers from the above four sample matrix were ranged from 83.6% to 107%, with relative standard deviations (RSD) in the range of 1.0-5.8%. Coefficients of determination R(2)≥0.998 were achieved for each enantiomer in paddy water, rice straw, brown rice and paddy soil matrix calibration curves within the range of 5-500 μg/kg. The limits of quantification (LOQ) for all stereoisomers in the above four matrices were all below 2.0 μg/kg. The methodology was successfully applied for simultaneously enantioselective analysis of flufiprole enantiomers and their chiral metabolite in the real samples, indicating its efficacy in investigating the environmental stereochemistry of flufiprole in paddy field ecosystem. Copyright © 2016 Elsevier B.V. All rights reserved.

Simultaneous Analysis of Malondialdehyde, 4-Hydroxy-2-hexenal, and 4-Hydroxy-2-nonenal in Vegetable Oil by Reversed-Phase High-Performance Liquid Chromatography.

PubMed

Ma, Lukai; Liu, Guoqin

2017-12-27

A group of toxic aldehydes such as, malondialdehyde (MDA), 4-hydroxy-2-hexenal (HHE), and 4-hydroxy-2-nonenal (HNE) have been found in various vegetable oils and oil-based foods. Then simultaneous determination of them holds a great need in both the oil chemistry field and food field. In the present study, a simple and efficient analytical method was successfully developed for the simultaneous separation and detection of MDA, HHE, and HNE in vegetable oils by reversed-phase-high-performance liquid chromatography (RP-HPLC) coupled with photodiode array detector (PAD) at dual-channel detection mode. The effect of various experimental factors on the extraction performance, such as coextraction solvent system, butylated hydroxytoluene addition, and trichloroacetic acid addition were systematically investigated. Results showed that the linear ranges were 0.02-10.00 μg/mL for MDA, 0.02-4.00 μg/mL for HHE, and 0.03-4.00 μg/mL for HNE with the satisfactory correlation coefficient of >0.999 for all detected aldehydes. The limit of detection (LOD) and limit of quantification (LOQ) of MDA, HHE, and HNE were ∼0.021and 0.020 μg/mL, ∼0.009 and 0.020 μg/mL, and ∼0.014 and 0.030 μg/mL, respectively. Their recoveries were 99.64-102.18%, 102.34-104.61%, and 98.87-103.04% for rapeseed oil and 96.38-98.05%, 96.19-101.34%, and 96.86-99.04% for French fries, separately. Under the selected conditions, the developed methods was successfully applied to the simultaneous determination of MDA, HHE, and HNE in different tested vegetable oils. The results indicated that this method could be employed for the quality assessment of vegetable oils.

Simultaneous saccharification and fermentation of industrial sweetpotatoes for ethanol production and anthocyanins extraction

USDA-ARS?s Scientific Manuscript database

A simultaneous saccharification fermentation (SSF) system was studied for ethanol production in flour industrial sweetpotato (ISP) feedstocks (lines: white DM02-180 and purple NC-413) as an integrated cost saving process, and to examine the feasibility of extracting anthocyanins from flour purple IS...

Short-term Variability of Extinction by Broadband Stellar Photometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Musat, I.C.; Ellingson, R.G.

2005-03-18

Aerosol optical depth variation over short-term time intervals is determined from broadband observations of stars with a whole sky imager. The main difficulty in such measurements consists of accurately separating the star flux value from the non-stellar diffuse skylight. Using correction method to overcome this difficulty, the monochromatic extinction at the ground due to aerosols is extracted from heterochromatic measurements. A form of closure is achieved by comparison with simultaneous or temporally close measurements with other instruments, and the total error of the method, as a combination of random error of measurements and systematic error of calibration and model, ismore » assessed as being between 2.6 and 3% rms.« less

Multiplexed, quantitative, and targeted metabolite profiling by LC-MS/MRM.

PubMed

Wei, Ru; Li, Guodong; Seymour, Albert B

2014-01-01

Targeted metabolomics, which focuses on a subset of known metabolites representative of biologically relevant metabolic pathways, is a valuable tool to discover biomarkers and link disease phenotypes to underlying mechanisms or therapeutic modes of action. A key advantage of targeted metabolomics, compared to discovery metabolomics, is its immediate readiness for extracting biological information derived from known metabolites and quantitative measurements. However, simultaneously analyzing hundreds of endogenous metabolites presents a challenge due to their diverse chemical structures and properties. Here we report a method which combines different chromatographic separation conditions, optimal ionization polarities, and the most sensitive triple-quadrupole MS-based data acquisition mode, multiple reaction monitoring (MRM), to quantitatively profile 205 endogenous metabolites in 10 min.

BX-U linear trap for one-way production and confinement of Li+ and e- plasmas

NASA Astrophysics Data System (ADS)

Himura, Haruhiko

2016-03-01

A modified version of the Penning-Malmberg trap was developed wherein both positive and negative harmonic potential wells were created by using multi-ring electrodes. The sequence of particle injection, particle trapping, and plasma extraction from the potential wells was controlled by a set of switching circuits. All the guns launching charged particles were collected together in one side of the linear trap. Nevertheless, pure electron (e-) and lithium-ion (Li+) plasmas were not only separately produced on the machine axis but also confined simultaneously. Preliminary data show that for B ≈ 0.13 T the e- plasma lasted for 15 s and the Li+ plasma lasted for ~ 4 s.

Wavelength-division-multiplexing method of polarized low-coherence interferometry for fiber Fabry-Perot interferometric sensors.

PubMed

Yin, Jinde; Liu, Tiegen; Jiang, Junfeng; Liu, Kun; Wang, Shuang; Wu, Fan; Ding, Zhenyang

2013-10-01

We propose a new wavelength-division-multiplexing method for extrinsic fiber Fabry-Perot interferometric (EFPI) sensing in a polarized low-coherence interferometer configuration. In the proposed method, multiple LED sources are used with different center wavelengths, and each LED is used by a specific sensing channel, and therefore the spatial frequency of the low-coherence interferogram of each channel can be separated. A bandpass filter is used to extract the low-coherence interferogram of each EFPI channel, and thus the cavity length of each EFPI channel can be identified through demultiplexing. We successfully demonstrate the simultaneous demodulation of EFPI sensors with same nominal cavity length while maintaining high measurement precision.

Combined radiochemical procedure for determination of plutonium, americium and strontium-90 in the soil samples from SNTS

NASA Astrophysics Data System (ADS)

Kazachevskii, I. V.; Lukashenko, S. N.; Chumikov, G. N.; Chakrova, E. T.; Smirin, L. N.; Solodukhin, V. P.; Khayekber, S.; Berdinova, N. M.; Ryazanova, L. A.; Bannyh, V. I.; Muratova, V. M.

1999-01-01

The results of combined radiochemical procedure for the determination of plutonium, americium and90Sr (via measurement of90Y) in the soil samples from SNTS are presented. The processes of co-precipitation of these nuclides with calcium fluoride in the strong acid solutions have been investigated. The conditions for simultaneous separation of americium and yttrium using extraction chromatography have been studied. It follows from analyses of real soil samples that the procedure developed provides the chemical recovery of plutonium and yttrium in the range of 50-95% and 60-95%, respectively. The execution of the procedure requires 3.5 working days including a sample decomposition study.

Assessment of Agroforestry Trees in Dry-land Savanna Supports Ecohydrologic Separation

NASA Astrophysics Data System (ADS)

Ceperley, Natalie; Mande, Theophile; Van de Giesen, Nick; Tyler, Scott; Parlange, Marc

2016-04-01

We use stable isotopes of water to demonstrate the ecohydrologic separation, or the plant controlled compartmentalization, of different water sources in a catchment in South Eastern Burkina Faso. We analyze water extracted from the groundwater, stream water, precipitation, perched aquifer, xylem water of agroforestry trees, and sub-canopy soil water over a 6 year period to explore how the separation affects different components of the system over time. The ratio between deuterium and O18 allows us to assess whether the water that plants use is the same as the water that recharges the aquifer and runs off in the stream. Water extracted from the tree at leaf out in February corresponded to deuterium and O18 concentrations of the groundwater, a drop from its dry season, enriched, levels which mimicked the soil water. Examination of the isotopic signature suggests that the size of tree plays an important role in duration and timing of this leaf-out as well as the degree of enrichment during the peak of the dry season. Dates of leaf out were confirmed by analyzing sub-canopy radiation and photographs. Water extracted from roots suggests that the trees are performing hydraulic redistribution, or lifting the ground water and 'sharing it' with the rooting zone soil during the dry season. The enriched level of xylem, in this case, is a product of water loss and enrichment along the travel path of the water from the roots to the tip of the branch, as evidenced by the variation according to size of tree. Vapor pressure deficit, sap flow, soil water, and soil moisture interactions support this picture of interacting controls, separate from hydrologic triggers on the water movement in the tree. A second round of sampling focused on the leaf out period by extracting and analyzing stem water from throughout the canopy during the leaf out. Simultaneous large eddy correlation revealed high levels of latent energy flux, even during the dry season. Our isotope analysis allowed us to conclude that tree level transpiration explains this discrepancy since it does not access the same reservoirs of water as the rest of the catchment. Most current land surface models do not differentiate between different reservoirs of water.

Simultaneous HPLC-F analysis of three recent antiepileptic drugs in human plasma.

PubMed

Mercolini, Laura; Mandrioli, Roberto; Amore, Mario; Raggi, Maria Augusta

2010-09-21

An original high-performance liquid chromatographic method with fluorescence detection is presented for the simultaneous determination of the three antiepileptic drugs gabapentin, vigabatrin and topiramate in human plasma. After pre-column derivatisation with dansyl chloride, the analytes were separated on a Hydro-RP column with a mobile phase composed of phosphate buffer (55%) and acetonitrile (45%) and detected at lambda(em)=500 nm, exciting at 300 nm. An original pre-treatment procedure on biological samples, based on solid-phase extraction with MCX cartridges for gabapentin and vigabatrin, and with Plexa cartridges for topiramate, gave high extraction yields (>91%), satisfactory precision (RSD<6.4%) and good selectivity. Linearity was found in the 0.2-50.0 microg mL(-1) range for gabapentin, in the 1.0-100.0 microg mL(-1) range for vigabatrin and in the 1.0-50.0 microg mL(-1) range for topiramate, with limits of detection (LODs) between 0.1 and 0.3 microg mL(-1). After validation, the method was successfully applied to some plasma samples from patients undergoing therapy with one or more of these drugs. Accuracy results were satisfactory (recovery >91%). Therefore, the method seems to be suitable for the therapeutic drug monitoring (TDM) of patients treated with gabapentin, vigabatrin and topiramate. Copyright 2010 Elsevier B.V. All rights reserved.

Development and validation of an ultra high performance liquid chromatography electrospray ionization tandem mass spectrometry method for the simultaneous determination of selected flavonoids in Ginkgo biloba.

PubMed

Pandey, Renu; Chandra, Preeti; Arya, Kamal Ram; Kumar, Brijesh

2014-12-01

A rapid and sensitive ultra high performance liquid chromatography electrospray ionization tandem mass spectrometry method was developed and validated for the simultaneous determination of 13 flavonoids in leaf, stem, and fruit extracts of male and female trees of Ginkgo biloba to investigate gender- and age-related variations of flavonoids content. Chromatographic separation was accomplished on an Acquity UPLC BEH C18 column (50 mm × 2.1 mm id, 1.7 μm) in 5 min. Quantitation was performed using negative electrospray ionization mass spectrometry in multiple reaction monitoring mode. The calibration curves of all analytes showed a good linear relationship (r(2) ≥ 0.9977) over the concentration range of 1-1000 ng/mL. The precision evaluated by an intra- and interday study showed RSD ≤ 1.98% and good accuracy with overall recovery in the range from 97.90 to 101.09% (RSD ≤ 1.67%) for all analytes. The method sensitivity expressed as the limit of quantitation was typically 0.25-3.57 ng/mL. The results showed that the total content of 13 flavonoids was higher in the leaf extract of an old male Ginkgo tree compared to young female Ginkgo trees. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous analysis of 17 diuretics in dietary supplements by HPLC and LC-MS/MS.

PubMed

Woo, H; Kim, J W; Han, K M; Lee, J H; Hwang, I S; Lee, J H; Kim, J; Kweon, S J; Cho, S; Chae, K R; Han, S Y; Kim, J

2013-01-01

In order to test health foods for illegally added diuretics for weight loss, we developed simple, rapid, selective, and sensitive methods using HPLC and LC-MS/MS for the simultaneous analysis of 17 diuretics in dietary supplements. HPLC conditions were set with a Capcell-pak C18, using a mobile phase consisting of gradient conditions, UV detection at 254 nm and validated for linearity (r(2)> 0.999), precision (CV ≤ 3%), recoveries (90.4-102.8%) and reproducibility. Identification and quantification of 17 diuretics were accomplished by ion-spray LC-MS/MS using multiple reaction monitoring (MRM). The chromatographic separation was carried out under the reversed-phase mechanism on an HSS-T3 column. The LC-MS/MS method was validated for linearity (r(2)> 0.99) and precision (CV < 13%). Sixteen dietary supplements were tested with the developed methods. Diuretics were not detected in all samples. Extraction recovery was also investigated and the extraction recoveries in different formulations were from 88% to 110% and from 81% to 116% using HPLC and LC-MS/MS, respectively. There was no significant difference in recoveries in the type of dietary supplements. Based on this result, the developed methods to monitor illegal drug adulterations in dietary supplements using HPLC and LC-MS/MS are simple, fast and reliable. Therefore, it is applicable to routine drug-adulteration screening.

Simultaneous determination of blonanserin and its four metabolites in human plasma using ultra-performance liquid chromatography-tandem mass spectrometry.

PubMed

Zhou, Ying; Liu, Ming; Jiang, Ji; Wang, Hongyun; Hu, Pei

2013-11-15

A sensitive and rapid method based on ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) was developed and validated for the simultaneous determination of blonanserin, its major active metabolite (N-deethyl form) and other three metabolites (N-oxide form, Ethylenediamine form and Carboxylate form) in human plasma. Plasma samples were pre-purified by solid-phase extraction (SPE) and analyzed using a gradient chromatographic separation over an Acquity UPLC CSH C18 column. The mobile phase consisted of acetonitrile-water containing 5mM ammonium formate and 0.1% formic acid at a flow rate of 0.5mL/min. Positive electrospray ionization was employed as the ionization source in the multiple reaction monitoring (MRM) mode. The analysis time was about 3.5min. The method was fully validated over the concentration range of 0.01-1ng/mL for all analytes. The lower limit of quantification (LLOQ) was 0.01ng/mL. Inter- and intra-batch precision was less than 15% and the accuracy was within 85-115%. The mean extraction recoveries of all analytes at two concentration levels were consistent. Selectivity, matrix effect and stability were also validated. The method was applied to the pharmacokinetic study of blonanserin in Chinese healthy subjects. Copyright © 2013 Elsevier B.V. All rights reserved.

Simultaneous quantitative analysis of dextromethorphan, dextrorphan and chlorphenamine in human plasma by liquid chromatography-electrospray tandem mass spectrometry.

PubMed

Ding, Ying; Huang, Kai; Chen, Lan; Yang, Jie; Xu, Wen-Yan; Xu, Xue-Jiao; Duan, Ru; Zhang, Jing; He, Qing

2014-03-01

A sensitive and accurate HPLC-MS/MS method was developed for the simultaneous determination of dextromethorphan, dextrorphan and chlorphenamine in human plasma. Three analytes were extracted from plasma by liquid-liquid extraction using ethyl acetate and separated on a Kromasil 60-5CN column (3 µm, 2.1 × 150 mm) with mobile phase of acetonitrile-water (containing 0.1% formic acid; 50:50, v/v) at a flow rate of 0.2 mL/min. Quantification was performed on a triple quadrupole tandem mass spectrometer in multiple reaction monitoring mode using positive electrospray ionization. The calibration curve was linear over the range of 0.01-5 ng/mL for dextromethorphan, 0.02-5 ng/mL for dextrorphan and 0.025-20 ng/mL for chlorphenamine. The lower limits of quantification for dextromethorphan, dextrorphan and chlorphenamine were 0.01, 0.02 and 0.025 ng/mL, respectively. The intra- and inter-day precisions were within 11% and accuracies were in the range of 92.9-102.5%. All analytes were proved to be stable during sample storage, preparation and analytic procedures. This method was first applied to the pharmacokinetic study in healthy Chinese volunteers after a single oral dose of the formulation containing dextromethorphan hydrobromide (18 mg) and chlorpheniramine malaeate (8 mg). Copyright © 2013 John Wiley & Sons, Ltd.

A sensitive liquid chromatography-electrospray ionization-mass spectrometry method for the simultaneous determination of pentoxyverine citrate and guaifenesin in human plasma---application to pharmacokinetic and bioequivalence studies.

PubMed

Wen, Jinhua; Zhang, Hong; Xia, Chunhua; Hu, Xiao; Xu, Wenwei; Cheng, Xiaohua; Gao, Jun; Xiong, Yuqing

2010-04-01

A sensitive and specific liquid chromatography-electrospray ionization-mass spectrometry method for the identification and quantification of pentoxyverine citrate and guaifenesin in human plasma has been developed. After extraction from plasma samples by ethyl acetate, the internal standard and analytes were separated by high-performance liquid chromatographic on a Shim-pack VP-ODS C(18) column (150 x 2.0 mm) using a mobile phase consisting of A (methanol) and B (0.4% glacial acetic acid and 4 mmol/L ammonium acetate) (A:B, 43 : 57). Analysis was performed on a Shimadzu LC/MS-2010A in selected ion monitoring mode with a positive electrospray ionization interface. The method was linear in the concentration range of 1.0-640.0 ng/mL for pentoxyverine citrate and 0.025-6.4 microg/mL for guaifenesin. The inter- and intra- precision were all within 12% and accuracy ranged from 85 to 115%.The lower limits of quantification were 1.0 ng/mL for pentoxyverine citrate and 25.0 ng/mL for guaifenesin. The extraction recovery was on average 81.95% for pentoxyverine citrate and 89.03% for guaifenesin. This is the first assay method reported for the simultaneous determination of pentoxyverine citrate and guaifenesin in plasma using one chromatographic run. Copyright (c) 2009 John Wiley & Sons, Ltd.

Simultaneous determination of carisoprodol and aspirin in human plasma using liquid chromatography-tandem mass spectrometry in polarity switch mode: application to a human pharmacokinetic study.

PubMed

Sreenivasulu, Vudagandla; Ramesh, Mullangi; Kumar, Inamadugu Jaswanth; Babu, Ravi Vasu; Pilli, Nageswara Rao; Krishnaiah, Abburi

2013-02-01

A simple, sensitive and rapid LC-MS/MS-ESI method has been developed and validated for simultaneous quantification of the carisoprodol and aspirin in human plasma. Carisoprodol was detected in positive ion mode, whereas aspirin was detected in negative ion mode. Carbamazepine and furosemide were used as internal standards (IS) for quantification of carisoprodol and aspirin, respectively. The extraction procedure involves a liquid-liquid extraction method with ter-butyl methyl ether. Chromatographic separation was achieved on a Zorbax XDB-Phenyl (4.6 × 75 mm, 3.5 µm) column using an isocratic mobile phase (5 mm ammonium acetate:methanol, 20:80, v/v) at a flow rate of 0.8 mL/min with a total run time of 2.2 min. A detailed method validation was performed as per the FDA guidelines. The standard curves found to be linear in the range of 25.5-4900 and 15.3-3000 ng/mL for carisoprodol and aspirin, respectively. The results met the acceptance criteria. Carisoprodol and aspirin were found to be stable in various stability studies. The validated method was successfully applied to a pharmacokinetic study following co-administration of carisoprodol (250 mg) and aspirin (75 mg) tablets by oral route to human volunteers. Copyright © 2012 John Wiley & Sons, Ltd.

Simultaneous quantification of Δ9-tetrahydrocannabinol, 11-hydroxy-Δ9-tetrahydrocannabinol, and 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid in human plasma using two-dimensional gas chromatography, cryofocusing, and electron impact-mass spectrometry

PubMed Central

Lowe, Ross H.; Karschner, Erin L.; Schwilke, Eugene W.; Barnes, Allan J.; Huestis, Marilyn A.

2009-01-01

A two-dimensional (2D) gas chromatography/electron impact-mass spectrometry (GC/EI-MS) method for simultaneous quantification of Δ9-tetrahydrocannabinol (THC), 11-hydroxy-Δ9-tetrahydrocannabinol (11-OH-THC), and 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THCCOOH) in human plasma was developed and validated. The method employs 2D capillary GC and cryofocusing for enhanced resolution and sensitivity. THC, 11-OH-THC, and THCCOOH were extracted by precipitation with acetonitrile followed by solid-phase extraction. GC separation of trimethylsilyl derivatives of analytes was accomplished with two capillary columns in series coupled via a pneumatic Deans switch system. Detection and quantification were accomplished with a bench-top single quadrupole mass spectrometer operated in electron impact-selected ion monitoring mode. Limits of quantification (LOQ) were 0.125, 0.25 and 0.125 ng/mL for THC, 11-OH-THC, and THCCOOH, respectively. Accuracy ranged from 86.0 to 113.0% for all analytes. Intra- and inter-assay precision, as percent relative standard deviation, was less than 14.1% for THC, 11-OH-THC, and THCCOOH. The method was successfully applied to quantification of THC and its 11-OH-THC and THCCOOH metabolites in plasma specimens following controlled administration of THC. PMID:17640656

Simultaneous determination of 17 sulfonamides and the potentiators ormetoprim and trimethoprim in salmon muscle by liquid chromatography with tandem mass spectrometry detection.

PubMed

Potter, Ross A; Burns, B Garth; van de Riet, Jeffrey M; North, David H; Darvesh, Rozina

2007-01-01

A simple, robust method using liquid chromatography/tandem mass spectrometry (LC/MS/MS) for the simultaneous determination of 17 sulfonamides [sulfanilamide (SNL), sulfacetamide (SAA), sulfaguanidine (SGD), sulfapyridine (SPY), sulfadiazine (SDZ), sulfathiazole (STZ), sulfamerazine (SMR), sulfamethoxazole (SOZ), sulfamoxole (SXL), sulfisoxazole (SXZ), sulfamethizole (SML), sulfamethazine (SMZ), sulfamethoxypyridazine (SMP), sulfamonomethoxine (SMM), sulfachloropyridazine (SCP), sulfaquinoxaline (SQX), and sulfadimethoxine (SDM)] and 2 potentiators [ormetoprim (OMP) and trimethoprim (TMP)] in fish tissue has been developed. The analytes were extracted from homogenized fish tissue with water-acetonitrile (50 + 50). The extract was clarified by centrifugation and a portion defatted with hexane. The analytes were partitioned into chloroform and evaporated to dryness. The redissolved residue was applied to a C18 reversed-phase column with a water-acetonitrile (0.1% acetic acid) gradient. All of the compounds were completely separated and detected in <10 min at 30 degrees C using LC/MS/MS. Standard curves were linear over the range of 0.02 to 5 ng injected. The limit of detection varied from 0.1 ng/g for SMZ and OMP to 0.9 ng/g for SXL and SOZ. Recoveries varied from 100% for SDM, SOZ, and SQX and 85% for SMR, OMP, and TMP to approximately 30% for SAA. Relative standard deviations for repeat analysis varied from 4% for SMZ and SCP to 23% for SAA.

Simultaneous determination of 13 phytohormones in oilseed rape tissues by liquid chromatography-electrospray tandem mass spectrometry and the evaluation of the matrix effect.

PubMed

Fan, Sufang; Wang, Xiupin; Li, Peiwu; Zhang, Qi; Zhang, Wen

2011-03-01

In the experiment, a high-performance liquid chromatography and electrospray ionization-tandem mass spectrometry with selected reaction monitoring was used to simultaneously determine various classes of phytohormones, including indole-3-acetic acid, α-naphthaleneacetic acid, 2-chlorobenzoic acid, 4-chlorobenzoic acid, indole-3-butyric acid, gibberellic acid, 2,4-dichlorophenoxyacetic acid, 2-naphthoxyacetic acid, abscisic acid, 2,3,5-triiodobenzoic acid, uniconazole, paclobutrazol and 2,4-epibassinolide in rape tissues. The analyses were separated by an HPLC equipped with a reversed-phase column using a binary solvent system composed of methanol and water, both containing 0.1% of formic acid. The matrix effect was also considered and determined. The technology was applied to analyze rape tissues, including roots, stems, leaves, flowers, immature pods and rape seeds. The rape tissues were subjected to ultrasound-assisted extraction and purified by dispersive solid-phase extraction, and then transferred into the liquid chromatography system. The detection limit for each plant hormone was defined by the ratio of signal/background noise (S/N) of 3. The results showed perfect linearity (R(2) values of 0.9987-1.0000) and reproducibility of elution times (relative standard deviations, RSDs,<1%) and peak areas (RSDs,<7%) for all target compounds. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous determination of ezetimibe and its glucuronide metabolite in human plasma by solid phase extraction and liquid chromatography-tandem mass spectrometry.

PubMed

Guo, Lin; Wang, Meng-meng; He, Min; Qiu, Fu-rong; Jiang, Jian

2015-04-01

A liquid chromatography-tandem mass spectrometry method (LC-MS/MS) was developed to quantify ezetimibe (EZM) and its major glucuronide (ezetimibe glucuronide, EZM-G) in human plasma simultaneously. The analytes were purified by solid phase extraction (SPE) without hydrolysis. Separation of the analytes was achieved using acetonitrile-water (0.08% formic acid) (70:30, v/v) as the mobile phase at a flow rate of 0.8 mL/min on an Agilent Extend C18 column. The analytes were detected by LC-MS/MS using negative ionization in multiple reaction monitoring (MRM) mode. The mass transition pairs of m/z 408.4→271.0 and m/z 584.5→271.0 were used to detect EZM and EZM-G, respectively. The analytical method was linear over the concentration range of 0.1-20 ng/mL for EZM and 0.5-200 ng/mL for EZM-G. Within- and between-run precision for EZM was no more than 8.6% and 12.8%; and for EZM-G was no more than 9.0% and 8.7%, respectively. This method was reproducible and reliable, and was successfully used to analyze human plasma samples for application in a bioequivalence study. Copyright © 2015 Elsevier B.V. All rights reserved.

Enough Room for the Eagle and Dragon Chinese Resource Extraction and its Impact on U.S. on U.S Military Operations in West Africa

DTIC Science & Technology

2017-06-09

Africa, China was already firmly rooted with deep economic ties, and a plethora of trade deals to extract resources. Simultaneously, trans- national...In West Africa, China was already firmly rooted with deep economic ties, and a plethora of trade deals to extract resources. Simultaneously, trans...60 viii ACRONYMS CCDR Combatant Commander DoD Department of Defense ECOWAS Economic

Simultaneous determination of vasicine and vasicinone by High-performance liquid chromatography in roots of eight Sida species.

PubMed

Subramanya, M D; Pai, Sandeep R; Ankad, Gireesh M; Hegde, Harsha V; Roy, Subarna; Hoti, S L

2016-01-01

Sida L. is a medicinally important genus widely used in conventional systems of medicine in India. The present study aims toward simultaneous determination of two bioactive compounds vasicine and vasicinone in root extracts of eight Sida spp. from Western Ghats, India. Determination of vasicine and vasicinone was undertaken in methanolic root extracts (10% w/v) of Sida acuta , Sida cordata , Sida cordifolia , Sida rhombifolia , Sida spinosa , Sida indica , Sida retusa and Sida mysorensis by high performance liquid chromatography (HPLC) method. The standards were prepared with the concentration of mg/mL. Data were expressed as mean values of three reading and relative standard deviations. The separation was achieved on a Waters, Nova-Pack, C18 (250 mm × 4.6 mm, 5 μ) column, with acetonitrile - 0.1 M phosphate buffer-glacial acetic acid (15: 85: 1, v/v/v) as solvent system at a flow-rate of 1.0 mL/min. The effluent was monitored using ultraviolet detection at a wavelength of 300 nm. Both calibration curves of standard showed good linear regression ( R 2 > 0.994). The limit of detection and the limit of quantification for vasicine was 0.110 and 0.333 μg/mL and for vasicinone was 0.059 and 0.179 μg/mL respectively. The vasicine content was highest in S. cordifolia (9.891 ± 0.495 μg/100 mg) and vasicinone content was rich in S. cordata (33.013 ± 1.651 μg/100 mg.) The content of vasicinone was higher than vasicine. HPLC method provides simple, accurate, and reproducible quantitative analysis for simultaneous determination of vasicine and vasicinone. Among the selected Sida species, S. cordifolia and S. cordata were found to be rich in the vasicine and vasicinone contents, respectively.

Simultaneous determination of vitamins A and D3 in dairy products by liquid chromatography-tandem mass spectrometry (LC-MS/MS)

NASA Astrophysics Data System (ADS)

Barakat, I. S. A.; Hammouri, M. K.; Habib, I.

2015-10-01

A potential method for simultaneous determination of vitamin A and vitamin D3 (25- hydroxyvitamin D3) in fresh milk samples is addressed. The method is based on combination of high performance liquid chromatography and mass spectrometry during the course of analysis. The method applied for determination of vitamins A and D3 on eighteen (18) different fresh milk samples using liquid chromatography along with tandem -mass spectrometry. The work describes the suitability of the proposed method for the simultaneous determination of both vitamins using LC-MS/MS as a specific and quantitative technique. The vitamins of milk were separated by C18 Thermo gold column(100mm × 4.6mm × 5 μm) with a flow rate of 1ml/min (using an isocratic mobile phase). The method was validated using duplicate analyses, relative recovery experiment, and comparative analysis with control samples. Liquid- liquid extraction was employed as a pre-concentration step with n-hexane - dichloromethane mixture (90%:10%) as an extraction solvent. The molecular ions (m/z) appeared near 286 and 385nm and for the base peaks were appeared near 255 and 355nm for vitamins A and D3. Good correlation coefficients were obtained, 0.9999 for vitamin D3 and 0.9994 for vitamin A. The limit of detection and the limit of quantification were found to be 0.09ng/ml and 0.54ng/ml for vitamin D3 and 0.32ng/ml and 1.8ng/ml and for vitamin A. The proposed method showed excellent recoveries, about 98% for both vitamins A and D3.

Simultaneous determination of metolazone and valsartan in plasma by on-line SPE coupled with liquid chromatography/tandem mass spectrometry.

PubMed

Zhou, Jiezhao; Chen, Meiling; Li, Ying; Yu, Fanglin; Cheng, Xiaohui; Yang, Yang; Liu, Yan; Xie, Xiangyang; Li, Zhiping; Zhang, Hui; Mei, Xingguo

2017-10-01

Combination of metolazone (0.5 mg) and valsartan (80 mg) has been verified as a promising therapy treatment for hypertension. In order to facilitate to pharmacokinetic research, it needs a method for the simultaneously determination of metolazone and valsartan in biological samples. However, there are no relative reports so far. In order to facilitate to pharmacokinetic research, an on-line solid phase extraction coupled with liquid chromatography-tandem mass spectrometry method for the simultaneous determination of metolazone and valsartan in beagle dog plasma was developed and validated in this study. An on-line solid phase extraction column Retain PEP Javelin (10 mm × 2.1 mm) was used to remove impurities in plasma samples. The metolazone, valsartan and internal standard (losartan) were separated on a Poroshell 120 SB-C18 column (4.6 mm × 50 mm × 2.7 µm) with a gradient elution procedure. Acidified acetonitrile/water mixture was used as a mobile phase. The selected multiple-reaction monitoring mode in positive ion was performed and the parent to the product transitions m/z 366/259, m/z 436.2/291 and m/z 423.4/207 were used to measure the metolazone, valsartan and losartan. The method was linear over the range of 0.1-100 ng/mL and 1-1000 ng/mL for metolazone and valsartan, respectively. This method was validated in terms of specificity, linearity, sensitivity, precision, accuracy, matrix effect, and stability and then successfully applied to pharmacokinetic studies of the metolazone and valsartan combination tablets in beagle dogs.

System and method for conditioning a hardwood pulp liquid hydrolysate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Waite, Darrell; Arnold, Richard; St. Pierre, James

2015-06-30

A system and method for hardwood pulp liquid hydrolysate conditioning includes a first evaporator receives a hardwood mix extract and outputting a quantity of vapor and extract. A hydrolysis unit receives the extract, hydrolyzes and outputs to a lignin separation device, which separates and recovers a quantity of lignin. A neutralization device receives extract from the lignin separation device and a neutralizing agent, producing a mixture of solid precipitate and a fifth extract. The solid precipitate is removed from the fifth extract. A second evaporator removes a quantity of acid from the fifth extract in a vapor form. This vapormore » may be recycled to improve total acid recovery or discarded. A desalination device receives the diluted extract, separates out some of the acid and salt and outputs a desalinated solution.« less

Intermittency and universality of small scales of passive scalar in turbulence

NASA Astrophysics Data System (ADS)

Gotoh, Toshiyuki; Watanabe, Takeshi

2014-11-01

Recent experiments and Direct Numerical Simulations (DNSs) suggest that the small scale statistics of passive scalar may not be as ``universal'' as in the velocity case. To address this problem, we study the moments of scalar increment in steady turbulence at Rλ > 800 by using DNS up to the grid points of 40963. In order for the scalar and turbulent flow to be as faithful as possible to the assumptions that would be made in theories, Scalar 1 and Scalar 2 are simultaneously convected by the identical isotropic turbulent flow but excited by two different methods. Scalar 1 is excited by the random scalar injection which is isotropic, Gaussian and white in time at low wavenumber band, while Scalar 2 is excited by the uniform mean scalar gradient. The moments of two scalars as functions of the separation vector are expanded in terms of the Legendre polynomials to extract the scaling exponents of the moments up to the 4th anisotropic sector for Scalar 2. It is found that the exponents of the isotropic sectors seem to have the same values at separation distances in the narrow range over which the 4/3 law holds simultaneously for two scalars. The exponents of the anisotropic sectors and the cumulants of the moments will also be reported. HPCI, JHPCN, Grant-in-Aid for Sci. Res. No.24360068, Ministry of Edu. Sci., Japan.

Simultaneous separation of water- and fat-soluble vitamins in isocratic pressure-assisted capillary electrochromatography using a methacrylate-based monolithic column.

PubMed

Yamada, Hiroki; Kitagawa, Shinya; Ohtani, Hajime

2013-06-01

A method of simultaneous separation of water- and fat-soluble vitamins using pressure-assisted CEC with a methacrylate-based capillary monolithic column was developed. In the proposed method, water-soluble vitamins were mainly separated electrophoretically, while fat soluble-ones were separated chromatographically by the interaction with a methacrylate-based monolith. A mixture of six water-soluble and four fat-soluble vitamins was separated simultaneously within 20 min with an isocratic elution using 1 M formic acid (pH 1.9)/acetonitrile (30:70, v/v) containing 10 mM ammonium formate as a mobile phase. When the method was applied to a commercial multivitamin tablet and a spiked one, the vitamins were successfully analyzed, and no influence of the matrix contained in the tablet was observed. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ionic-Liquid-Mediated Extraction and Separation Processes for Bioactive Compounds: Past, Present, and Future Trends.

PubMed

Ventura, Sónia P M; E Silva, Francisca A; Quental, Maria V; Mondal, Dibyendu; Freire, Mara G; Coutinho, João A P

2017-05-24

Ionic liquids (ILs) have been proposed as promising media for the extraction and separation of bioactive compounds from the most diverse origins. This critical review offers a compilation on the main results achieved by the use of ionic-liquid-based processes in the extraction and separation/purification of a large range of bioactive compounds (including small organic extractable compounds from biomass, lipids, and other hydrophobic compounds, proteins, amino acids, nucleic acids, and pharmaceuticals). ILs have been studied as solvents, cosolvents, cosurfactants, electrolytes, and adjuvants, as well as used in the creation of IL-supported materials for separation purposes. The IL-based processes hitherto reported, such as IL-based solid-liquid extractions, IL-based liquid-liquid extractions, IL-modified materials, and IL-based crystallization approaches, are here reviewed and compared in terms of extraction and separation performance. The key accomplishments and future challenges to the field are discussed, with particular emphasis on the major lacunas found within the IL community dedicated to separation processes and by suggesting some steps to overcome the current limitations.

Ionic-Liquid-Mediated Extraction and Separation Processes for Bioactive Compounds: Past, Present, and Future Trends

PubMed Central

2017-01-01

Ionic liquids (ILs) have been proposed as promising media for the extraction and separation of bioactive compounds from the most diverse origins. This critical review offers a compilation on the main results achieved by the use of ionic-liquid-based processes in the extraction and separation/purification of a large range of bioactive compounds (including small organic extractable compounds from biomass, lipids, and other hydrophobic compounds, proteins, amino acids, nucleic acids, and pharmaceuticals). ILs have been studied as solvents, cosolvents, cosurfactants, electrolytes, and adjuvants, as well as used in the creation of IL-supported materials for separation purposes. The IL-based processes hitherto reported, such as IL-based solid–liquid extractions, IL-based liquid–liquid extractions, IL-modified materials, and IL-based crystallization approaches, are here reviewed and compared in terms of extraction and separation performance. The key accomplishments and future challenges to the field are discussed, with particular emphasis on the major lacunas found within the IL community dedicated to separation processes and by suggesting some steps to overcome the current limitations. PMID:28151648

New 3D-printed sorbent for extraction of steroids from human plasma preceding LC-MS analysis.

PubMed

Konieczna, Lucyna; Belka, Mariusz; Okońska, Magdalena; Pyszka, Magdalena; Bączek, Tomasz

2018-04-13

In recent years, there has been an increasing worldwide interest in the use of alternative sample preparation methods that are proceeded by separation techniques. Fused deposition modeling (FDM) is a 3D printing technique that is based the consecutive layering of softened/melted thermoplastic materials. In this study, a group of natural steroids and sexual hormones - namely, aldosterone, cortisol, β-estradiol, testosterone, dihydrotestosterone, and synthetic methyltestosterone and betamethasone - were separated and determined using an optimized high-performance liquid chromatography coupled to mass spectrometry (LC-MS) method in positive ionization mode. 3D-printed sorbents were selected as the pre-concentration technique because they are generally low cost, fast, and simple to make and automate. Furthermore, the use of 3D-printed sorbents helps to minimize potential errors due to their repeatability and reproducibility, and their ability to eliminate carry over by using one printed sorbent for a single extraction of steroids from biological matrices. The extraction procedure was optimized and the parameters influencing 3D-printed Layfomm 60 ® based sorbent and LC-MS were studied, including the type of extraction solvent used, sorption and desorption times, temperature, and the salting-out effect. To demonstrate this method's applicability for biological sample analysis, the SPME-LC-MS method was validated for its ability to simultaneously quantify endogenous steroids. This evaluation confirmed good linearity and an R 2 that was between 0.9970 and 0.9990. The recovery rates for human plasma samples were 86.34-93.6% for the studied steroids with intra- and inter-day RSDs of 1.44-7.42% and 1.44-9.46%, respectively. To our knowledge, this study is the first time that 3D-printed sorbents have been used to extract trace amounts of endogenous low-molecular-weight compounds, such as steroids, from biological samples, such as plasma. Copyright © 2018 Elsevier B.V. All rights reserved.

Hydrothermal pentose to furfural conversion and simultaneous extraction with SC-CO2--kinetics and application to biomass hydrolysates.

PubMed

Gairola, Krishan; Smirnova, Irina

2012-11-01

This work explores hydrothermal d-xylose and hemicellulose to furfural conversion coupled with simultaneous furfural extraction by SC-CO(2) and the underlying reaction pathway. A maximum furfural yield of 68% was attained from d-xylose at 230°C and 12MPa. Additionally missing kinetic data for l-arabinose to furfural conversion was provided, showing close similarity to d-xylose. Furfural yields from straw and brewery waste hydrolysates were significantly lower than those obtained from model compounds, indicating side reactions with other hydrolysate components. Simultaneous furfural extraction by SC-CO(2) significantly increased extraction yield in all cases. The results indicate that furfural reacts with intermediates of pentose dehydration. The proposed processing route can be well integrated into existing lignocellulose biorefinery concepts. Copyright © 2012 Elsevier Ltd. All rights reserved.

Fast trace determination of nine odorant and estrogenic chloro- and bromo-phenolic compounds in real water samples through automated solid-phase extraction coupled with liquid chromatography tandem mass spectrometry.

PubMed

Yuan, Su-Fen; Liu, Ze-Hua; Lian, Hai-Xian; Yang, Chuang-Tao; Lin, Qing; Yin, Hua; Lin, Zhang; Dang, Zhi

2018-02-01

A fast and reliable method was developed for simultaneous trace determination of nine odorous and estrogenic chloro- and bromo-phenolic compounds (CPs and BPs) in water samples using solid-phase extraction (SPE) coupled with liquid chromatography tandem mass spectrometry (LC-MS/MS). For sample preparation, the extraction efficiencies of two widely applied cartridges Oasis HLB and Sep-Pak C18 were compared, and the Oasis HLB cartridge showed much better extraction performance; pH of water sample also plays important role on extraction, and pH = 2-3 was found to be most appropriate. For separation of the target compounds, small addition of ammonium hydroxide can obviously improve the detection sensitivity, and the optimized addition concentration was determined as 0.2%. The developed efficient method was validated and showed excellent linearity (R 2  > 0.995), low limit of detection (LOD, 1.9-6.2 ng/L), and good recovery efficiencies of 57-95% in surface and tap water with low relative standard deviation (RSD, 1.3-17.4%). The developed method was finally applied to one tap and one surface water samples and most of these nine targets were detected, but all of them were below their odor thresholds, and their estrogen equivalent (EEQ) were also very low.

Simultaneous quantification of eight organic acid components in Artemisia capillaris Thunb (Yinchen) extract using high-performance liquid chromatography coupled with diode array detection and high-resolution mass spectrometry.

PubMed

Yu, Fangjun; Qian, Hao; Zhang, Jiayu; Sun, Jie; Ma, Zhiguo

2018-04-01

We aim to determine the chemical constituents of Yinchen extract and Yinchen herbs using high-performance liquid chromatography coupled with diode array detection and high-resolution mass spectrometry. The method was developed to analyze of eight organic acid components of Yinchen extract (including neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, caffeic acid, 1,3-dicaffeoylquinic acid, 3,4-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid and 4,5-dicaffeoylquinic acid). The separation was conducted using an Agilent TC-C18 column with acetonitrile - 0.2% formic acid solution as the mobile phases under gradient elution. The analytical method was fully validated in terms of linearity, sensitivity, precision, repeatability as well as recovery, and subsequently the method was performed for the quantitative assessment of Yinchen extracts and Yinchen herbs. In addition, the changes of selected markers were studied when Yinchen herbs decocting in water and isomerization occurred between the chlorogenic acids. The proposed method enables both qualitative and quantitative analyses and could be developed as a new tool for the quality evaluation of Yinchen extract and Yinchen herbs. The changes of selected markers in water decoction process could give us some novel idea when studying the link between substances and drug efficacy. Copyright © 2017. Published by Elsevier B.V.

Speciation of chromium in environmental samples by dual electromembrane extraction system followed by high performance liquid chromatography.

PubMed

Safari, Meysam; Nojavan, Saeed; Davarani, Saied Saeed Hosseiny; Morteza-Najarian, Amin

2013-07-30

This study proposes the dual electromembrane extraction followed by high performance liquid chromatography for selective separation-preconcentration of Cr(VI) and Cr(III) in different environmental samples. The method was based on the electrokinetic migration of chromium species toward the electrodes with opposite charge into the two different hollow fibers. The extractant was then complexed with ammonium pyrrolidinedithiocarbamate for HPLC analysis. The effects of analytical parameters including pH, type of organic solvent, sample volume, stirring rate, time of extraction and applied voltage were investigated. The results showed that Cr(III) and Cr(VI) could be simultaneously extracted into the two different hollow fibers. Under optimized conditions, the analytes were quantified by HPLC instrument, with acceptable linearity ranging from 20 to 500 μg L(-1) (R(2) values≥0.9979), and repeatability (RSD) ranging between 9.8% and 13.7% (n=5). Also, preconcentration factors of 21.8-33 that corresponded to recoveries ranging from 31.1% to 47.2% were achieved for Cr(III) and Cr(VI), respectively. The estimated detection limits (S/N ratio of 3:1) were less than 5.4 μg L(-1). Finally, the proposed method was successfully applied to determine Cr(III) and Cr(VI) species in some real water samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Field method for the determination of hexavalent chromium by ultrasonication and strong anion-exchange solid-phase extraction.

PubMed

Wang, J; Ashley, K; Marlow, D; England, E C; Carlton, G

1999-03-01

A simple, fast, sensitive, and economical field method was developed and evaluated for the determination of hexavalent chromium (CrVI) in environmental and workplace air samples. By means of ultrasonic extraction in combination with a strong anion-exchange solid-phase extraction (SAE-SPE) technique, the filtration, isolation, and determination of CrVI in the presence of trivalent chromium (CrIII) and potential interferents was achieved. The method entails (1) ultrasonication in basic ammonium buffer solution to extract CrVI from environmental matrixes; (2) SAE-SPE to separate CrVI from CrIII and interferences; (3) elution/acidification of the eluate; (4) complexation of chromium with 1,5-diphenylcarbazide; and (5) spectrophotometric determination of the colored chromium-diphenylcarbazone complex. Several critical parameters were optimized in order to effect the extraction of both soluble (K2CrO4) and insoluble (PbCrO4) forms of CrVI without inducing CrIII oxidation or CrVI reduction. The method allowed for the dissolution and purification of CrVI from environmental and workplace air sample matrixes for up to 24 samples simultaneously in less than 90 min (including ultrasonication). The results demonstrated that the method was simple, fast, quantitative, and sufficiently sensitive for the determination of occupational exposures of CrVI. The method is applicable for on-site monitoring of CrVI in environmental and industrial hygiene samples.

Simultaneous determination of ozone and carbonyls using trans-1,2-bis(4-pyridyl)ethylene as an ozone scrubber for 2,4-dinitrophenylhydrazine-impregnated silica cartridge.

PubMed

Uchiyama, Shigehisa; Otsubo, Yasufumi

2008-05-01

A new method for the simultaneous determination of ozone and carbonyls in air using a two-bed cartridge system has been developed. Each bed consists of reagent-impregnated silica particles. The first contains trans-1,2-bis-(4-pyridyl) ethylene (BPE) while the second contains 2,4-dinitrophenylhydrazine (DNPH). Air samples are drawn through the cartridge first through the BPE and then through the DNPH. Ozone in the air sample is trapped in the first bed by the BPE-coated silica particles and produce pyridine-4-aldehyde. Airborne carbonyls pass unimpeded thorough the BPE and are trapped in the second bed by the DNPH-coated silica particles. They produce carbonyl 2,4-DNPhydrazones. DNPH and carbonyl 2,4-DNPhydrazones are not influenced by ozone because of effective trapping by the BPE. Extraction is performed in the direction reverse to air sampling. When solvent is eluted through the BEP/DNPH cartridge, excess DNPH is washed into the BPE bed where it reacted with pyridine-4-aldehyde and forms the corresponding hydrazone derivative. All of the hydrazones derived from airborne carbonyls and pyridine-4-aldehyde (derived from ozone) are completely separated and measured using high-performance liquid chromatography. An Ascentis RP-Amide column is used, and the mobile phase is 40% aqueous acetonitrile containing 2 mmol/L ammonium acetate. The use of a BPE/DNPH cartridge has made possible the simultaneous determination of ozone and carbonyls. A separate ozone scrubber is not necessary with the BPE/DNPH cartridge because the BPE portion of the sampler serves this function.

Simultaneous determination of nickel and copper by H-point standard addition method-first-order derivative spectrophotometry in plant samples after separation and preconcentration on modified natural clinoptilolite as a new sorbent.

PubMed

Roohparvar, Rasool; Taher, Mohammad Ali; Mohadesi, Alireza

2008-01-01

For the simultaneous determination of nickel(ll) and copper(ll) in plant samples, a rapid and accurate method was developed. In this method, solid-phase extraction (SPE) and first-order derivative spectrophotometry (FDS) are combined, and the result is coupled with the H-point standard addition method (HPSAM). Compared with normal spectrophotometry, derivative spectrophotometry offers the advantages of increased selectivity and sensitivity. As there is no need for carrying out any pretreatment of the sample, the spectrophotometry method is easy, but because of a high detection limit, it is not so practical. In order to decrease the detection limit, it is suggested to combine spectrophotometry with a preconcentration method such as SPE. In the present work, after separation and preconcentration of Ni(ll) and Cu(ll) on modified clinoptilolite zeolite that is loaded with 2-[1-(2-hydroxy-5-sulforphenyl)-3-phenyl-5-formaza-no]-benzoic acid monosodium salt (zincon) as a selective chromogenic reagent, FDS-HPSAM, which is a simple and selective spectrophotometric method, has been applied for simultaneous determination of these ions. With optimum conditions, the detection limit in original solutions is 0.7 and 0.5 ng/mL, respectively, for nickel and copper. The linear concentration ranges in the proposed method for nickel and copper ions in original solutions are 1.1 to 3.0 x 10(3) and 0.9 to 2.0 x 10(3) ng/mL, respectively. The recommended procedure is applied to successful determination of Cu(ll) and Ni(ll) in standard and real samples.

A Generic multi-dimensional feature extraction method using multiobjective genetic programming.

PubMed

Zhang, Yang; Rockett, Peter I

2009-01-01

In this paper, we present a generic feature extraction method for pattern classification using multiobjective genetic programming. This not only evolves the (near-)optimal set of mappings from a pattern space to a multi-dimensional decision space, but also simultaneously optimizes the dimensionality of that decision space. The presented framework evolves vector-to-vector feature extractors that maximize class separability. We demonstrate the efficacy of our approach by making statistically-founded comparisons with a wide variety of established classifier paradigms over a range of datasets and find that for most of the pairwise comparisons, our evolutionary method delivers statistically smaller misclassification errors. At very worst, our method displays no statistical difference in a few pairwise comparisons with established classifier/dataset combinations; crucially, none of the misclassification results produced by our method is worse than any comparator classifier. Although principally focused on feature extraction, feature selection is also performed as an implicit side effect; we show that both feature extraction and selection are important to the success of our technique. The presented method has the practical consequence of obviating the need to exhaustively evaluate a large family of conventional classifiers when faced with a new pattern recognition problem in order to attain a good classification accuracy.

Ultrasound extracted flavonoids from four varieties of Portuguese red grape skins determined by reverse-phase high-performance liquid chromatography with electrochemical detection.

PubMed

Novak, Ivana; Janeiro, Patricia; Seruga, Marijan; Oliveira-Brett, Ana Maria

2008-12-23

Several flavonoids present in red grape skins from four varieties of Portuguese grapes were determined by reverse-phase high-performance liquid chromatography (RP-HPLC) with electrochemical detection (ECD). Extraction of flavonoids from red grape skins was performed by ultrasonication, and hydrochloric acid in methanol was used as extraction solvent. The developed RP-HPLC method used combined isocratic and gradient elution with amperometric detection with a glassy carbon-working electrode. Good peak resolution was obtained following direct injection of a sample of red grape extract in a pH 2.20 mobile phase. Eleven different flavonoids: cyanidin-3-O-glucoside (kuromanin), delphinidin-3-O-glucoside (myrtillin), petunidin-3-O-glucoside, peonidin-3-O-glucoside, malvidin-3-O-glucoside (oenin), (+)-catechin, rutin, fisetin, myricetin, morin and quercetin, can be separated in a single run by direct injection of sample solution. The limit of detection obtained for these compounds by ECD was 20-90 pg/L, 1000 times lower when compared with photodiode array (PDA) limit of detection of 12-55 ng/L. RP-HPLC-ECD was characterized by an excellent sensitivity and selectivity, and appropriate for the simultaneous determination of these electroactive phenolic compounds present in red grape skins.

Analysis of flavonoids from lotus (Nelumbo nucifera) leaves using high performance liquid chromatography/photodiode array detector tandem electrospray ionization mass spectrometry and an extraction method optimized by orthogonal design.

PubMed

Chen, Sha; Wu, Ben-Hong; Fang, Jin-Bao; Liu, Yan-Ling; Zhang, Hao-Hao; Fang, Lin-Chuan; Guan, Le; Li, Shao-Hua

2012-03-02

The extraction protocol of flavonoids from lotus (Nelumbo nucifera) leaves was optimized through an orthogonal design. The solvent was the most important factor comparing solvent, solvent:tissue ratio, extraction time, and temperature. The highest yield of flavonoids was achieved with 70% methanol-water and a solvent:tissue ratio of 30:1 at 4 °C for 36 h. The optimized analytical method for HPLC was a multi-step gradient elution using 0.5% formic acid (A) and CH₃CN containing 0.1% formic acid (B), at a flow rate of 0.6 mL/min. Using this optimized method, thirteen flavonoids were simultaneously separated and identified by high performance liquid chromatography coupled with photodiode array detection/electrospray ionization mass spectrometry (HPLC/DAD/ESI-MS(n)). Five of the bioactive compounds are reported in lotus leaves for the first time. The flavonoid content of the leaves of three representative cultivars was assessed under the optimized extraction and HPLC analytical conditions, and the seed-producing cultivar 'Baijianlian' had the highest flavonoid content compared with rhizome-producing 'Zhimahuoulian' and wild floral cultivar 'Honglian'. Copyright © 2012 Elsevier B.V. All rights reserved.

Metal-organic framework mixed-matrix disks: Versatile supports for automated solid-phase extraction prior to chromatographic separation.

PubMed

Ghani, Milad; Font Picó, Maria Francesca; Salehinia, Shima; Palomino Cabello, Carlos; Maya, Fernando; Berlier, Gloria; Saraji, Mohammad; Cerdà, Víctor; Turnes Palomino, Gemma

2017-03-10

We present for the first time the application of metal-organic framework (MOF) mixed-matrix disks (MMD) for the automated flow-through solid-phase extraction (SPE) of environmental pollutants. Zirconium terephthalate UiO-66 and UiO-66-NH 2 MOFs with different size (90, 200 and 300nm) have been incorporated into mechanically stable polyvinylidene difluoride (PVDF) disks. The performance of the MOF-MMDs for automated SPE of seven substituted phenols prior to HPLC analysis has been evaluated using the sequential injection analysis technique. MOF-MMDs enabled the simultaneous extraction of phenols with the concomitant size exclusion of molecules of larger size. The best extraction performance was obtained using a MOF-MMD containing 90nm UiO-66-NH 2 crystals. Using the selected MOF-MMD, detection limits ranging from 0.1 to 0.2μgL -1 were obtained. Relative standard deviations ranged from 3.9 to 5.3% intra-day, and 4.7-5.7% inter-day. Membrane batch-to-batch reproducibility was from 5.2 to 6.4%. Three different groundwater samples were analyzed with the proposed method using MOF-MMDs, obtaining recoveries ranging from 90 to 98% for all tested analytes. Copyright © 2017 Elsevier B.V. All rights reserved.

Determination of perfluoroalkyl carboxylic, sulfonic, and phosphonic acids in food.

PubMed

Ullah, Shahid; Alsberg, Tomas; Vestergren, Robin; Berger, Urs

2012-11-01

A sensitive and accurate method was developed and validated for simultaneous analysis of perfluoroalkyl carboxylic acids, sulfonic acids, and phosphonic acids (PFPAs) at low picograms per gram concentrations in a variety of food matrices. The method employed extraction with acetonitrile/water and cleanup on a mixed-mode co-polymeric sorbent (C8 + quaternary amine) using solid-phase extraction. High-performance liquid chromatographic separation was achieved on a C18 column using a mobile phase gradient containing 5 mM 1-methyl piperidine for optimal chromatographic resolution of PFPAs. A quadrupole time-of-flight high-resolution mass spectrometer operating in negative ion mode was used as detector. Method detection limits were in the range of 0.002 to 0.02 ng g(-1) for all analytes. Sample preparation (extraction and cleanup) recoveries at a spiking level of 0.1 ng g(-1) to a baby food composite were in the range of 59 to 98 %. A strong matrix effect was observed in the analysis of PFPAs in food extracts, which was tentatively assigned to sorption of PFPAs to the injection vial in the solvent-based calibration standard. The method was successfully applied to a range of different food matrices including duplicate diet samples, vegetables, meat, and fish samples.

Superbase-derived protic ionic liquid extractants for metal ion separation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bell, Jason R.; Dai, Sheng; Luo, Huimin

2014-04-19

Solvent extraction of La 3+ and Ba 2+ by an ionic liquid extractant in an imidazolium-based ionic liquid diluent was investigated. Seven protic ionic liquid extractants were examined and these protic ILs are based on five organic superbases and either 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octadione (Hfod) or 1,1,1,5,5,5-hexafluoroacetylacetone (Hhfac) -diketones as anion. For fod-based extractants, the extraction efficiencies and separation factors were found to be concentration dependent. The effects of aqueous phase acidity, extractant structure, and extractant concentration on separation properties of La 3+ and Ba 2+ are discussed in this paper.

Poly(methyloctylsiloxane) immobilized on silica as a sorbent for solid-phase extraction of some pesticides.

PubMed

Vigna, Camila R M; Morais, Lais S R; Collins, Carol H; Jardim, Isabel C S F

2006-05-12

A laboratory-made sorbent for solid-phase extraction (SPE) was obtained by thermal immobilization of poly(methyloctylsiloxane) (PMOS) onto silica. Cartridges packed with the new sorbent were used for the simultaneous determination of imazethapyr, nicosulfuron, diuron, linuron and chlorimuron-ethyl in water. These pesticides were separated and quantified using high-performance liquid chromatography with diode array detection (HPLC-DAD). The recoveries achieved with the laboratory-made PMOS cartridges were compared with those of some commercially available silica-based and polymer-based cartridges having C18, C8 and NH(2) pendant groups. Method validation using the laboratory-made sorbent was performed for the five pesticides at three fortifications levels (1x, 2x and 10x the limit of quantification of each pesticide). The laboratory-made PMOS cartridge has low cost preparation and showed good recoveries (72-111%) for all pesticides. Repeatability and intermediate precision were lower than 15%. Its performance was similar or even better, in some cases, than those of the commercial cartridges.

Enzymatic saccharification and bioethanol production from Cynara cardunculus pretreated by steam explosion.

PubMed

Fernandes, Maria C; Ferro, Miguel D; Paulino, Ana F C; Mendes, Joana A S; Gravitis, Janis; Evtuguin, Dmitry V; Xavier, Ana M R B

2015-06-01

The correct choice of the specific lignocellulosic biomass pretreatment allows obtaining high biomass conversions for biorefinery implementations and cellulosic bioethanol production from renewable resources. Cynara cardunculus (cardoon) pretreated by steam explosion (SE) was involved in second-generation bioethanol production using separate hydrolysis and fermentation (SHF) or simultaneous saccharification and fermentation (SSF) processes. Steam explosion pretreatment led to partial solubilisation of hemicelluloses and increased the accessibility of residual polysaccharides towards enzymatic hydrolysis revealing 64% of sugars yield against 11% from untreated plant material. Alkaline extraction after SE pretreatment of cardoon (CSEOH) promoted partial removal of degraded lignin, tannins, extractives and hemicelluloses thus allowing to double glucose concentration upon saccharification step. Bioethanol fermentation in SSF mode was faster than SHF process providing the best results: ethanol concentration 18.7 g L(-1), fermentation efficiency of 66.6% and a yield of 26.6g ethanol/100 g CSEOH or 10.1 g ethanol/100 g untreated cardoon. Copyright © 2015 Elsevier Ltd. All rights reserved.

Determination of residual fluoroquinolones in honey by liquid chromatography using metal chelate affinity chromatography.

PubMed

Yatsukawa, Yoh-Ichi; Ito, Hironobu; Matsuda, Takahiro; Nakamura, Munetomo; Watai, Masatoshi; Fujita, Kazuhiro

2011-01-01

A new analytical method for the simultaneous determination of seven fluoroquinolones, namely, norfloxacin, ciprofloxacin, danofloxacin, enrofloxacin, orbifloxacin, sarafloxacin, and difloxacin, especially in dark-colored honey, has been developed. Fluoroquinolone antibiotics were extracted from samples with MacIlvaine buffer solution (pH 4.0) containing EDTA disodium salt dihydrate. The extracts were treated with both a polymeric cartridge and a metal chelate affinity column preloaded with ferric ion (Fe3+). LC separation with fluorescence detection was performed at 40 degrees C using an Inertsil ODS-4 analytical column (150 x 4.6 mm, 3 microm). The mobile phase was composed of 20 mM/L citrate buffer solution (pH 3.1)-acetonitrile mixture (70 + 30, v/v) containing 1 mM/L sodium dodecyl sulfate. Lomefloxacin was used as an internal standard. The developed method was validated according to the criteria of European Commission Decision 2002/657/EC. Decision limits and detection capabilities were below 2.9 and 4.4 microg/kg, respectively.

Determination of seven flavonoids in Ixeridium gracile (DC.) Shih by high-performance liquid chromatography.

PubMed

Chen, Juan; Ma, Xue-Mei; Shi, Yan-Ping

2009-01-01

A high-performance liquid chromatographic technique coupled with photodiode array detection was proposed for the simultaneous determination of 7 flavonoids, i.e., quercetin, kaempferol, 7-hydroxyflavanone, 7-methoxyflavanone, 2',4'-dihydroxychalcone, 2',4'-dihydroxydihydrochalcone, and 7,2'-dihydroxy-3', 4'-dimethoxyisoflavane, in extracts of the plant Ixeridium gracile. Optimum separation was obtained by using a reversed-phase C18 method. Because of the different UV characteristics of these components, 5 detection wavelengths were used for the quantitative analysis. All of the flavonoids showed good linearity (r > 0.9999). The limit of detection and limit of quantitation values for the analytes ranged from 0.06 to 0.46 microg/mL and from 0.18 to 1.48 microg/mL, respectively. The method was validated by evaluating repeatability, precision, stability, and accuracy. Five different extraction and purification procedures were investigated for preparation of the sample solution. The optimized method was applied to the determination of flavonoids in I. gracile and was found to be efficient.

Three immobilized-cell columnar bioreactors for enhanced production of commodity chemicals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davison, B.H.; Scott, C.D.; Kaufman, E.N.

1993-07-01

Immobilized-cell fluidized-bed bioreactors (FBRS) can be used with a variety of fermentations to increase production of fuels, solvents, organic acids, and other fermentation products. Part of the increased rates and yields are due to the immobilization of the biocatalyst at high concentrations. This FBR system with immobilized Zymomonas mobiles increased ethanol productivity more than tenfold with 99% conversion and near stoichiometric yields. FBRs also offer several additional modes of operation for simultaneous fermentation and separation to further increase production by removing the inhibitory products directly from the continuous fermentation. The production of lactic acid by immobilized Lactobacillus was augmented withmore » the addition and removal of solid adsorbent particles to the FBR. An immiscible organic extractant also was used to extract butanol from the acetone-butanol fermentation by Clostridium acetobutylicum. Demonstrations with these FBR systems have already shown definite advantages by improved overall product yields (decreasing feed costs) and by increased rates (decreasing capital and operating costs). Further demonstration and scale-up continue.« less

Three immobilized-cell columnar bioreactors for enhanced production of commodity chemicals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davison, B.H.; Scott, C.D.; Kaufman, E.N.

1993-12-31

Immobilized-cell fluidized-bed bioreactors (FBRs) can be used with a variety of fermentations to increase production of fuels, solvents, organic acids, and other fermentation products. Part of the increased rates and yields are due to the immobilization of the biocatalyst at high concentrations. This FBR system with immobilized Zymomonas mobilis increased ethanol productivity more than tenfold with 99% conversion and near stoichiometric yields. FBRs also offer several additional modes of operation for simultaneous fermentation and separation to further increase production by removing the inhibitory products directly from the continuous fermentation. The production of lactic acid by immobilized Lactobacillus was augmented withmore » the addition and removal of solid adsorbent particles to the FBR. An immiscible organic extractant also was used to extract butanol from the acetone-butanol fermentation by Clostridium acetobutylicum. Demonstrations with these FBR systems have already shown definite advantages by improved overall product yields (decreasing feed costs) and by increased rates (decreasing capital and operating costs). Further demonstration and scale-up continue.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saudari, Sangameshwar R.; Kagan, Cherie R.; Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104

Solution-processed, ambipolar, thin-film pentacene field-effect transistors were employed to study both electron and hole transport simultaneously in a single, organic solid-state device. Electron and hole mobilities were extracted from the respective unipolar saturation regimes and show thermally activated behavior and gate voltage dependence. We fit the gate voltage dependent saturation mobility to a power law to extract the characteristic Meyer-Neldel (MN) energy, a measure of the width of the exponential distribution of localized states extending into the energy gap of the organic semiconductor. The MN energy is ∼78 and ∼28 meV for electrons and holes, respectively, which reflects a greater densitymore » of localized tail states for electrons than holes. This is consistent with the lower measured electron than hole mobility. For holes, the well-behaved linear regime allows for four-point probe measurement of the contact resistance independent mobility and separate characterization of the width of the localized density of states, yielding a consistent MN energy of 28 meV.« less

Electron and hole transport in ambipolar, thin film pentacene transistors

NASA Astrophysics Data System (ADS)

Saudari, Sangameshwar R.; Kagan, Cherie R.

2015-01-01

Solution-processed, ambipolar, thin-film pentacene field-effect transistors were employed to study both electron and hole transport simultaneously in a single, organic solid-state device. Electron and hole mobilities were extracted from the respective unipolar saturation regimes and show thermally activated behavior and gate voltage dependence. We fit the gate voltage dependent saturation mobility to a power law to extract the characteristic Meyer-Neldel (MN) energy, a measure of the width of the exponential distribution of localized states extending into the energy gap of the organic semiconductor. The MN energy is ˜78 and ˜28 meV for electrons and holes, respectively, which reflects a greater density of localized tail states for electrons than holes. This is consistent with the lower measured electron than hole mobility. For holes, the well-behaved linear regime allows for four-point probe measurement of the contact resistance independent mobility and separate characterization of the width of the localized density of states, yielding a consistent MN energy of 28 meV.

Isoforms of a cuticular protein from larvae of the meal beetle, Tenebrio molitor, studied by mass spectrometry in combination with Edman degradation and two-dimensional polyacrylamide gel electrophoresis.

PubMed Central

Haebel, S.; Jensen, C.; Andersen, S. O.; Roepstorff, P.

1995-01-01

Simultaneous sequencing, using a combination of mass spectrometry and Edman degradation, of three approximately 15-kDa variants of a cuticular protein extracted from the meal beetle Tenebrio molitor larva is demonstrated. The information obtained by matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) time-course monitoring of enzymatic digests was found essential to identify the differences among the three variants and for alignment of the peptides in the sequence. To determine whether each individual insect larva contains all three protein variants, proteins extracted from single animals were separated by two-dimensional gel electrophoresis, electroeluted from the gel spots, and analyzed by MALDI MS. Molecular weights of the proteins present in each sample could be obtained, and mass spectrometric mapping of the peptides after digestion with trypsin gave additional information. The protein isoforms were found to be allelic variants. PMID:7795523

Isoforms of a cuticular protein from larvae of the meal beetle, Tenebrio molitor, studied by mass spectrometry in combination with Edman degradation and two-dimensional polyacrylamide gel electrophoresis.

PubMed

Haebel, S; Jensen, C; Andersen, S O; Roepstorff, P

1995-03-01

Simultaneous sequencing, using a combination of mass spectrometry and Edman degradation, of three approximately 15-kDa variants of a cuticular protein extracted from the meal beetle Tenebrio molitor larva is demonstrated. The information obtained by matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) time-course monitoring of enzymatic digests was found essential to identify the differences among the three variants and for alignment of the peptides in the sequence. To determine whether each individual insect larva contains all three protein variants, proteins extracted from single animals were separated by two-dimensional gel electrophoresis, electroeluted from the gel spots, and analyzed by MALDI MS. Molecular weights of the proteins present in each sample could be obtained, and mass spectrometric mapping of the peptides after digestion with trypsin gave additional information. The protein isoforms were found to be allelic variants.

Hierarchical learning induces two simultaneous, but separable, prediction errors in human basal ganglia.

PubMed

Diuk, Carlos; Tsai, Karin; Wallis, Jonathan; Botvinick, Matthew; Niv, Yael

2013-03-27

Studies suggest that dopaminergic neurons report a unitary, global reward prediction error signal. However, learning in complex real-life tasks, in particular tasks that show hierarchical structure, requires multiple prediction errors that may coincide in time. We used functional neuroimaging to measure prediction error signals in humans performing such a hierarchical task involving simultaneous, uncorrelated prediction errors. Analysis of signals in a priori anatomical regions of interest in the ventral striatum and the ventral tegmental area indeed evidenced two simultaneous, but separable, prediction error signals corresponding to the two levels of hierarchy in the task. This result suggests that suitably designed tasks may reveal a more intricate pattern of firing in dopaminergic neurons. Moreover, the need for downstream separation of these signals implies possible limitations on the number of different task levels that we can learn about simultaneously.

The use of a polymer inclusion membrane in flow injection analysis for the on-line separation and determination of zinc.

PubMed

Zhang, Lujia L; Cattrall, Robert W; Kolev, Spas D

2011-06-15

This paper reports the first use of a polymer inclusion membrane (PIM) for on-line separation in flow injection analysis (FIA) involving simultaneous extraction and back-extraction. The FIA system containing the PIM separation module was used for the determination of Zn(II) in aqueous samples in the presence of Mg(II), Ca(II), Cd(II), Co(II), Ni(II), Cu(II), and Fe(III). The Fe(III) and Cu(II) interferences were eliminated by off-line precipitation with phosphate and on-line complexation with chloride, respectively. The concentration of Zn(II) was determined spectrophotometrically using 4-(2-pyridylazo) resorcinol (PAR). The optimal composition of the PIM consisted of 40% (m/m) di(2-ethlyhexyl) phosphoric acid (D2EHPA) as carrier, 10% (m/m) dioctyl phthalate (DOP) as plasticizer and 50% (m/m) poly(vinyl chloride) (PVC) as the base polymer. The optimized FIA system was characterized by a linear calibration curve in the range from 1.0 to 30.0 mg L(-1) Zn(II), a detection limit of 0.05 mg L(-1) and a relative standard deviation of 3.4% with a sampling rate of 4h(-1). Reproducible results were obtained for 20 replicate injections over a 5h period which demonstrated a good membrane stability. The FIA system was applied to the determination of Zn(II) in pharmaceuticals and samples from the galvanizing industry and very good agreement with atomic absorption spectrometry was obtained. Copyright © 2011 Elsevier B.V. All rights reserved.

DT-CWT Robust Filtering Algorithm for The Extraction of Reference and Waviness from 3-D Nano Scalar Surfaces

NASA Astrophysics Data System (ADS)

Ren, Zhi Ying.; Gao, ChengHui.; Han, GuoQiang.; Ding, Shen; Lin, JianXing.

2014-04-01

Dual tree complex wavelet transform (DT-CWT) exhibits superiority of shift invariance, directional selectivity, perfect reconstruction (PR), and limited redundancy and can effectively separate various surface components. However, in nano scale the morphology contains pits and convexities and is more complex to characterize. This paper presents an improved approach which can simultaneously separate reference and waviness and allows an image to remain robust against abnormal signals. We included a bilateral filtering (BF) stage in DT-CWT to solve imaging problems. In order to verify the feasibility of the new method and to test its performance we used a computer simulation based on three generations of Wavelet and Improved DT-CWT and we conducted two case studies. Our results show that the improved DT-CWT not only enhances the robustness filtering under the conditions of abnormal interference, but also possesses accuracy and reliability of the reference and waviness from the 3-D nano scalar surfaces.

A lignocellulosic ethanol strategy via nonenzymatic sugar production: process synthesis and analysis.

PubMed

Han, Jeehoon; Luterbacher, Jeremy S; Alonso, David Martin; Dumesic, James A; Maravelias, Christos T

2015-04-01

The work develops a strategy for the production of ethanol from lignocellulosic biomass. In this strategy, the cellulose and hemicellulose fractions are simultaneously converted to sugars using a γ-valerolactone (GVL) solvent containing a dilute acid catalyst. To effectively recover GVL for reuse as solvent and biomass-derived lignin for heat and power generation, separation subsystems, including a novel CO2-based extraction for the separation of sugars from GVL, lignin and humins have been designed. The sugars are co-fermented by yeast to produce ethanol. Furthermore, heat integration to reduce utility requirements is performed. It is shown that this strategy leads to high ethanol yields and the total energy requirements could be satisfied by burning the lignin. The integrated strategy using corn stover feedstock leads to a minimum selling price of $5 per gallon of gasoline equivalent, which suggests that it is a promising alternative to current biofuels production approaches. Copyright © 2015 Elsevier Ltd. All rights reserved.

High-performance liquid chromatographic separation and electrochemical or spectrophotometric determination of R(-)N-n-propylnorapomorphine and R(-)10,11-methylenedioxy-N-n-propylnoraporphine in primate plasma.

PubMed

Lampen, P; Neumeyer, J L; Baldessarini, R J

1988-04-29

The dopamine receptor agonist R(-)N-n-propylnorapomorphine (NPA) and its proposed pro-drug R(-)10,11-methylenedioxy-N-n-propylnoraporphine (MDO-NPA) were isolated simultaneously from monkey plasma using a solid-phase extraction procedure. R(-)Apomorphine (APO) and R(-)10,11-methylenedioxyaporphine (MDO-APO) were added as internal standards, and separation and quantification were by high-performance liquid chromatography with electrochemical or ultraviolet detection of the free catechol and MDO compounds, respectively. The detection limits for NPA and MDO-NPA in plasma were 0.5 and 10 ng/ml and the coefficient of variation (S.D./mean) within assays and between days of assays for both drugs was 5.6% or less. Quantification of plasma levels of NPA and MDO-NPA was possible at ranges of 2-1000 and 40-5000 ng/ml, respectively, including concentrations found after intravenous administration of these agents.

A simple assay for the simultaneous determination of rosuvastatin acid, rosuvastatin-5S-lactone, and N-desmethyl rosuvastatin in human plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS).

PubMed

Macwan, Joyce S; Ionita, Ileana A; Akhlaghi, Fatemeh

2012-01-01

A simple and sensitive assay was developed and validated for the simultaneous quantification of rosuvastatin acid (RST), rosuvastatin-5S-lactone (RST-LAC), and N-desmethyl rosuvastatin (DM-RST), in buffered human plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS). All the three analytes and the corresponding deuterium-labeled (d6) internal standards were extracted from 50 μL of buffered human plasma by protein precipitation. The analytes were chromatographically separated using a Zorbax-SB Phenyl column (2.1 mm × 100 mm, 3.5 μm). The mobile phase comprised of a gradient mixture of 0.1% v/v glacial acetic acid in 10% v/v methanol in water (solvent A) and 40% v/v methanol in acetonitrile (solvent B). The analytes were separated at baseline within 6.0 min using a flow rate of 0.35 mL/min. Mass spectrometry detection was carried out in positive electrospray ionization mode. The calibration curves for all three analytes were linear (R ≥ 0.9964, n = 3) over the concentration range of 0.1-100 ng/mL for RST and RST-LAC, and 0.5-100 ng/mL for DM-RST. Mean extraction recoveries ranged within 88.0-106%. Intra- and inter-run mean percent accuracy were within 91.8-111% and percent imprecision was ≤15%. Stability studies revealed that all the analytes were stable in matrix during bench-top (6 h on ice-water slurry), at the end of three successive freeze and thaw cycles and at -80°C for 1 month. The method was successfully applied in a clinical study to determine the concentrations of RST and the lactone metabolite over 12-h post-dose in patients who received a single dose of rosuvastatin.

Rapid determination of thiamine, riboflavin, niacinamide, pantothenic acid, pyridoxine, folic acid and ascorbic acid in Vitamins with Minerals Tablets by high-performance liquid chromatography with diode array detector.

PubMed

Jin, Pengfei; Xia, Lufeng; Li, Zheng; Che, Ning; Zou, Ding; Hu, Xin

2012-11-01

A simple, isocratic, and stability-indicating high-performance liquid chromatography (HPLC) method has been developed for the rapid determination of thiamine (VB(1)), niacinamide (VB(3)), pyridoxine (VB(6)), ascorbic acid (VC), pantothenic acid (VB(5)), riboflavin (VB(2)) and folic acid (VB(9)) in Vitamins with Minerals Tablets (VMT). An Alltima C(18) column (250 mm × 4.6 mm i.d., 5 μm) was used for the separation at ambient temperature, with 50mM ammonium dihydrogen phosphate (adjusting with phosphoric acid to pH 3.0) and acetonitrile as the mobile phase at the flow rate of 0.5 ml min(-1). VB(1), VB(3), VB(6), VC and VB(5) were extracted with a solution containing 0.05% phosphoric acid (v/v) and 0.3% sodium thiosulfate (w/v), and were then simultaneously analyzed by using the mobile phase of phosphate buffer-acetonitrile (95:5, v/v), while VB(2) and VB(9) were extracted with a solution containing 0.5% ammonium hydroxide solution (v/v), and were then simultaneously analyzed by using the mobile phase of phosphate buffer-acetonitrile (85:15, v/v). The detection wavelengths were 275 nm for VB(1), VB(3), VB(6), VC, 210 nm for VB(5), and 282 nm for VB(2) and VB(9). The method showed good system suitability, sensitivity, linearity, specificity, precision, stability and accuracy. All the seven water-soluble vitamins were well separated from other ingredients and degradation products. Method comparison indicated good concordance between the developed method and the USP method. The developed method was reliable and convenient for the rapid determination of VB(1), VB(3), VB(6), VC, VB(5), VB(2) and VB(9) in VMT. Copyright © 2012 Elsevier B.V. All rights reserved.

[Simultaneous determination of seven high risk pesticide residues in royal jelly by high performance liquid chromatography-tandem mass spectrometry].

PubMed

Li, Yinghong; Zhou, Ping; Xu, Quanhua; Zhao, Huan; Shao, Qiaoyun

2018-02-08

A method was developed for the simultaneous determination of seven high risk pesticides in the royal jelly, eg. tau-fluvalinate, triadimenol, coumaphos, haloxyfop, carbendazim, thiophanate-ethyl and thiophanate-methyl by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). First, the royal jelly samples were extracted with acetonitrile under alkaline conditions. After dehydration by anhydrous sodium sulfate, the extracts were enriched and purified through solid-phase extraction (SPE) with Oasis HLB cartridges. Finally, the pesticides were detected by HPLC-MS/MS method. The separation was carried out on a Venusil MP C18 column with gradient elution. Methanol (containing 0.1% (v/v) formic acid) and 0.5 mmol/L ammonium acetate aqueous solution (containing 0.1% (v/v) formic acid) were used as the mobile phases. The detection was achieved using electrospray ionization in positive ion (ESI + ) mode and multiple reaction monitoring (MRM) mode for data collection. Quantification was carried out using internal standard method. The results showed that the seven high risk pesticides were linear in the range of 5-100 μg/kg. The linear correlation coefficients ( r 2 ) were 0.9921-0.9996. The limits of detection (LODs) and limits of quantification (LOQs) of the seven high risk pesticides were 0.5-2.0 μg/kg and 1.0-5.0 μg/kg, respectively. The average recoveries at the three spiked levels were 80.5%-101.3%, and the relative standard deviations were 3.6%-9.4% ( n =3). This method is simple, effective and sensitive, and is suitable for the determination of the pesticide residues in royal jelly.

Simultaneous analysis of thiamphenicol and its prodrug thiamphenicol glycinate in human plasma and urine by high performance liquid chromatography: application to pharmacokinetic study.

PubMed

Chen, Xijing; Yang, Bing; Ni, Liang; Wang, Guangji

2006-06-07

A simple and sensitive method for simultaneous determination of the active compound, thiamphenicol (TAP) and its prodrug, thiamphenicol glycinate (TG) in human plasma and urine is described. The procedure involved extraction of TG and TAP with ethyl acetate (plasma) or 100-fold dilution with the mobile phase (urine) followed by determination by reversed-phase high performance liquid chromatography (HPLC) with UV detection at 224 nm. Separation of the compounds was achieved on a column packed with Hypersil ODS2. The mobile phase consisted of acetonitrile-water containing 0.003 M tetrabutyl ammonium bromide and 0.056 M ammonium acetate (87:13, v/v) with a flow rate of 1.0 ml/min. The chromatograms did not contain interfering peaks due to the suitable extraction procedure and chromatographic conditions. The calibration curves of TG and TAP were linear ranging from 0.78 to 100 microg/ml in plasma and in urine. The intra-day and inter-day relative standard deviations (S.D.) were less than 10%. The recoveries of TG and TAP in plasma and urine were above 80%. TG was not stable in plasma samples and after extraction at ambient temperature or in freeze-thaw cycles, and hence the samples for injection on HPLC column should be stored in refrigerator or under ice cooling prior to analysis, and the plasma samples should not experience the freeze-thaw cycle more than one time. Unlike TAP, TG could not be detected in most urine samples. Application of this method demonstrated that it was feasible for the clinical pharmacokinetic study.

Simultaneous multiresidue determination of metronidazole and spiramycin in fish muscle using high performance liquid chromatography with UV detection.

PubMed

Maher, Hadir M; Youssef, Rasha M; Khalil, Riad H; El-Bahr, Sabry M

2008-12-15

An efficient multiresidue method for the simultaneous determination of metronidazole (MET) and spiramycin (SPY) in tilapia fish muscle, based on high performance liquid chromatography with UV detection (HPLC-UV), has been developed. The drugs were extracted with 0.2% orthophosphoric acid-methanol (6:4), and the extracts were cleaned up on a solid phase extraction cartridge, C18 Sep-Pak light column. The LC separation was performed on a RP stainless-steel C-18 analytical column (150 mm x 4.6 mm, 5 microm) with a gradient elution system of 0.05 M phosphate buffer adjusted to pH 2.4-acetonitrile as the mobile phase at the flow rate of 1.0 ml min(-1). A wavelength programming was applied for the UV detection of the analytes. The method not only enabled the determination of the parent drugs, MET and SPY, but also permitted the determination of their metabolites, hydroxymetronidazole (HMET) and neospiramycin (NSPY). The calibration graphs for each drug were rectilinear in the range of 0.005-1.000 microg g(-1) for MET and HMET and 0.025-1.000 microg g(-1) for SPY and NSPY. With this method, the cited drugs with their metabolites were determined in fortified fish muscle tissues at levels of 0.025, 0.1 and 1.0 microg g(-1) with good accuracy and precision. LOD and LOQ obtained for each drug were as follows: 0.002 and 0.005 microg g(-1) for MET and HMET and 0.005 and 0.025 microg g(-1) for SPY and NSPY. Utilization of the method to successfully analyze tilapia fish muscle samples incurred with MET and SPY was described.

Simultaneous quantification of twelve compounds in ethyl acetate extracts of Euphorbia kansui before and after fry-baked with vinegar by UPLC-MS/MS and its toxic effect on zebrafish.

PubMed

Zhang, Qiao; Zhang, Kai-Cheng; Lou, Jian-Wei; Guo, Shu-Chen; Zhang, Yi; Yao, Wei-Feng; Tang, Yu-Ping; Wu, Jian-Hua; Zhang, Li

2018-06-05

The dried roots of Euphorbia kansui T.N. Liou ex T.P. Wang have been traditionally used for edema in China. However, the severe toxicity caused by Euphorbia kansui has seriously restricted its clinical application. Therefore, in order to study the material basis of the toxicity attenuation effect of processing with vinegar, a rapid, sensitive, validated and reliable UPLC-MS/MS method was developed to determine twelve compounds in ethyl acetate extracts of Euphorbia kansui before and after fry-baked with vinegar simultaneously. Meanwhile, the study of their toxic effect on zebrafish was conducted. Chromatographic separation was accomplished on Waters BEH C 18 UPLC column. 0.3% formic acid in water and acetonitrile were used as mobile phase with a flow rate of 0.40 mL/min and a temperature at 30 °C. The analysis was performed in multiple reaction monitoring (MRM) mode using positive electrospray ionization (ESI). Furthermore, the toxic research results indicated that the toxicity of Euphorbia kansui was decreased after vinegar-processed, which might because of the increase in the content of 5-O-benzoyl-20-deoxyingenol and the decrease in the contents of the remaining terpenoids in ethyl acetate extracts of Euphorbia kansui fry-baked with vinegar. This study demonstrated that the method used is a powerful approach to determine the content of twelve compounds that responsible for the toxic effect of Euphorbia kansui at the same instant. And provided the experimental evidence for the rationale behind the reduction of toxicity. Copyright © 2018 Elsevier B.V. All rights reserved.

Simultaneous determination of atorvastatin and valsartan in human plasma by solid-based disperser liquid-liquid microextraction followed by high-performance liquid chromatography-diode array detection.

PubMed

Farajzadeh, Mir Ali; Khorram, Parisa; Pazhohan, Azar

2016-04-01

A simple, sensitive, and efficient method has been developed for simultaneous estimation of valsartan and atorvastatin in human plasma by combination of solid-based dispersive liquid-liquid microextraction and high performance liquid chromatography-diode array detection. In the proposed method, 1,2-dibromoethane (extraction solvent) is added on a sugar cube (as a solid disperser) and it is introduced into plasma sample containing the analytes. After manual shaking and centrifugation, the resultant sedimented phase is subjected to back extraction into a small volume of sodium hydrogen carbonate solution using air-assisted liquid-liquid microextraction. Then the cloudy solution is centrifuged and the obtained aqueous phase is transferred into a microtube and analyzed by the separation system. Under the optimal conditions, extraction recoveries are obtained in the range of 81-90%. Calibration curves plotted in drug-free plasma sample are linear in the ranges of 5-5000μgL(-1) for valsartan and 10-5000μgL(-1) for atorvastatin with the coefficients of determination higher than 0.997. Limits of detection and quantification of the studied analytes in plasma sample are 0.30-2.6 and 1.0-8.2μgL(-1), respectively. Intra-day (n=6) and inter-days (n=4) precisions of the method are satisfactory with relative standard deviations less than 7.4% (at three levels of 10, 500, and 2000μgL(-1), each analyte). These data suggest that the method can be successfully applied to determine trace amounts of valsartan and atorvastatin in human plasma samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Simultaneous determination of gallic acid and gentisic acid in organic anion transporter expressing cells by liquid chromatography-tandem mass spectrometry.

PubMed

Wang, Li; Halquist, Matthew S; Sweet, Douglas H

2013-10-15

In order to elucidate the role of organic anion transporters (OATs) in the renal elimination of gallic acid and gentisic acid, a new, rapid, and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the simultaneous determination of gallic acid and gentisic acid in cell lysate, using Danshensu as the internal standard (IS). After a simple liquid-liquid extraction, the analytes were detected in negative ESI mode using selected reaction monitoring. The precursor-to-product ion transitions (m/z) were 169.0→125.0, 153.1→108.0, and 196.8→135.2 for gallic acid, gentisic acid, and the IS, respectively. Chromatographic separation was achieved on a C18 column using mobile phases consisting of water with 0.1% acetic acid (A) and acetonitrile with 0.05% formic acid. (B) The total run time was 3min and calibration curves were linear over the concentrations of 0.33-2400ng/mL for both compounds (r(2)>0.995). Good precision (between 3.11% and 14.1% RSD) and accuracy (between -12.7% and 11% bias) was observed for quality controls at concentrations of 0.33 (lower limit of quantification), 1, 50, and 2000ng/mL. The mean extraction recovery of gallic acid and gentisic acid was 80.7% and 83.5%, respectively. Results from post-column infusion and post-extraction methods indicated that the analytical method exhibited negligible matrix effects. Finally, this validated assay was successfully applied in a cellular uptake study to determine the intracellular concentrations of gallic acid and gentisic acid in OAT expressing cells. Copyright © 2013 Elsevier B.V. All rights reserved.

Periodic mesoporous organosilica materials as sorbents for solid-phase extraction of drugs prior to simultaneous enantiomeric separation by capillary electrophoresis.

PubMed

Valimaña-Traverso, Jesús; Morante-Zarcero, Sonia; Pérez-Quintanilla, Damián; García, María Ángeles; Sierra, Isabel; Marina, María Luisa

2018-06-19

Two novel periodic mesoporous organosilica materials were synthesized with a neutral phenylene-bridged ligand, 1,4-bis(trimethoxysilylethyl)benzene, one of them using tetraethyl orthosilicate as additional silica source (PMO-TMSEB-1 and PMO-TMSEB-2). A third material was also synthesized with 1,4-bis(triethoxysilyl)benzene ligand (PMO-TESB-1) which use has scarcely been reported. The three materials were evaluated as solid-phase extraction (SPE) sorbents for the off-line extraction of a mixture of seven drugs of different nature (duloxetine, terbutaline, econazole, propranolol, verapamil, metoprolol, and betaxolol) from water samples. Subsequent simultaneous enantiomeric analysis by CE, using sulfated-β-cyclodextrin (2% w/v) dissolved in a 25 mM phosphate buffer (pH 3.0) and a voltage of -20 kV (negative polarity) was carried out. Enantiomeric resolutions ranging from 2.4 to 8.5 were obtained in an analysis time of 16 min. After optimization of SPE parameters, it was shown that using just 100 mg of PMO-TESB-1 as sorbent, a preconcentration factor of 400 with 200 mL solution was achieved, allowing recoveries between 80.5 and 103.1% (except for terbutaline), with good repeatability (% RSD = 2-8 %, n = 5). Analytical characteristics of the method were evaluated in terms of precision, linearity and accuracy with method quantitation limits between 5.6 and 21.9 μg/L. The developed method was applied to the analysis of spiked wastewater samples collected in different treatment plants, with recoveries between 73.9 and 102.9% except for econazole with recovery values ranging between 58.5 and 72.4%. Copyright © 2018 Elsevier B.V. All rights reserved.

Extensive intestinal first-pass metabolism of arctigenin: evidenced by simultaneous monitoring of both parent drug and its major metabolites.

PubMed

Gao, Qiong; Zhang, Yufeng; Wo, Siukwan; Zuo, Zhong

2014-03-01

The current study aims to investigate intestinal absorption and metabolism of arctigenin (AR) through simultaneous monitoring of AR and its major metabolites in rat plasma. An UPLC/MS/MS assay was developed with chromatographic separation of all analytes achieved by a C18 Column (3.9mm×150mm, 3.5μm) and a gradient elution with acetonitrile and 0.1% formic acid within 9min. Sample extraction with acetonitrile was optimized to achieve satisfactory recovery for both AR and its major metabolites. The lower limit of quantification (LLOQ) for all analytes was 25ng/ml. The intra-day and inter-day precision and accuracy of each analyte at LLOQ and three quality control (QC) concentrations (low, middle and high) in rat plasma was within 15.0% RSD and 15.0% bias. The extraction recoveries were within the range of 83.8-94.0% for all analytes. The developed and validated assay was then applied to the absorption study of AR in both Caco-2 cell monolayer model and in situ single-pass rat intestinal perfusion model. High absorption permeability of AR was demonstrated in both models with Papp of (1.76±0.48)×10(-5) (A→B) (Caco-2) and Pblood of (8.6±3.0)×10(-6)cm/s (intestinal perfusion). Extensive first-pass metabolism of AR to arctigenic acid (AA) and arctigenin-4'-O-glucuronide (AG) was identified in rat intestinal perfusion study with Cummins's extraction ratios of 0.458±0.012 and 0.085±0.013, respectively. The current assay method demonstrated to be a practical tool for pharmacokinetics investigation of AR with complicated metabolism pathways and multiple metabolites. Copyright © 2013 Elsevier B.V. All rights reserved.

Carbon coated magnetic nanoparticles as a novel magnetic solid phase extraction adsorbent for simultaneous extraction of methamphetamine and ephedrine from urine samples.

PubMed

Taghvimi, Arezou; Hamishehkar, Hamed

2017-01-15

This paper develops a highly selective, specific and efficient method for simultaneous determination of ephedrine and methamphetamine by a new carbon coated magnetic nanoparticles (C/MNPs) as a magnetic solid phase extraction (MSPE) adsorbent in biological urine medium. The characterization of synthesized magnetic nano adsorbent was completely carried out by various characterization techniques like Fourier transform infrared (FT-IR) spectroscopy, powder x-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). Nine important parameters influencing extraction efficiency including amount of adsorbent, amounts of sample volume, pH, type and amount of extraction organic solvent, time of extraction and desorption, agitation rate and ionic strength of extraction medium, were studied and optimized. Under optimized extraction conditions, a good linearity was observed in the concentration range of 100-2000ng/mL for ephedrine and 100-2500ng/mL for methamphetamine. Analysis of positive urine samples was carried out by proposed method with the recovery of 98.71 and 97.87% for ephedrine and methamphetamine, respectively. The results indicated that carbon coated magnetic nanoparticles could be applied in clinical and forensic laboratories for simultaneous determination of abused drugs in urine media. Copyright © 2016 Elsevier B.V. All rights reserved.

Simultaneous separation and quantitation of amino acids and polyamines of forest tree tissues and cell cultures within a single high-performance liquid chromatography run using dansyl derivatization

Treesearch

Rakesh Minocha; Stephanie Long

2004-01-01

The objective of the present study was to develop a rapid HPLC method for simultaneous separation and quantitation of dansylated amino acids and common polyamines in the same matrix for analyzing forest tree tissues and cell cultures. The major modifications incorporated into this method as compared to previously published HPLC methods for separation of only dansyl...

Simultaneous estimation of lisofylline and pentoxifylline in rat plasma by high performance liquid chromatography-photodiode array detector and its application to pharmacokinetics in rat.

PubMed

Italiya, Kishan S; Sharma, Saurabh; Kothari, Ishit; Chitkara, Deepak; Mittal, Anupama

2017-09-01

Lisofylline (LSF) is an anti-inflammatory and immunomodulatory agent with proven activity in serious infections associated with cancer chemotherapy, hyperoxia-induced acute lung injury, autoimmune disorders including type-1 diabetes (T1DM) and islet rejection after islet transplantation. It is also an active metabolite of another anti-inflammatory agent, Pentoxifylline (PTX). LSF bears immense therapeutic potential in multiple pharmacological activities and hence appropriate and accurate quantification of LSF is very important. Although a number of analytical methods for quantification of LSF and PTX have been reported for pharmacokinetics and metabolic studies, each of these have certain limitations in terms of large sample volume required, complex extraction procedure and/or use of highly sophisticated instruments like LC-MS/MS. The aim of current study is to develop a simple reversed-phase HPLC method in rat plasma for simultaneous determination of LSF and PTX with the major objective of ensuring minimum sample volume, ease of extraction, economy of analysis, selectivity and avoiding use of instruments like LC-MS/MS to ensure a widespread application of the method. A simple liquid-liquid extraction method using methylene chloride as extracting solvent was used for extracting LSF and PTX from rat plasma (200μL). Samples were then evaporated, reconstituted with mobile phase and injected into HPLC coupled with photo-diode detector (PDA). LSF, PTX and 3-isobutyl 1-methyl xanthine (IBMX, internal standard) were separated on Inertsil® ODS (C18) column (250×4.6mm, 5μm) with mobile phase consisting of A-methanol B-water (50:50v/v) run in isocratic mode at flow rate of 1mL/min for 15min and detection at 273nm. The method showed linearity in the concentration range of 50-5000ng/mL with LOD of 10ng/mL and LLOQ of 50ng/mL for both LSF and PTX. Weighted linear regression analysis was also performed on the calibration data. The mean absolute recoveries were found to be 80.47±3.44 and 80.89±3.73% for LSF and PTX respectively. The method was successfully applied for studying the pharmacokinetics of LSF and PTX after IV bolus administration at dose of 25mg/kg in Wistar rat. In conclusion, a simple, sensitive, accurate and precise reversed-phase HPLC-UV method was established for simultaneous determination of LSF and PTX in rat plasma. Copyright © 2017 Elsevier B.V. All rights reserved.

A UPLC-MS/MS method for simultaneous quantitation of three monoterpene glycosides and four alkaloids in rat plasma: application to a comparative pharmacokinetic study of Huo Luo Xiao Ling Dan and single herb extract.

PubMed

Ai, Yu; Wu, Yun; Wang, Fenrong; Ma, Wen; Bian, Qiaoxia; Lee, David Y-W; Dai, Ronghua

2015-03-01

The objective of this study was to develop a sensitive and reliable ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for simultaneous quantitation of three monoterpene glycosides (paeoniflorin, alibiflorin and oxypaeoniflorin) and four alkaloids (tetrahydropalmatine, corydaline, dehydrocorydaline and berberine), the main active ingredients of Radix Paeoniae Rubra extract (RPE) and Corydalis yanhusuo extract (CYE) in Huo Luo Xiao Ling Dan (HLXLD), and to compare the pharmacokinetics of these active ingredients in normal and arthritic rats orally administrated with HLXLD or RPE/CYE alone. The analytes and internal standard (IS) (geniposide) were separated on a XBridge C18 column (150 × 4.6 mm, 3.5 µm) using gradient elution with the mobile phase consisting of methanol and 0.01% formic acid in water at a flow rate of 0.6 ml/min. The detection of the analytes was performed on Acquity UPLC-MS/MS system with an electrospray ionization and multiple reaction monitoring mode via polarity switching between negative (for monoterpene glycosides) and positive (for alkaloids) ionization mode. The lower limits of quantification were 2.5, 1, 0.5, 0.2, 0.2, 0.02 and 0.01 ng/ml for paeoniflorin, alibiflorin, oxypaeoniflorin, tetrahydropalmatine, corydaline, dehydrocorydaline and berberine, respectively. Intra-day and inter-day precision and accuracy of analytes were well within acceptance criteria (15%). The mean extraction recoveries of analytes and IS from rat plasma were all more than 83.1%. The validated method has been successfully applied to determination of the analytes. Results showed that there were remarkable differences in pharmacokinetic properties of the analytes between herbal formula and single herb group, normal and arthritic group. Copyright © 2015 John Wiley & Sons, Ltd.

In situ continuous derivatization/pre-concentration of carbonyl compounds with 2,4-dinitrophenylhydrazine in aqueous samples by solid-phase extraction Application to liquid chromatography determination of aldehydes.

PubMed

Baños, Clara-Eugenia; Silva, Manuel

2009-03-15

A rapid and straightforward continuous solid-phase extraction system has been developed for in situ derivatization and pre-concentration of carbonyl compounds in aqueous samples. Initially 2,4-dinitrophenylhydrazine, the derivatizing agent, was adsorbed on a C(18) mini-column and then 15-ml of sample were continuously aspirated into the flow system, where the derivatization and pre-concentration of the analytes (low-molecular mass aldehydes) were performed simultaneously. Following elution, 20 microl of the extract were injected into a LC-DAD system, in which hydrazones were successfully separated in 12 min on a RP-C(18) column using a linear gradient mobile phase of acetonitrile-water of 60-100% acetonitrile for 8 min, flowing at 0.5 ml/min. The whole analytical process can be accomplished within ca. 35 min. Under optimum conditions, limits of detection were obtained between 0.3 and 1.0 microg/l and RSDs (inter-day precision) from 1.2 to 4.6%. Finally, some applications on water samples are presented with recoveries ranged from 95.8 to 99.4%.

Quantitative liquid chromatographic determination of bromadoline and its N-demethylated metabolites in blood, plasma, serum, and urine samples.

PubMed

Peng, G W; Sood, V K; Rykert, U M

1985-03-01

Bromadoline and its two N-demethylated metabolites were extracted into ether:butyl chloride after the addition of internal standard and basification of the various biological fluids (blood, plasma, serum, and urine). These compounds were then extracted into dilute phosphoric acid from the organic phase and separated on a reversed-phase chromatographic system using a mobile phase containing acetonitrile and a buffer of 1,4-dimethylpiperazine and perchloric acid. The overall absolute extraction recoveries of these compounds were approximately 50-80%. The background interferences from the biological fluids were negligible and allowed quantitative determination of bromadoline and the metabolites at levels as low as 2-5 ng/mL. At mobile phase flow rate of 1 mL/min, the sample components and the internal standard were eluted at the retention times within approximately 7-12 min. The drug- and metabolite-to-internal standard peak height ratios showed excellent linear relationships with their corresponding concentrations. The analytical method showed satisfactory within- and between-run assay precision and accuracy, and has been utilized in the simultaneous determination of bromadoline and its two N-demethylated metabolites in biological fluids collected from humans and from dogs after administration of bromadoline maleate.

Gas chromatography--inductively coupled plasma--time-of-flight mass spectrometry for the speciation analysis of organolead compounds in environmental water samples.

PubMed

Heisterkamp, M; Adams, F C

2001-07-01

The application of inductively coupled plasma--time-of-flight mass spectrometry for the speciation analysis of organolead compounds in environmental waters is described. Construction of the transfer line was achieved by means of a relatively simple and rapid coupling procedure. Derivatization of the ionic lead species was achieved by in-situ propylation with sodium tetrapropylborate; simultaneous extraction of the derivatized compounds in hexane was followed by separation and detection by capillary gas chromatography hyphenated to inductively coupled plasma-time-of-flight mass spectrometry. Detection limits for the different organolead species ranged from 10 to 15 fg (as Pb), corresponding to procedural detection limits between 50 and 75 ng L(-1), on the basis of a 50 mL snow sample, extraction with 200 microL hexane, and subsequent injection of 1 microL of the organic extract on to the column. The accuracy of the system was confirmed by additional analysis of the water samples by capillary gas chromatography coupled with microwave-induced plasma-atomic-emission spectrometry and the analysis of a standard reference material CRM 605 (road dust) with a certified content of trimethyllead.

A novel green chemistry method for nonaqueous extraction and high-performance liquid chromatography detection of first-, second-, and third-generation tetracyclines, 4-epitetracycline, and tylosin in animal feeds.

PubMed

Granados-Chinchilla, Fabio; Sánchez, Jorge; García, Fernando; Rodríguez, César

2012-07-25

Although tetracyclines and macrolides are common additives for animal nutrition, methods for their simultaneous determination in animal feeds are nonexistent. By coupling an organic extraction and solid-phase extraction cleanup to a high-performance liquid chromatography separation and a nonaqueous postcolumn derivatization, we succeeded in detecting from 0.2 to 24.0 μg kg(-1) of tetracycline, oxytetracycline, chlortetracycline, doxycycline, tigecycline, and 4-epitetracycline in this complex and heterogeneous matrix. Minocycline and tylosin could also be detected with our procedure, but using UV spectrophotometry (1.5 ≤ LOD ≤ 1.9 mg kg(-1)). Linear responses with correlation coefficients between 0.996 and 0.999 were obtained for all analytes in the 0.5-10 mg kg(-1) concentration range. Average recoveries between 59 and 97% and between 98 and 102% were obtained for the tetracyclines and tylosin, respectively. Replicate standard deviations were typically below 5%. When this method was applied to 20 feeds marketed in Costa Rica, we detected labeling inconsistencies, banned mixtures of tetracyclines, and tetracycline concentrations that contravene international regulation.

Determination of fructooligosaccharides in burdock using HPLC and microwave-assisted extraction.

PubMed

Li, Jing; Liu, Xiaomei; Zhou, Bin; Zhao, Jing; Li, Shaoping

2013-06-19

The root of burdock ( Arctium lappa L.) is a commonly used vegetable in Asia. Fructooligosaccharides (FOS) are usually considered as its main bioactive components. Thus, quantitative analysis of these components is very important for the quality control of burdock. In this study, an HPLC-ELSD and microwave-assisted extraction method was developed for the simultaneous determination of seven FOS with degrees of polymerization (DP) between 3 and 9, as well as fructose, glucose, and sucrose in burdock from different regions. The separation was performed on a Waters XBridge Amide column (4.6 × 250 mm i.d., 3.5 μm) with gradient elution. All calibration curves for investigated analytes showed good linear regression (r > 0.9990). Their LODs and LOQs were lower than 3.63 and 24.82 μg/mL, respectively. The recoveries ranged from 99.2 to 102.6%. The developed method was successfully applied to determination of ten sugars in burdock from different locations of Asia. The results showed that the contents of FOS in different samples of burdock collected at appropriate times were similar, and the developed HPLC-ELSD with microwave-assisted extraction method is helpful to control the quality of burdock.

Peroxyoxalate chemiluminescence detection for the highly sensitive determination of fluorescence-labeled chlorpheniramine with Suzuki coupling reaction.

PubMed

Adutwum, Lawrence Asamoah; Kishikawa, Naoya; Ohyama, Kaname; Harada, Shiro; Nakashima, Kenichiro; Kuroda, Naotaka

2010-09-01

A sensitive and selective high performance liquid chromatography-peroxyoxalate chemiluminescence (PO-CL) method has been developed for the simultaneous determination of chlorpheniramine (CPA) and monodesmethyl chlorpheniramine (MDCPA) in human serum. The method combines fluorescent labeling with 4-(4,5-diphenyl-1H-imidazole-2-yl)phenyl boronic acid using Suzuki coupling reaction with PO-CL detection. CPA and MDCPA were extracted from human serum by liquid-liquid extraction with n-hexane. Excess labeling reagent, which interfered with trace level determination of analytes, was removed by solid-phase extraction using a C18 cartridge. Separation of derivatives of both analytes was achieved isocratically on a silica column with a mixture of acetonitrile and 60 mM imidazole-HNO(3) buffer (pH 7.2; 85:15, v/v) containing 0.015% triethylamine. The proposed method exhibited a good linearity with a correlation coefficient of 0.999 for CPA and MDCPA within the concentration range of 0.5-100 ng/mL. The limits of detection (S/N = 3) were 0.14 and 0.16 ng/mL for CPA and MDCPA, respectively. Using the proposed method, CPA could be selectively determined in human serum after oral administration.

Silica-based ionic liquid coating for 96-blade system for extraction of aminoacids from complex matrixes.

PubMed

Mousavi, Fatemeh; Pawliszyn, Janusz

2013-11-25

1-Vinyl-3-octadecylimidazolium bromide ionic liquid [C18VIm]Br was prepared and used for the modification of mercaptopropyl-functionalized silica (Si-MPS) through surface radical chain-transfer addition. The synthesized octadecylimidazolium-modified silica (SiImC18) was characterized by thermogravimetric analysis (TGA), infrared spectroscopy (IR), (13)C NMR and (29)Si NMR spectroscopy and used as an extraction phase for the automated 96-blade solid phase microextraction (SPME) system with thin-film geometry using polyacrylonitrile (PAN) glue. The new proposed extraction phase was applied for extraction of aminoacids from grape pulp, and LC-MS-MS method was developed for separation of model compounds. Extraction efficiency, reusability, linearity, limit of detection, limit of quantitation and matrix effect were evaluated. The whole process of sample preparation for the proposed method requires 270min for 96 samples simultaneously (60min preconditioning, 90min extraction, 60min desorption and 60min for carryover step) using 96-blade SPME system. Inter-blade and intra-blade reproducibility were in the respective ranges of 5-13 and 3-10% relative standard deviation (RSD) for all model compounds. Limits of detection and quantitation of the proposed SPME-LC-MS/MS system for analysis of analytes were found to range from 0.1 to 1.0 and 0.5 to 3.0μgL(-1), respectively. Standard addition calibration was applied for quantitative analysis of aminoacids from grape juice and the results were validated with solvent extraction (SE) technique. Copyright © 2013 Elsevier B.V. All rights reserved.

Quantitative determination of environmental levels of uranium, thorium and plutonium in bone by solvent extraction and alpha spectrometry

NASA Astrophysics Data System (ADS)

Singh, Narayani P.; Zimmerman, Carol J.; Lewis, Laura L.; Wrenn, McDonald E.

1984-06-01

Solvent extraction and alpha-spectrometry have been emplyed in the quantitative simultaneous determination of uranium. thorium and plutonium. The bone specimens, spiked with 232U, 229Th and 242Pu tracers, are wet ashed with HNO 3 followed by alternate additions of a new drops of HNO 3 and H 2O 2. Uranium is reduced to the tetravalent state with 200 mg SnCl 2 and 25 ml HI. Uranium, thorium and plutonium are then coprecipitated with calcium as oxalate, heated to 550°C, dissolved in 50 ml HCl, and the acidity adjusted to 10 M. Uranium and plutonium are extracted into a 20% tri-lauryl amine (TLA) solution in xylene, leaving thorium in the aqueous phase. Plutonium is first back-extracted from the TLA phase by shaking with a 1:1.5 volume of 0.05 M NH 4I in 8 M HCl, which reduces Pu(IV) to Pu(III). Uranium is then back-extracted with an equal volume of 0.1 M HCl. Thorium, which was left in the aqueous phase, is evaporated to dryness, dissolved in 4 M HNO 3, and the acidity adjusted to 4 M. Thorium is then extracted into 20% TLA solution in xylene pre-equilibrated with 4 M HNO 3, and back-extracted with 10 M HCl. Uranium, thorium, and plutonium are then electrodeposited separately onto platinum discs and counted by an alpha-spectrometer with a multi-channel analyzer and surface barrier silicon diodes. The mean recoveries of uranium, thorium, and plutonium in bovine, dog, and human bones were over 70%.

The Influence of Lactic Acid Concentration on the Separation of Light Rare Earth Elements by Continuous Liquid-Liquid Extraction with 2-Ethylhexyl Phosphonic Acid Mono-2-ethylhexyl Ester

NASA Astrophysics Data System (ADS)

de Carvalho Gomes, Rafael; Seruff, Luciana Amaral; Scal, Maira Labanca Waineraich; Vera, Ysrael Marrero

2018-02-01

The separation of rare earth elements (REEs) using solvent extraction adding complexing agents appears to be an alternative to saponification of the extractant. We evaluated the effect of lactic acid concentration on didymium (praseodymium and neodymium) and lanthanum extraction with 2-ethylhexyl phosphonic acid mono-2-ethyl hexyl ester [HEH(EHP)] as extractant. First, we investigated in batch experiments the separation of lanthanum (La) and didymium (Pr and Nd) using McCabe-Thiele diagrams to estimate the number of extraction stages when the feed solution was or was not conditioned with lactic acid. Additionally, we conducted continuous liquid-liquid extraction experiments and evaluated the influence of lactic acid concentration on the REE extraction and separation. The tests showed that the extraction percentage of REEs and the separation factor Pr/La increased when the lactic acid concentration increased, but the didymium purity decreased. Lanthanum, praseodymium, and neodymium extraction rate were 23.0, 89.7, and 99.2 pct, respectively, with 1:1 aqueous/organic volume flow rate and feed solution doped with 0.52 mol L-1 lactic acid. The highest didymium purity reached was 92.0 pct with 0.26 mol L-1 lactic acid concentration.

Simultaneous analysis of steviol and steviol glycosides by liquid chromatography with ultraviolet detection on a mixed-mode column: application to Stevia plant material and Stevia-containing dietary supplements.

PubMed

Jaworska, Karolina; Krynitsky, Alexander J; Rader, Jeanne I

2012-01-01

Simultaneous separation of steviol and steviol glycosides is challenging because of differences in their polarity and chemical structure. In this study, simultaneous analysis of steviol and steviol glycosides was achieved by LC with UV detection using a mixed-mode RP weak anion exchange chromatography column. Steviol and seven steviol glycosides were analyzed on an Acclaim Mixed-Mode Wax-1 (Dionex) column with a linear gradient of deionized water adjusted to pH 3.00 with phosphoric acid and acetonitrile. The extraction was performed by sonicating dry plant material at 40 degreesC in acetonitrile-water (30 + 70, v/v). LOQ values (mg/g dry weight of plant material) were rebaudioside B, 0.50; steviol, 0.70, dulcoside A, 1.0; steviolbioside, 1.2; stevioside and rebaudioside C, 2.0; rebaudioside D, 3.3; and rebaudioside A, 5.0. The method demonstrated suitable performance for all analytes tested with respect to accuracy (mean recoveries 95-99%), intraday and interday precision for retention times (0.070-0.28% and 0.33-1.0% RSD, respectively), and linearity. The method was used to authenticate steviol glycosides in several samples of Stevia plant material as well as to quantitate steviol glycosides in dietary supplements containing Stevia.

Sediment Quality Characterization Naval Station San Diego

DTIC Science & Technology

1999-01-01

Bioassays using an am- phipod (Rhepoxynius abronius), larvae of the sea urchin (Strongylocentrotus purpuratus), and larval abalone (Haliotis sp.) indicated...sulfide (AVS) and simultaneously extracted metal ( SEM ) in bulk sedim ent (pm ole.g-dry1...Diego Gas & Electric SDIWQR San Diego Interagency Water Quality Control Board SEM Simultaneously Extracted Metals Si Silicon SI Site Investigation SOD

An alternative procedure for uranium analysis in drinking water using AQUALIX columns: application to varied French bottled waters.

PubMed

Bouvier-Capely, C; Bonthonneau, J P; Dadache, E; Rebière, F

2014-01-01

The general population is chronically exposed to uranium ((234)U, (235)U, and (238)U) and polonium ((210)Po) mainly through day-to-day food and beverage intake. The measurement of these naturally-occurring radionuclides in drinking water is important to assess their health impact. In this work the applicability of calix[6]arene-derivatives columns for uranium analysis in drinking water was investigated. A simple and effective method was proposed on a specific column called AQUALIX, for the separation and preconcentration of U from drinking water. This procedure is suitable for routine analysis and the analysis time is considerably shortened (around 4h) by combining the separation on AQUALIX with fast ICP-MS measurement. This new method was tested on different French bottled waters (still mineral water, sparkling mineral water, and spring water). Then, the case of simultaneous presence of uranium and polonium in water was considered due to interferences in alpha spectrometry measurement. A protocol was proposed using a first usual step of spontaneous deposition of polonium on silver disc in order to separate Po, followed by the uranium extraction on AQUALIX column before alpha spectrometry counting. © 2013 Published by Elsevier B.V.

Optimization and development of a SPE-HPLC-UV method to determine astaxanthin in Saccharina japonica.

PubMed

Zhou, Jun; Bi, Wentao; Row, Kyung Ho

2011-04-01

An effective and accurate method including extraction, saponification, and separation was developed to determine astaxanthin (AX) in Saccharina japonica. The optimal extraction conditions with different solvents were investigated. 29.30 μg/g of AX was extracted from dry Saccharina japonica powder by solvent. After subsequent saponification, the extracted amount of AX was increased to 37.26 μg/g. Furthermore, 3 different ionic liquid-based silicas were prepared as sorbents for the solid phase extraction of AX from the extract. By comparing the adsorption isotherms of AX on different ionic liquid-based silicas, suitable sorbent was successfully selected and applied for separation of AX from extract. Astaxanthin, in 3 main forms (free, monoesters, and diesters), can be obtained from marine plants and animals. By extraction with subsequent saponification, the astaxanthin was extracted from Saccharina japonica. And then, ionic liquid-based silicas were used to separate the astaxanthin from the extract solution. This method can be widely applied for determination, or even industrial separation and purification of astaxanthin from many other algae.

Two-Stage Separation of V(IV) and Al(III) by Crystallization and Solvent Extraction from Aluminum-Rich Sulfuric Acid Leaching Solution of Stone Coal

NASA Astrophysics Data System (ADS)

Shi, Qihua; Zhang, Yimin; Liu, Tao; Huang, Jing; Liu, Hong

2017-10-01

To improve separation of V(IV) and Al(III) from aluminum-rich sulfuric acid leaching solution of stone coal, the two-stage separation by crystallization and solvent extraction methods have been developed. A co-extraction coefficient ( k) was put forward to evaluate comprehensively co-extraction extent in different solutions. In the crystallization stage, 68.2% of aluminum can be removed from the solution. In the solvent extraction stage, vanadium was selectively extracted using di-2-ethylhexyl phosphoric acid/tri-n-butyl phosphate from the crystalline mother solution, followed by H2SO4 stripped efficiently. A V2O5 product with purity of 98.39% and only 0.10% Al was obtained after oxidation, precipitation, and calcination. Compared with vanadium extraction from solution without crystallization, the counter-current extraction stage of vanadium can be decreased from 6 to 3 and co-extraction coefficient ( k) decreased from 2.51 to 0.58 with two-stage separation. It is suggested that the aluminum removal by crystallization can evidently weaken the influence of aluminum co-extraction on vanadium extraction and improve the selectivity of solvent extraction for vanadium.

Hierarchical Learning Induces Two Simultaneous, But Separable, Prediction Errors in Human Basal Ganglia

PubMed Central

Tsai, Karin; Wallis, Jonathan; Botvinick, Matthew

2013-01-01

Studies suggest that dopaminergic neurons report a unitary, global reward prediction error signal. However, learning in complex real-life tasks, in particular tasks that show hierarchical structure, requires multiple prediction errors that may coincide in time. We used functional neuroimaging to measure prediction error signals in humans performing such a hierarchical task involving simultaneous, uncorrelated prediction errors. Analysis of signals in a priori anatomical regions of interest in the ventral striatum and the ventral tegmental area indeed evidenced two simultaneous, but separable, prediction error signals corresponding to the two levels of hierarchy in the task. This result suggests that suitably designed tasks may reveal a more intricate pattern of firing in dopaminergic neurons. Moreover, the need for downstream separation of these signals implies possible limitations on the number of different task levels that we can learn about simultaneously. PMID:23536092

Solid-phase extraction combined with dispersive liquid-liquid microextraction and chiral liquid chromatography-tandem mass spectrometry for the simultaneous enantioselective determination of representative proton-pump inhibitors in water samples.

PubMed

Zhao, Pengfei; Deng, Miaoduo; Huang, Peiting; Yu, Jia; Guo, Xingjie; Zhao, Longshan

2016-09-01

This report describes, for the first time, the simultaneous enantioselective determination of proton-pump inhibitors (PPIs-omeprazole, lansoprazole, pantoprazole, and rabeprazole) in environmental water matrices based on solid-phase extraction combined with dispersive liquid-liquid microextraction (SPE-DLLME) and chiral liquid chromatography-tandem mass spectrometry. The optimized results of SPE-DLLME were obtained with PEP-2 column using methanol-acetonitrile (1/1, v/v) as elution solvent, dichloroethane, and acetonitrile as extractant and disperser solvent, respectively. The separation and determination were performed using reversed-phase chromatography on a cellulose chiral stationary phase, a Chiralpak IC (250 mm × 4.6 mm, 5 μm) column, under isocratic conditions at 0.6 mL min(-1) flow rate. The analytes were detected in multiple reaction monitoring (MRM) mode by triple quadrupole mass spectrometry. Isotopically labeled internal standards were used to compensate matrix interferences. The method provided enrichment factors of around 500. Under optimal conditions, the mean recoveries for all eight enantiomers from the water samples were 89.3-107.3 % with 0.9-10.3 % intra-day RSD and 2.3-8.1 % inter-day RSD at 20 and 100 ng L(-1) levels. Correlation coefficients (r (2)) ≥ 0.999 were achieved for all enantiomers within the range of 2-500 μg L(-1). The method detection and quantification limits were at very low levels, within the range of 0.67-2.29 ng L(-1) and 2.54-8.68 ng L(-1), respectively. This method was successfully applied to the determination of the concentrations and enantiomeric fractions of the targeted analytes in wastewater and river water, making it applicable to the assessment of the enantiomeric fate of PPIs in the environment. Graphical Abstract Simultaneous enantioselective determination of representative proton-pump inhibitors in water samples.

Gear fault diagnosis based on the structured sparsity time-frequency analysis

NASA Astrophysics Data System (ADS)

Sun, Ruobin; Yang, Zhibo; Chen, Xuefeng; Tian, Shaohua; Xie, Yong

2018-03-01

Over the last decade, sparse representation has become a powerful paradigm in mechanical fault diagnosis due to its excellent capability and the high flexibility for complex signal description. The structured sparsity time-frequency analysis (SSTFA) is a novel signal processing method, which utilizes mixed-norm priors on time-frequency coefficients to obtain a fine match for the structure of signals. In order to extract the transient feature from gear vibration signals, a gear fault diagnosis method based on SSTFA is proposed in this work. The steady modulation components and impulsive components of the defective gear vibration signals can be extracted simultaneously by choosing different time-frequency neighborhood and generalized thresholding operators. Besides, the time-frequency distribution with high resolution is obtained by piling different components in the same diagram. The diagnostic conclusion can be made according to the envelope spectrum of the impulsive components or by the periodicity of impulses. The effectiveness of the method is verified by numerical simulations, and the vibration signals registered from a gearbox fault simulator and a wind turbine. To validate the efficiency of the presented methodology, comparisons are made among some state-of-the-art vibration separation methods and the traditional time-frequency analysis methods. The comparisons show that the proposed method possesses advantages in separating feature signals under strong noise and accounting for the inner time-frequency structure of the gear vibration signals.

A rapid UPLC-MS/MS assay for eicosanoids in human plasma: Application to evaluate niacin responsivity.

PubMed

Miller, Tricia M; Poloyac, Samuel M; Anderson, Kacey B; Waddell, Brooke L; Messamore, Erik; Yao, Jeffrey K

2017-01-18

A rapid and sensitive method using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed to simultaneously quantify hydroxyeicosatetraenoic (HETE), dihydroxyeicosatrienoic (DiHETrE), epoxyeicosatrienoic acid (EET), and prostaglandin metabolites of arachidonic acid in human plasma. Sample preparation consisted of solid phase extraction with Oasis HLB (30mg) cartridges for all metabolites. Separation of HETEs, EETs, and DiHETrEs was achieved on an Acquity UPLC BEH C18, 1.7µm (100×2.1mm) reversed-phase column (Waters Corp, Millford, MA) with negative electrospray ionization mass spectrometric detection. A second injection of the same extracted sample allowed for separation and assessment of prostaglandin metabolites under optimized UPLC-MS/MS conditions. Additionally, the endogenous levels of these metabolites in five different matrices were determined in order to select the optimal matrix for assay development. Human serum albumin was shown to have the least amount of endogenous metabolites, a recovery efficiency of 79-100% and a matrix effect of 71 - 100%. Linear calibration curves ranging from 0.416 to 66.67ng/ml were validated. Inter-assay and intra-assay variance was less than 15% at most concentrations. This method was successfully applied to quantify metabolite levels in plasma samples of healthy control subjects receiving niacin administration to evaluate the association between niacin administration and eicosanoid plasma level response. Published by Elsevier Ltd.

Validation a solid-phase extraction-HPLC method for determining the migration behaviour of five aromatic amines from packaging bags into seafood simulants.

PubMed

OuYang, Xiao-Kun; Luo, Yu-Yang; Wang, Yang-Guang; Yang, Li-Ye

2014-01-01

The simultaneous determination of five aromatic amines and their potential migration from packaging bags into seafood simulants were investigated. A validated HPLC method was developed for the separation and qualification of five aromatic amines in seafood simulants. By combining solid-phase extraction (SPE), these amines were efficiently separated on a Halo C18 column (150 × 4.6 mm i.d., 2.7 μm, particle size) using a mobile phase of methanol/phosphate buffer solution (5 mmol l(-1), pH 6.9) with gradient elution. The linear range was 0.1-10.0 mg l(-1); the absolute recoveries ranged from 85.3% to 98.4%; and the limits of detection of the five aromatic amines were between 0.015 and 0.08 mg l(-1). In this work the migration profile of aromatic amines from black plastic bags was investigated at temperatures of 4°C with water, 3% acetic acid solution, 10% ethanol solution and 50% ethanol solution as seafood simulants, respectively. The migration of the five aromatic amines under different conditions showed that residual o-methoxyaniline, p-chloroaniline, aniline and 2,6-dimethylaniline leaching from black plastic bags increased with incubation time. No detectable 3,3´-dimethylbenzidine was found to leach from the bags.

Determination of alkaloids in onion nectar by micellar electrokinetic chromatography.

PubMed

Carolina Soto, Verónica; Jofré, Viviana Patricia; Galmarini, Claudio Romulo; Silva, María Fernanda

2016-07-01

Nectar is the most important floral reward offered by plants to insects. Minor components such as alkaloid compounds in nectar affect bee foraging, with great influence in seed production. CE is an advantageous tool for the analysis of unexplored samples such as onion nectar due to the limited amounts of samples. Considering the importance of these compounds, a simultaneous determination of nicotine, theophylline, theobromine, caffeine, harmaline, piperine in onion nectar by MEKC-UV is herein reported. The extraction of alkaloid compounds in nectar was performed by SPE using a homemade miniaturized column (C18 ). Effects of several important factors affecting extraction efficiency as well as electrophoretic performance were investigated to acquire optimum conditions. Under the proposed conditions, the analytes can be separated within 15 min in a 50 cm effective length capillary (75 μm id) at a separation voltage of 20 kV in 20 mmol/L sodium tretraborate, 100 mmol/L SDS. The amount of sample requirement was reduced up to 2000 times, when compared to traditional methods, reaching limits of detection as low as 0.0153 ng/L. For the first time, this study demonstrates that there are marked qualitative and quantitative differences in nectar alkaloids between open pollinated and male sterile lines (MSLs) and also within MSLs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of a simultaneous multiple solid-phase microextraction-single shot-gas chromatography/mass spectrometry method and application to aroma profile analysis of commercial coffee.

PubMed

Lee, Changgook; Lee, Younghoon; Lee, Jae-Gon; Buglass, Alan J

2013-06-21

A simultaneous multiple solid-phase microextraction-single shot-gas chromatography mass spectrometry (smSPME-ss-GC/MS) method has been developed for headspace analysis. Up to four fibers (50/30 μm DVB/CAR/PDMS) were used simultaneously for the extraction of aroma components from the headspace of a single sample chamber in order to increase sensitivity of aroma extraction. To avoid peak broadening and to maximize resolution, a simple cryofocusing technique was adopted during sequential thermal desorption of multiple SPME fibers prior to a 'single shot' chromatographic run. The method was developed and validated on a model flavor mixture, containing 81 known pure components. With the conditions of 10 min of incubation and 30 min of extraction at 50 °C, single, dual, triple and quadruple SPME extractions were compared. The increase in total peak area with increase in the number of fibers showed good linearity (R(2)=0.9917) and the mean precision was 12.0% (RSD) for the total peak sum, with quadruple simultaneous SPME extraction. Using a real sample such as commercial coffee granules, aroma profile analysis was conducted using single, dual, triple and quadruple SPME fibers. The increase in total peak intensity again showed good linearity with increase in the number of SPME fibers used (R(2)=0.9992) and the precision of quadruple SPME extraction was 9.9% (RSD) for the total peak sum. Copyright © 2013 Elsevier B.V. All rights reserved.

Method for separating water soluble organics from a process stream by aqueous biphasic extraction

DOEpatents

Chaiko, David J.; Mego, William A.

1999-01-01

A method for separating water-miscible organic species from a process stream by aqueous biphasic extraction is provided. An aqueous biphase system is generated by contacting a process stream comprised of water, salt, and organic species with an aqueous polymer solution. The organic species transfer from the salt-rich phase to the polymer-rich phase, and the phases are separated. Next, the polymer is recovered from the loaded polymer phase by selectively extracting the polymer into an organic phase at an elevated temperature, while the organic species remain in a substantially salt-free aqueous solution. Alternatively, the polymer is recovered from the loaded polymer by a temperature induced phase separation (cloud point extraction), whereby the polymer and the organic species separate into two distinct solutions. The method for separating water-miscible organic species is applicable to the treatment of industrial wastewater streams, including the extraction and recovery of complexed metal ions from salt solutions, organic contaminants from mineral processing streams, and colorants from spent dye baths.

Efficient extraction and preparative separation of four main isoflavonoids from Dalbergia odorifera T. Chen leaves by deep eutectic solvents-based negative pressure cavitation extraction followed by macroporous resin column chromatography.

PubMed

Li, Lu; Liu, Ju-Zhao; Luo, Meng; Wang, Wei; Huang, Yu-Yan; Efferth, Thomas; Wang, Hui-Mei; Fu, Yu-Jie

2016-10-15

In this study, green and efficient deep eutectic solvent-based negative pressure cavitation-assisted extraction (DES-NPCE) followed by macroporous resin column chromatography was developed to extract and separate four main isoflavonoids, i.e. prunetin, tectorigenin, genistein and biochanin A from Dalbergia odorifera T. Chen leaves. The extraction procedure was optimized systematically by single-factor experiments and a Box-Behnken experimental design combined with response surface methodology. The maximum extraction yields of prunetin, tectorigenin, genistein and biochanin A reached 1.204, 1.057, 0.911 and 2.448mg/g dry weight, respectively. Moreover, the direct enrichment and separation of four isoflavonoids in DES extraction solution was successfully achieved by macroporous resin AB-8 with recovery yields of more than 80%. The present study provides a convenient and efficient method for the green extraction and preparative separation of active compounds from plants. Copyright © 2016 Elsevier B.V. All rights reserved.

Fabrication of enrofloxacin imprinted organic-inorganic hybrid mesoporous sorbent from nanomagnetic polyhedral oligomeric silsesquioxanes for the selective extraction of fluoroquinolones in milk samples.

PubMed

He, Hai-Bo; Dong, Chen; Li, Bin; Dong, Jun-Ping; Bo, Tian-Yu; Wang, Tian-Lin; Yu, Qiong-Wei; Feng, Yu-Qi

2014-09-26

This paper reports a nanomagnetic polyhedral oligomeric silsesquioxanes (POSS)-directing strategy toward construction of molecularly imprinted hybrid materials for antibiotic residues determination in milk samples. The imprinted polymeric layer was facilely obtained through the copolymerization of active vinyl groups present on the nanomagnetic POSS (Fe3O4@POSS) surface and functional monomer (methacrylic acid) binding with template (enrofloxacin). Herein, the octavinyl POSS acted as not only the building blocks for hybrid rigid architectures but also the cross-linker for the formation of effective recognition sites during the imprinting process. The molecularly imprinted Fe3O4@POSS nanoparticles (Fe3O4@MI-POSS) demonstrated much higher adsorption capacity and selectivity toward enrofloxacin molecules and its analogs than the non-imprinted Fe3O4@POSS (Fe3O4@NI-POSS) materials. The imprinted particles were applied as a selective sorbent in solid-phase extraction focusing upon sample pretreatment in complex matrices prior to chromatographic analysis. The three FQs (ofloxacin, enrofloxacin, danofloxacin) could be selectively extracted from the biological matrix, while the matrix interferences were effectively eliminated simultaneously under the optimum extraction conditions. A simple, rapid and sensitive method based on the Fe3O4@MI-POSS material combined with HPLC-UV detection was then established for the simultaneous determination of three FQs from milk samples. The average recoveries of the three FQs were in the range of 75.6-108.9%. The relative standard deviations of intra- and inter-day ranging from 2.91 to 8.87% and from 3.6 to 11.5%, respectively. The limits of detections (S/N=3) were between 1.76 and 12.42 ng mL(-1). It demonstrates the effectiveness of trace analysis in complicated biological matrices utilizing magnetic separation in combination with molecularly imprinted solid-phase extraction, the rich chemistry of POSS makes it possible to be an ideal platform for generating molecular imprinted hybrid materials is also exhibited. Copyright © 2014 Elsevier B.V. All rights reserved.

Sun and aureole spectrometer for airborne measurements to derive aerosol optical properties.

PubMed

Asseng, Hagen; Ruhtz, Thomas; Fischer, Jürgen

2004-04-01

We have designed an airborne spectrometer system for the simultaneous measurement of the direct Sun irradiance and aureole radiance. The instrument is based on diffraction grating spectrometers with linear image sensors. It is robust, lightweight, compact, and reliable, characteristics that are important for airborne applications. The multispectral radiation measurements are used to derive optical properties of tropospheric aerosols. We extract the altitude dependence of the aerosol volume scattering function and of the aerosol optical depth by using flight patterns with descents and ascents ranging from the surface level to the top of the boundary layer. The extinction coefficient and the product of single scattering albedo and phase function of separate layers can be derived from the airborne measurements.

Reliable simultaneous zymographic method of characterization of cellulolytic enzymes from fungal cellulase complex.

PubMed

Dojnov, Biljana; Grujić, Marica; Vujčić, Zoran

2015-08-01

A method for zymographic detection of specific cellulases in a complex (endocellulase, exocellulase, and cellobiase) from crude fermentation extracts, after a single electrophoretic separation, is described in this paper. Cellulases were printed onto a membrane and, subsequently, substrate gel. Cellobiase isoforms were detected on the membrane using esculine as substrate, endocellulase isoforms on substrate gel with copolymerized carboxymethyl cellulose (CMC), while exocellulase isoforms were detected in electrophoresis gel with 4-methylumbelliferyl-β-d-cellobioside (MUC). This can be a useful additional tool for monitoring and control of fungal cellulase production in industrial processes and fundamental research, screening for particular cellulase producers, or testing of new lignocellulose substrates. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mesoscopic pairing without superconductivity

NASA Astrophysics Data System (ADS)

Hofmann, Johannes

2017-12-01

We discuss pairing signatures in mesoscopic nanowires with a variable attractive pairing interaction. Depending on the wire length, density, and interaction strength, these systems realize a simultaneous bulk-to-mesoscopic and BCS-BEC crossover, which we describe in terms of the parity parameter that quantifies the odd-even energy difference and generalizes the bulk Cooper pair binding energy to mesoscopic systems. We show that the parity parameter can be extracted from recent measurements of conductance oscillations in SrTiO3 nanowires by Cheng et al. [Nature (London) 521, 196 (2015), 10.1038/nature14398], where it marks the critical magnetic field that separates pair and single-particle currents. Our results place the experiment in the fluctuation-dominated mesoscopic regime on the BCS side of the crossover.

Static hand gesture recognition from a video

NASA Astrophysics Data System (ADS)

Rokade, Rajeshree S.; Doye, Dharmpal

2011-10-01

A sign language (also signed language) is a language which, instead of acoustically conveyed sound patterns, uses visually transmitted sign patterns to convey meaning- "simultaneously combining hand shapes, orientation and movement of the hands". Sign languages commonly develop in deaf communities, which can include interpreters, friends and families of deaf people as well as people who are deaf or hard of hearing themselves. In this paper, we proposed a novel system for recognition of static hand gestures from a video, based on Kohonen neural network. We proposed algorithm to separate out key frames, which include correct gestures from a video sequence. We segment, hand images from complex and non uniform background. Features are extracted by applying Kohonen on key frames and recognition is done.

Enzyme-assisted extraction and liquid chromatography mass spectrometry for the determination of arsenic species in chicken meat.

PubMed

Liu, Qingqing; Peng, Hanyong; Lu, Xiufen; Le, X Chris

2015-08-12

Chicken is the most consumed meat in North America. Concentrations of arsenic in chicken range from μg kg(-1) to mg kg(-1). However, little is known about the speciation of arsenic in chicken meat. The objective of this research was to develop a method enabling determination of arsenic species in chicken breast muscle. We report here enzyme-enhanced extraction of arsenic species from chicken meat, separation using anion exchange chromatography (HPLC), and simultaneous detection with both inductively coupled plasma mass spectrometry (ICPMS) and electrospray ionization tandem mass spectrometry (ESIMS). We compared the extraction of arsenic species using several proteolytic enzymes: bromelain, papain, pepsin, proteinase K, and trypsin. With the use of papain-assisted extraction, 10 arsenic species were extracted and detected, as compared to 8 detectable arsenic species in the water/methanol extract. The overall extraction efficiency was also improved using a combination of ultrasonication and papain digestion, as compared to the conventional water/methanol extraction. Detection limits were in the range of 1.0-1.8 μg arsenic per kg chicken breast meat (dry weight) for seven arsenic species: arsenobetaine (AsB), inorganic arsenite (As(III)), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), inorganic arsenate (As(V)), 3-nitro-4-hydroxyphenylarsonic acid (Roxarsone), and N-acetyl-4-hydroxy-m-arsanilic acid (NAHAA). Analysis of breast meat samples from six chickens receiving feed containing Roxarsone showed the presence of (mean±standard deviation μg kg(-1)) AsB (107±4), As(III) (113±7), As(V) (7±2), MMA (51±5), DMA (64±6), Roxarsone (18±1), and four unidentified arsenic species (approximate concentration 1-10 μg kg(-1)). Copyright © 2015 Elsevier B.V. All rights reserved.

Separation of Ce and La from Synthetic Chloride Leach Solution of Monazite Sand by Precipitation and Solvent Extraction

NASA Astrophysics Data System (ADS)

Banda, Raju; Jeon, Ho Seok; Lee, Man Seung

2014-12-01

Precipitation and solvent extraction experiments have been performed to recover light rare earths from simulated monazite sand chloride leach solutions. Precipitation conditions were obtained to recover Ce by adding NaClO as an oxidant. Among some cationic extractants (PC 88A, D2EHPA, Cyanex 272, LIX 63), PC 88A showed the best performance to separate La from the resulting chloride solution. Furthermore, the mixture of PC 88A with other solvating (TBP, TOPO) and amine extractants (Alamine 336, Aliquat 336) was tested to increase the separation factor of La from Pr and Nd. The use of mixed extractants greatly enhanced the separation of La from the two other metals. McCabe-Thiele diagrams for the extraction of Pr and Nd with the PC 88A/Alamine 336 mixture were constructed.

Simultaneous determination of nucleotide sugars with ion-pair reversed-phase HPLC.

PubMed

Nakajima, Kazuki; Kitazume, Shinobu; Angata, Takashi; Fujinawa, Reiko; Ohtsubo, Kazuaki; Miyoshi, Eiji; Taniguchi, Naoyuki

2010-07-01

Nucleotide sugars are important in determining cell surface glycoprotein glycosylation, which can modulate cellular properties such as growth and arrest. We have developed a conventional HPLC method for simultaneous determination of nucleotide sugars. A mixture of nucleotide sugars (CMP-NeuAc, UDP-Gal, UDP-Glc, UDP-GalNAc, UDP-GlcNAc, GDP-Man, GDP-Fuc and UDP-GlcUA) and relevant nucleotides were perfectly separated in an optimized ion-pair reversed-phase mode using Inertsil ODS-4 and ODS-3 columns. The newly developed method enabled us to determine the nucleotide sugars in cellular extracts from 1 x 10(6) cells in a single run. We applied this method to characterize nucleotide sugar levels in breast and pancreatic cancer cell lines and revealed that the abundance of UDP-GlcNAc, UDP-GalNAc, UDP-GlcUA and GDP-Fuc were a cell-type-specific feature. To determine the physiological significance of changes in nucleotide sugar levels, we analyzed their changes by glucose deprivation and found that the determination of nucleotide sugar levels provided us with valuable information with respect to studying the overview of cellular glycosylation status.

A Facile Stable-Isotope Dilution Method for Determination of Sphingosine Phosphate Lyase Activity

PubMed Central

Suh, Jung H.; Eltanawy, Abeer; Rangan, Apoorva; Saba, Julie D.

2015-01-01

A new technique for quantifying sphingosine phosphate lyase activity in biological samples is described. In this procedure, 2-hydrazinoquinoline is used to convert (2E)-hexadecenal into the corresponding hydrazone derivative to improve ionization efficiency and selectivity of detection. Combined utilization of liquid chromatographic separation and multiple reaction monitoring-mass spectrometry allows for simultaneous quantification of the substrate S1P and product (2E)-hexadecenal. Incorporation of (2E)-d5-hexadecenal as an internal standard improves detection accuracy and precision. A simple one-step derivatization procedure eliminates the need for further extractions. Limits of quantification for (2E)-hexadecenal and sphingosine-1-phosphate are 100 and 50 fmol, respectively. The assay displays a wide dynamic detection range useful for detection of low basal sphingosine phosphate lyase activity in wild type cells, SPL-overexpressing cell lines, and wild type mouse tissues. Compared to current methods, the capacity for simultaneous detection of sphingosine-1-phosphate and (2E)-hexadecenal greatly improves the accuracy of results and shows excellent sensitivity and specificity for sphingosine phosphate lyase activity detection. PMID:26408264

The simultaneous separation and determination of chloropropanols in soy sauce and other flavoring with gas chromatography-mass spectrometry in negative chemical and electron impact ionization modes.

PubMed

Xu, Xiaomin; Ren, Yiping; Wu, Pinggu; Han, Jianlong; Shen, Xianghong

2006-02-01

Both gas chromatography-mass spectrometry in electron ionization (GC-MS-EI) and negative chemical ionization (GC-MS-NCI) modes are reported in this paper for the simultaneous determination of 1,3-dichloropropan-2-ol (1,3-DCP), 2,3-dichloropropan-1-ol (2,3-DCP), 3-chloropropane-1,2-diol (3-MCPD) and 2-chloropropane-1,3-diol (2-MCPD) in soy sauce and other flavoring. D(5)-3-MCPD (for 3-MCPD and 2-MCPD) and d(5)-1,3-DCP (for 1,3-DCP and 2,3-DCP) were used as the deuterium isotopic labelled internal standards. The feasibility of using heptafluorobutyric anhydride modified with triethylamine (HFBA-Et(3)N) as a new derivatization reagent to replace heptafluorobutyrylimidazole (HFBI) is proposed. Liquid/liquid extraction with hexane was introduced for high lipid content samples. A small survey was carried out of soy sauces (103 samples) and instant noodles (45 samples) and the applicability of GC-MS-NCI and GC-MS-EI was assessed in these different matrices.

Simultaneous quantification of reparixin and paclitaxel in plasma and urine using ultra performance liquid chromatography-tandem mass spectroscopy (UHPLC-MS/MS): Application to a preclinical pharmacokinetic study in rats.

PubMed

Malhi, Sarandeep; Stesco, Nicholas; Alrushaid, Samaa; Lakowski, Ted M; Davies, Neal M; Gu, Xiaochen

2017-03-01

A liquid chromatography-tandem mass spectroscopy (LC-MS/MS) assay was developed and validated to simultaneously quantify anticancer drugs reparixin and paclitaxel in this study. The compounds were extracted from plasma and urine samples by protein precipitation with acetone (supplemented with 0.1% formic acid). Chromatographic separation was achieved using a C18 column, and drug molecules were ionized using dual ion source electrospray and atmospheric pressure chemical ionization (DUIS: ESI-APCI). Reparixin and paclitaxel were quantified using negative and positive multiple reaction monitoring (MRM) mode, respectively. Stable isotope palcitaxel-D5 was used as the internal standard (IS). The assay was validated for specificity, recovery, carryover and sample stability under various storage conditions; it was also successfully applied to measure drug concentrations collected from a pharmacokinetic study in rats. The results confirmed that the assay was accurate and simple in quantifying both reparixin and paclitaxel in plasma and urine with minimal sample pretreatment. Copyright © 2016 Elsevier B.V. All rights reserved.

High-sensitivity simultaneous liquid chromatography-tandem mass spectrometry assay of ethinyl estradiol and levonorgestrel in human plasma.

PubMed

Gandhi, Abhishek; Guttikar, Swati; Trivedi, Priti

2015-10-01

A sensitive and simultaneous liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of ethinyl estradiol and levonorgestrel. The analytes were extracted with methyl-tert-butyl ether: n-hexane (50:50, v/v) solvent mixture, followed by dansyl derivatization. The chromatographic separation was performed on a Kinetex C 18 (50 mm×4.6 mm, 2.6 µm) column with a mobile phase of 0.1% (v/v) formic acid in water and acetonitrile in gradient composition. The mass transitions were monitored in electrospray positive ionization mode. The assay exhibited a linear range of 0.100-20.0 ng/mL for levonorgestrel and 4.00-500 pg/mL for ethinyl estradiol in human plasma. A run time of 9.0 min for each sample made it possible to analyze a throughput of more than 100 samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic and bioequivalence studies.

Simultaneous Determination of 13 Anticoagulant Rodenticidesin Human Blood by Liquid Chromatography-Tandem Mass Spectrometry and its Application in Three Poisoning Cases.

PubMed

Qiao, Zheng; Xiang, Ping; Shen, Baohua; Shen, Min; Yan, Hui

2018-05-01

Anticoagulant rodenticides are widely used for rodent control around the world. A rapid and sensitive method was developed and validated for the simultaneous determination of 13 anticoagulant rodenticides (coumafuryl, pindone, valone, warfarin, coumatetralyl, coumachlor, diphacinone, dicumarol, chlorophacinone, bromadiolone, difenacoum, flocoumafen, and brodifacoum) in human blood by liquid chromatography-tandem mass spectrometry. After liquid-liquid extraction, the anticoagulant rodenticides were separated on an Eclipse Plus C18 column. Linearities were observed for each analyte in blood ranging from 0.5 to 50 ng/mL, with correlation coefficients over 0.99. The limits of detection ranged from 0.01 to 0.2 ng/mL, and the limits of quantification were 0.5 ng/mL for all analytes. The intraday and interday precisions were <15%, and accuracies ranged from 80.3% to 111.0%. This validated method with high sensitivity has been applied in three anticoagulant rodenticide poisoning cases and has been used successfully in monitoring blood concentrations for months. © 2017 American Academy of Forensic Sciences.

QuEChERS Purification Combined with Ultrahigh-Performance Liquid Chromatography Tandem Mass Spectrometry for Simultaneous Quantification of 25 Mycotoxins in Cereals

PubMed Central

Sun, Juan; Li, Weixi; Zhang, Yan; Hu, Xuexu; Wu, Li; Wang, Bujun

2016-01-01

A method based on the QuEChERS (quick, easy, cheap, effective, rugged, and safe) purification combined with ultrahigh performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS), was optimized for the simultaneous quantification of 25 mycotoxins in cereals. Samples were extracted with a solution containing 80% acetonitrile and 0.1% formic acid, and purified with QuEChERS before being separated by a C18 column. The mass spectrometry was conducted by using positive electrospray ionization (ESI+) and multiple reaction monitoring (MRM) models. The method gave good linear relations with regression coefficients ranging from 0.9950 to 0.9999. The detection limits ranged from 0.03 to 15.0 µg·kg−1, and the average recovery at three different concentrations ranged from 60.2% to 115.8%, with relative standard deviations (RSD%) varying from 0.7% to 19.6% for the 25 mycotoxins. The method is simple, rapid, accurate, and an improvement compared with the existing methods published so far. PMID:27983693

[Simultaneous determination of sugar alcohols and sugars in functional foods by precolumn ultraviolet derivatization--high performance liquid chromatography].

PubMed

Liu, Ya-Pan; Ran, Xue-Qin; Chen, Lu-Ying; Zhang, Jing; Ruan, Jia; Li, Yong-Xin; Sun, Chengjun

2014-09-01

To establish a method using precolumn ultraviolet derivatization coupled with high performance liquid chromatography (HPLC) for simultaneous determination of erythritol, xylitol, galactitol, sorbitol, mannitol, maltitol, glucose and sucrose in functional foods. Target sugar alcohols and sugars in food samples were extracted in water by ultrasonic method and then reacted with benzoyl chloride to form violet-absorbing products, which were separated on a C18 column with gradient elution using methanol and water as mobile phase. The experiment was performed using a flow rate of 1.00 mL/min, column temperature at 30 degrees C and detected wavelength at 232 nm. The linear correlation coefficients of all the derivatives were more than 0. 999. The detection limits of the method were as low as 2. 2 microg/mL. The average recoveries were 89.6%-117.0%, with intraday relative standard derivations lower than 5%. This method is simple, inexpensive and easy to operate and it is suitable for the determination of sugar alcohols and glucose and sucrose in functional foods.

Development and validation of a method for the determination of low-ppb levels of macrocyclic lactones in butter, using HPLC-fluorescence.

PubMed

Macedo, Fabio; Marsico, Eliane Teixeira; Conte-Júnior, Carlos Adam; de Resende, Michele Fabri; Brasil, Taila Figueiredo; Pereira Netto, Annibal Duarte

2015-07-15

An analytical method was developed and validated for the simultaneous determination of four macrocyclic lactones (ML) (abamectin, doramectin, ivermectin and moxidectin) in butter, using liquid chromatography with fluorescence detection. The method employed heated liquid-liquid extraction and a mixture of acetonitrile, ethyl acetate and water, with preconcentration and derivatization, to produce stable fluorescent derivatives. The chromatographic run time was <12.5 min, with excellent separation. The method validation followed international guidelines and employed fortified butter samples. The figures of merit obtained, e.g. recovery (72.4-106.5%), repeatability (8.8%), within-laboratory reproducibility (15.7%) and limits of quantification (0.09-0.16 μg kg(-1)) were satisfactory for the desired application. The application of the method to real samples showed that ML residues were present in six of the ten samples evaluated. The method proved to be simple, easy and appropriate for simultaneous determination of ML residues in butter. To our knowledge, this is the first method described for the evaluation of ML in butter. Copyright © 2015. Published by Elsevier Ltd.

Building Development Monitoring in Multitemporal Remotely Sensed Image Pairs with Stochastic Birth-Death Dynamics.

PubMed

Benedek, C; Descombes, X; Zerubia, J

2012-01-01

In this paper, we introduce a new probabilistic method which integrates building extraction with change detection in remotely sensed image pairs. A global optimization process attempts to find the optimal configuration of buildings, considering the observed data, prior knowledge, and interactions between the neighboring building parts. We present methodological contributions in three key issues: 1) We implement a novel object-change modeling approach based on Multitemporal Marked Point Processes, which simultaneously exploits low-level change information between the time layers and object-level building description to recognize and separate changed and unaltered buildings. 2) To answer the challenges of data heterogeneity in aerial and satellite image repositories, we construct a flexible hierarchical framework which can create various building appearance models from different elementary feature-based modules. 3) To simultaneously ensure the convergence, optimality, and computation complexity constraints raised by the increased data quantity, we adopt the quick Multiple Birth and Death optimization technique for change detection purposes, and propose a novel nonuniform stochastic object birth process which generates relevant objects with higher probability based on low-level image features.

Simultaneous extraction and clean-up of polychlorinated biphenyls and their metabolites from small tissue samples using pressurized liquid extraction

PubMed Central

Kania-Korwel, Izabela; Zhao, Hongxia; Norstrom, Karin; Li, Xueshu; Hornbuckle, Keri C.; Lehmler, Hans-Joachim

2008-01-01

A pressurized liquid extraction-based method for the simultaneous extraction and in situ clean-up of polychlorinated biphenyls (PCBs), hydroxylated (OH)-PCBs and methylsulfonyl (MeSO2)-PCBs from small (< 0.5 gram) tissue samples was developed and validated. Extraction of a laboratory reference material with hexane:dichloromethane:methanol (48:43:9, v/v) and Florisil as fat retainer allowed an efficient recovery of PCBs (78–112%; RSD: 13–37%), OH-PCBs (46±2%; RSD: 4%) and MeSO2-PCBs (89±21%; RSD: 24%). Comparable results were obtained with an established analysis method for PCBs, OH-PCBs and MeSO2-PCBs. PMID:19019378

Ultrasound assisted dialysis of semi-permeable membrane devices for the simultaneous analysis of a wide number of persistent organic pollutants.

PubMed

Bustamante, Julen; Navarro, Patricia; Arana, Gorka; de Diego, Alberto; Madariaga, Juan Manuel

2013-09-30

A new procedure based on ultrasound assisted dialysis (UAD) for the simultaneous and quantitative extraction of a wide number of persistent organic pollutants (POPs) such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) or some other organochlorinated pesticides (OCPs) contained in semi-permeable membrane devices (SPMDs) has been developed. This extraction technique combines the advantages of the organic solvent dialysis (OSD) and the speed of the ultrasound assisted extraction. The extraction was performed in an ultrasound bath for 32 min placing the SPMD in a glass flask covered with 80 mL of hexane. This set-up is able to extract simultaneously up to 8 samples. The proposed method entails good repeatabilities (RSD 2-13%) and recoveries (around 100% for almost every analyte). Limits of detection were at ng SPMD(-1) level and enough for the determination of the target analytes in a slightly polluted aquatic environment, as it was tested by successfully comparing the OSD to the proposed methodology. Therefore, the results obtained show that the UAD can be a good alternative for the extraction of POPs in SPMDs as it requires short extraction times and solvent volumes, and provides a cleaner extract for the subsequent clean-up step. Moreover, it fits better than the OSD to the general requirements of Green Chemistry. Copyright © 2013 Elsevier B.V. All rights reserved.

Lipid extraction from isolated single nerve cells

NASA Technical Reports Server (NTRS)

Krasnov, I. V.

1977-01-01

A method of extracting lipids from single neurons isolated from lyophilized tissue is described. The method permits the simultaneous extraction of lipids from 30-40 nerve cells and for each cell provides equal conditions of solvent removal at the conclusion of extraction.

Simultaneous determination of usnic, diffractaic, evernic and barbatic acids in rat plasma by ultra-high-performance liquid chromatography-quadrupole exactive Orbitrap mass spectrometry and its application to pharmacokinetic studies.

PubMed

Wang, Hanxue; Yang, Tao; Cheng, Xuemei; Kwong, Sukfan; Liu, Chenghai; An, Rui; Li, Guowen; Wang, Xinhong; Wang, Changhong

2018-03-01

Usnea longissima Ach. (Usnea) is used in pharmaceuticals, food and cosmetics. Evernic acid (EA), barbatic acid (BA), diffractaic acid (DA) and usnic acid (UA) are the most typical ingredients in U. longissima and exert a wide variety of biological functions. The study aimed to develop a sensitive method for simultaneous analysis of EA, BA, DA and UA in rat plasma and was applied to pharmacokinetic studies after consumption of UA and ethanol extract from U. longissima (UE). The samples were separated on a BEH C 18 column by gradient elution with 0.5% formic acid in water and in methanol. The relative molecular masses of analytes were obtained in full-scan range from 50.0 to 750.0 m/z under negative ionization mode by UPLC-Q-Exactive Orbitrap MS. All validation parameters, such as lower limit of quantitation, linearity, specificity, precision, accuracy, extraction recovery, matrix effect and stability, were within acceptable ranges and the method was appropriate for biological specimen analysis. The pharmacokinetic results indicated that the absolute bioavailabilities of UA after oral administration of UA and UE reached 69.2 and 146.9%, respectively. Compared with UA in UE, the relative bioavailability of DA, BA and EA reached 103.7, 10.4 and 0.7% after oral administration of UE. Copyright © 2017 John Wiley & Sons, Ltd.

Simultaneous determination of eight cyclopolypeptide antibiotics in feed by high performance liquid chromatography coupled with evaporation light scattering detection.

PubMed

Song, Xuqin; Xie, Jingmeng; Zhang, Meiyu; Zhang, Yingxia; Li, Jiufeng; Huang, Qiwen; He, Limin

2018-02-15

A high throughput, reliable and reproducible analysis strategy based on high performance liquid chromatography combined to evaporative light scattering detector (HPLC-ELSD) was developed for simultaneous determination of eight cyclopolypeptide antibiotics including vancomycin, polymyxin B (polymyxin B1 and polymyxin B2), polymyxin E (colistin A and colistin B), teicoplanin, bacitracin A, daptomycin and virginiamycin M1 in animal Feed. Feed samples were extracted with methanol-2% formic acid aqueous solution, followed by a solid-phase extraction step using a HLB cartridge. Under the optimum chromatographic conditions and ELSD parameters, target compounds were separated well on a short column filled with biphenyl stationary phase. The method was developed in accordance with pig complete feed and then extended to detect polypeptide antibiotics in piglet premix, pig feed additive, poultry complete feed and fattening pig premix. The results showed that logarithmic calibration curves of eight analytes were linear (r 2  > 0.99) within the concentration range of 5-200 mg mL -1 . The developed method provided good accuracy and precision for quantification of eight polypeptides in five kinds of feeds with recoveries ranging from 72.0% to 105.4% with relative standard deviations <9.5%. The limits of detection ranged from 2 to 5 mg kg -1 . Finally, the method was successfully applied to analyze polypeptide antibiotics in commercial feed. Copyright © 2018 Elsevier B.V. All rights reserved.

Simultaneous determination of 15 phenolic constituents of Chinese black rice wine by HPLC-MS/MS with SPE.

PubMed

Wang, Yutang; Liu, Yuanyuan; Xiao, Chunxia; Liu, Laping; Hao, Miao; Wang, Jianguo; Liu, Xuebo

2014-06-01

This study established a new method for quantitative and qualitative determination of certain components in black rice wine, a traditional Chinese brewed wine. Specifically, we combined solid-phase extraction and high-performance liquid chromatography (HPLC) with triple quadrupole mass spectrometry (MS/MS) to determine 8 phenolic acids, 3 flavonols, and 4 anthocyanins in black rice wine. First, we clean samples with OASIS HLB cartridges and optimized extraction parameters. Next, we performed separation on a SHIM-PACK XR-ODS column (I.D. 3.0 mm × 75 mm, 2.2 μm particle size) with a gradient elution of 50% aqueous acetonitrile (V/V) and water, both containing 0.2% formic acid. We used multiple-reaction monitoring scanning for quantification, with switching electrospray ion source polarity between positive and negative modes in a single chromatographic run. We detected 15 phenolic compounds properly within 38 min under optimized conditions. Limits of detection ranged from 0.008 to 0.030 mg/L, and average recoveries ranged from 60.8 to 103.1% with relative standard deviation ≤8.6%. We validated the method and found it to be sensitive and reliable for quantifying phenolic compounds in rice wine matrices. This study developed a new, reliable HPLC-MS/MS method for simultaneous determination of 15 bioactive components in black rice wine. This method was validated and found to be sensitive and reliable for quantifying phenolic compounds in rice wine. © 2014 Institute of Food Technologists®

A validated solid-phase extraction HPLC method for the simultaneous determination of the citrus flavanone aglycones hesperetin and naringenin in urine.

PubMed

Kanaze, Feras Imad; Kokkalou, Eugene; Georgarakis, Manolis; Niopas, Ioannis

2004-09-21

A simple, specific, precise, accurate, and robust HPLC assay for the simultaneous analysis of hesperetin and naringenin in human urine was developed and validated. Urine samples were incubated with beta-glucuronidase/sulphatase and the analytes were isolated by solid-phase extraction using C18 cartridges and separated on a C8 reversed phase column using a mixture of methanol/water/acetic acid (40:58:2, v/v/v) at 45 degrees C. The method was found to be linear in the 50-1200 ng/ml concentration range for both hesperetin and naringenin (r > 0.999). The accuracy of the method was greater than 94.8%, while the intra- and inter-day precision for hesperetin was better than 4.9 and 8.2%, respectively and for naringenin was better than 5.3 and 7.8%, respectively. Recovery for hesperetin, naringenin and internal standard 7-ethoxycoumarin was greater than 70.9%. The method has been applied for the determination of hesperetin and naringenin in urine samples obtained from a male volunteer following a single 300 mg oral dose of each of the corresponding flavanone glycosides hesperidin and naringin. The intra- and inter-day reproducibility through enzyme hydrolysis was less than 3.9% for both total (free + conjugated) hesperetin and naringenin. Stability studies showed urine quality control samples to be stable for both hesperetin and naringenin through three freeze-thaw cycles and at room temperature for 24 h (error < or = 3.6%).

A UPLC-MS/MS method for simultaneous determination of five flavonoids from Stellera chamaejasme L. in rat plasma and its application to a pharmacokinetic study.

PubMed

Li, Yun-Qing; Li, Cheng-Jian; Lv, Lei; Cao, Qing-Qing; Qian, Xian; Li, Si Wei; Wang, Hui; Zhao, Liang

2018-06-01

Stellera chamaejasme L. has been used as a traditional Chinese medicine for the treatment of scabies, tinea, stubborn skin ulcers, chronic tracheitis, cancer and tuberculosis. A sensitive and selective ultra-high liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the simultaneous determination of five flavonoids (stelleranol, chamaechromone, neochamaejasmin A, chamaejasmine and isochamaejasmin) of S. chamaejasme L. in rat plasma. Chromatographic separation was accomplished on an Agilent Poroshell 120 EC-C 18 column (2.1 × 100 mm, 2.7 μm) with gradient elution at a flow rate of 0.4 mL/min and the total analysis time was 7 min. The analytes were detected using multiple reaction monitoring in positive ionization mode. The samples were prepared by liquid-liquid extraction with ethyl acetate. The UPLC-MS/MS method was validated for specificity, linearity, sensitivity, accuracy and precision, recovery, matrix effect and stability. The validated method exhibited good linearity (r ≥ 0.9956), and the lower limits of quantification ranged from 0.51 to 0.64 ng/mL for five flavonoids. The intra- and inter-day precision were both <10.2%, and the accuracy ranged from -11.79 to 9.21%. This method was successfully applied to a pharmacokinetic study of five flavonoids in rats after oral administration of ethyl acetate extract of S. chamaejasme L. Copyright © 2018 John Wiley & Sons, Ltd.

Simultaneous determination of triptolide, tripdiolide and tripterine in human urine by high-performance liquid chromatography coupled with ion trap atmospheric-pressure chemical ionization mass spectrometry.

PubMed

Jin, Mi-cong; Chen, Xiao-hong; OuYang, Xiao-kun

2009-03-01

An accurate and selective method for the simultaneous determination of triptolide, tripdiolide and tripterine in human urine using hydrocortisone as an internal standard (IS) by high-performance liquid chromatography coupled with atmospheric-pressure chemical ionization mass spectrometry in negative ion mode has been developed. After triptolide, tripdiolide and tripterine in human urine were extracted with ethyl acetate and cleaned by solid-phase extraction with C(18) cartridges, a satisfactory separation was achieved on an XDB C(18) short column (30 x 2.1 mm i.d., 3 microm) using the mobile phase of acetic acid-ammonium acetate (5 mmol/L, pH = 4.5)-acetonitrile-methanol in gradient elution. Detection was operated by APCI in selected ion monitoring mode. The target ions m/z 359, m/z 375, m/z 449 and m/z 419 were selected for the quantification of triptolide, tripdiolide, tripterine and IS, respectively. The linear range was 1.0-100.0 ng mL(-1), and the limits of quantification in human urine were found to be 0.1-0.5 ng mL(-1) for the three compounds. The precisions (CV%) and accuracies were 6.6-12.9 and 85.1-97.0%, respectively. The developed method could be applied to the determination of triptolide, tripdiolide and tripterine in human urine for diagnosis of the intoxication and for forensic purposes. 2008 John Wiley & Sons, Ltd.

Simultaneous speciation and preconcentration of ultra traces of inorganic tellurium and selenium in environmental samples by hollow fiber liquid phase microextraction prior to electrothermal atomic absorption spectroscopy determination.

PubMed

Ghasemi, Ensieh; Najafi, Nahid Mashkouri; Raofie, Farhad; Ghassempour, Alireza

2010-09-15

A simple and effective speciation and preconcentration method based on hollow fiber liquid phase microextraction (HF-LPME) was developed for simultaneous separation of trace inorganic tellurium and selenium in environmental samples prior to electrothermal atomic absorption spectroscopy (ETAAS) determination. The method involves the selective extraction of the Te (IV) and Se (IV) species by HF-LPME with the use of ammonium pyrrolidinecarbodithioate (APDC) as the chelating agent. The complex compounds were extracted into 10 microL of toluene and the solutions were injected into a graphite furnace for the determination of Te (IV) and Se (IV). To determine the total tellurium and selenium in the samples, first Te (VI) and Se (VI) were reduced to Te (IV) and Se (IV), and then the microextraction method was performed. The experimental parameters of HF-LPME were optimized using a central composite design after a 2(n-1) fractional factorial experimental design. Under optimum conditions, enrichment factors of up to 520 and 480 were achieved for Te (IV) and Se (IV), respectively. The detection limits were 4 ng L(-1) with 3.5% RSD (n=5, c=2.0 microg L(-1)) for Te (IV) and 5 ng L(-1) with 3.1% RSD for Se (IV). The applicability of the developed technique was evaluated by application to spiked, environmental water and soil samples. Copyright 2010 Elsevier B.V. All rights reserved.

Simultaneous determination of ambroxol and salbutamol in human plasma by ultra-performance liquid chromatography-tandem mass spectrometry and its application to a pharmacokinetic study.

PubMed

Guo, Zhening; Chen, Yangsheng; Ding, Xiaoliang; Huang, Chenrong; Miao, Liyan

2016-11-01

A rapid, selective and sensitive liquid chromatography-tandem mass spectrometry assay method was developed for simultaneous determination of ambroxol and salbutamol in human plasma using citalopram hydrobromide as internal standard (IS). The sample was alkalinized with ammonia water (33:67, v/v) and extracted by single liquid-liquid extraction with ethyl acetate. Separation was achieved on Waters Acquity UPLC BEH C 18 column using a gradient program at a flow rate of 0.2 mL/min. Detection was performed using electrospray ionization in positive ion multiple reaction monitoring mode by monitoring the ion transitions m/z 378.9 → 263.6 (ambroxol), m/z 240.2 → 147.7 (salbutamol) and m/z 325.0 → 261.7 (IS). The total analytical run time was relatively short (3 min). Calibration curves were linear in the concentration range of 0.5-100.0 ng/mL for ambroxol and 0.2-20.0 ng/mL for salbutamol, with intra- and inter-run precision (relative standard deviation) <15% and accuracy (relative error) ranging from 97.7 to 112.1% for ambroxol and from 94.5 to 104.1% for salbutamol. The method was successfully applied in a clinical pharmacokinetic study of the compound ambroxol and salbutamol tablets. Copyright © 2016 John Wiley & Sons, Ltd.

Simultaneous quantification of neuroactive dopamine serotonin and kynurenine pathway metabolites in gender-specific youth urine by ultra performance liquid chromatography tandem high resolution mass spectrometry.

PubMed

Lu, Haihua; Yu, Jing; Wang, Jun; Wu, Linlin; Xiao, Hang; Gao, Rong

2016-04-15

Neuroactive metabolites in dopamine, serotonin and kynurenine metabolic pathways play key roles in several physiological processes and their imbalances have been implicated in the pathophysiology of a wide range of disorders. The association of these metabolites' alterations with various pathologies has raised interest in analytical methods for accurate quantification in biological fluids. However, simultaneous measurement of various neuroactive metabolites represents great challenges due to their trace level, high polarity and instability. In this study, an analytical method was developed and validated for accurately quantifying 12 neuroactive metabolites covering three metabolic pathways in youth urine by ultra performance liquid chromatography coupled to electrospray tandem high resolution mass spectrometry (UPLC-ESI-HRMS/MS). The strategy of dansyl chloride derivatization followed by solid phase extraction on C18 cartridges were employed to reduce matrix interference and improve the extraction efficiency. The reverse phase chromatographic separation was achieved with a gradient elution program in 20 min. The high resolution mass spectrometer (Q Exactive) was employed, with confirmation and quantification by Target-MS/MS scan mode. Youth urine samples collected from 100 healthy volunteers (Female:Male=1:1) were analyzed to explore the differences in metabolite profile and their turnover between genders. The results demonstrated that the UPLC-ESI-HRMS/MS method is sensitive and robust, suitable for monitoring a large panel of metabolites and for discovering new biomarkers in the medical fields. Copyright © 2016 Elsevier B.V. All rights reserved.

[Simultaneous determination of 6 pesticides in drinking water by high performance liquid chromatography-tandem mass spectrometry with solid phase extraction].

PubMed

Liu, Hua-liang; Wang, Lian-hong

2013-05-01

To develop an analytical method for simultaneous determination of 6 pesticides, namely bentazone, 2,4-dichlorophenoxyacetic acid,carbofuran, carbaryl, atrazine and pentachlorophenol, in drinking water by high performance liquid chromatography-tandem mass spectrometry, and thereby to provide a reference to revise the Health Standards for Drinking Water (GB/T 5750-2006). Meanwhile, to evaluate the content of the above 6 pesticides in the drinking water samples supplied by 12 centralized water plants in Jiangsu province. The 10 ml water sample was acidized by hydrochloric acid to pH ≤ 2, and then concentrated by solid phase extraction cartridge and eluted with acetone. The solvent was changed into methanol after drying by nitrogen blow. The target compounds were separated by C18 column using methanol/water as mobile phase, and detected by mass spectrometry with multi-reaction-monitoring(MRM) mode. The repeatability and sensitivity of the assay were evaluated. The drinking water samples from the 12 water plants were then detected. In this experimental method, the minimum detectable concentration were around 0.02-0.41 µg/L, with the recovery rate at 75%-115%, and the RSD between 2% and 10%. Under the experimental condition, there were no pesticides detected in the drinking water samples from the 12 centralized water plants. The method is efficient and environment-friendly, with little discharge of effluent, which could meet the requirement of the drinking water monitor.

Deproteinization of water-soluble ß-glucan during acid extraction from fruiting bodies of Pleurotus ostreatus mushrooms.

PubMed

Szwengiel, Artur; Stachowiak, Barbara

2016-08-01

Some ß-glucans can be easily extracted from Basidiomycete mushrooms but commonly used extraction procedures are not satisfactory. A simultaneous method for acid extraction and deproteinization in the case of Pleurotus ostreatus was developed using response surface methodology. The optimized extraction conditions proposed here (30°C, 3.8% HCl, 300min, stirring) allow for the simultaneous extraction and deproteinization of polysaccharides. Additionally, the acid extraction yield was 7 times greater than that of hot water extraction. The combined enzymatic digestion with lyticase, ß-glucanase, exo-1,3-ß-d-glucanase, and ß-glucosidase results elucidated that an extract containing ß-1,3-ß-1,6-ß-1,4-glucan. The gel permeation chromatography (GPC) results showed that the two glucan fractions obtained do not contain linked proteins. The weight average molecular weight of the first fraction (Mw=1137kDa) was 60 times higher than that of the second fraction (Mw=19kDa). Copyright © 2016 Elsevier Ltd. All rights reserved.

Simultaneous quantification of paeoniflorin, nobiletin, tangeretin, liquiritigenin, isoliquiritigenin, liquiritin and formononetin from Si-Ni-San extract in rat plasma and tissues by liquid chromatography-tandem mass spectrometry.

PubMed

Li, Tianxue; Yan, Zhixiang; Zhou, Chen; Sun, Jian; Jiang, Chuan; Yang, Xinghao

2013-08-01

In this study, a sensitive and reliable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of seven bioactive components including paeoniflorin, nobiletin, tangeretin, liquiritigenin, isoliquiritigenin, liquiritin and formononetin in rat plasma and tissues after oral administration of Si-Ni-San extract using astragaloside IV as internal standard (IS). The plasma and tissue samples were extracted by solid-phase extraction. Chromatographic separation was accomplished on a C18 column with a multiple-step gradient elution. The quantification was obtained by scanning with multiple reaction monitoring via an electrospray ionization source that was operated by switching between the positive and negative modes in two MS/MS scan segments. Full validation of the assay was implemented. In conclusion, this method demonstrated good linearity and specificity. The lower limits of quantification for the analytes were <7.5 ng/mL. Intra- and inter-day precisions (RSD) were <12.5% and accuracy (RE) ranged from -10.2 to 7.3%. The average recoveries of the analytes from rat plasma and tissues were >65.2% and 58.6%, respectively. The validated method was further applied to the determination of actual rat plasma and tissues after oral administration of Si-Ni-San extract. The results provided a meaningful basis for the clinical application of this prescription. Copyright © 2013 John Wiley & Sons, Ltd.

SOLVENT EXTRACTION PROCESS FOR SEPARATING ACTINIDE AND LANTHANIDE METAL VALUES

DOEpatents

Hildebrandt, R.A.; Hyman, H.H.; Vogler, S.

1962-08-14

A process of countercurrently extracting an aqueous mineral acid feed solution for the separation of actinides from lanthanides dissolved therern is described. The feed solution is made acid-defrcient with alkali metal hydroxide prior to.contact with acid extractant; during extraction, however, acid is transferred from organic to aqueous solution and the aqueous solution gradually becomes acid. The acid-deficient phase ' of the process promotes the extraction of the actinides, while the latter acid phase'' of the process improves retention of the lanthanides in the aqueous solution. This provides for an improved separation. (AEC)

Efficient HPTLC-dual wavelength spectrodensitometric method for simultaneous determination of sofosbuvir and daclatasvir: Biological and pharmaceutical analysis.

PubMed

Abo-Zeid, Mohammad Nabil; El-Gizawy, Samia M; Atia, Noha N; El-Shaboury, Salwa R

2018-05-01

Sofosbuvir (SOF) and daclatasvir (DCS) are newly discovered anti-hepatitis C drugs that have direct antiviral activity. A novel and simple high-performance thin-layer chromatography (HPTLC) method was designed for simultaneous determination of SOF and DCS in miscellaneous matrices. The method adopts coupling HPTLC with dual wavelength spectrodensitometry. Consequently, this enabled sensitive, specific and cost-effective determination of the SOF-DCS mixture. The developed HPTLC procedure is based on a simple liquid-liquid extraction, enrichment of the analytes and subsequent chromatographic separation with UV detection. Separations were performed on HPTLC silica gel 60 F 254 aluminum plates with a mobile phase consisting of ethyl acetate-isopropanol (85:15, v/v). Dual wavelength scanning was carried out in the absorbance mode at 265 and 311 nm for SOF and DCS, respectively. The linear ranges were 40-640 and 20-320 ng band -1 for SOF and DCS, respectively with correlation coefficients of ≥0.9997. The detection limits were 11.3 and 6.5 ng band -1 for SOF and DCS, respectively indicating high sensitivity of the proposed method. Consequently, this permits in vitro and in vivo application of the proposed method in human plasma with good percentage recovery (94.1-103.5%). Validation parameters were assessed according to ICH guidelines and US-FDA guidelines. Furthermore, the application was extended to analysis of SOF and DCS in their pharmaceutical formulations. Copyright © 2018 Elsevier B.V. All rights reserved.

Simultaneous Quantification of Limonin, Two Indolequinazoline Alkaloids, and Four Quinolone Alkaloids in Evodia rutaecarpa (Juss.) Benth by HPLC-DAD Method.

PubMed

Zhang, Pei-Ting; Pan, Bi-Yan; Liao, Qiong-Feng; Yao, Mei-Cun; Xu, Xin-Jun; Wan, Jin-Zhi; Liu, Dan; Xie, Zhi-Yong

2013-01-01

A simple and efficient HPLC-DAD (225 nm) method was developed and validated for the simultaneous determination of limonin and six key alkaloids (evodiamine, rutaecarpine, 1-methyl-2-undecyl-4(1H)-quinolone, evocarpine, 1-methy-2-[(6Z,9Z)]-6,9-pentadecadienyl-4-(1H)-quinolone, and dihydroevocarpine) in Evodia rutaecarpa (Juss.) Benth, which has been widely used as one of the Traditional Chinese Medicines. The chromatographic separation was carried out on a Hypersil BDS C18 column, and gradient elution was employed with a mobile phase containing acetonitrile and water. Contents of the analytes in 18 batches of samples were analyzed by ultrasonic extraction with ethanol and water mixture (80 : 20, v/v) followed by HPLC analysis. Separation of the seven analytes was achieved within 60 min with good linearity (r > 0.999). The RSD of both the intraday and interday precision was below 1.85%. The accuracy at different concentrations was within the range of 97.91 to 100.49%. Hierarchical clustering analysis was performed to differentiate and classify the samples based on the contents of the seven constituents. This study indicated that the quality control of E. rutaecarpa could be simplified to the measurement of four constituents, and that limonin, 1-methyl-2-undecyl-4(1H)-quinolone, and dihydroevocarpine should also be served as the chemical markers together with evodiamine for the quality control of Evodia rutaecarpa (Juss.) Benth.

Simultaneous Quantification of Limonin, Two Indolequinazoline Alkaloids, and Four Quinolone Alkaloids in Evodia rutaecarpa (Juss.) Benth by HPLC-DAD Method

PubMed Central

Zhang, Pei-ting; Pan, Bi-yan; Liao, Qiong-feng; Yao, Mei-cun; Xu, Xin-jun; Wan, Jin-zhi; Liu, Dan; Xie, Zhi-yong

2013-01-01

A simple and efficient HPLC-DAD (225 nm) method was developed and validated for the simultaneous determination of limonin and six key alkaloids (evodiamine, rutaecarpine, 1-methyl-2-undecyl-4(1H)-quinolone, evocarpine, 1-methy-2-[(6Z,9Z)]-6,9-pentadecadienyl-4-(1H)-quinolone, and dihydroevocarpine) in Evodia rutaecarpa (Juss.) Benth, which has been widely used as one of the Traditional Chinese Medicines. The chromatographic separation was carried out on a Hypersil BDS C18 column, and gradient elution was employed with a mobile phase containing acetonitrile and water. Contents of the analytes in 18 batches of samples were analyzed by ultrasonic extraction with ethanol and water mixture (80 : 20, v/v) followed by HPLC analysis. Separation of the seven analytes was achieved within 60 min with good linearity (r > 0.999). The RSD of both the intraday and interday precision was below 1.85%. The accuracy at different concentrations was within the range of 97.91 to 100.49%. Hierarchical clustering analysis was performed to differentiate and classify the samples based on the contents of the seven constituents. This study indicated that the quality control of E. rutaecarpa could be simplified to the measurement of four constituents, and that limonin, 1-methyl-2-undecyl-4(1H)-quinolone, and dihydroevocarpine should also be served as the chemical markers together with evodiamine for the quality control of Evodia rutaecarpa (Juss.) Benth. PMID:23738236

Simple and fast analysis of tetrabromobisphenol A, hexabromocyclododecane isomers, and polybrominated diphenyl ethers in serum using solid-phase extraction or QuEChERS extraction followed by tandem mass spectrometry coupled to HPLC and GC.

PubMed

Li, Jian; Chen, Tian; Wang, Yuwei; Shi, Zhixiong; Zhou, Xianqing; Sun, Zhiwei; Wang, Dejun; Wu, Yongning

2017-02-01

Two simplified sample preparation procedures for simultaneous extraction and clean-up of tetrabromobisphenol A, α-, β-, and γ-hexabromocyclododecane and polybrominated diphenyl ethers in human serum were developed and validated. The first procedure was based on solid-phase extraction. Sample extraction, purification, and lipid removal were carried out directly on an Oasis HLB cartridge. The second procedure was a quick, easy, cheap, effective, rugged, and safe-based approach using octadecyl-modified silica particles as a sorbent. After sample extraction and cleanup, tetrabromobisphenol A/hexabromocyclododecane was separated from polybrominated diphenyl ethers by using a Si-based cartridge. Tetrabromobisphenol A and hexabromocyclododecane were then detected by high-performance liquid chromatography coupled to tandem mass spectrometry, while polybrominated diphenyl ethers were detected by gas chromatography coupled to tandem mass spectrometry. The results of the spike recovery test using fetal bovine serum showed that the average recoveries of the analytes ranged from 87.3 to 115.3% with relative standard deviations equal to or lower than 13.4 %. Limits of detection of the analytes were in the range of 0.4-19 pg/mL except for decabromodiphenyl ether. The developed method was successfully applied to routine analysis of human serum samples from occupational workers and the general population. Extremely high serum polybrominated diphenyl ethers levels up to 3.32 × 10 4 ng/g lipid weight were found in occupational workers. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Oxysterols in cosmetics-Determination by planar solid phase extraction and gas chromatography-mass spectrometry.

PubMed

Schrack, S; Hohl, C; Schwack, W

2016-11-18

Sterol oxidation products (SOPs) are linked to several toxicological effects. Therefore, investigation of potential dietary uptake sources particularly food of animal origin has been a key issue for these compounds. For the simultaneous determination of oxysterols from cholesterol, phytosterols, dihydrolanosterol and lanosterol in complex cosmetic matrices, planar solid phase extraction (pSPE) was applied as clean-up tool. SOPs were first separated from more non-polar and polar matrix constituents by normal phase thin-layer chromatography and then focussed into one target zone. Zone extraction was performed with the TLC-MS interface, followed by gas chromatography-mass spectrometry analysis. pSPE showed to be effective for cleaning up cosmetic samples as sample extracts were free of interferences, and gas chromatographic columns did not show any signs of overloading. Recoveries were between 86 and 113% with relative standard deviations of below 10% (n=6). Results of our market survey in 2016 showed that some cosmetics with ingredients of plant origin contained phytosterol oxidation products (POPs) in the low ppm range and therefore in line with levels reported for food. In lanolin containing products, total SOPs levels (cholesterol oxidation products (COPs), lanosterol oxidation products (LOPs), dihydrolanosterol oxidation products (DOPs)) being in the low percent range exceeded reported levels for food by several orders of magnitudes. Copyright © 2016 Elsevier B.V. All rights reserved.

[Simultaneous determination of trichloroethylene and trichloroethanol in blood by liquid-liquid extraction-gas chromatography].

PubMed

Ye, H P; Shao, J; Tan, S W; Shan, X Y; Shi, Y P

2017-10-20

Objective: To establish a method for determing the trichloroethylene(TCE)and trichloroethanol(TCOH)in blood samples by liquid-liquid extraction-gas chromatography with electron capture detector. Methods: With this method,ether was used as extraction solvent and trichloromethane was used as an internal standard. The whole blood sample was extracted with ether, and dehydrated by anhydrous sodium sulfate. Then the analytes were separated on HP-5 capillary column(30m×0.32mm×0.15μm)and detected byECD.The retention time was for qualitative analysis and the internal standard was for quantitation. Results: The standard curves of TCE and TCOH showed significant linearity between 95.5μg/L-7640.0μg/L( r =0.9997)and 19.0μg/L-1520.0μg/L( r =0.9992). The average recovery was 95.5%-103.6%.The intra-day and inter-day precisions( RSD )were 2.5%-6.8%( n =6)and 1.6%-4.3%( n =6) respectively. The detect limit of TCE and TCOH were 2.10 μg/L and 0.56μg/L(S/N=3)respectively.The blood can be kept 7 days at-20℃ refrigerator without significantly loss. Conclusion: This method is proved to be simple,practical and highly sensitive. It can satisfy the request for the determination of blood samples of humans exposed to TCE.

Establishment of a New Drug Code for Marihuana Extract. Final rule.

PubMed

2016-12-14

The Drug Enforcement Administration is creating a new Administration Controlled Substances Code Number for "Marihuana Extract." This code number will allow DEA and DEA-registered entities to track quantities of this material separately from quantities of marihuana. This, in turn, will aid in complying with relevant treaty provisions. Under international drug control treaties administered by the United Nations, some differences exist between the regulatory controls pertaining to marihuana extract versus those for marihuana and tetrahydrocannabinols. The DEA has previously established separate code numbers for marihuana and for tetrahydrocannabinols, but not for marihuana extract. To better track these materials and comply with treaty provisions, DEA is creating a separate code number for marihuana extract with the following definition: "Meaning an extract containing one or more cannabinoids that has been derived from any plant of the genus Cannabis, other than the separated resin (whether crude or purified) obtained from the plant." Extracts of marihuana will continue to be treated as Schedule I controlled substances.

Extraction and separation of Co(II) and Ni(II) from acidic sulfate solutions using Aliquat 336.

PubMed

Nayl, A A

2010-01-15

Extraction and separation of Co(II) and Ni(II) from acidic sulfate solutions by solvent extraction technique were studied using different forms of Aliquat 336 diluted with kerosene. The extraction percent of each metal ion was found to increase with increasing pH and extractant concentration. Co(II) was preferentially extracted by different forms of Aliquat 336 over Ni(II) under the same extraction conditions. From analysis of the experimental results, the extraction mechanism of R(4)N-forms was proposed with Co(II). It was found that the highest separation factor (S(Co/Ni)) value of 606.7 was obtained with 0.36 M R(4)N-SCN in kerosene from 2.0M H(2)SO(4) solution at pH 4.8 and shaking time of 20 min. Stripping of the two metal ions from the organic phase was also investigated. Based on the experimental results, a separation method was developed and tested to separate high purity Co(II), Ni(II) and Ln(III) from Ni-MH batteries leached by 2.0M H(2)SO(4). Based on the experimental results, a flow sheet was developed and tested and 0.34 g Co, 1.39 g Ln and 5.2g Ni were obtained from the leaching process.

Development and validation of a sensitive UHPLC-MS/MS method for the simultaneous analysis of tramadol, dextromethorphan chlorpheniramine and their major metabolites in human plasma in forensic context: application to pharmacokinetics.

PubMed

Heneedak, Hala M; Salama, Ismail; Mostafa, Samia; El-Kady, Ehab; El-Sadek, Mohamed

2015-07-01

The prerequisites for forensic confirmatory analysis by LC/MS/MS with respect to European Union guidelines are chromatographic separation, a minimum number of two MS/MS transitions to obtain the required identification points and predefined thresholds for the variability of the relative intensities of the MS/MS transitions (MRM transitions) in samples and reference standards. In the present study, a fast, sensitive and robust method to quantify tramadol, chlorpheniramine, dextromethorphan and their major metabolites, O-desmethyltramadol, dsmethyl-chlorpheniramine and dextrophan, respectively, in human plasma using ibuprofen as internal standard (IS) is described. The analytes and the IS were extracted from plasma by a liquid-liquid extraction method using ethyl acetate-diethyl-ether (1:1). Extracted samples were analyzed by ultra-high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS). Chromatographic separation was performed by pumping the mobile phase containing acetonitrile, water and formic acid (89.2:11.7:0.1) for 2.0 min at a flow rate of 0.25 μL/min into a Hypersil-Gold C18 column, 20 × 2.0 mm (1.9 µm) from Thermoscientific, New York, USA. The calibration curve was linear for the six analytes. The intraday precision (RSD) and accuracy (RE) of the method were 3-9.8 and -1.7-4.5%, respectively. The analytical procedure herein described was used to assess the pharmacokinetics of the analytes in 24 healthy volunteers after a single oral dose containing 50 mg of tramadol hydrochloride, 3 mg chlorpheniramine maleate and 15 mg of dextromethorphan hydrobromide. Copyright © 2014 John Wiley & Sons, Ltd.

Simultaneous Quantification of Syringic Acid and Kaempferol in Extracts of Bergenia Species Using Validated High-Performance Thin-Layer Chromatographic-Densitometric Method.

PubMed

Srivastava, Nishi; Srivastava, Amit; Srivastava, Sharad; Rawat, Ajay Kumar Singh; Khan, Abdul Rahman

2016-03-01

A rapid, sensitive, selective and robust quantitative densitometric high-performance thin-layer chromatographic method was developed and validated for separation and quantification of syringic acid (SYA) and kaempferol (KML) in the hydrolyzed extracts of Bergenia ciliata and Bergenia stracheyi. The separation was performed on silica gel 60F254 high-performance thin-layer chromatography plates using toluene : ethyl acetate : formic acid (5 : 4: 1, v/v/v) as the mobile phase. The quantification of SYA and KML was carried out using a densitometric reflection/absorption mode at 290 nm. A dense spot of SYA and KML appeared on the developed plate at a retention factor value of 0.61 ± 0.02 and 0.70 ± 0.01. A precise and accurate quantification was performed using linear regression analysis by plotting the peak area vs concentration 100-600 ng/band (correlation coefficient: r = 0.997, regression coefficient: R(2) = 0.996) for SYA and 100-600 ng/band (correlation coefficient: r = 0.995, regression coefficient: R(2) = 0.991) for KML. The developed method was validated in terms of accuracy, recovery and inter- and intraday study as per International Conference on Harmonisation guidelines. The limit of detection and limit of quantification of SYA and KML were determined, respectively, as 91.63, 142.26 and 277.67, 431.09 ng. The statistical data analysis showed that the method is reproducible and selective for the estimation of SYA and KML in extracts of B. ciliata and B. stracheyi. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Liquid chromatography/tandem mass spectrometry method for simultaneous determination of cocaine and its metabolite (-)ecgonine methyl ester in human acidified stabilized plasma samples.

PubMed

Liu, Yongzhen; Zheng, Bo; Strafford, Stephanie; Orugunty, Ravi; Sullivan, Michael; Gus, Jeffrey; Heidbreder, Christian; Fudala, Paul J; Nasser, Azmi

2014-06-15

Two simple, sensitive and rapid liquid chromatography/electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) methods (low range and high range) were developed and validated for the quantification of cocaine and its metabolite (-)ecgonine methyl ester (EME) in human acidified stabilized plasma samples. In the low range assay, cocaine and the internal standard, cocaine-D3, were extracted using a single step liquid-liquid extraction from human acidified stabilized plasma. For the high range assay, human acidified stabilized plasma containing cocaine, EME, and the internal standards, cocaine-D3 and EME-D3, was mixed with acetonitrile, and the protein precipitate was separated by centrifugation. Both cocaine and EME extracted from both assays were separated on a HILIC column and detected in positive ion mode using multiple reaction monitoring (MRM). Both methods were validated and the specificity, linearity, lower limit of quantitation (LLOQ), precision, accuracy, recoveries and stability were determined. The linear range for the low range assay was 0.01-5ng/mL for cocaine; in the high range assay values were 5-1000ng/mL for cocaine and 1-200ng/mL for EME. The correlation coefficient (R(2)) values for both assays were 0.993 or greater. The precision and accuracy for intra-day and inter-day were better than 13.0%. The recovery was above 85% and matrix effects were low with the matrix factor ranging from 0.817 to 1.10 for both analytes in both assays. The validated methods were successfully used to quantify the plasma concentrations of cocaine and EME in clinical pharmacokinetic and pharmacodynamic studies. Copyright © 2014 Elsevier B.V. All rights reserved.

Catalytic reactive separation system for energy-efficient production of cumene

DOEpatents

Buelna, Genoveva [Nuevo Laredo, MX; Nenoff, Tina M [Albuquerque, NM

2009-07-28

The present invention relates to an atmospheric pressure, reactive separation column packed with a solid acid zeolite catalyst for producing cumene from the reaction of benzene with propylene. Use of this un-pressurized column, where simultaneous reaction and partial separation occur during cumene production, allow separation of un-reacted, excess benzene from other products as they form. This high-yielding, energy-efficient system allows for one-step processing of cumene, with reduced need for product purification. Reacting propylene and benzene in the presence of beta zeolite catalysts generated a selectivity greater than 85% for catalytic separation reactions at a reaction temperature of 115 degrees C and at ambient pressure. Simultaneously, up to 76% of un-reacted benzene was separated from the product; which could be recycled back to the reactor for re-use.

Facile Separation of 5-O-Galloylquinic Acid from Chinese Green Tea Extract using Mesoporous Zirconium Phosphate.

PubMed

Ma, Yilong; Shang, Yafang; Zhu, Danye; Wang, Caihong; Zhong, Zhifeng; Xu, Ziyang

2016-05-01

5-O-Galloylquinic acid from green tea and other plants is attracting increasing attention for its antioxidant and antileishmanial bioactivities. It is always isolated using a silica column, a Sephadex column and high-performance liquid chromatography (HPLC) methods, which are either laborious or instrument dependent. To develop a new method to easily separate 5-O-galloylquinic acid. Mesoporous zirconium phosphate (m-ZrP) was prepared to conveniently separate 5-O-galloylquinic acid from Chinese green tea extract, and the target compound was easily obtained by simple steps of adsorption, washing and desorption. The effects of the green tea extraction conditions, extract concentrations, and m-ZrP adsorption/desorption dynamics on the 5-O-galloylquinic acid separation were evaluated. 5-O-Galloylquinic acid that was separated from a 70% ethanol extract of green tea was of moderate HPLC purity (92%) and recovery (88%), and an increased non-specific binding of epigallocatechin gallate (EGCG) on m-ZrP was observed in the diluted tea extract. The times for maximal adsorption of 5-O-galloylquinic acid in 70% ethanol extract and maximal desorption of 5-O-galloylquinic acid in 0.4% phosphoric acid solution were confirmed as 7 h and 5 h, respectively. A facile method to separate 5-O-galloylquinic acid from Chinese green tea extract using m-ZrP was established. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

[Research of the essential oil of Plumeria rubra var. actifolia from Laos by supercritical carbon dioxide extraction].

PubMed

Xiao, Xin-Yu; Cui, Long-Hai; Zhou, Xin-Xin; Wu, Yan; Ge, Fa-Huan

2011-05-01

The orthogonal test and the supercritical carbon dioxide fluid extraction were used for optimizing the extraction of the essential oil from Plumeria rubra var. actifolia for the first time. Compared with the steam distillation, the optimal operation parameter of extraction was as follows: extraction pressure 25 MPa, extraction temperature 45 degrees C; separator I pressure 12 MPa, separator I temperature 55 degrees C; separator II pressure 6 MPa, separator II temperature 30 degrees C. Under this condition the yield of the essential oil was 5.8927%. The components were separated and identified by GC-MS. 53 components of Plumeria rubra var. actifolia measured by SFE method were identified and determined by normalization method. The main components were 1, 6, 10-dodecatrien-3-ol, 3, 7, 11-trimethyl, benzoic acid, 2-hydroxy-, phenylmethyl ester, 1, 2-benzenedicarboxylic acid, bis(2-methylpropyl) ester,etc.. 1, 2-Benzenedicarboxylic acid, bis (2-methylpropyl) este. took up 66.11% of the total amount, and there was much difference of the results from SD method.

A Comparative Study on Fetal Heart Rates Estimated from Fetal Phonography and Cardiotocography

PubMed Central

Ibrahim, Emad A.; Al Awar, Shamsa; Balayah, Zuhur H.; Hadjileontiadis, Leontios J.; Khandoker, Ahsan H.

2017-01-01

The aim of this study is to investigate that fetal heart rates (fHR) extracted from fetal phonocardiography (fPCG) could convey similar information of fHR from cardiotocography (CTG). Four-channel fPCG sensors made of low cost (<$1) ceramic piezo vibration sensor within 3D-printed casings were used to collect abdominal phonogram signals from 20 pregnant mothers (>34 weeks of gestation). A novel multi-lag covariance matrix-based eigenvalue decomposition technique was used to separate maternal breathing, fetal heart sounds (fHS) and maternal heart sounds (mHS) from abdominal phonogram signals. Prior to the fHR estimation, the fPCG signals were denoised using a multi-resolution wavelet-based filter. The proposed source separation technique was first tested in separating sources from synthetically mixed signals and then on raw abdominal phonogram signals. fHR signals extracted from fPCG signals were validated using simultaneous recorded CTG-based fHR recordings.The experimental results have shown that the fHR derived from the acquired fPCG can be used to detect periods of acceleration and deceleration, which are critical indication of the fetus' well-being. Moreover, a comparative analysis demonstrated that fHRs from CTG and fPCG signals were in good agreement (Bland Altman plot has mean = −0.21 BPM and ±2 SD = ±3) with statistical significance (p < 0.001 and Spearman correlation coefficient ρ = 0.95). The study findings show that fHR estimated from fPCG could be a reliable substitute for fHR from the CTG, opening up the possibility of a low cost monitoring tool for fetal well-being. PMID:29089896

Measurement of dielectric constant of organic solvents by indigenously developed dielectric probe

NASA Astrophysics Data System (ADS)

Keshari, Ajay Kumar; Rao, J. Prabhakar; Rao, C. V. S. Brahmmananda; Ramakrishnan, R.; Ramanarayanan, R. R.

2018-04-01

The extraction, separation and purification of actinides (uranium and plutonium) from various matrices are an important step in nuclear fuel cycle. One of the separation process adopted in an industrial scale is the liquid-liquid extraction or solvent extraction. Liquid-liquid extraction uses a specific ligand/extractant in conjunction with suitable diluent. Solvent extraction or liquid-liquid extraction, involves the partitioning of the solute between two immiscible phases. In most cases, one of the phases is aqueous, and the other one is an organic solvent. The solvent used in solvent extraction should be selective for the metal of interest, it should have optimum distribution ratio, and the loaded metal from the organic phase should be easily stripped under suitable experimental conditions. Some of the important physical properties which are important for the solvent are density, viscosity, phase separation time, interfacial surface tension and the polarity of the extractant.

Easy, fast and environmental friendly method for the simultaneous extraction of the 16 EPA PAHs using magnetic molecular imprinted polymers (mag-MIPs).

PubMed

Villar-Navarro, Mercedes; Martín-Valero, María Jesús; Fernández-Torres, Rut Maria; Callejón-Mochón, Manuel; Bello-López, Miguel Ángel

2017-02-15

An easy and environmental friendly method, based on the use of magnetic molecular imprinted polymers (mag-MIPs) is proposed for the simultaneous extraction of the 16 U.S. EPA polycyclic aromatic hydrocarbons (PAHs) priority pollutants. The mag-MIPs based extraction protocol is simple, more sensitive and low organic solvent consuming compared to official methods and also adequate for those PAHs more retained in the particulate matter. The new proposed extraction method followed by HPLC determination has been validated and applied to different types of water samples: tap water, river water, lake water and mineral water. Copyright © 2017 Elsevier B.V. All rights reserved.

Technical note: Simultaneous carotenoid and vitamin analysis of milk from total mixed ration-fed cows optimized for xanthophyll detection.

PubMed

Stout, M A; Benoist, D M; Drake, M A

2018-06-01

Concentrations of retinol, α-tocopherol, and major carotenoids in dairy products are often determined simultaneously by liquid chromatography. These compounds have different polarity and solubility; thus, extracting them simultaneously can be difficult and inefficient. In milks with low carotenoid concentrations, the xanthophylls lutein and zeaxanthin may not be completely resolved using common extraction techniques. A simplified method was developed to optimize extraction efficiency and the limit of detection and limit of quantification (LoQ) of lutein and zeaxanthin in bovine milk without decreasing sensitivity to other vitamins or carotenoids. The developed method evaluates lutein, zeaxanthin, β-carotene, retinol, and α-tocopherol simultaneously by ultra-high performance liquid chromatography-photodiode array detection. Common saponification temperatures (40-60°C) and concentrations of KOH in water (10-50% KOH wt/vol) were evaluated. Multiple solvents were evaluated for optimal xanthophyll extraction (diethyl ether, dichloromethane, hexane, and tetrahydrofuran) following saponification. The limit of detection and LoQ were defined as 3:1 and 10:1 signal-to-noise ratio, respectively. All experiments were performed in triplicate. The optimal saponification procedure was a concentration of 25% KOH at either 40 or 50°C. Saponified extracts solubilized in solutions containing diethyl ether had greater concentrations of lutein- than hexane- or tetrahydrofuran-based solutions, with peak areas above LoQ values. The solution containing diethyl ether solubilized similar concentrations of retinol, α-tocopherol, and β-carotene when compared with other solutions. The proposed optimized method allows for the simultaneous determination of carotenoids from milk with increased lutein and zeaxanthin sensitivity without sacrificing recovery of retinol, α-tocopherol, and β-carotene. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

A flowsheet concept for an Am/Ln separation based on Am{sup VI} solvent extraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mincher, B.J.; Law, J.D.

2013-07-01

The separation of Am from the lanthanides and curium is a key step in proposed advanced fuel cycle scenarios. The partitioning and transmutation of Am is desirable to minimize the long-term radiotoxicity of material interred in a future high-level waste repository. However, a separation amenable to process scale-up remains elusive. Higher oxidation states of americium have recently been used to demonstrate solvent extraction-based separations using conventional fuel cycle ligands. Here, the successful partitioning of Am{sup VI} from the bulk of lanthanides and curium using diamyl-amyl-phosphonate (DAAP) extraction is reported. Due to the instability of Am{sup VI} in the organic phasemore » it was readily selectively stripped to a new acidic aqueous phase to provide separation from co-extracted Ce{sup IV}. The use of NaBiO{sub 3} as an oxidant to separate Am from the lanthanides and Cm by solvent extraction has been successfully demonstrated on the bench scale. Based on these results, flowsheet concepts can be designed that result in 96 % Am recovery in the presence of a few percent of the remaining Cm and the lanthanides in two extraction contacts. Preliminary results also indicate that the DAAP extractant is robust toward γ- irradiation under realistic conditions of acidity and dissolved oxygen concentration.« less

Determination of cytokinins in coconut (Cocos nucifera L.) water using capillary zone electrophoresis-tandem mass spectrometry.

PubMed

Ge, Liya; Yong, Jean Wan Hong; Tan, Swee Ngin; Ong, Eng Shi

2006-06-01

The applicability of CZE in combination with MS and MS/MS methods for the simultaneous separation and determination of 12 cytokinins was investigated for the first time. Cytokinins were first completely separated by CZE within less than 20 min using a volatile buffer and then detected directly by MS or MS/MS. Satisfactory separation of the 12 cytokinin standards was achieved using a 25 mM ammonium formate/formic acid buffer (pH 3.4) and 3% ACN v/v with a separation voltage of 25 kV. On the basis of the resolution of the neighboring peaks, the various parameters for CZE-MS optimization, such as buffer pH value, concentration of buffer and organic modifier, applied voltage and sheath liquid, were evaluated systematically. MS/MS with multiple reaction monitoring detection was carried out to obtain sufficient selectivity and sensitivity. The combination of on-line sample stacking and CZE-MS/MS achieved a detection limit in the range of 0.05-0.18 microM for the 12 cytokinins at an S/N of 3. The optimized CZE-MS/MS method was simple, rapid, low cost, robust and highly selective. Furthermore, the developed method was successfully applied to screen for endogenous cytokinins in purified coconut water extract sample. Nine cytokinins were detected and quantified in coconut water after SPE.

Antibacterial and antioxidant activities and chemical compositions of volatile oils extracted from Schisandra chinensis Baill. seeds using simultaneous distillation extraction method, and comparison with Soxhlet and microwave-assisted extraction.

PubMed

Teng, Hui; Lee, Won Y

2014-01-01

The volatile oils were isolated from dried Schisandra chinensis Baill. seeds by Soxhlet extraction (SE), microwave-assisted extraction (MAE), and simultaneous distillation extraction (SDE), and fractions were identified by gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). The essential oils were assessed for their antioxidant and antibacterial activities. GC-MS results also revealed that the major ingredients in the oil extracted by SDE were terpenoids compounds such as ylangene (15.01%), α-phellandrene (8.23%), β-himachalene (6.95%), and cuparene (6.74), and the oil extracts of MAE and SE mainly contained aromatics such as schizandrins, wuweizisu C, and gomisin A. HPLC analysis results confirmed that more schizandrin was obtained through extraction by MAE (996.64 μg/g) and SE (722.13 μg/g). SDE oil extract showed more significant antioxidant activity than MAE or SE oil. Only volatile oil from SDE showed good antibacterial activity against all tested strains.

Supercritical fluid extraction and separation of uranium from other actinides.

PubMed

Quach, Donna L; Mincher, Bruce J; Wai, Chien M

2014-06-15

The feasibility of separating U from nitric acid solutions of mixed actinides using tri-n-butylphosphate (TBP)-modified supercritical fluid carbon dioxide (sc-CO2) was investigated. The actinides U, Np, Pu, and Am were extracted into sc-CO2 modified with TBP from a range of nitric acid concentrations, in the absence of, or in the presence of, a number of traditional reducing and/or complexing agents to demonstrate the separation of these metals from U under sc-CO2 conditions. The separation of U from Pu using sc-CO2 was successful at nitric acid concentrations of less than 3M in the presence of acetohydroxamic acid (AHA) or oxalic acid (OA) to mitigate Pu extraction, and the separation of U from Np was successful at nitric acid concentrations of less than 1M in the presence of AHA, OA, or sodium nitrite to mitigate Np extraction. Americium was not well extracted under any condition studied. Copyright © 2014 Elsevier B.V. All rights reserved.

Biochar- and phosphate-induced immobilization of heavy metals in contaminated soil and water: implication on simultaneous remediation of contaminated soil and groundwater.

PubMed

Liang, Yuan; Cao, Xinde; Zhao, Ling; Arellano, Eduardo

2014-03-01

Long-term wastewater irrigation or solid waste disposal has resulted in the heavy metal contamination in both soil and groundwater. It is often separately implemented for remediation of contaminated soil or groundwater at a specific site. The main objective of this study was to demonstrate the hypothesis of simultaneous remediation of both heavy metal contaminated soil and groundwater by integrating the chemical immobilization and pump-and-treat methods. To accomplish the objective, three experiments were conducted, i.e., an incubation experiment was first conducted to determine how dairy-manure-derived biochar and phosphate rock tailing induced immobilization of Cd in the Cd-contaminated soils; second, a batch sorption experiment was carried out to determine whether the pre-amended contaminated soil still had the ability to retain Pb, Zn and Cd from aqueous solution. BCR sequential extraction as well as XRD and SEM analysis were conducted to explore the possible retention mechanism; and last, a laboratory-scale model test was undertaken by leaching the Pb, Zn, and Cd contaminated groundwater through the pre-amended contaminated soils to demonstrate how the heavy metals in both contaminated soil and groundwater were simultaneously retained and immobilized. The incubation experiment showed that the phosphate biochar were effective in immobilizing soil Cd with Cd concentration in TCLP (toxicity characteristics leaching procedure) extract reduced by 19.6 % and 13.7 %, respectively. The batch sorption experiment revealed that the pre-amended soil still had ability to retain Pb, Zn, and Cd from aqueous solution. The phosphate-induced metal retention was mainly due to the metal-phosphate precipitation, while both sorption and precipitation were responsible for the metal stabilization in the biochar amendment. The laboratory-scale test demonstrated that the soil amended with phosphate removed groundwater Pb, Zn, and Cd by 96.4 %, 44.6 %, and 49.2 %, respectively, and the soil amended with biochar removed groundwater Pb, Zn, and Cd by 97.4 %, 53.4 %, and 54.5 %, respectively. Meanwhile, the metals from both groundwater and soil itself were immobilized with the amendments, with the leachability of the three metals in the CaCl2 and TCLP extracts being reduced by up to 98.1 % and 62.7 %, respectively. Our results indicate that the integrated chemical immobilization and pump-and-treat method developed in this study provides a novel way for simultaneous remediation of both metal-contaminated soil and groundwater.

Chemical analysis and quality control of Ginkgo biloba leaves, extracts, and phytopharmaceuticals.

PubMed

van Beek, Teris A; Montoro, Paola

2009-03-13

The chemical analysis and quality control of Ginkgo leaves, extracts, phytopharmaceuticals and some herbal supplements is comprehensively reviewed. The review is an update of a similar, earlier review in this journal [T.A. van Beek, J. Chromatogr. A 967 (2002) 21-55]. Since 2001 over 3000 papers on Ginkgo biloba have appeared, and about 400 of them pertain to chemical analysis in a broad sense and are cited herein. The more important ones are discussed and, where relevant, compared with the best methods published prior to 2002. In the same period over 2500 patents were filed on Ginkgo and the very few related to analysis are mentioned as well. Important constituents include terpene trilactones, i.e. ginkgolide A, B, C, J and bilobalide, flavonol glycosides, biflavones, proanthocyanidins, alkylphenols, simple phenolic acids, 6-hydroxykynurenic acid, 4-O-methylpyridoxine and polyprenols. In the most common so-called "standardised" Ginkgo extracts and phytopharmaceuticals several of these classes are no longer present. About 130 new papers deal with the analysis of the terpene trilactones. They are mostly extracted with methanol or water or mixtures thereof. Supercritical fluid extraction and pressurised water extraction are also possible. Sample clean-up is mostly by liquid-liquid extraction with ethyl acetate although no sample clean-up at all in combination with LC/MS/MS is gaining in importance. Separation and detection can be routinely carried out by RP-HPLC with ELSD, RI or MS, or by GC/FID or GC/MS after silylation. Hydrolysis followed by LC/MS allows the simultaneous analysis of terpene trilactones and flavonol aglycones. No quantitative procedure for all major flavonol glycosides has yet been published because they are not commercially available. The quantitation of a few available glycosides has been carried out but does not serve a real purpose. After acidic hydrolysis to the aglycones quercetin, kaempferol and isorhamnetin and separation by HPLC, quantitation is straightforward and yields by recalculation an estimation of the original total flavonol glycoside content. A profile of the genuine flavonol glycosides can detect poor storage or adulteration. Although the toxicity of Ginkgo alkylphenols upon oral administration has never been undoubtedly proven, most suppliers limit their content in extracts to 5 ppm and dozens of papers on their analysis were published. One procedure in which a methanolic extract is directly injected on a C8 HPLC column appears superior in terms of sensitivity (<5 ppm), separation, simplicity and validation and will be incorporated in the European Pharmacopoeia. Alternatively GC/MS and ELISA methods can be used. A sharp contrast to the plethora of papers on terpene trilactones, flavonol glycosides, and ginkgolic acids forms the low number of papers on biflavones, proanthocyanidins, simple phenolics, simple acids, and other constituents that make up the remaining 70% of Ginkgo standardised extracts. More research in this direction is clearly needed. For the analysis of Ginkgo proanthocyanidins (7%) for instance, no reliable assays are yet existing. Finally the growing literature on pharmacokinetic and fingerprinting studies of Ginkgo is briefly summarised.

Quality testing of an innovative cascade separation system for multiple cell separation

NASA Astrophysics Data System (ADS)

Pierzchalski, Arkadiusz; Moszczynska, Aleksandra; Albrecht, Bernd; Heinrich, Jan-Michael; Tarnok, Attila

2012-03-01

Isolation of different cell types from mixed samples in one separation step by FACS is feasible but expensive and slow. It is cheaper and faster but still challenging by magnetic separation. An innovative bead-based cascade-system (pluriSelect GmbH, Leipzig, Germany) relies on simultaneous physical separation of different cell types. It is based on antibody-mediated binding of cells to beads of different size and isolation with sieves of different mesh-size. We validated pluriSelect system for single parameter (CD3) and simultaneous separation of CD3 and CD15 cells from EDTA blood-samples. Results were compared with those obtained by MACS (Miltenyi-Biotech) magnetic separation (CD3 separation). pluriSelect separation was done in whole blood, MACS on Ficoll gradient isolated leukocytes, according to the manufacturer's protocols. Isolated and residual cells were immunophenotyped (7-color 8-antibody panel (CD3; CD16/56; CD4; CD8; CD14; CD19; CD45; HLADR) on a CyFlowML flow cytometer (Partec GmbH). Cell count (Coulter), purity, yield and viability (7-AAD exclusion) were determined. There were no significant differences between both systems regarding purity (92-98%), yield (50-60%) and viability (92-98%) of isolated cells. PluriSelect separation was slightly faster than MACS (1.15 h versus 1.5h). Moreover, no preenrichment steps were necessary. In conclusion, pluriSelect is a fast, simple and gentle system for efficient simultaneous separation of two cell subpopulation directly from whole blood and can provide a simple alternative to FACS. The isolated cells can be used for further research applications.

Simultaneous extraction and quantitation of several bioactive amines in cheese and chocolate.

PubMed

Baker, G B; Wong, J T; Coutts, R T; Pasutto, F M

1987-04-17

A method is described for simultaneous extraction and quantitation of the amines 2-phenylethylamine, tele-methylhistamine, histamine, tryptamine, m- and p-tyramine, 3-methoxytyramine, 5-hydroxytryptamine, cadaverine, putrescine, spermidine and spermine. This method is based on extractive derivatization of the amines with a perfluoroacylating agent, pentafluorobenzoyl chloride, under basic aqueous conditions. Analysis was done on a gas chromatograph equipped with an electron-capture detector and a capillary column system. The procedure is relatively rapid and provides derivatives with good chromatographic properties. Its application to analysis of the above amines in cheese and chocolate products is described.

Multiple feature extraction by using simultaneous wavelet transforms

NASA Astrophysics Data System (ADS)

Mazzaferri, Javier; Ledesma, Silvia; Iemmi, Claudio

2003-07-01

We propose here a method to optically perform multiple feature extraction by using wavelet transforms. The method is based on obtaining the optical correlation by means of a Vander Lugt architecture, where the scene and the filter are displayed on spatial light modulators (SLMs). Multiple phase filters containing the information about the features that we are interested in extracting are designed and then displayed on an SLM working in phase mostly mode. We have designed filters to simultaneously detect edges and corners or different characteristic frequencies contained in the input scene. Simulated and experimental results are shown.

NEPTUNIUM SOLVENT EXTRACTION PROCESS

DOEpatents

Dawson, L.R.; Fields, P.R.

1959-10-01

The separation of neptunium from an aqueous solution by solvent extraction and the extraction of neptunium from the solvent solution are described. Neptunium is separated from an aqueous solution containing tetravalent or hexavalent neptunium nitrate, nitric acid, and a nitrate salting out agent, such as sodium nitrate, by contacting the solution with an organic solvent such as diethyl ether. Subsequently, the neptunium nitrate is extracted from the organic solvent extract phase with water.

Supercritical separation process for complex organic mixtures

DOEpatents

Chum, Helena L.; Filardo, Giuseppe

1990-01-01

A process is disclosed for separating low molecular weight components from complex aqueous organic mixtures. The process includes preparing a separation solution of supercritical carbon dioxide with an effective amount of an entrainer to modify the solvation power of the supercritical carbon dioxide and extract preselected low molecular weight components. The separation solution is maintained at a temperature of at least about 70.degree. C. and a pressure of at least about 1,500 psi. The separation solution is then contacted with the organic mixtures while maintaining the temperature and pressure as above until the mixtures and solution reach equilibrium to extract the preselected low molecular weight components from the organic mixtures. Finally, the entrainer/extracted components portion of the equilibrium mixture is isolated from the separation solution.

[Simultaneous determination of cocaine and its metabolite ecgonine methyl ester in human blood using microwave extraction-gas chromatography].

PubMed

Wang, Xiaobo; Ye, Nengsheng; Wang, Jifen; Gu, Xuexin

2010-07-01

A method was developed for the simultaneous determination of cocaine (COC) and its metabolite ecgonine methyl ester (EME) in human blood using gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detection (GC-FID). The blood sample was prepared by microwave extraction (MWE). The optimal parameters of MWE were as follows: 6 mL of chloroform-isopropanol (9: 1, v/v) mixture as extraction solvent, the pH value of the sample was adjusted at 10.0 with 0.05 mol/L Na2CO3-NaHCO3 buffer, the extraction was performed at 40 degrees C for 6 min. The COC and EME in the extract were qualified using GC-MS and quantitated using GC-FID. The average recoveries of COC and EME were from 79.91% to 99.85%, the relative standard deviations were less than 3.10%, and the limits of detection (LOD) were 60 and 40 mg/L, respectively. In the method COC and EME were detected without derivatization. The method is rapid, accurate and sensitive, and can be used for the simultaneous determination of COC and EME in blood samples.

Can we trust mass spectrometry for determination of arsenic peptides in plants: comparison of LC-ICP-MS and LC-ES-MS/ICP-MS with XANES/EXAFS in analysis of Thunbergia alata.

PubMed

Bluemlein, Katharina; Raab, Andrea; Meharg, Andrew A; Charnock, John M; Feldmann, Jörg

2008-04-01

The weakest step in the analytical procedure for speciation analysis is extraction from a biological material into an aqueous solution which undergoes HPLC separation and then simultaneous online detection by elemental and molecular mass spectrometry (ICP-MS/ES-MS). This paper describes a study to determine the speciation of arsenic and, in particular, the arsenite phytochelatin complexes in the root from an ornamental garden plant Thunbergia alata exposed to 1 mg As L(-1) as arsenate. The approach of formic acid extraction followed by HPLC-ES-MS/ICP-MS identified different As(III)-PC complexes in the extract of this plant and made their quantification via sulfur (m/z 32) and arsenic (m/z 75) possible. Although sulfur sensitivity could be significantly increased when xenon was used as collision gas in ICP-qMS, or when HR-ICP-MS was used in medium resolution, the As:S ratio gave misleading results in the identification of As(III)-PC complexes due to the relatively low resolution of the chromatography system in relation to the variety of As-peptides in plants. Hence only the parallel use of ES-MS/ICP-MS was able to prove the occurrence of such arsenite phytochelatin complexes. Between 55 and 64% of the arsenic was bound to the sulfur of peptides mainly as As(III)(PC(2))(2), As(III)(PC(3)) and As(III)(PC(4)). XANES (X-ray absorption near-edge spectroscopy) measurement, using the freshly exposed plant root directly, confirmed that most of the arsenic is trivalent and binds to S of peptides (53% As-S) while 38% occurred as arsenite and only 9% unchanged as arsenate. EXAFS data confirmed that As-S and As-O bonds occur in the plants. This study confirms, for the first time, that As-peptides can be extracted by formic acid and chromatographically separated on a reversed-phase column without significant decomposition or de-novo synthesis during the extraction step.

PCA Tomography: how to extract information from data cubes

NASA Astrophysics Data System (ADS)

Steiner, J. E.; Menezes, R. B.; Ricci, T. V.; Oliveira, A. S.

2009-05-01

Astronomy has evolved almost exclusively by the use of spectroscopic and imaging techniques, operated separately. With the development of modern technologies, it is possible to obtain data cubes in which one combines both techniques simultaneously, producing images with spectral resolution. To extract information from them can be quite complex, and hence the development of new methods of data analysis is desirable. We present a method of analysis of data cube (data from single field observations, containing two spatial and one spectral dimension) that uses Principal Component Analysis (PCA) to express the data in the form of reduced dimensionality, facilitating efficient information extraction from very large data sets. PCA transforms the system of correlated coordinates into a system of uncorrelated coordinates ordered by principal components of decreasing variance. The new coordinates are referred to as eigenvectors, and the projections of the data on to these coordinates produce images we will call tomograms. The association of the tomograms (images) to eigenvectors (spectra) is important for the interpretation of both. The eigenvectors are mutually orthogonal, and this information is fundamental for their handling and interpretation. When the data cube shows objects that present uncorrelated physical phenomena, the eigenvector's orthogonality may be instrumental in separating and identifying them. By handling eigenvectors and tomograms, one can enhance features, extract noise, compress data, extract spectra, etc. We applied the method, for illustration purpose only, to the central region of the low ionization nuclear emission region (LINER) galaxy NGC 4736, and demonstrate that it has a type 1 active nucleus, not known before. Furthermore, we show that it is displaced from the centre of its stellar bulge. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the National Science Foundation on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência e Tecnologia (Brazil) and SECYT (Argentina). E-mail: steiner@astro.iag.usp.br

Simultaneous Analysis of Monovalent Anions and Cations with a Sub-Microliter Dead-Volume Flow-Through Potentiometric Detector for Ion Chromatography

PubMed Central

Dumanli, Rukiye; Attar, Azade; Erci, Vildan; Isildak, Ibrahim

2016-01-01

A microliter dead-volume flow-through cell as a potentiometric detector is described in this article for sensitive, selective and simultaneous detection of common monovalent anions and cations in single column ion chromatography for the first time. The detection cell consisted of less selective anion- and cation-selective composite membrane electrodes together with a solid-state composite matrix reference electrode. The simultaneous separation and sensitive detection of sodium (Na+), potassium (K+), ammonium (NH4+), chloride (Cl−) and nitrate (NO3−) in a single run was achieved by using 98% 1.5 mM MgSO4 and 2% acetonitrile eluent with a mixed-bed ion-exchange separation column without suppressor column system. The separation and simultaneous detection of the anions and cations were completed in 6 min at the eluent flow-rate of 0.8 mL/min. Detection limits, at S/N = 3, were ranged from 0.2 to 1.0 µM for the anions and 0.3 to 3.0 µM for the cations, respectively. The developed method was successfully applied to the simultaneous determination of monovalent anions and cations in several environmental and biological samples. PMID:26786906

The MPLEx Protocol for Multi-omic Analyses of Soil Samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nicora, Carrie D.; Burnum-Johnson, Kristin E.; Nakayasu, Ernesto S.

Mass spectrometry (MS)-based integrated metaproteomic, metabolomic and lipidomic (multi-omic) studies are transforming our ability to understand and characterize microbial communities in environmental and biological systems. These measurements are even enabling enhanced analyses of complex soil microbial communities, which are the most complex microbial systems known to date. Multi-omic analyses, however, do have sample preparation challenges since separate extractions are typically needed for each omic study, thereby greatly amplifying the preparation time and amount of sample required. To address this limitation, a 3-in-1 method for simultaneous metabolite, protein, and lipid extraction (MPLEx) from the exact same soil sample was created bymore » adapting a solvent-based approach. This MPLEx protocol has proven to be simple yet robust for many sample types and even when utilized for limited quantities of complex soil samples. The MPLEx method also greatly enabled the rapid multi-omic measurements needed to gain a better understanding of the members of each microbial community, while evaluating the changes taking place upon biological and environmental perturbations.« less

Analysis of aldehydes in beer by gas-diffusion microextraction: characterization by high-performance liquid chromatography-diode-array detection-atmospheric pressure chemical ionization-mass spectrometry.

PubMed

Gonçalves, Luís Moreira; Magalhães, Paulo Jorge; Valente, Inês Maria; Pacheco, João Grosso; Dostálek, Pavel; Sýkora, David; Rodrigues, José António; Barros, Aquiles Araújo

2010-06-11

In this work, a recently developed extraction technique for sample preparation aiming the analysis of volatile and semi-volatile compounds named gas-diffusion microextraction (GDME) is applied in the chromatographic analysis of aldehydes in beer. Aldehydes-namely acetaldehyde (AA), methylpropanal (MA) and furfural (FA)-were simultaneously extracted and derivatized with 2,4-dinitrophenylhydrazine (DNPH), then the derivatives were separated and analyzed by high-performance liquid chromatography with spectrophotometric detection (HPLC-UV). The identity of the eluted compounds was confirmed by high-performance liquid chromatography-atmospheric pressure chemical ionization-mass-spectrometry detection in the negative ion mode (HPLC-APCI-MS). The developed methodology showed good repeatability (ca. 5%) and linearity as well as good limits of detection (AA-12.3, FA-1.5 and MA 5.4microgL(-1)) and quantification (AA-41, FA-4.9 and MA 18microgL(-1)); it also appears to be competitive in terms of speed and cost of analysis. Copyright 2010 Elsevier B.V. All rights reserved.

An intelligent fault diagnosis method of rolling bearings based on regularized kernel Marginal Fisher analysis

NASA Astrophysics Data System (ADS)

Jiang, Li; Shi, Tielin; Xuan, Jianping

2012-05-01

Generally, the vibration signals of fault bearings are non-stationary and highly nonlinear under complicated operating conditions. Thus, it's a big challenge to extract optimal features for improving classification and simultaneously decreasing feature dimension. Kernel Marginal Fisher analysis (KMFA) is a novel supervised manifold learning algorithm for feature extraction and dimensionality reduction. In order to avoid the small sample size problem in KMFA, we propose regularized KMFA (RKMFA). A simple and efficient intelligent fault diagnosis method based on RKMFA is put forward and applied to fault recognition of rolling bearings. So as to directly excavate nonlinear features from the original high-dimensional vibration signals, RKMFA constructs two graphs describing the intra-class compactness and the inter-class separability, by combining traditional manifold learning algorithm with fisher criteria. Therefore, the optimal low-dimensional features are obtained for better classification and finally fed into the simplest K-nearest neighbor (KNN) classifier to recognize different fault categories of bearings. The experimental results demonstrate that the proposed approach improves the fault classification performance and outperforms the other conventional approaches.

QuEChERS-based extraction procedure for multifamily analysis of phytohormones in vegetables by UHPLC-MS/MS.

PubMed

Flores, María Isabel Alarcón; Romero-González, Roberto; Frenich, Antonia Garrido; Vidal, José Luis Martínez

2011-07-01

A new method has been developed and validated for the simultaneous analysis of different phytohormones (auxins, cytokinins and gibberellins) in vegetables. The compounds were extracted using a QuEChERS-based method (acronym of quick, easy, cheap, effective, rugged and safe). The separation and determination of the selected phytohormones were carried out by ultra high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS), using electrospray ionization source (ESI) in positive and negative ion modes. The method was validated and mean recoveries were evaluated at three concentration levels (50, 100 and 250 μg/kg), ranging from 75 to 110% at the three levels assayed. Intra- and interday precisions, expressed as relative standard deviations (RSDs), were lower than 20 and 25%, respectively. Limits of quantification (LOQs) were equal or lower than 10 μg/kg. The developed procedure was applied to seven courgette samples, and naphthylacetic acid, naphthylacetamide and benzyladenine were found in some of the analysed samples. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous degumming and production of a natural gum from Crotalaria juncea seeds: Physicochemical and rheological characterization.

PubMed

Sadhukhan, Suvra; Bhattacharjee, Annesha; Sarkar, Ujjaini; Baidya, Pabitra Kumar; Baksi, Sibashish

2018-05-01

The oil extracted from Crotalaria juncea (Sunn-hemp) contains 70% of gum. Several methods of degumming are attempted in order to maximize the yield of gum. During appropriate water induced degumming, about 95-98% of phosphatides are separated. The maximum oil yield for two types of degummimg processes are 0.59% and 0.69% corresponding to hot water and pure O-phosphoric acid (19.88 N) treatment respectively. The % oil yield obtained for TOP degumming is about 0.78%. Physico-chemical characteristics of the isolated gum such as moisture, ash, protein, fat and aqueous solubility along with FTIR and TGA analysis are studied in order to evaluate the effect of extraction process. The behaviour of gum on the molecular scale is evaluated through alcohol treatment. Chromatographic analysis determines the monosaccharide content of the gum with glucose: xylose: arabinose::54: 34:1. Rheological characterization shows that the juncea gum solutions are shear rate dependent and the behaviour is shear-thinning (or pseudoplastic). Results show that the temperature dependent viscosity decreases with increasing shear rate. Copyright © 2018 Elsevier B.V. All rights reserved.

LC-MS-based quantification method for Achyranthes root saponins.

PubMed

Kawahara, Yuki; Hoshino, Tatsuro; Morimoto, Hidetaka; Shinizu, Tomofumi; Narukawa, Yuji; Fuchino, Hiroyuki; Kawahara, Nobuo; Kiuchi, Fumiyuki

2016-01-01

A liquid chromatography mass spectrometry (LC-MS) method was developed for simultaneous quantitative analysis of Achyranthes root saponins: chikusetsusaponins IVa (1) and V (2), achyranthosides B (3), C (4), D (5), E (6), and G (7), sulfachyranthosides B (8) and D (9), and betavulgarosides II (10) and IV (11). Satisfactory separation of the saponins was achieved with the use of a volatile ion-pair reagent (dihexyl ammonium acetate) on a phenyl-hexylated silica gel column, and the amounts of saponins extracted under three different conditions were determined. When Achyranthes root was extracted with water at room temperature, achyranthosides B (3) and D (5) were the major saponins, and smaller amounts of other saponins (4, 6-11) were present. However, the amounts of chikusetsusaponins (1 and 2) were negligible. Under the condition to make a standard decoction of a Kampo formula, the major saponins were achyranthosides B (3), C (4), and D (5), and small amounts of chikusetsusaponins IVa (1) and V (2) appeared, whereas prolonged heating largely increased the amounts of chikusetsusaponins. This method can be used for quality control of Achyranthes root.