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Sample records for accurate high-performance liquid

  1. High Performance Liquid Chromatography

    NASA Astrophysics Data System (ADS)

    Talcott, Stephen

    High performance liquid chromatography (HPLC) has many applications in food chemistry. Food components that have been analyzed with HPLC include organic acids, vitamins, amino acids, sugars, nitrosamines, certain pesticides, metabolites, fatty acids, aflatoxins, pigments, and certain food additives. Unlike gas chromatography, it is not necessary for the compound being analyzed to be volatile. It is necessary, however, for the compounds to have some solubility in the mobile phase. It is important that the solubilized samples for injection be free from all particulate matter, so centrifugation and filtration are common procedures. Also, solid-phase extraction is used commonly in sample preparation to remove interfering compounds from the sample matrix prior to HPLC analysis.

  2. High-Performance Liquid Chromatography

    NASA Astrophysics Data System (ADS)

    Reuhs, Bradley L.; Rounds, Mary Ann

    High-performance liquid chromatography (HPLC) developed during the 1960s as a direct offshoot of classic column liquid chromatography through improvements in the technology of columns and instrumental components (pumps, injection valves, and detectors). Originally, HPLC was the acronym for high-pressure liquid chromatography, reflecting the high operating pressures generated by early columns. By the late 1970s, however, high-performance liquid chromatography had become the preferred term, emphasizing the effective separations achieved. In fact, newer columns and packing materials offer high performance at moderate pressure (although still high pressure relative to gravity-flow liquid chromatography). HPLC can be applied to the analysis of any compound with solubility in a liquid that can be used as the mobile phase. Although most frequently employed as an analytical technique, HPLC also may be used in the preparative mode.

  3. Accurate mass analysis of ethanesulfonic acid degradates of acetochlor and alachlor using high-performance liquid chromatography and time-of-flight mass spectrometry

    USGS Publications Warehouse

    Thurman, E.M.; Ferrer, Imma; Parry, R.

    2002-01-01

    Degradates of acetochlor and alachlor (ethanesulfonic acids, ESAs) were analyzed in both standards and in a groundwater sample using high-performance liquid chromatography-time-of-flight mass spectrometry with electrospray ionization. The negative pseudomolecular ion of the secondary amide of acetochlor ESA and alachlor ESA gave average masses of 256.0750+/-0.0049 amu and 270.0786+/-0.0064 amu respectively. Acetochlor and alachlor ESA gave similar masses of 314.1098+/-0.0061 amu and 314.1153+/-0.0048 amu; however, they could not be distinguished by accurate mass because they have the same empirical formula. On the other hand, they may be distinguished using positive-ion electrospray because of different fragmentation spectra, which did not occur using negative-ion electrospray.

  4. Accurate mass analysis of ethanesulfonic acid degradates of acetochlor and alachlor using high-performance liquid chromatography and time-of-flight mass spectrometry

    USGS Publications Warehouse

    Thurman, E.M.; Ferrer, I.; Parry, R.

    2002-01-01

    Degradates of acetochlor and alachlor (ethanesulfonic acids, ESAs) were analyzed in both standards and in a groundwater sample using high-performance liquid chromatography-time-of-flight mass spectrometry with electrospray ionization. The negative pseudomolecular ion of the secondary amide of acetochlor ESA and alachlor ESA gave average masses of 256.0750??0.0049 amu and 270.0786??0.0064 amu respectively. Acetochlor and alachlor ESA gave similar masses of 314.1098??0.0061 amu and 314.1153??0.0048 amu; however, they could not be distinguished by accurate mass because they have the same empirical formula. On the other hand, they may be distinguished using positive-ion electrospray because of different fragmentation spectra, which did not occur using negative-ion electrospray.

  5. The determination of phenolic profiles of Serbian unifloral honeys using ultra-high-performance liquid chromatography/high resolution accurate mass spectrometry.

    PubMed

    Kečkeš, Silvio; Gašić, Uroš; Veličković, Tanja Ćirković; Milojković-Opsenica, Dušanka; Natić, Maja; Tešić, Živoslav

    2013-05-01

    Polyphenolic profiles of 44 unifloral Serbian honeys were analyzed using ultra-high-performance liquid chromatography (UHPLC) coupled with hybrid mass spectrometer which combines the Linear Trap Quadrupole (LTQ) and OrbiTrap mass analyzer. Rapid UHPLC method was developed in combination with a high sensitivity accurate mass scan and a simultaneous data dependent scan. The honey samples were of different botanical origin: acacia (Robinia pseudoacacia), sunflower (Helianthus annuus), linden (Tilia cordata), basil (Ocimum basilicum), buckwheat (Fagopyrum esculentum), oilseed rape (Brassica napus), and goldenrod (Solidago virgaurea). The presence of 43 compounds, mainly flavonoids, was proven in all honey samples by their characteristic mass spectra and fragmentation pattern. Relatively high amounts of chrysin, pinocembrin and galangin were identified in all honey extracts. p-Coumaric acid was not detected in basil, buckwheat and goldenrod honey extracts. A larger amount of gallic acid (max value 1.45 mg/kg) was found in the sunflower honey, while a larger amount of apigenin (0.97 mg/kg) was determined in the buckwheat honey in comparison with other honeys. The samples were classified according to the botanical origin using pattern recognition technique, Principal Component Analysis (PCA). The LTQ OrbiTrap technique was proven to be reliable for the unambiguous detection of phenolic acids, their derivatives, and flavonoid aglycones based on their molecular masses and fragmentation pattern.

  6. Ultra-high-performance liquid chromatography electrospray ionization tandem mass spectrometry for accurate analysis of glycerophospholipids and sphingolipids in drug resistance tumor cells.

    PubMed

    Li, Lin; Wang, Linlin; Shangguan, Dihua; Wei, Yanbo; Han, Juanjuan; Xiong, Shaoxiang; Zhao, Zhenwen

    2015-02-13

    Glycerophospholipids and sphingolipids are important signaling molecules which are involved in many physiological and pathological processes. Here we reported an effective method for accurate analysis of these lipids by liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The methanol method was adopted for extraction of lipids due to its simplicity and high efficiency. It was found that two subclasses of sphingolipids, sulfatide (ST) and cerebroside (CB), were heat labile, so a decreased temperature in the ion source of MS might be necessary for these compounds analysis. In addition, it was found that the isobaric interferences were commonly existent, for example, the m/z of 16:0/18:1 PC containing two (13)C isotope being identical to that of 16:0/18:0 PC determined by a unit mass resolution mass spectrometer; therefore, a baseline separation of interferential species was required to maintain selectivity and accuracy of analysis. In this work, an ultra-high-performance liquid chromatography (UHPLC)-based method was developed for separation of interferential species. Moreover, in order to deal with the characteristics of different polarity and wide dynamic range of glycerophospholipids and sphingolipids in biological systems, three detecting conditions were combined together for comprehensive and rational analysis of glycerophospholipids and sphingolipids. The method was utilized to profile glycerophospholipids and sphingolipids in drug resistant tumor cells. Our results showed that many lipids were significantly changed in drug resistant tumor cells compared to paired drug sensitive tumor cells. This is a systematic report about the isobaric interferences and heat labile compounds interferences when analyzing glycerophospholipids and sphingolipids by ESI-MS/MS, which aids in ruling out one potential source of systematic error to ensure the accuracy of analysis.

  7. Sensitive, accurate and rapid detection of trace aliphatic amines in environmental samples with ultrasonic-assisted derivatization microextraction using a new fluorescent reagent for high performance liquid chromatography.

    PubMed

    Chen, Guang; Liu, Jianjun; Liu, Mengge; Li, Guoliang; Sun, Zhiwei; Zhang, Shijuan; Song, Cuihua; Wang, Hua; Suo, Yourui; You, Jinmao

    2014-07-25

    A new fluorescent reagent, 1-(1H-imidazol-1-yl)-2-(2-phenyl-1H-phenanthro[9,10-d]imidazol-1-yl)ethanone (IPPIE), is synthesized, and a simple pretreatment based on ultrasonic-assisted derivatization microextraction (UDME) with IPPIE is proposed for the selective derivatization of 12 aliphatic amines (C1: methylamine-C12: dodecylamine) in complex matrix samples (irrigation water, river water, waste water, cultivated soil, riverbank soil and riverbed soil). Under the optimal experimental conditions (solvent: ACN-HCl, catalyst: none, molar ratio: 4.3, time: 8 min and temperature: 80°C), micro amount of sample (40 μL; 5mg) can be pretreated in only 10 min, with no preconcentration, evaporation or other additional manual operations required. The interfering substances (aromatic amines, aliphatic alcohols and phenols) get the derivatization yields of <5%, causing insignificant matrix effects (<4%). IPPIE-analyte derivatives are separated by high performance liquid chromatography (HPLC) and quantified by fluorescence detection (FD). The very low instrumental detection limits (IDL: 0.66-4.02 ng/L) and method detection limits (MDL: 0.04-0.33 ng/g; 5.96-45.61 ng/L) are achieved. Analytes are further identified from adjacent peaks by on-line ion trap mass spectrometry (MS), thereby avoiding additional operations for impurities. With this UDME-HPLC-FD-MS method, the accuracy (-0.73-2.12%), precision (intra-day: 0.87-3.39%; inter-day: 0.16-4.12%), recovery (97.01-104.10%) and sensitivity were significantly improved. Successful applications in environmental samples demonstrate the superiority of this method in the sensitive, accurate and rapid determination of trace aliphatic amines in micro amount of complex samples.

  8. Development and validation of a high-performance liquid chromatography-fluorescence detection method for the accurate quantification of colistin in human plasma.

    PubMed

    Chepyala, Divyabharathi; Tsai, I-Lin; Sun, Hsin-Yun; Lin, Shu-Wen; Kuo, Ching-Hua

    2015-02-01

    Recently, colistin has become one of the most important drugs for treating infections caused by multidrug-resistant Gram-negative bacteria. Therapeutic drug monitoring is recommended to ensure the safety and efficacy of colistin and to improve clinical outcomes. This study developed an accurate and sensitive high-performance liquid chromatography-fluorescence detection (HPLC-FLD) method for the quantification of colistin in human plasma. The sample preparation included protein precipitation using trichloroacetic acid (TCA) and methanol, followed by in-solid phase extraction (In-SPE) derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl). A Poroshell 120 EC-C18 2.1×100mm (2.7μm) column was used in the HPLC method with a mobile phase composed of acetonitrile (ACN), tetrahydrofuran (THF), and deionized (DI) water (82%, 2%, 16% (v/v), respectively). Polymyxin B1 was used as the internal standard. The total analysis time was 22min under optimal separation conditions. The HPLC-FLD method was validated over a therapeutic range of 0.3-6.0μgmL(-1). The intra-day and inter-day precisions for colistin A and colistin B were below 9.9% and 4.5% relative standard deviations, respectively. The accuracy test results were between 100.2 and 118.4%. The extraction recoveries were between 81.6 and 94.1%. The method was linear over the test range, with a 0.9991 coefficient of determination. The limit of detection was 0.1μgmL(-1). The validated HPLC-FLD method was successfully applied to quantify the colistin concentrations in 2 patient samples for therapeutic drug monitoring.

  9. Accurate and sensitive high-performance liquid chromatographic method for geometrical and structural photoisomers of bilirubin IX alpha using the relative molar absorptivity values.

    PubMed

    Itoh, S; Isobe, K; Onishi, S

    1999-07-02

    It has been reported that considerable differences exist between the relative molar absorptivity values of the geometrical and structural photoisomers of bilirubin. We have devised an accurate HPLC method for photoisomer quantification based on the following principle: the sum of both the integrated peak areas corrected by each factor for each photoisomer, and the integrated peak area of unchanged (ZZ)-bilirubin [(ZZ)-B] after an anaerobic photoirradiation, should be constant and equal to the integrated peak area of initial (ZZ)-bilirubin [(ZZ)-Bi] before photoirradiation. On this basis, the following equation can be used to determine each factor. [equation: see text] alpha, beta, gamma and delta represent the factors used to correct the integrated peak areas of individual bilirubin photoisomers, and they are arranged in the order of the formula. It was demonstrated that the relative 455 nm molar absorptivity values for (ZZ)-bilirubin and all its geometrical and structural photoisomers, i.e., (ZZ)-bilirubin, (ZE)-bilirubin (EZ)-bilirubin, (EZ)-cyclobilirubin (= lumirubin) and (EE)-cyclobilirubin in the HPLC eluent, are, respectively, 1.0, 0.81 (= alpha), 0.54 (= beta), 0.47 (= gamma) and 0.39 (= delta).

  10. Determination of Caffeine in Beverages by High Performance Liquid Chromatography.

    ERIC Educational Resources Information Center

    DiNunzio, James E.

    1985-01-01

    Describes the equipment, procedures, and results for the determination of caffeine in beverages by high performance liquid chromatography. The method is simple, fast, accurate, and, because sample preparation is minimal, it is well suited for use in a teaching laboratory. (JN)

  11. High Performance Liquid Chromatography/Video Fluorometry. Part I. Instrumentation.

    DTIC Science & Technology

    1981-09-30

    High Performance Liquid Chromatography /Video...PERIOD COVERED High Performance Liquid Chromatography /Video .. / Fluorometry. Part I. Instrumentation. . Interim/ echnicaliepart,. 6. PERFORMING ORG...34Entered SECURITY CLASSIFICATION OF THIS OlAGE (When Data Entered) II1| III I I I I E I II ... .. High Performance Liquid Chromatography

  12. Countercurrent chromatography separation of saponins by skeleton type from Ampelozizyphus amazonicus for off-line ultra-high-performance liquid chromatography/high resolution accurate mass spectrometry analysis and characterisation.

    PubMed

    de Souza Figueiredo, Fabiana; Celano, Rita; de Sousa Silva, Danila; das Neves Costa, Fernanda; Hewitson, Peter; Ignatova, Svetlana; Piccinelli, Anna Lisa; Rastrelli, Luca; Guimarães Leitão, Suzana; Guimarães Leitão, Gilda

    2017-01-20

    Ampelozizyphus amazonicus Ducke (Rhamnaceae), a medicinal plant used to prevent malaria, is a climbing shrub, native to the Amazonian region, with jujubogenin glycoside saponins as main compounds. The crude extract of this plant is too complex for any kind of structural identification, and HPLC separation was not sufficient to resolve this issue. Therefore, the aim of this work was to obtain saponin enriched fractions from the bark ethanol extract by countercurrent chromatography (CCC) for further isolation and identification/characterisation of the major saponins by HPLC and MS. The butanol extract was fractionated by CCC with hexane - ethyl acetate - butanol - ethanol - water (1:6:1:1:6; v/v) solvent system yielding 4 group fractions. The collected fractions were analysed by UHPLC-HRMS (ultra-high-performance liquid chromatography/high resolution accurate mass spectrometry) and MS(n). Group 1 presented mainly oleane type saponins, and group 3 showed mainly jujubogenin glycosides, keto-dammarane type triterpene saponins and saponins with C31 skeleton. Thus, CCC separated saponins from the butanol-rich extract by skeleton type. A further purification of group 3 by CCC (ethyl acetate - ethanol - water (1:0.2:1; v/v)) and HPLC-RI was performed in order to obtain these unusual aglycones in pure form.

  13. Identification of mycobacteria by high-performance liquid chromatography.

    PubMed Central

    Butler, W R; Jost, K C; Kilburn, J O

    1991-01-01

    Mycolic acids extracted from saponified mycobacterial cells were examined as p-bromophenacyl esters by high-performance liquid chromatography (HPLC). Standard HPLC patterns were developed for species of Mycobacterium by examination of strains from culture collections and other well-characterized isolates. Relative retention times of peaks and peak height comparisons were used to develop a differentiation scheme that was 98% accurate for the species examined. A rapid, cost-effective HPLC method which offers an alternative approach to the identification of mycobacteria is described. PMID:1774251

  14. High Performance Liquid Chromatography/Video Fluorometry. Part II. Applications.

    DTIC Science & Technology

    1981-09-30

    HIGH PERFORMANCE LIQUID CHROMATOGRAPHY /VIDEO FLUOROMETRY. PART...REP«T_N&:-ŗ/ High Performance Liquid Chromatography /Video Fluorometry» Part II. Applications« by | Dennis C./Shelly* Michael P./Vogarty and...Data EnlirtdJ REPORT DOCUMENTATION PAGE t. REPORT NUMBER 2 GOVT ACCESSION NO 4. T1TI.F (and Submit) lP-^fffsyva High Performance Liquid Chromatography

  15. A sensitive and accurate method for the determination of perfluoroalkyl and polyfluoroalkyl substances in human serum using a high performance liquid chromatography-online solid phase extraction-tandem mass spectrometry.

    PubMed

    Yu, Chang Ho; Patel, Bhupendra; Palencia, Marilou; Fan, Zhihua Tina

    2017-01-13

    A selective, sensitive, and accurate analytical method for the measurement of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in human serum, utilizing LC-MS/MS (liquid chromatography-tandem mass spectrometry), was developed and validated according to the Centers for Disease Control and Prevention (CDC) guidelines for biological sample analysis. Tests were conducted to determine the optimal analytical column, mobile phase composition and pH, gradient program, and cleaning procedure. The final analytical column selected for analysis was an extra densely bonded silica-packed reverse-phase column (Agilent XDB-C8, 3.0×100mm, 3.5μm). Mobile phase A was an aqueous buffer solution containing 10mM ammonium acetate (pH=4.3). Mobile phase B was a mixture of methanol and acetonitrile (1:1, v/v). The gradient program was programmed by initiating a fast elution (%B, from 40 to 65%) between 1.0 and 1.5min, followed by a slow elution (%B: 65-80%) in the period of 1.5-7.5min. The cleanup procedures were augmented by cleaning with (1) various solvents (isopropyl alcohol, methanol, acetonitrile, and reverse osmosis-purified water); (2) extensive washing steps for the autosampler and solid phase extraction (SPE) cartridge; and (3) a post-analysis cleaning step for the whole system. Under the above conditions, the resolution and sensitivity were significantly improved. Twelve target PFASs were baseline-separated (2.5-7.0min) within a 10-min of acquisition time. The limits of detection (LODs) were 0.01ng/mL or lower for all of the target compounds, making this method 5 times more sensitive than previously published methods. The newly developed method was validated in the linear range of 0.01-50ng/mL, and the accuracy (recovery between 80 and 120%) and precision (RSD<20%) were acceptable at three spiked levels (0.25, 2.5, and 25ng/mL). The method development and validation results demonstrated that this method was precise, accurate, and robust, with high-throughput (∼10min per

  16. Multichannel Detection in High-Performance Liquid Chromatography.

    ERIC Educational Resources Information Center

    Miller, James C.; And Others

    1982-01-01

    A linear photodiode array is used as the photodetector element in a new ultraviolet-visible detection system for high-performance liquid chromatography (HPLC). Using a computer network, the system processes eight different chromatographic signals simultaneously in real-time and acquires spectra manually/automatically. Applications in fast HPLC…

  17. High-Performance Liquid Chromatography-Mass Spectrometry.

    ERIC Educational Resources Information Center

    Vestal, Marvin L.

    1984-01-01

    Reviews techniques for online coupling of high-performance liquid chromatography with mass spectrometry, emphasizing those suitable for application to nonvolatile samples. Also summarizes the present status, strengths, and weaknesses of various techniques and discusses potential applications of recently developed techniques for combined liquid…

  18. Quantification of Tea Flavonoids by High Performance Liquid Chromatography

    ERIC Educational Resources Information Center

    Freeman, Jessica D.; Niemeyer, Emily D.

    2008-01-01

    We have developed a laboratory experiment that uses high performance liquid chromatography (HPLC) to quantify flavonoid levels in a variety of commercial teas. Specifically, this experiment analyzes a group of flavonoids known as catechins, plant-derived polyphenolic compounds commonly found in many foods and beverages, including green and black…

  19. Mallow carotenoids determined by high-performance liquid chromatography

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mallow (corchorus olitorius) is a green vegetable, which is widely consumed either fresh or dry by Middle East population. This study was carried out to determine the contents of major carotenoids quantitatively in mallow, by using a High Performance Liquid Chromatography (HPLC) equipped with a Bis...

  20. Micro-polarimeter for high performance liquid chromatography

    DOEpatents

    Yeung, Edward E.; Steenhoek, Larry E.; Woodruff, Steven D.; Kuo, Jeng-Chung

    1985-01-01

    A micro-polarimeter interfaced with a system for high performance liquid chromatography, for quantitatively analyzing micro and trace amounts of optically active organic molecules, particularly carbohydrates. A flow cell with a narrow bore is connected to a high performance liquid chromatography system. Thin, low birefringence cell windows cover opposite ends of the bore. A focused and polarized laser beam is directed along the longitudinal axis of the bore as an eluent containing the organic molecules is pumped through the cell. The beam is modulated by air gap Faraday rotators for phase sensitive detection to enhance the signal to noise ratio. An analyzer records the beams's direction of polarization after it passes through the cell. Calibration of the liquid chromatography system allows determination of the quantity of organic molecules present from a determination of the degree to which the polarized beam is rotated when it passes through the eluent.

  1. Hydrazine Determination in Sludge Samples by High Performance Liquid Chromatography

    SciTech Connect

    G. Elias; G. A. Park

    2006-02-01

    A high-performance liquid chromatographic method using ultraviolet (UV) detection was developed to detect and quantify hydrazine in a variety of environmental matrices. The method was developed primarily for sludge samples, but it is also applicable to soil and water samples. The hydrazine in the matrices was derivatized to their hydrazones with benzaldehyde. The derivatized hydrazones were separated using high performance liquid chromatography (HPLC) with a reversed-phase C-18 column in an isocratic mode with methanol-water (95:5, v/v), and detected with UV detection at 313 nm. The detection limit (25 ml) for the new analytical method is 0.0067 mg ml-1of hydrazine. Hydrazine showed low recovery in soil samples because components in soil oxidized hydrazine. Sludge samples that contained relatively high soil content also showed lower recovery. The technique is relatively simple and cost-effective, and is applicable for hydrazine analysis in different environmental matrices.

  2. High-performance liquid chromatography of organophosphorus insecticides.

    PubMed

    Szalontai, G

    1976-09-01

    The high-performance liquid chromatographic behaviour of 23 organophosphorus insecticides has been studied on a stainless-steel column packed with silica gel. It has been stated that the usual classification of organophosphorus compounds into phosphonic, phosphoric, thiophosphoric and dithiophosphoric acid ester types gives some information about their adsorption properties. The chromatographic conditions of the analyses and a method for separation of the stereoisomers of tetrachlorvinphos are presented.

  3. Trends in High Performance Liquid Chromatography for Cultural Heritage.

    PubMed

    Degano, Ilaria; La Nasa, Jacopo

    2016-04-01

    The separation, detection and quantitation of specific species contained in a sample in the field of Cultural Heritage requires selective, sensitive and reliable methods. Procedures based on liquid chromatography fulfil these requirements and offer a wide range of applicability in terms of analyte types and concentration range. The main applications of High Performance Liquid Chromatography in this field are related to the separation and detection of dyestuffs in archaeological materials and paint samples by reversed-phase liquid chromatography with suitable detectors. The relevant literature will be revised, with particular attention to sample treatment strategies and future developments. Reversed phase chromatography has also recently gained increasing importance in the analysis of lipid binders and lipid materials in archaeological residues: the main advantages and disadvantages of the new approaches will be discussed. Finally, the main applications of ion chromatography and size exclusion chromatography in the field of Cultural Heritage will be revised in this chapter.

  4. Thermal expansion pump for capillary high-performance liquid chromatography.

    PubMed

    Tao, Qian; Wu, Qian; Zhang, Xiangmin

    2010-02-01

    A thermal expansion pump (TEP) based on a principle of liquid thermal expansion for capillary high-performance liquid chromatography has been developed. The novel pump is capable of generating a continuous flow at high pressure for constant and stable delivery of binary solvents from nanoliters to microliters per minute without splitting. Theoretical equations for controlling fluidic output of this pump have been established and validated by a series of experiments. Factors affecting flow rate, such as density discrepancy, liquid compressibility, and mass loss in output, were taken into account. An assembly of the pump system employing two groups of thermal expansion pumps (TEPs) working in turns were fabricated, and a controlling strategy for the pump system to maintain a continuous delivery without pressure fluctuation even at switching points was also developed. Both isocratic and gradients of binary solvent delivery by the TEPs were performed. Reproducibility and standard deviation at different flow rates were determined. A capillary high-performance liquid chromatography (micro-HPLC) system consisting of the TEPs, an injection valve, a homemade packed capillary column (20 cm x 100 microm i.d. with 5 microm C18), and a laser-induced fluorescence detector was set up, and sample separations were carried out. Results of RSD = 4% for flow and RSD = 2% for retention times at 500 nL/min were achieved. Such a pump system has almost no moving parts except for the solvent switches. Its overall costs of manufacture and running are very low. It is proven that the TEPs system has great potential and competitive capabilities in capillary liquid chromatography.

  5. Training software for high-performance liquid chromatography.

    PubMed

    Reijenga, J C

    2000-12-01

    A computer simulation program of reversed-phase high-performance liquid chromatography was developed for training purposes. Experimental retention values of 75 organic compounds on a reversed-phase column at four different percentages of organic modifiers were reduced to a two-parameter retention model with the modifier content as variable. Modifiers used were acetonitrile, methanol and tetrahydrofuran. Isocratic and programmed solvent composition were included together with the usual experimental parameters available in modern HPLC equipment, such as UV diode array and refractive index detection. Instrument specifications were made variable within wide ranges. Detailed dispersion data were made available as tabulated output.

  6. Temperature selectivity in reversed-phase high performance liquid chromatography.

    PubMed

    Dolan, John W

    2002-08-02

    Column temperature plays two important roles in reversed-phase high-performance liquid chromatography (RP-HPLC): control of retention (k) and control of selectivity (a). While changes in retention as a function of temperature are ubiquitous, selectivity changes for any given solute pair are more pronounced for ionized samples and samples with more polar substituents. With many samples, column temperature can be selected in a manner that optimizes resolution. The selectivity effects observed for temperature changes in RP-HPLC generally are complementary to those observed for mobile phase strength changes, so it is often possible to improve resolution by simultaneous optimization of temperature and mobile phase percent organic or gradient steepness. Computer simulation is a powerful tool for such optimization experiments. This paper reviews the influence of temperature on chromatographic selectivity for RP-HPLC.

  7. Structural analysis of amorphous phosphates using high performance liquid chromatography

    SciTech Connect

    Sales, B.C.; Boatner, L.A.; Chakoumakos, B.C.; McCallum, J.C.; Ramey, J.O.; Zuhr, R.A.

    1993-12-31

    Determining the atomic-scale structure of amorphous solids has proven to be a formidable scientific and technological problem for the past 100 years. The technique of high-performance liquid chromatography (HPLC) provides unique detailed information regarding the structure of partially disordered or amorphous phosphate solids. Applications of the experimental technique of HPLC to phosphate solids are reviewed, and examples of the type of information that can be obtained with HPLC are presented. Inorganic phosphates encompass a large class of important materials whose applications include: catalysts, ion-exchange media, solid electrolytes for batteries, linear and nonlinear optical components, chelating agents, synthetic replacements for bone and teeth, phosphors, detergents, and fertilizers. Phosphate ions also represent a unique link between living systems and the inorganic world.

  8. [Determination of amygdalin in hawthorn by high performance liquid chromatography].

    PubMed

    Lü, Weifeng; Ding, Mingyu

    2005-09-01

    A suitable method for extraction of amygdalin from hawthorn has been established. At first, the lipophilic components were removed with petroleum ether by ultrasonic extraction. The amygdalin was then extracted by methanol in a Soxhlet's apparatus. For quantitation, a high performance liquid chromatographic method was developed by using a reversed-phase C18 column, mobile phase of methanol-water (15:85, v/v) and a detection wavelengh of 215 nm. It can be concluded that the content of amygdalin is higher in the seeds than that in the hawthorn powder without the seeds and the yield of amygdalin is higher in the hawthorn pieces than that in the hawthorn powder.

  9. High performance liquid chromotography of prostaglandins: biological applications.

    PubMed

    Carr, K; Sweetman, B J; Frölich, J C

    1976-01-01

    Two procedures are described for separation and purification of prostaglandins by high performance liquid chromatography. Both systems show excellent resolution of PGA2, PGE2 and PGF2a. Peak definition on the micro-particle silicic acid system is particularly good with the PGs appearing in 2-3 ml of organs effluent. Studies on reproducibility showed that PGE2 and PGE2a could be recovered with a retention volume of 54.2+/-0.76 ml and 64+/-0.6 ml, respectively (n=7, mean +/-50) with good recovery. The column can be run in about one hour and can be regenerated indefinitely (greater than 200 times). The degree of purification is compatible with analysis by gas chromatography-mass spectrometry. Examples showing the application of this chromatographic method to human seminal fluid, human renal tissue, platelet rich plasma and human urine samples indicate that it makes possible analysis of these samples even at low levels.

  10. Analysis of Free Fatty Acids on the Fingertips by High Performance Liquid Chromatography.

    DTIC Science & Technology

    1978-12-20

    This investigation studied the efficiency of high performance liquid chromatography in the determination of free fatty acids present on the...utilized to eliminate the microbial contamination. The high performance liquid chromatography provided excellent separation of skin fatty acids for

  11. Determination of a Jet Fuel Metal Deactivator by High Performance Liquid Chromatography

    DTIC Science & Technology

    1983-06-01

    HIGH PERFORMANCE LIQUID CHROMATOGRAPHY Paul C. Hayes, Jr. Fuels Branch...SUPPLEMENTARY NOTES 19. KEY WORDS (Continue on reverse side if necessary and identify by block number) High Performance Liquid Chromatography absorbance...SYMBOL HPLC High Performance Liquid Chromatography P-4 jet propulsion fuel, wide-boiling range, conforming to MIL-T-5624L MDA metal deactivator,

  12. Determination of Stabiliser Contents in Advanced Gun Propellants by Reverse Phase High Performance Liquid Chromatography

    DTIC Science & Technology

    1994-03-01

    HIGH PERFORMANCE LIQUID CHROMATOGRAPHY N"m A.R. TURNER AND A. WHITE...TO biEPROOU.; AND SELL THIS REPORT Determination of Stabiliser Contents in Advanced Gun Propellants by Reverse Phase High Performance Liquid Chromatography A.R...8217/......... .. Availability Cooes Dist Avaiardlo A-i Determination of Stabiliser Contents in Advanced Gun Propellants by Reverse Phase High Performance Liquid Chromatography

  13. Quantitative analysis of benzodiazepines in vitreous humor by high-performance liquid chromatography

    PubMed Central

    Bazmi, Elham; Behnoush, Behnam; Akhgari, Maryam; Bahmanabadi, Leila

    2016-01-01

    Objective: Benzodiazepines are frequently screened drugs in emergency toxicology, drugs of abuse testing, and in forensic cases. As the variations of benzodiazepines concentrations in biological samples during bleeding, postmortem changes, and redistribution could be biasing forensic medicine examinations, hence selecting a suitable sample and a validated accurate method is essential for the quantitative analysis of these main drug categories. The aim of this study was to develop a valid method for the determination of four benzodiazepines (flurazepam, lorazepam, alprazolam, and diazepam) in vitreous humor using liquid–liquid extraction and high-performance liquid chromatography. Methods: Sample preparation was carried out using liquid–liquid extraction with n-hexane: ethyl acetate and subsequent detection by high-performance liquid chromatography method coupled to diode array detector. This method was applied to quantify benzodiazepines in 21 authentic vitreous humor samples. Linear curve for each drug was obtained within the range of 30–3000 ng/mL with coefficient of correlation higher than 0.99. Results: The limit of detection and quantitation were 30 and 100 ng/mL respectively for four drugs. The method showed an appropriate intra- and inter-day precision (coefficient of variation < 10%). Benzodiazepines recoveries were estimated to be over 80%. The method showed high selectivity; no additional peak due to interfering substances in samples was observed. Conclusion: The present method was selective, sensitive, accurate, and precise for the quantitative analysis of benzodiazepines in vitreous humor samples in forensic toxicology laboratory. PMID:27635251

  14. High-performance computing and networking as tools for accurate emission computed tomography reconstruction.

    PubMed

    Passeri, A; Formiconi, A R; De Cristofaro, M T; Pupi, A; Meldolesi, U

    1997-04-01

    It is well known that the quantitative potential of emission computed tomography (ECT) relies on the ability to compensate for resolution, attenuation and scatter effects. Reconstruction algorithms which are able to take these effects into account are highly demanding in terms of computing resources. The reported work aimed to investigate the use of a parallel high-performance computing platform for ECT reconstruction taking into account an accurate model of the acquisition of single-photon emission tomographic (SPET) data. An iterative algorithm with an accurate model of the variable system response was ported on the MIMD (Multiple Instruction Multiple Data) parallel architecture of a 64-node Cray T3D massively parallel computer. The system was organized to make it easily accessible even from low-cost PC-based workstations through standard TCP/IP networking. A complete brain study of 30 (64x64) slices could be reconstructed from a set of 90 (64x64) projections with ten iterations of the conjugate gradients algorithm in 9 s, corresponding to an actual speed-up factor of 135. This work demonstrated the possibility of exploiting remote high-performance computing and networking resources from hospital sites by means of low-cost workstations using standard communication protocols without particular problems for routine use. The achievable speed-up factors allow the assessment of the clinical benefit of advanced reconstruction techniques which require a heavy computational burden for the compensation effects such as variable spatial resolution, scatter and attenuation. The possibility of using the same software on the same hardware platform with data acquired in different laboratories with various kinds of SPET instrumentation is appealing for software quality control and for the evaluation of the clinical impact of the reconstruction methods.

  15. [Determination of scopoletin and umbelliferone contents in Saussurea medusa Maxim by high-performance liquid chromatography].

    PubMed

    Su, Wei-wei; Zhao, Jie; Lin, Jing-ming

    2005-01-01

    The contents of scopoletin and umbelliferone in Saussurea medusa Maxim were determined by high-performance liquid chromatography (HPLC) using Merck Lichrospher100 RP-18e column (250 mm x 4.0 mm, 5 microm) with the mobile phase of methanol-tetrahydrofuran-water solution and the absorbance of the compounds observed at 346 nm. HPLC yielded an average recovery and RSD of 100.07% and 1.42% for scopoletin, and 99.41% and 2.06% for umbelliferone, respectively, suggesting that HPLC is a simple, rapid and accurate method for quality control of Saussurea medusa Maxim.

  16. [Determination of organic acids in fermentation broth of spiramycin by high performance liquid chromatography].

    PubMed

    Li, You-yuan; Chen, Chang-hua; Tao, Ping

    2002-01-01

    A method for determining organic acids in spiramycin fermentation broth by high performance liquid chromatography is described. The operating conditions were Zorbax 300-SB C18 column (5 microns, 4.6 mm i.d. x 15 cm) at 35 degrees C, 0.01 mol/L phosphoric acid buffer solution (pH 2.32) and methanol as mobile phase at a flow rate of 0.6 mL/min and UV detection at 210 nm. The relative standard deviations were 0.33%-0.10% and the recoveries were 99.95%-100.08%. It's a simple, rapid and accurate method.

  17. High Performance Liquid Chromatography Experiments to Undergraduate Laboratories

    ERIC Educational Resources Information Center

    Kissinger, Peter T.; And Others

    1977-01-01

    Reviews the principles of liquid chromatography with electrochemical detection (LCEC), an analytical technique that incorporates the advantages of both liquids chromatography and electrochemistry. Also suggests laboratory experiments using this technique. (MLH)

  18. Cholesterol determination in foods: Comparison between high performance and ultra-high performance liquid chromatography.

    PubMed

    Albuquerque, Tânia Gonçalves; Oliveira, M Beatriz P P; Sanches-Silva, Ana; Costa, Helena S

    2016-02-15

    Analytical methods for cholesterol evaluation in foods are crucial since this compound was closely related with cardiovascular disease. In the present study, two chromatographic methods were implemented and validated, in order to achieve the ideal analytical method for the quantification of cholesterol in food matrices. The developed methods were applied to different foodstuffs, sour cream, egg, egg yolk and chicken nuggets. Both HPLC and UHPLC methods are rapid, specific, sensitive, precise (RSD<2.5%) and accurate. The achieved LOD and LOQ for UHPLC were 0.7 and 2.4μg/mL, respectively, while for HPLC were 3 and 11μg/mL. UHPLC method allowed reduction of the organic solvents consumption (8 times lower) and decreased analysis time in 4min, being more eco-friendly, than conventional HPLC methods. Moreover, it will be very useful for the quality control of cholesterol content in food matrices and can be easily adopted by analytical laboratories.

  19. [Simultaneous determination of pantothenic acid and D-panthenol in cosmetics by high performance liquid chromatography].

    PubMed

    Mao, Xiqin; Hu, Xia; Pan, Wei

    2010-11-01

    A high performance liquid chromatographic method (HPLC) and sample pretreatment method were developed for the simultaneous determination of pantothenic acid (vitamin B5) and D-panthenol (provitamin B5) in cosmetics with different matrices (including of creams, lotions, aqueous cosmetics, oily cosmetics, wax-based cosmetics, nail polish etc). A liquid-liquid extraction system composed of water and water-immiscible solvent was used to preliminarily separate the target components from other oil-soluble components and surfactants in cosmetics, then macromolecular water-soluble matrices in cosmetics were removed by coprecipitation with potassium ferrocyanide-zinc acetate precipitating agent, and then under acid condition, pantothenic acid and D-panthenol were enriched on a C18 solid-phase extraction sorbent. After the removal of other water-soluble impurities, target components were eluted by 40% methanol and then separated and quantitatively analyzed by high performance liquid chromatography with external standard method. Good linear relationship was achieved in the concentration range of 0.1-10 microg/g for pantothenic acid and D-panthenol. The linear correlation coefficients were separately 0.998 9 and 0.999 6. The average recoveries of the target components in cosmetics were more than 90%. Limit of detection of the method was 30 microg/g and the limit of quantification was 100 microg/g. This method can be used to simultaneously determine pantothenic acid and D-panthenol in cosmetics. The results are accurate and reliable.

  20. Determination of Selected Colored Smokes on Glass Fiber Discs by High Performance Liquid Chromatography (HPLC)

    DTIC Science & Technology

    1991-05-01

    High Performance Liquid Chromatography (HPLC) 12. PERSONAL AUTHOR(S) F F_ n.ipl’prifl. Alan R...GROUP SUB-GROUP High Performance Liquid Chromatography (HPLC), Analytical IMethod, 1,4-diamino-2,3-dihydroanthraquinone, 2-(2 - _ quinolinyl)-1,3...weights, low vapor pressures and low thermal stability. High performance liquid chromatography (HPLC) appears to be the analytical method of choice

  1. High Performance Liquid Chromatography of Vitamin A: A Quantitative Determination.

    ERIC Educational Resources Information Center

    Bohman, Ove; And Others

    1982-01-01

    Experimental procedures are provided for the quantitative determination of Vitamin A (retinol) in food products by analytical liquid chromatography. Standard addition and calibration curve extraction methods are outlined. (SK)

  2. High Performance Immobilized Liquid Membrane for Carbon Dioxide Separations

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2005-01-01

    An immobilized liquid membrane has a substrate. A plurality of capsules is disposed on the substrate. Each of the capsules is permeable to a first gas of a mixture of gases comprising the st gas and a second gas. Each of the capsules is substantially impermeable to the second gas. A liquid is disposed in each of the capsules that is permeable to the first gas and substantially impermeable to the second gas.

  3. High performance batteries with carbon nanomaterials and ionic liquids

    DOEpatents

    Lu, Wen [Littleton, CO

    2012-08-07

    The present invention is directed to lithium-ion batteries in general and more particularly to lithium-ion batteries based on aligned graphene ribbon anodes, V.sub.2O.sub.5 graphene ribbon composite cathodes, and ionic liquid electrolytes. The lithium-ion batteries have excellent performance metrics of cell voltages, energy densities, and power densities.

  4. High performance ultracapacitors with carbon nanomaterials and ionic liquids

    DOEpatents

    Lu, Wen; Henry, Kent Douglas

    2012-10-09

    The present invention is directed to the use of carbon nanotubes and/or electrolyte structures in various electrochemical devices, such as ultracapacitors having an ionic liquid electrolyte. The carbon nanotubes are preferably aligned carbon nanotubes. Compared to randomly entangled carbon nanotubes, aligned carbon nanotubes can have better defined pore structures and higher specific surface areas.

  5. High Performance Mars Liquid Cooling and Ventilation Garment Project

    NASA Technical Reports Server (NTRS)

    Terrier, Douglas; Clayton, Ronald; Whitlock, David; Conger, Bruce

    2015-01-01

    EVA space suit mobility in micro-gravity is enough of a challenge and in the gravity of Mars, improvements in mobility will enable the suited crew member to efficiently complete EVA objectives. The idea proposed is to improve thermal efficiencies of the liquid cooling and ventilation garment (LCVG) in the torso area in order to free up the arms and legs by removing the liquid tubes currently used in the ISS EVA suit in the limbs. By using shaped water tubes that greatly increase the contact area with the skin in the torso region of the body, the heat transfer efficiency can be increased to provide the entire liquid cooling requirement and increase mobility by freeing up the arms and legs. Additional potential benefits of this approach include reduced LCVG mass, enhanced evaporation cooling, increased comfort during Mars EVA tasks, and easing of the overly dry condition in the helmet associated with the Advanced Extravehicular Mobility Unit (EMU) ventilation loop currently under development.

  6. [Quantitative determination of niphensamide by high performance liquid chromatography (HPLC)].

    PubMed

    Long, C; Chen, S; Shi, T

    1998-01-01

    An HPLC method for the quantitative determination of Niphensamide in pesticide powder was developed. Column:Micropak-CH 5 microns (300 mm x 4.0 mm i.d.), mobile phase: CH3OH-H2O(1:1), detector: UV 254 nm, flow rate: 0.7 mL/min, column temperature: 25 degrees C. Under the above conditions, Niphensamide and other components were separated from each other. The method is simple, rapid, sensitive and accurate.

  7. Rapid analysis of phentolamine by high-performance liquid chromatography.

    PubMed

    Webster, Gregory K; Lemmer, Robert R; Greenwald, Steven

    2003-02-01

    A rapid liquid chromatographic method is validated for the quantitative analysis of phentolamine. Phentolamine exists in three forms for this investigation: as a mesylate salt, hydrochloride salt, and free base. In solution, phentolamine dissociates from its salt and is chromatographed as free phentolamine. This validation confirms the analysis of each form, which is simply based upon molar mass differences encountered in weighing. As such, both the United States Pharmacopeia hydrochloride and mesylate standards are used throughout this validation to demonstrate this equivalency. The validation demonstrates that this method may be used to quantitate phentolamine, regardless of its salt form.

  8. High-performance liquid chromatography using UV detection for the simultaneous quantification of ropivacaine and bupivacaine in human plasma.

    PubMed

    Gaudreault, François; Drolet, Pierre; Varin, France

    2009-12-01

    A specific high-performance liquid chromatography assay coupled with UV detection has been developed and validated for the simultaneous determination of ropivacaine and bupivacaine in human plasma. A liquid-liquid back extraction procedure was used to increase specificity, and very good and consistent recoveries were obtained: 93%-95% for ropivacaine and 90%-96% for bupivacaine. The lowest limit of quantification was 4 and 8 ng/mL for ropivacaine and bupivacaine, respectively. The method was sensitive, reproducible (coefficient of variation accurate (96%-102%) and was applied successfully to study the pharmacokinetics of ropivacaine and bupivacaine in a perioperative context.

  9. Free malonaldehyde determination in tissues by high-performance liquid chromatography.

    PubMed

    Csallany, A S; Der Guan, M; Manwaring, J D; Addis, P B

    1984-11-01

    A high-performance liquid chromatographic method was developed for the quantification of free malonaldehyde (MA) in tissues. HPLC separation was performed using a TSK G1000 PW column (7.5-mm i.d. X 30 cm) with a mobile phase of 0.1 M Na3PO4 buffer, pH 8.0, at a flow rate of 0.6 ml/min. The eluant was monitored at 267 nm. Free MA in the tissue sample was separated and quantified in approximately 50 min. The lowest amount of MA that can be determined by this HPLC technique is approximately 1 ng per injection. This method was successfully applied to rat liver and beef, pork, and chicken muscle and was compared to the thiobarbituric acid (TBA) test. It was found to be more sensitive, accurate, and specific for the determination of free MA than the TBA method.

  10. Mycolic Acid Analysis by High-Performance Liquid Chromatography for Identification of Mycobacterium Species

    PubMed Central

    Butler, W. Ray; Guthertz, Linda S.

    2001-01-01

    Mycobacterium tuberculosis is the etiologic agent of tuberculosis and can be accurately detected by laboratories using commercial genetic tests. Nontuberculosis mycobacteria (NTM) causing other mycobacterioses can be difficult to identify. The identification processes are confounded by an increasing diversity of newly characterized NTM species. The ubiquitous nature of NTM, combined with their potential to be opportunistic pathogens in immunocompromised as well as nonimmunodeficient patients, further complicates the problem of their identification. Since clinical case management varies depending on the etiologic agent, laboratories must identify the species in a timely manner. However, only a few identification methods can detect the species diversity within the Mycobacterium genus. Over the last decade, high-performance liquid chromatography analysis of the mycolic acids has become an accepted method for identification of mycobacteria. In this review, we assess its development and usefulness as an identification technique for Mycobacterium species. PMID:11585782

  11. [Determination of writing age of blue ballpoint pen inks by high performance liquid chromatography].

    PubMed

    Shi, Xiao-Fan; Li, Xin-Qian; Xu, Ying-Jian; Wang, Jing-Han; Wang, Yan-Ji

    2006-09-01

    As it is a frequently encountered problem in the laboratory of forensic science nowadays to distinguish whether the questioned documents, such as deeds, contracts, and receipts, written in ballpoint pen inks are true or not, and identify the writing age of them, it is very essential to establish a simple, sensitive and accurate method to examine the similarities and differences of the ballpoint pen inks and identify the writing age. The present paper introduces a technique that allows identifying the kind and the writing age of the blue ballpoint pen inks. The technique is based on using a high performance liquid chromatographic method for distinguishing the similarities and differences in dyes of blue ballpoint pen inks and determining changes in dyes of blue ballpoint pen inks developed with age, and these changes can be evaluated by the ratio of peak areas.

  12. Determination of Harmine and Harmaline in Peganum harmala Seeds by High-Performance Liquid Chromatography

    NASA Astrophysics Data System (ADS)

    Monsef-Esfahani, Hamid Reza; Faramarzi, Mohammad Ali; Mortezaee, Venus; Amini, Mohsen; Rouini, Mohammad Reza

    A High-Performance Liquid Chromatography (HPLC) method was developed for determination of harmine, harmaline, harmol and harmalol in the extract of Peganum harmala seeds. The sample preparation was performed using liquid-liquid extraction. Chromatographic separation was achieved with a Tracer Excel 120 ODSA (150x4.6 mm) column, using a mixture of potassium phosphate buffer (10 mM, pH 7.0): acetonitrile (100:30; v/v) as mobile phase, in an isocratic mode at 1.5 mL min-1. UV detection (λ = 330 nm) was used. The calibration curves were linear (r2>0.998) in the concentration range of 0.5-20 μg mL-1 for all analytes. The lower limit of quantification for all analytes was 0.5 μg mL-1. The within and between day precisions in the measurement of QC samples at three tested concentrations were in the range of 0.6-10.2% for all analytes. The HPLC method is able to measure the harmala alkaloids in the plant extract. The method has suitable reproducibility, sensitivity and resolution for routine and accurate use with UV detection.

  13. HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY OF SELECTED ORGANIC PEROXIDES WITH OXIDATIVE AMPEROMETRIC DETECTION

    EPA Science Inventory

    Reversed-phase high-performance liquid chromatography with oxidative amperometric detection was optimized for the determination of several organic peroxides in drinking water under ideal conditions.The determinations were performed under isocratic conditions using acetonitrile an...

  14. HIGH PERFORMANCE LIQUID CHROMATOGRAPHIC SEPARATION OF THE ENANTIOMERS OF ORGANOPHOSPHORUS PESTICIDES ON POLYSACCHARIDE CHIRAL STATIONARY PHASES

    EPA Science Inventory

    High-performance liquid chromatographic separation of the individual enantiomers of 12 organophosphorus pesticides (OPs) was obtained on polysaccharide enantioselective HPLC columns using alkane-alcohol mobile phase. The OP pesticides were crotoxyphos, dialifor, fonofos, fenamiph...

  15. Determination of sulfonamides in butter samples by ionic liquid magnetic bar liquid-phase microextraction high-performance liquid chromatography.

    PubMed

    Wu, Lijie; Song, Ying; Hu, Mingzhu; Xu, Xu; Zhang, Hanqi; Yu, Aimin; Ma, Qiang; Wang, Ziming

    2015-01-01

    A novel, simple, and environmentally friendly pretreatment method, ionic liquid magnetic bar liquid-phase microextraction, was developed for the determination of sulfonamides in butter samples by high-performance liquid chromatography. The ionic liquid magnetic bar was prepared by inserting a stainless steel wire into the hollow of a hollow fiber and immobilizing ionic liquid in the micropores of the hollow fiber. In the extraction process, the ionic liquid magnetic bars were used to stir the mixture of sample and extraction solvent and enrich the sulfonamides in the mixture. After extraction, the analyte-adsorbed ionic liquid magnetic bars were readily isolated with a magnet from the extraction system. It is notable that the present method was environmentally friendly since water and only several microliters of ionic liquid were used in the whole extraction process. Several parameters affecting the extraction efficiency were investigated and optimized, including the type of ionic liquid, sample-to-extraction solvent ratio, the number of ionic liquid magnetic bars, extraction temperature, extraction time, salt concentration, stirring speed, pH of the extraction solvent, and desorption conditions. The recoveries were in the range of 73.25-103.85 % and the relative standard deviations were lower than 6.84 %. The experiment results indicated that the present method was effective for the extraction of sulfonamides in high-fat content samples.

  16. Simultaneous Determination of Eight Bioactive Compounds in Dianthus superbus by High-performance Liquid Chromatography

    PubMed Central

    Yun, Bo-Ra; Yang, Hye Jin; Weon, Jin Bae; Lee, Jiwoo; Eom, Min Rye; Ma, Choong Je

    2016-01-01

    Background: Dianthus superbus, one of traditional herbal medicine, is widely used to treat urethritis, carbuncles and carcinoma. Objective: A simultaneous determination method was established for controlling the quality of D. superbus using the eight compounds, (E)-methyl-4-hydroxy-4-(8a-methyl-3-oxodecahydronaphthalen-4a-yl) (1), diosmetin-7-O(2'',6''-di-O-α-L-rhamnopyranosyl)-β-D-glucopyranoside (2), vanillic acid (3), 4-hydroxyphenyl acetic acid (4), 4-methoxyphenyl acetic acid (5), (E)-4-methoxycinnamic acid (6), 3-methoxy-4-hydroxyphenylethanol (7), and methyl hydroferulate (8) isolated from D. superbus. Materials and Methods: This analysis method was developed using high performance liquid chromatography coupled with diode array detector with a Shishedo C18 column at a column temperature of 3°C. The mobile phase was composed of 0.1% trifluoroacetic acid in water and acetonitrile. The flow rate was 1 ml/min and detection wavelength was set at 205 nm and 280 nm. Validation was performed in order to demonstrate selectivity, accuracy and precision of the method. Results: The calibration curves showed good linearity (R2 > 0.99). The limits of detection and limits of quantification were within the ranges 0.0159–0.6205 μg/ml and 0.3210–1.8802 μg/ml, respectively. Moreover, the relative standard deviations of intra- and inter-day precision were both <2.98%. The overall recoveries were in the range of 96.23–109.87%. Quantitative analysis of eight compounds in 12 D. superbus samples (D-1–D-12) from various regions were analyzed and compared by developed method. Conclusion: As a result, this established method was accurate and sensitive for the quality evaluation of eight compounds isolated from D. superbus and may provide a new basis for quality control of D. superbus. SUMMARY A simultaneous determination method of eight compounds in Dianthus superbus was established by high performance liquid chromatography-diode array detectorDeveloped analysis method is

  17. Determination of Decabrominated Diphenyl Ether in Soils by Soxhlet Extraction and High Performance Liquid Chromatography

    PubMed Central

    Yang, Xing-Jian; Dang, Zhi; Zhang, Fang-Li; Lin, Zhao-Ying; Zou, Meng-Yao; Tao, Xue-Qin; Lu, Gui-Ning

    2013-01-01

    This study described the development of a method based on soxhlet extraction combining high performance liquid chromatography (soxhlet-HPLC) for the accurate detection of BDE-209 in soils. The solvent effect of working standard solutions in HPLC was discussed. Results showed that 1 : 1 of methanol and acetone was the optimal condition which could totally dissolve the BDE-209 in environmental samples and avoid the decrease of the peak area and the peak deformation difference of BDE-209 in HPLC. The preliminary experiment was conducted on the configured grassland (1 μg/g) to validate the method feasibility. The method produced reliable reproducibility, simulated soils (n = 4) RSD 1.0%, and was further verified by the analysis e-waste contaminated soils, RSD range 5.9–11.4%. The contamination level of BDE-209 in burning site was consistent with the previous study of Longtang town but lower than Guiyu town, and higher concentration of BDE-209 in paddy field mainly resulted from the long-standing disassembling area nearby. This accurate and fast method was successfully developed to extract and analyze BDE-209 in soil samples, showing its potential use for replacing GC to determinate BDE-209 in soil samples. PMID:24302876

  18. Determination of decabrominated diphenyl ether in soils by Soxhlet extraction and high performance liquid chromatography.

    PubMed

    Yang, Xing-Jian; Dang, Zhi; Zhang, Fang-Li; Lin, Zhao-Ying; Zou, Meng-Yao; Tao, Xue-Qin; Lu, Gui-Ning

    2013-01-01

    This study described the development of a method based on Soxhlet extraction combining high performance liquid chromatography (Soxhlet-HPLC) for the accurate detection of BDE-209 in soils. The solvent effect of working standard solutions in HPLC was discussed. Results showed that 1:1 of methanol and acetone was the optimal condition which could totally dissolve the BDE-209 in environmental samples and avoid the decrease of the peak area and the peak deformation difference of BDE-209 in HPLC. The preliminary experiment was conducted on the configured grassland (1 μ g/g) to validate the method feasibility. The method produced reliable reproducibility, simulated soils (n = 4) RSD 1.0%, and was further verified by the analysis e-waste contaminated soils, RSD range 5.9-11.4%. The contamination level of BDE-209 in burning site was consistent with the previous study of Longtang town but lower than Guiyu town, and higher concentration of BDE-209 in paddy field mainly resulted from the long-standing disassembling area nearby. This accurate and fast method was successfully developed to extract and analyze BDE-209 in soil samples, showing its potential use for replacing GC to determinate BDE-209 in soil samples.

  19. A Method for the Quantitation of Trace Levels of Dimethyl Sulfoxide in Urine by High Performance Liquid Chromatography

    DTIC Science & Technology

    1989-05-01

    HIGH PERFORMANCE LIQUID CHROMATOGRAPHY by...for the sample cleanup and concentration, followed by separation by reversed phase high performance liquid chromatography . EXPERIMENTAL Materials...DIMETHYL SULFOXIDE IN URINE BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY 4. AUTHORS (Last name, first name, middle initial. If military, show rank, e.g.

  20. Determination of Dimethyl Sulfoxide (DMSO), Ethanol (ETOH), Formamide (F) and Glycerol/Formal (GF) by High Performance Liquid Chromatography (HPLC)

    DTIC Science & Technology

    1989-01-30

    HIGH PERFORMANCE LIQUID CHROMATOGRAPHY (HPLC...Classification) (U) Determination of Dimethyl Sulfoxide (DMSO), Ethanol, (ETOH), Formamide (F), and Glycerol/ Formal (GF) by High Performance Liquid Chromatography (HPLC...and 5). High performance liquid chromatography (HPLC) was the analytical method of choice for analyzing DMSO, ethanol, formamide and

  1. Determination of 5-Bromo-2’-Deoxyuridine (BrdU) in Well Water by High Performance Liquid Chromatography (HPLC)

    DTIC Science & Technology

    1992-09-01

    HIGH PERFORMANCE LIQUID CHROMATOGRAPHY (HPLC...Securrty Classification) Determination of 5-Bromo-2’-Deoxyuridine (BrdU) in Well Water by High Performance Liquid Chromatography (hPLC) 12. PERSONAL...PLOT OF BrdU STABILITY VERSUS TIME ....................... 10 ii DETERMINATION OF 5-BROMO-2’-DEOXY-URIDINE (BrdU) IN WELL WATER BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

  2. Crosslinked polymeric ionic liquids as solid-phase microextraction sorbent coatings for high performance liquid chromatography.

    PubMed

    Yu, Honglian; Merib, Josias; Anderson, Jared L

    2016-03-18

    Neat crosslinked polymeric ionic liquid (PIL) sorbent coatings for solid-phase microextraction (SPME) compatible with high-performance liquid chromatography (HPLC) are reported for the first time. Six structurally different PILs were crosslinked to nitinol supports and applied for the determination of select pharmaceutical drugs, phenolics, and insecticides. Sampling conditions including sample solution pH, extraction time, desorption solvent, desorption time, and desorption solvent volume were optimized using design of experiment (DOE). The developed PIL sorbent coatings were stable when performing extractions under acidic pH and remained intact in various organic desorption solvents (i.e., methanol, acetonitrile, acetone). The PIL-based sorbent coating polymerized from the IL monomer 1-vinyl-3-(10-hydroxydecyl) imidazolium chloride [VC10OHIM][Cl] and IL crosslinker 1,12-di(3-vinylbenzylimidazolium) dodecane dichloride [(VBIM)2C12] 2[Cl] exhibited superior extraction performance compared to the other studied PILs. The extraction efficiency of pharmaceutical drugs and phenolics increased when the film thickness of the PIL-based sorbent coating was increased while many insecticides were largely unaffected. Satisfactory analytical performance was obtained with limits of detection (LODs) ranging from 0.2 to 2 μg L(-1) for the target analytes. The accuracy of the analytical method was examined by studying the relative recovery of analytes in real water samples, including tap water and lake water, with recoveries varying from 50.2% to 115.9% and from 48.8% to 116.6%, respectively.

  3. DETERMINATION OF CARBENDAZIM IN WATER BY HIGH-PERFORMANCE IMMUNOAFFINITY CHROMATOGRAPHY ON-LINE WITH HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY WITH DIODE-ARRAY OR MASS SPECTROMETRIC DETECTION

    EPA Science Inventory

    An automated method for the determination of carbendazim in water that combines high-performance immunoaffinity chromatography (HPIAC), high-performance liquid chromatography (HPLC) in the reversed-phase mode, and detection by either UV-Vis diode array detector (DAD) spectroscopy...

  4. Quality evaluation of moluodan concentrated pill using high-performance liquid chromatography fingerprinting coupled with chemometrics.

    PubMed

    Tao, Lingyan; Zhang, Qing; Wu, Yongjiang; Liu, Xuesong

    2016-12-01

    In this study, a fast and effective high-performance liquid chromatography method was developed to obtain a fingerprint chromatogram and quantitative analysis simultaneously of four indexes including gallic acid, chlorogenic acid, albiflorin and paeoniflorin of the traditional Chinese medicine Moluodan Concentrated Pill. The method was performed by using a Waters X-bridge C18 reversed phase column on an Agilent 1200S high-performance liquid chromatography system coupled with diode array detection. The mobile phase of the high-performance liquid chromatography method was composed of 20 mmol/L phosphate solution and acetonitrile with a 1 mL/min eluent velocity, under a detection temperature of 30°C and a UV detection wavelength of 254 nm. After the methodology validation, 16 batches of Moluodan Concentrated Pill were analyzed by this high-performance liquid chromatography method and both qualitative and quantitative evaluation results were achieved by similarity analysis, principal component analysis and hierarchical cluster analysis. The results of these three chemometrics were in good agreement and all indicated that batch 10 and batch 16 showed significant differences with the other 14 batches. This suggested that the developed high-performance liquid chromatography method could be applied in the quality evaluation of Moluodan Concentrated Pill.

  5. High Performance Fatty Acid-Based Vinyl Ester Resin for Liquid Molding

    DTIC Science & Technology

    2007-07-01

    Diglycidyl ether of bisphenol-A ( DGEBA ) Methacrylic Acid Figure 1: The reaction of DGEBA and methacrylic acid to produce the vinyl ester 2.3...High Performance Fatty Acid -Based Vinyl Ester Resin for Liquid Molding by Xing Geng, John J. La Scala, James M. Sands, and Giuseppe R...it to the originator. Army Research Laboratory Aberdeen Proving Ground, MD 21005-5069 ARL-RP-184 July 2007 High Performance Fatty Acid

  6. Development and validation of high-performance liquid chromatography and high-performance thin-layer chromatography methods for the quantification of khellin in Ammi visnaga seed

    PubMed Central

    Kamal, Abid; Khan, Washim; Ahmad, Sayeed; Ahmad, F. J.; Saleem, Kishwar

    2015-01-01

    Objective: The present study was used to design simple, accurate and sensitive reversed phase-high-performance liquid chromatography RP-HPLC and high-performance thin-layer chromatography (HPTLC) methods for the development of quantification of khellin present in the seeds of Ammi visnaga. Materials and Methods: RP-HPLC analysis was performed on a C18 column with methanol: Water (75: 25, v/v) as a mobile phase. The HPTLC method involved densitometric evaluation of khellin after resolving it on silica gel plate using ethyl acetate: Toluene: Formic acid (5.5:4.0:0.5, v/v/v) as a mobile phase. Results: The developed HPLC and HPTLC methods were validated for precision (interday, intraday and intersystem), robustness and accuracy, limit of detection and limit of quantification. The relationship between the concentration of standard solutions and the peak response was linear in both HPLC and HPTLC methods with the concentration range of 10–80 μg/mL in HPLC and 25–1,000 ng/spot in HPTLC for khellin. The % relative standard deviation values for method precision was found to be 0.63–1.97%, 0.62–2.05% in HPLC and HPTLC for khellin respectively. Accuracy of the method was checked by recovery studies conducted at three different concentration levels and the average percentage recovery was found to be 100.53% in HPLC and 100.08% in HPTLC for khellin. Conclusions: The developed HPLC and HPTLC methods for the quantification of khellin were found simple, precise, specific, sensitive and accurate which can be used for routine analysis and quality control of A. visnaga and several formulations containing it as an ingredient. PMID:26681890

  7. High-performance liquid chromatography of oligoguanylates at high pH

    NASA Technical Reports Server (NTRS)

    Stribling, R.; Deamer, D. (Principal Investigator)

    1991-01-01

    Because of the stable self-structures formed by oligomers of guanosine, standard high-performance liquid chromatography techniques for oligonucleotide fractionation are not applicable. Previously, oligoguanylate separations have been carried out at pH 12 using RPC-5 as the packing material. While RPC-5 provides excellent separations, there are several limitations, including the lack of a commercially available source. This report describes a new anion-exchange high-performance liquid chromatography method using HEMA-IEC BIO Q, which successfully separates different forms of the guanosine monomer as well as longer oligoguanylates. The reproducibility and stability at high pH suggests a versatile role for this material.

  8. Analysis of lipoprotein profiles of healthy cats by gel-permeation high-performance liquid chromatography

    PubMed Central

    MIZUTANI, Hisashi; SAKO, Toshinori; OKUDA, Hiroko; ARAI, Nobuaki; KURIYAMA, Koji; MORI, Akihiro; YOSHIMURA, Itaru; KOYAMA, Hidekazu

    2016-01-01

    Density gradient ultracentrifugation (DGUC) and gel electrophoresis are conventionally used to obtain lipoprotein profiles of animals. We recently applied high-performance liquid chromatography with a gel permeation column (GP-HPLC) and an on-line dual enzymatic system to dogs for lipoprotein profile analysis. We compared the GP-HPLC with DGUC as a method to obtain a feline lipoprotein profile. The lipoprotein profiles showed large and small peaks, which corresponded to high-density lipoprotein (HDL) and low-density lipoprotein (LDL), respectively, whereas very low-density lipoprotein (VLDL) and chylomicron (CM) were only marginally detected. This profile was very similar to that of dogs reported previously. Healthy cats also had a small amount of cholesterol-rich particles distinct from the normal LDL or HDL profile. There was no difference in lipoprotein profiles between the sexes, but males had a significantly larger LDL particle size (P=0.015). This study shows the feasibility of GP-HPLC for obtaining accurate lipoprotein profiles with small sample volumes and provides valuable reference data for healthy cats that should facilitate diagnoses. PMID:27170431

  9. Simultaneous analysis of eprosartan and hydrochlorothiazide in tablets by high-performance liquid chromatography

    PubMed Central

    Patel, Harsha U.; Suhagia, Bhanubhai N.; Patel, Chhaganbhai N.

    2011-01-01

    Objective: A simple, precise and accurate isocratic reversed phase (RP) column high-performance liquid chromatographic (HPLC) method has been developed for simultaneous analysis of eprosartan (EPR) and hydrochlorothiazide (HCT) in tablet formulations. Materials and Methods: Isocratic RP-HPLC separation was achieved on phenomenex C18 column (250 × 4.6 mm i.d., 5 μm particle size) using mobile phase composed of 0.5% formic acid-methanol-acetonitrile [(80 : 25 : 20 v/v/v) pH, 2.80 ± 0.04] at a flow rate of 1.0 ml/min. The retention time for EPR and HCT was 7.69 ± 0.10 and 4.24 ± 0.09 minutes, respectively. The detection was performed at 272 nm. Results: The method was linear in the concentration range of 60-600 μg/ml for EPR and 2.5-25 μg/ml for HCT with a correlation coefficient of 0.9992 and 0.9997, respectively. The repeatability for six samples was 0.53 and 0.61 % RSD for EPR and HCT, respectively. The accuracy (recovery) was found to be in the range of 99.46 to 100.61% for EPR and 99.06 to 100.93% for HCT, respectively. Conclusions: The method was validated and successfully used for determination of the drugs in tablets. PMID:23781445

  10. Determination of linezolid in human plasma by high-performance liquid chromatography with ultraviolet detection.

    PubMed

    Cattaneo, Dario; Baldelli, Sara; Conti, Francesca; Cozzi, Valeria; Clementi, Emilio

    2010-08-01

    A high-performance liquid chromatographic method for the determination of linezolid in human plasma was developed and validated. After precipitation of plasma proteins with perchloric acid, the protein-free supernatant was separated by isocratic reverse-phase chromatography on a X Bridge C18 column. The mobile phase consisted of a mixture of phosphoric acid 0.05%: acetonitrile (75:25, v/v) with a flow rate of 1 mL/min. The column elute was monitored at 254 nm. The method was linear from 0.2 to 48 mg/L (mean r2 = 0.9996, n = 10). The observed intra- and inter-day assay imprecision ranged from 2.83% to 8.16% (18.80% at the lower limit of quantification); inaccuracy varied between -0.33% and 8.18%. Mean drug recovery was 99.8% for linezolid and 90.0% for the internal standard (para-toluic acid). The method was found to be precise and accurate and suitable for therapeutic drug monitoring of linezolid in routine clinical practice.

  11. Quantitative structure-retention relationships of pesticides in reversed-phase high-performance liquid chromatography.

    PubMed

    Aschi, Massimiliano; D'Archivio, Angelo Antonio; Maggi, Maria Anna; Mazzeo, Pietro; Ruggieri, Fabrizio

    2007-01-23

    In this paper, a quantitative structure-retention relationships (QSRR) method is employed to predict the retention behaviour of pesticides in reversed-phase high-performance liquid chromatography (HPLC). A six-parameter nonlinear model is developed by means of a feed-forward artificial neural network (ANN) with back-propagation learning rule. Accurate description of the retention factors of 26 compounds including commonly used insecticides, herbicides and fungicides and some metabolites is successfully achieved. In addition to the acetonitrile content, included to describe composition of the water-acetonitrile mobile phase, the octanol-water partition coefficient (from literature) and four quantum chemical descriptors are considered to account for the effect of solute structure on the retention. These are: the total dipole moment, the mean polarizability, the anisotropy of polarizability and a descriptor of hydrogen bonding ability based on the atomic charges on hydrogen bond donor and acceptor chemical functionalities. The proposed nonlinear QSRR model exhibits a high degree of correlation between observed and computed retention factors and a good predictive performance in wide range of mobile phase composition (40-65%, v/v acetonitrile) that supports its application for the prediction of the chromatographic behaviour of unknown pesticides. A multilinear regression model based on the same six descriptors shows a significantly worse predictive capability.

  12. Development and Validation of Reversed-Phase High Performance Liquid Chromatographic Method for Hydroxychloroquine Sulphate.

    PubMed

    Singh, A; Roopkishora; Singh, C L; Gupta, R; Kumar, S; Kumar, M

    2015-01-01

    In the present work new, simple reversed-phase high performance liquid chromatographic method was developed and validated for the determination of hydroxychloroquine sulphate in blood plasma. Chloroquine sulphate was used as an internal standard. The chromatographic separation was achieved with octadecyl silane Hypersil C18 column (250×6 mm, 5 μm) using water and organic (acetonitrile:methanol: 50:50, v/v) mobile phase in 75:25 v/v ratio, with sodium 1-pentanesulfonate and phosphoric acid. This organic phase was maintained at pH 3.0 by orthophosphoric acid. The flow rate of 2.0 ml/min(.) with detection at 343 nm was used in the analysis. The calibration curve of standard hydroxychloroquine sulphate was linear in range 0.1-20.0 μg/ml. The method was validated with respected to linearity, range, precision, accuracy, specificity and robustness studies according to ICH guidelines. The method was found to be accurate and robust to analyze the hydroxychloroquine sulphate in plasma samples.

  13. [Determination of lutein in infant formula milk powder using ultra-high performance liquid chromatography].

    PubMed

    Wang, Lin; Huang, Junrong; Zhang, Li; Feng, Feng; Ling, Yun; Chu, Xiaogang; Li, Hongliang

    2013-12-01

    An ultra-high performance liquid chromatography (U-HPLC) method for the determination of lutein in the infant formula milk powder was developed. The sample was extracted with acetone and defatted using freezing centrifugation method. The U-HPLC separation was achieved using a YMC Carotenoid C30 column (150 mm x 4.6 mm, 3 microm) with the mixture of methanol/methyl tert-butyl ether (70: 30, v/v) as the mobile phase under isocratic elution. The flow rate was 0.5 mL/min and the column oven temperature was 25 degrees C. The injection volume was 5 microL. It was detected on a photodiode array detector at a wavelength of 445 nm. The results showed that the linear range was 20-500 microg/L (r = 0.9999), and the limit of quantification was 20 microg/L. The mean recoveries of lutein varied from 97.9% to 104.4% spiked at 50, 250 and 2,000 microg/kg. The established method is simple, accurate and sensitive for the rapid determination of lutein in infant formula milk powder.

  14. Simultaneous determination of amlodipine and aliskren in tablets by high-performance liquid chromatography.

    PubMed

    Özdemir, Filiz Arıöz; Akyüz, Atalay

    2014-08-01

    A new, simple, rapid and specific reversed-phase high-performance liquid chromatography (HPLC) method was developed and validated for the simultaneous determination of amlodipine besylate and aliskiren hemifumarate. The HPLC separation was achieved on an RP-18 column (250 × 4.6 mm) using a mobile phase of triethylamine-orthophosphoric acid buffer (50 mM, pH 3.0), acetonitrile and methanol (50:40:10, v/v/v) at a flow rate of 1 mL/min. The method was validated for specificity, linearity, precision, accuracy and robustness. The degree of linearity of the calibration curves, the percent recovery values of amlodipine and aliskiren and the limits of detection (LOD) and quantification (LOQ) for the HPLC method were determined. The linearity of the method was found to be in the concentration range of 5.0-50.0 µg/mL for aliskiren hemifumarate and 2.65-26.50 µg/mL for amlodipine besylate, LOD and LOQ values were 0.51, 0.95, 1.70 and 3.18 µg/mL for amlodipine besylate and aliskiren hemifumarate. The proposed method was successfully applied to amlodipine besylate and aliskiren hemifumarate in pharmaceutical dosage mixtures without any interference from the excipients. The method was found to be precise, accurate, reproducible and robust. The results agreed with those obtained using the developed reference method.

  15. [Determination of dicyandiamide in dairy products by high performance liquid chromatography].

    PubMed

    Chen, Xiaozhen; Chen, Wanqin; Wang, Jin; Huang, Liying; Zhang, Donglei

    2013-09-01

    A high performance liquid chromatographic (HPLC) method for the determination of dicyandiamide in dairy products was developed. The sample was extracted by acetonitrile, separated on an XBridge Amide column (250 mm x 4.6 mm, 3.5 microm) using acetonitrile-water (90/10, v/v) containing 0.2% (v/v) formic acid as the mobile phase at a flow rate of 1.0 mL/min, and determined by a photodiode array detector at the wavelength of 218 nm. The calibration curve was linear in the range of 0.5 - 50 mg/L with the correlation coefficient (r2) of 0.999 9. The recoveries were from 96.7% to 101.0% with the relative standard deviations (RSDs) in the range of 4.5% to 4.9% (n = 6). The limit of detection was 0.2 mg/kg, and the limit of quantification was 0.5 mg/kg. The method is simple, sensitive, accurate and precise for the determination of dicyandiamide in dairy products.

  16. Group-type hydrocarbon standards for high-performance liquid chromatographic analysis of middistillate fuels

    NASA Technical Reports Server (NTRS)

    Otterson, D. A.; Seng, G. T.

    1984-01-01

    A new high-performance liquid chromatographic (HPLC) method for group-type analysis of middistillate fuels is described. It uses a refractive index detector and standards that are prepared by reacting a portion of the fuel sample with sulfuric acid. A complete analysis of a middistillate fuel for saturates and aromatics (including the preparation of the standard) requires about 15 min if standards for several fuels are prepared simultaneously. From model fuel studies, the method was found to be accurate to within 0.4 vol% saturates or aromatics, and provides a precision of + or - 0.4 vol%. Olefin determinations require an additional 15 min of analysis time. However, this determination is needed only for those fuels displaying a significant olefin response at 200 nm (obtained routinely during the saturated/aromatics analysis procedure). The olefin determination uses the responses of the olefins and the corresponding saturates, as well as the average value of their refractive index sensitivity ratios (1.1). Studied indicated that, although the relative error in the olefins result could reach 10 percent by using this average sensitivity ratio, it was 5 percent for the fuels used in this study. Olefin concentrations as low as 0.1 vol% have been determined using this method.

  17. Sources of Variability in Chlorophyll Analysis by Fluorometry and by High Performance Liquid Chromatography. Chapter 22

    NASA Technical Reports Server (NTRS)

    VanHeukelem, Laurie; Thomas, Crystal S.; Glibert, Patricia M.

    2001-01-01

    The need for accurate determination of chlorophyll a (chl a) is of interest for numerous reasons. From the need for ground-truth data for remote sensing to pigment detection for laboratory experimentation, it is essential to know the accuracy of the analyses and the factors potentially contributing to variability and error. Numerous methods and instrument techniques are currently employed in the analyses of chl a. These methods range from spectrophotometric quantification, to fluorometric analysis and determination by high performance liquid chromatography. Even within the application of HPLC techniques, methods vary. Here we provide the results of a comparison among methods and provide some guidance for improving the accuracy of these analyses. These results are based on a round-robin conducted among numerous investigators, including several in the Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) and HyCODE Programs. Our purpose here is not to present the full results of the laboratory intercalibration; those results will be presented elsewhere. Rather, here we highlight some of the major factors that may contribute to the variability observed. Specifically, we aim to assess the comparability of chl a analyses performed by fluorometry and HPLC, and we identify several factors in the analyses which may contribute disproportionately to this variability.

  18. Quality Evaluation of Potentilla fruticosa L. by High Performance Liquid Chromatography Fingerprinting Associated with Chemometric Methods

    PubMed Central

    Liu, Wei; Wang, Dongmei; Liu, Jianjun; Li, Dengwu; Yin, Dongxue

    2016-01-01

    The present study was performed to assess the quality of Potentilla fruticosa L. sampled from distinct regions of China using high performance liquid chromatography (HPLC) fingerprinting coupled with a suite of chemometric methods. For this quantitative analysis, the main active phytochemical compositions and the antioxidant activity in P. fruticosa were also investigated. Considering the high percentages and antioxidant activities of phytochemicals, P. fruticosa samples from Kangding, Sichuan were selected as the most valuable raw materials. Similarity analysis (SA) of HPLC fingerprints, hierarchical cluster analysis (HCA), principle component analysis (PCA), and discriminant analysis (DA) were further employed to provide accurate classification and quality estimates of P. fruticosa. Two principal components (PCs) were collected by PCA. PC1 separated samples from Kangding, Sichuan, capturing 57.64% of the variance, whereas PC2 contributed to further separation, capturing 18.97% of the variance. Two kinds of discriminant functions with a 100% discrimination ratio were constructed. The results strongly supported the conclusion that the eight samples from different regions were clustered into three major groups, corresponding with their morphological classification, for which HPLC analysis confirmed the considerable variation in phytochemical compositions and that P. fruticosa samples from Kangding, Sichuan were of high quality. The results of SA, HCA, PCA, and DA were in agreement and performed well for the quality assessment of P. fruticosa. Consequently, HPLC fingerprinting coupled with chemometric techniques provides a highly flexible and reliable method for the quality evaluation of traditional Chinese medicines. PMID:26890416

  19. [Simultaneous determination of four common nonprotein nitrogen substances in urine by high performance liquid chromatography].

    PubMed

    Ma, Yuhua; Huang, Dongqun; Zhang, Rui; Xu, Shiru; Feng, Shun

    2013-11-01

    A high performance liquid chromatographic (HPLC) method was proposed to simultaneously determine four common nonprotein nitrogen substances, including creatine (Cr), creatinine (Cn), uric acid (Ua) and pseudouridine (Pu) in urine. After proteins being removed by acetone precipitation method, freeze drying and redissolving, the urine samples were analyzed by HPLC. Chromatographic separation was performed on a Waters RP18 Column (150 mm x 4.60 mm, 3.5 microm) in gradient elution mode using 10.0 mmol/L KH2PO4 solution (pH 4.78) and acetonitrile as mobile phases at a flow rate of 0.8 mL/min. The samples were detected at 220 nm. Rapid separation was achieved within 7 min. Under the optimized conditions, good linearities of four common nonprotein nitrogen substances were obtained in the range of 0.1-250 mg/L. The detection limits were 9.31 (Cr), 26.19 (Cn), 4.70 (Ua), an 6.30 (Pu) microg/L and the recoveries were in the range of 81%-111% with the relative standar deviations of 0.23%-2.78% (n = 3). The results demonstrate that this method is simple, rapid and accurate with good reproducibility, and can provide early diagnosis and preliminary judgment for type 2 diabetes mellitus (T2DM) patients with renal damage.

  20. [Simultaneous determination of 3 benzalkonium chloride homologs in cosmetics by high performance liquid chromatography].

    PubMed

    Liu, Yanqin; Wang, Hao; Yang, Hongmei; Shi, Hailiang; Guo, Qilei

    2011-05-01

    An analytical method based on high performance liquid chromatography with a diode array detector (HPLC-DAD) has been established for the simultaneous determination of 3 benzalkonium chloride homologs (n-C12H25-C9H13NCl, n-C14H29-C9H13NCl, n-C16,H33-C9H13NCl) in cosmetics. The sample was extracted with methanol (including 0.5% formic acid) under ultrasonic operation, the HPLC separation was carried out on a CAPCELL PAK SCX column (250 mm x 4.6 mm, 5 microm), the mobile phases were 40 mmol/L ammonium acetate solution (including 0.1% triethylamine) and acetonitrile with gradient elution, the flow rate was 1.0 mL/min, the detection wavelength was 260 nm, the column temperature was 25 degrees C, and the injection volume was 20 microL. The limit of detection was 50.0 mg/kg and the quantitation limit was 200.0 mg/kg for 3 benzalkonium chloride homologs in cosmetics. The linear plots were obtained between 5.0 mg/L and 3000.0 mg/L. Overall recoveries were between 92.5% and 102.1% with the relative standard deviations (RSDs) between 3.81% and 6.66%. The method is simple, rapid, accurate and suitable for the determination of 3 benzalkonium chloride homologs in cosmetics.

  1. Identification of Dactylopius cochineal species with high-performance liquid chromatography and multivariate data analysis.

    PubMed

    Serrano, Ana; Sousa, Micaela; Hallett, Jessica; Simmonds, Monique S J; Nesbitt, Mark; Lopes, João A

    2013-10-21

    Identification of American cochineal species (Dactylopius genus) can provide important information for the study of historical works of art, entomology, cosmetics, pharmaceuticals and foods. In this study, validated species of Dactylopius, including the domesticated cochineal D. coccus, were analysed by high-performance liquid chromatography with a diode array detector (HPLC-DAD) and submitted to multivariate data analysis, in order to discriminate the species and hence construct a reference library for a wide range of applications. Principal components analysis (PCA) and partial least squares discriminant analysis (PLSDA) models successfully provided accurate species classifications. This library was then applied to the identification of 72 historical insect specimens of unidentified species, mostly dating from the 19th century, and belonging to the Economic Botany Collection, Royal Botanic Gardens, Kew, England. With this approach it was possible to identify anomalies in how insects were labelled historically, as several of them were revealed not to be cochineal. Nevertheless, more than 85% of the collection was determined to be species of Dactylopius and the majority of the specimens were identified as D. coccus. These results have shown that HPLC-DAD, in combination with suitable chemometric methods, is a powerful approach for discriminating related cochineal species.

  2. [Simultaneous determination of 38 limited colorants in cosmetics by high performance liquid chromatography].

    PubMed

    Mao, Xiqin; Li, Chunling; Ren, Guojie; Zhang, Guocui; Li, Xiaofei; Li, Peng

    2015-03-01

    A method has been established for the simultaneous determination of 38 limited colorants in cosmetics by high performance liquid chromatography (HPLC). The samples were extracted by ultrasonic with tetrahydrofuran, methanol, ammonium acetate solution as extraction solvents. After centrifugation, nitrogen blow and redissolved in turn, the extracts were separated on an Agilent zorbax SB-Aq column (150 mm x 3.0 mm, 3.5 µm) using a gradient elution program with acetonitrile and 30 mmol/L ammonium acetate containing 0.075% (v/v) formic acid as mobile phases. The detection wavelengths were set at 254, 416, 484, 514, 590 and 620 nm. The linear ranges of the 38 target compounds were all in the range of 1 to 10 mg/L with correlation coefficients more than 0.999. The limits of quantification (LOQs) for the 38 colorants were in the range of 5-50 µg/g. The average recoveries at two spiked levels ranged from 93.2% to 107.6% with the relative standard deviations (RSDs) less than 10% (n = 6). This method is accurate, simple, sensitive and reliable, and can be used for the analysis of the 38 limited colorants in cosmetics.

  3. [Determination of quercetin in apples by reversed-phase high performance liquid chromatography].

    PubMed

    Mao, Li; Jin, Nianzu; Chen, Jingheng

    2005-05-01

    A method for the determination of quercetin in pulp and peel of apples by reversed-phase high performance liquid chromatography with internal standard was developed. Samples were frozen at -80 degrees C for 24 h, then added 6 mol/L hydrochloride under the protection of antioxidant 2,6-di-tert-butyl-p-cresol. The slurry was hydrolyzed thermostatically at 90 degrees C for 2 h and centrifugated for 10 min. The separation was performed on an ODS column (150 mm x 6.0 mm i.d., 5 microm). Methanol-water (55:45, v/v) (pH adjusted to 3.3 with acetic acid) was used as the mobile phase with a flow rate of 1.0 mL/min. The injection volume was 20 microL. The detection wavelength was 370 nm. The results showed that the quercetin content in pulp and in peel were 3.11-10.78 microg/g and 253.57-744.59 microg/g, respectively. The mean recovery of quercetin in apple pulp was 100.4%. The method is simple, accurate, and reliable.

  4. Quantitation of meloxicam in the plasma of koalas (Phascolarctos cinereus) by improved high performance liquid chromatography

    PubMed Central

    Kimble, Benjamin; Li, Kong Ming

    2013-01-01

    An improved method to determine meloxicam (MEL) concentrations in koala plasma using reversed phase high performance liquid chromatography equipped with a photo diode array detector was developed and validated. A plasma sample clean-up step was carried out with hydrophilic-lipophilic copolymer solid phase extraction cartridges. MEL was separated from an endogenous interference using an isocratic mobile phase [acetonitrile and 50 mM potassium phosphate buffer (pH 2.15), 45:55 (v:v)] on a Nova-Pak C18 4-µm (300 × 3.9 mm) column. Retention times for MEL and piroxicam were 8.03 and 5.56 min, respectively. Peak area ratios of MEL to the internal standard (IS) were used for regression analysis of the calibration curve, which was linear from 10 to 1,000 ng/mL (r2 > 0.9998). Average absolute recovery rates were 91% and 96% for MEL and the IS, respectively. This method had sufficient sensitivity (lower quantitation limit of 10 ng/mL), precision, accuracy, and selectivity for routine analysis of MEL in koala plasma using 250-µL sample volumes. Our technique clearly resolved the MEL peak from the complex koala plasma matrix and accurately measured MEL concentrations in small plasma volumes. PMID:23388431

  5. Quality Evaluation of Potentilla fruticosa L. by High Performance Liquid Chromatography Fingerprinting Associated with Chemometric Methods.

    PubMed

    Liu, Wei; Wang, Dongmei; Liu, Jianjun; Li, Dengwu; Yin, Dongxue

    2016-01-01

    The present study was performed to assess the quality of Potentilla fruticosa L. sampled from distinct regions of China using high performance liquid chromatography (HPLC) fingerprinting coupled with a suite of chemometric methods. For this quantitative analysis, the main active phytochemical compositions and the antioxidant activity in P. fruticosa were also investigated. Considering the high percentages and antioxidant activities of phytochemicals, P. fruticosa samples from Kangding, Sichuan were selected as the most valuable raw materials. Similarity analysis (SA) of HPLC fingerprints, hierarchical cluster analysis (HCA), principle component analysis (PCA), and discriminant analysis (DA) were further employed to provide accurate classification and quality estimates of P. fruticosa. Two principal components (PCs) were collected by PCA. PC1 separated samples from Kangding, Sichuan, capturing 57.64% of the variance, whereas PC2 contributed to further separation, capturing 18.97% of the variance. Two kinds of discriminant functions with a 100% discrimination ratio were constructed. The results strongly supported the conclusion that the eight samples from different regions were clustered into three major groups, corresponding with their morphological classification, for which HPLC analysis confirmed the considerable variation in phytochemical compositions and that P. fruticosa samples from Kangding, Sichuan were of high quality. The results of SA, HCA, PCA, and DA were in agreement and performed well for the quality assessment of P. fruticosa. Consequently, HPLC fingerprinting coupled with chemometric techniques provides a highly flexible and reliable method for the quality evaluation of traditional Chinese medicines.

  6. Simultaneous determination of tolperisone and lidocaine by high performance liquid chromatography.

    PubMed

    Liawruangrath, S; Liawruangrath, B; Pibool, P

    2001-12-01

    A reversed phase high performance liquid chromatographic (RP-HPLC) method for the simultaneous determination of tolperisone (TP) and lidocaine (LD) has been developed. The drugs were separated on a column (4.60 x 250 mm(2)) Spherisorb ODS (5 microm) using 5.5% triethylamine in 70/30 v/v acetonitrile/water as mobile phase 0.7 ml min(-1)and UV detection at 254 nm. The detection limits for Tolperisone hydrochloride (TP-HCl) and lidocaine hydrochloride (LD-HCl) were 0.20 ng/20 microl and 100 ng/20 microl and the quantitation limits were 0.50 ng/20 microl and 250 ng/20 microl, respectively. Linear calibration curves over the ranges of 1-10, 10-100 and 150-500 microg ml(-1) for TP-HCl and 10-500 microg ml(-1) for LD-HCl were established. Different calibration slopes were found for TP probably owing to changes in refractive index due to increase in TP concentration. The average recoveries of the added TP in the samples (TP-HCl tablets and injection liquid). A solutions spiked with standard TP-HCl were 99.9 and 99.7% with the RSD (n=11) of 0.66 and 0.67%, respectively. The average recovery of the added LD in the sample (injection) spiked with standard LD-HCl was 98.9% with the RSD (n=11) of 0.59%. The proposed method has been applied to the determination of TP-HCl and LD-HCl in commercial products available in Thailand. Comparative determination of TP by UV spectrophotometry and LD by colorimetry were also carried out. The results obtained by both methods were in good agreement of those obtained by the proposed method verified by using t-test. The proposed RP-HPLC method is simple, accurate, reproducible and suitable for routine analysis.

  7. Vortex and air assisted liquid-liquid microextraction as a sample preparation method for high-performed liquid chromatography determinations.

    PubMed

    Hosseini, Mohammad; Heydari, Rouhollah; Alimoradi, Mohammad

    2014-12-01

    A novel, simple and sensitive method based on vortex and air assisted liquid-liquid microextraction (VAALLME) technique coupled with high-performance liquid chromatography (HPLC) has been developed for quantitative analysis of β-naphthol, naphthalene and anthracene as model analytes. Unlike the dispersive liquid-liquid microextraction (DLLME), dispersive solvent and centrifuging step were eliminated in proposed technique. In this technique, extraction solvent was dispersed into the aqueous sample solution by using vortex. Phase separation was achieved via motion of air bubbles from the bottom to top of the extraction tube, which promoted the analytes transfer into the supernatant organic phase. Influential parameters on the extraction efficiency such as type and volume of extraction solvent, salt type and its concentration, vortex and aeration times, and sample pH were evaluated and optimized. The calibration curves showed good linearity (r(2)>0.9947) and precision (RSD<5.0%) in the working concentration ranges. The limit of detection (LOD) for β-naphthol, naphthalene and anthracene were 10, 5.0 and 0.5 ng mL(-1), respectively. The recoveries were in the range of 97.0-102.0% with RSD values ranging from 2.2 to 5.2%.

  8. High-Performance Liquid Chromatography in the Undergraduate Chemical Engineering Laboratory

    ERIC Educational Resources Information Center

    Frey, Douglas D.; Guo, Hui; Karnik, Nikhila

    2013-01-01

    This article describes the assembly of a simple, low-cost, high-performance liquid chromatography (HPLC) system and its use in the undergraduate chemical engineering laboratory course to perform simple experiments. By interpreting the results from these experiments students are able to gain significant experience in the general method of…

  9. Sugar Determination in Foods with a Radially Compressed High Performance Liquid Chromatography Column.

    ERIC Educational Resources Information Center

    Ondrus, Martin G.; And Others

    1983-01-01

    Advocates use of Waters Associates Radial Compression Separation System for high performance liquid chromatography. Discusses instrumentation and reagents, outlining procedure for analyzing various foods and discussing typical student data. Points out potential problems due to impurities and pump seal life. Suggests use of ribose as internal…

  10. Going Beyond, Going Further: An Inexpensive Experiment for the Introduction of High Performance Liquid Chromatography.

    ERIC Educational Resources Information Center

    Bidlingmeyer, Brian A.; Warren, F. Vincent, Jr.

    1984-01-01

    Background information, materials needed, laboratory procedures, and typical results are provided for five high performance liquid chromatography experiments (three isocratic and two step gradient separations). Suggestions for further experimentation are also provided, including quantitative determinations and separation of charged solutes. (JN)

  11. Models of retention of adamantylamidrazones in reversed-phase high-performance liquid chromatography

    NASA Astrophysics Data System (ADS)

    Prokopov, S. V.; Kurbatova, S. V.

    2011-05-01

    Rules governing the chromatographic behavior of some amidrazones of the adamantane series were studied under the conditions of reversed-phase high-performance liquid chromatography. The characteristics of the retention of sorbates in elution by aqueous-acetonitrile phases with various compositions were calculated. Correlations between the structure and physicochemical characteristics of sorbate molecules and their retention were studied.

  12. Extraction and Purification of Glucoraphanin by Preparative High-Performance Liquid Chromatography (HPLC)

    ERIC Educational Resources Information Center

    Lee, Iris; Boyce, Mary C.

    2011-01-01

    A student activity that focuses on the isolation of glucoraphanin from broccoli using preparative high-performance liquid chromatography (HPLC) is presented here. Glucoraphanin is a glucosinolate, whose byproducts are known to possess anticancer properties. It is present naturally at high levels in broccoli and other "Brassica" vegetables. This…

  13. Simple Method for Assaying Colistin Methanesulfonate in Plasma and Urine Using High-Performance Liquid Chromatography

    PubMed Central

    Li, Jian; Milne, Robert W.; Nation, Roger L.; Turnidge, John D.; Coulthard, Kingsley; Valentine, Jason

    2002-01-01

    A simple and sensitive high-performance liquid chromatographic method is described for the determination of colistimethate sodium in plasma and urine. The accuracy and reproducibility was within 10.1 and 11.2% with rat plasma and urine, respectively. Several commonly coadministered antibacterial agents do not interfere with the assay. PMID:12234867

  14. DETERMINATION OF CHLOROPHEONIS, NITROPHENOIS AND METHYLPHENOIS IN GROUND-WATER SAMPLES USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

    EPA Science Inventory

    A high performance liquid chromatography (HPLC) method was developed to quantitatively determine phenolic compounds and their isomers in aqueous samples. The HPLC method can analyze a mixture of 15 contaminants in the same analytical run with an analysis time of 25 minutes. The...

  15. DETERMINATION OF CHLOROPHENOLS, NITROPHENOLS, AND METHYLPHENOLS IN GROUND-WATER SAMPLES USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

    EPA Science Inventory

    A high performance liquid chromatography (HPLC) method was developed to quantitatively determine phenolic compounds and their isomers in aqueous samples. The HPLC method can analyze a mixture of 15 contaminants in the same analytical run with an analysis time of 25 minutes. The...

  16. An Advanced, Interactive, High-Performance Liquid Chromatography Simulator and Instructor Resources

    ERIC Educational Resources Information Center

    Boswell, Paul G.; Stoll, Dwight R.; Carr, Peter W.; Nagel, Megan L.; Vitha, Mark F.; Mabbott, Gary A.

    2013-01-01

    High-performance liquid chromatography (HPLC) simulation software has long been recognized as an effective educational tool, yet many of the existing HPLC simulators are either too expensive, outdated, or lack many important features necessary to make them widely useful for educational purposes. Here, a free, open-source HPLC simulator is…

  17. New methods and materials for solid phase extraction and high performance liquid chromatography

    SciTech Connect

    Dumont, Philip John

    1996-04-23

    This paper describes methods for solid phase extraction and high performance liquid chromatography (HPLC). The following are described: Effects of Resin Sulfonation on the Retention of Polar Organic Compounds in Solid Phase Extraction; Ion-Chromatographic Separation of Alkali Metals In Non-Aqueous Solvents; Cation-Exchange Chromatography in Non-Aqueous Solvents; and Silicalite As a Stationary Phase For HPLC.

  18. Determination of low molecular weight thiols using monobromobimane fluorescent labeling and high-performance liquid chromatography

    NASA Technical Reports Server (NTRS)

    Fahey, Robert C.; Newton, Gerald L.

    1988-01-01

    Methods are described for the preparation and high-performance liquid chromatography (HPLC) analysis of monobromobimane derivatives of low molecular weight thiols in extracts of biological samples. Typical problems encountered in the development and application of these methods are discussed. Analysis of mung bean extract is used as an example.

  19. High Performance Liquid Chromatographic Analysis of Phytoplankton Pigments Using a C16-Amide Column

    EPA Science Inventory

    A reverse-phase high performance liquid chromatographic (RP-HPLC) method was developed to analyze in a single run, most polar and non-polar chlorophylls and carotenoids from marine phytoplankton. The method is based on a RP-C16-Amide column and a ternary gradient system consistin...

  20. Chemical fingerprint of Ganmaoling granule by double-wavelength ultra high performance liquid chromatography and ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry.

    PubMed

    Lou, Qiong; Ye, Xiaolan; Zhou, Yingyi; Li, Hua; Song, Fenyun

    2015-06-01

    A method incorporating double-wavelength ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry was developed for the investigation of the chemical fingerprint of Ganmaoling granule. The chromatographic separations were performed on an ACQUITY UPLC HSS C18 column (2.1 × 50 mm, 1.8 μm) at 30°C using gradient elution with water/formic acid (1%) and acetonitrile at a flow rate of 0.4 mL/min. A total of 11 chemical constituents of Ganmaoling granule were identified from their molecular weight, UV spectra, tandem mass spectrometry data, and retention behavior by comparing the results with those of the reference standards or literature. And 25 peaks were selected as the common peaks for fingerprint analysis to evaluate the similarities among 25 batches of Ganmaoling granule. The results of principal component analysis and orthogonal projection to latent structures discriminant analysis showed that the important chemical markers that could distinguish the different batches were revealed as 4,5-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid, and 4-O-caffeoylquinic acid. This is the first report of the ultra high performance liquid chromatography chemical fingerprint and component identification of Ganmaoling granule, which could lay a foundation for further studies of Ganmaoling granule.

  1. Determination of chloroacetanilide herbicide metabolites in water using high-performance liquid chromatography-diode array detection and high-performance liquid chromatography/mass spectrometry

    USGS Publications Warehouse

    Hostetler, K.A.; Thurman, E.M.

    2000-01-01

    Analytical methods using high-performance liquid chromatography-diode array detection (HPLC-DAD) and high-performance liquid chromatography/mass spectrometry (HPLC/MS) were developed for the analysis of the following chloroacetanilide herbicide metabolites in water: alachlor ethanesulfonic acid (ESA); alachlor oxanilic acid; acetochlor ESA; acetochlor oxanilic acid; metolachlor ESA; and metolachlor oxanilic acid. Good precision and accuracy were demonstrated for both the HPLC-DAD and HPLC/MS methods in reagent water, surface water, and ground water. The average HPLC-DAD recoveries of the chloroacetanilide herbicide metabolites from water samples spiked at 0.25, 0.5 and 2.0 ??g/l ranged from 84 to 112%, with relative standard deviations of 18% or less. The average HPLC/MS recoveries of the metabolites from water samples spiked at 0.05, 0.2 and 2.0 ??g/l ranged from 81 to 118%, with relative standard deviations of 20% or less. The limit of quantitation (LOQ) for all metabolites using the HPLC-DAD method was 0.20 ??g/l, whereas the LOQ using the HPLC/MS method was at 0.05 ??g/l. These metabolite-determination methods are valuable for acquiring information about water quality and the fate and transport of the parent chloroacetanilide herbicides in water. Copyright (C) 2000 Elsevier Science B.V.

  2. Determination of pyrazon residues in water by reversed phase high performance liquid chromatography.

    PubMed

    Ahmad, I

    1982-01-01

    A simple analytical method is described for the quantitative determination of pyrazon residues in water. It involves high performance liquid chromatography with ultraviolet detection at 270 nm. The procedure is used to determine 2 ppb to 1 ppm levels of pyrazon in water. The traditional liquid-liquid extraction method has been replaced by an adsorption-trapping method for the extraction of pyrazon. Average recovery of pyrazon from the laboratory spiked samples was 98.1%. The method can be used for water samples with concentrations as low as 2 ppb.

  3. Determination of synthetic hormones in animal urine by high-performance liquid chromatography/mass spectrometry.

    PubMed

    Rúbies, Antoni; Cabrera, Albert; Centrich, Francesc

    2007-01-01

    A method was developed for the extraction of stanozolol, taleranol, zeranol, hexestrol, dienestrol, ethynylestradiol, diethylstilbestrol, and trenbolone from animal urine. The analytes were extracted from the matrix by enzymatic hydrolysis, solid-phase extraction, and liquid-liquid extraction. Detection and quantitation were performed on a high-performance liquid chromatography system coupled to a triple quadrupole mass spectrometer. The identification criteria met the European Union regulations. Validation of this method established a decision limit between 0.2 and 0.9 microg/L and a detection capability between 0.3 and 1.0 microg/L, depending on the analyte.

  4. High Performance Liquid Chromatography of Propellants. Part 1. Analysis of M1, M6, and M10 Propellants

    DTIC Science & Technology

    1986-05-01

    High performance liquid chromatography permits the differentation among the stabilizers and their degradation products together with accurate quantitation. This progress report describes work carried out in the analysis of single base propellants containing diphenylamine (DPA) as the stabilizer. Several degradation products have been identified and the routine determination of these compounds is feasible. The degradation of DPA seems to follow a pattern that is unique for M1 and M6’s as compared to the pattern for M10’s. It is postulated

  5. Anion-exchange high-performance liquid chromatography with conductivity detection for the analysis of phytic acid in food.

    PubMed

    Talamond, P; Doulbeau, S; Rochette, I; Guyot, J P

    2000-02-25

    A sensitive method for the accurate determination of phytic acid in food samples is described. The proposed procedure involves the anion-exchange liquid chromatography with conductivity detection. Initially, two methods of determination of phytic acid were compared: absorptiometry and high-performance ion chromatography (HPIC) with chemically suppressed conductivity detector. Unlike most conventional methods involving precipitation by FeCl3, the simpler and more reliable HPIC assay avoids the numerous assumptions inherent in the iron precipitation and the accuracy is independent of the phytate content. The protocol was also applied to a survey of phytic acid concentration in some cereal, oil and legume seeds.

  6. Stir-membrane solid-liquid-liquid microextraction for the determination of parabens in human breast milk samples by ultra high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Rodríguez-Gómez, Rocío; Roldán-Pijuán, Mercedes; Lucena, Rafael; Cárdenas, Soledad; Zafra-Gómez, Alberto; Ballesteros, Oscar; Navalón, Alberto; Valcárcel, Miguel

    2014-08-08

    In this article, stir-membrane solid-liquid-liquid microextraction (SM-SLLME) is tailored for the analysis of solid matrices and it has been evaluated for the determination of parabens in l breast milk samples. A three-phase microextraction mode was used for the extraction of the target compounds taking advantage of their acid-base properties. The unit allows the simultaneous extraction of the target compounds from the solid sample to an organic media and the subsequent transference of the analytes to an aqueous acceptor phase. The method includes the identification and quantification of the analytes by ultra high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). All the variables involved in the extraction procedure have been accurately studied and optimized. The analytes were detected and quantified using a triple quadrupole mass spectrometer (QqQ). The selection of two specific fragmentation transitions for each compound allowed simultaneous quantification and identification. The method has been analytically characterized on the basis of its linearity, sensitivity and precision. Limits of detection ranged from 0.1 to 0.2ngmL(-1) with precision better than 8%, (expressed as relative standard deviation). Relative recoveries were in the range from 91 to 106% which demonstrated the applicability of the stir-membrane solid-liquid-liquid microextraction for the proposed analytical problem. Moreover, the method has been satisfactorily applied for the determination of parabens in lyophilized breast milk samples from 10 randomly selected individuals.

  7. High-performance liquid chromatographic assay for cinnarizine in human plasma.

    PubMed

    Nowacka-Krukowska, Hanna; Rakowska, Monika; Neubart, Kinga; Kobylińska, Maria

    2007-01-01

    The high performance liquid chromatography for the determination of cinnarizine in human plasma is described. The procedure involves liquid-liquid extraction followed by reversed phase high-performance chromatographic analysis with fluorometric detection. The method was validated for accuracy, precision, specificity, linearity, sensitivity, recovery, and stability. No endogenous compounds were found to interfere. The absolute extraction recovery of cinnarizine and clocinizine (internal standard) from plasma samples were 97% and 89%, respectively. The linearity was assessed in the range 1-100 ng/mL. The intra-day and inter-day relative standard deviations were less than 10%, and the accuracy of the assay expressed by bias was in the range 0.14-2.37%. The method was proved to be suitable for human pharmacokinetic studies following single oral dose.

  8. Separation of Nitration By-Products in Commercial-Grade Trinitro-Toluene by High Performance Liquid Chromatography.

    DTIC Science & Technology

    1982-06-01

    MRL-TN-464 SEPARATION OF NITRATION BY-PRODUCTS IN COMMERCIAL-GRADE TITR-TOLUENE BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY Peter J. Sanders ABSTRACT...UNCLASSIFIED TITLE SEPARATION OF NITRATION BY-PRODUCTS IN COMMERCIAL-GRADE TRXNITRO-TOLUENE BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY AUTHOR(S...PRODUCTS IN COMMERCIAL-GRADE TRINITRO-TOLUENE BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY 16 INTRODUCTION Fbr some time, a need has existed for the

  9. Determination of plasma lactic acid concentration and specific activity using high-performance liquid chromatography.

    PubMed

    Bleiberg, B; Steinberg, J J; Katz, S D; Wexler, J; LeJemtel, T

    1991-08-23

    Assessment of lactate metabolism is of particular interest during exercise and in disease states such as diabetes, shock, and absorptive abnormalities of short-chain fatty acids by the colon. We describe an analytical method that introduces radio-active tracers and high-performance liquid chromatography (HPLC) to simultaneously analyze concentrations and specific activities (SAs) of plasma lactate. The HPLC conditions included separation on a reversed-phase column (octadecylsilane) and an isocratic buffer (30% acetonitrile in water). [3H]Acetate served as an internal standard. Lactate and acetate were extracted from plasma samples with diethyl ether following a pH adjustment to less than 1.0 and back-extracted into a hydrophilic phase with sodium carbonate (2 mM, pH greater than 10.0). Lactate is detected in the ultraviolet range (242 and 320 nm) by derivatization with alpha-bromoacetophenone. Control plasma samples were studied after an overnight fast for precision and analytical recovery. Calibration curves were linear in the range 0.18-6.0 mM (r = 0.92). The precision was 3% and the analytical recovery was 87%. The detection limit of the method was 36 pmol. Determination of lactate metabolism was performed in a patient with chronic congestive heart failure who was administered primed-continuous L-[U-14C]lactate (10 microCi bolus and 0.3 microCi/min continuously) during a 60-min rest period. Mean arterial lactate concentration and SA were 1.69 +/- 0.2 mM and 253.8 +/- 22 dpm/mumol, respectively. Systemic lactate turnover was 25.65 mumol/kg per min. Lactic acid systemic turnover, organ uptake and release rates can be accurately determined by isocratic HPLC.

  10. Determination of acaricides in honey by high-performance liquid chromatography with photodiode array detection.

    PubMed

    Martel, Anne-Claire; Zeggane, Sarah

    2002-04-19

    Rapid analytical methods are described to control quality of honeys, concerning residues of acaricides applied in hives to prevent Varroa jacobsoni infestation. A liquid-liquid extraction with hexane-propanol-2-ammonia (60 ml:30 ml:0.28%) was used for the simultaneous analysis of coumaphos, bromopropylate, amitraz and fluvalinate. For thymol, one clean up on a solid-phase extraction C18 (500 mg, 6 ml) column was performed; for rotenone, a liquid extraction with dichloromethane was realised. Quantitative recoveries obtained with honey were satisfactory and were superior to 80%. All acaricides are identified by reversed-phase high-performance liquid chromatography with photodiode array detection. Quantification limits obtained were below maximal residue limits when these exist.

  11. Analyses of acute kidney injury biomarkers by ultra-high performance liquid chromatography with mass spectrometry.

    PubMed

    Al Za'abi, Mohammed; Ali, Badreldin H; ALOthman, Zeid A; Ali, Imran

    2016-01-01

    The newly developed acute kidney injury biomarkers are very important for the early and timely detection of kidney diseases. This review contains details of the analyses of several acute kidney injury biomarkers using ultra-high performance liquid chromatography-mass spectrometry in urine and plasma samples. In this review we attempt to discuss some aspects of the types of the biomarkers, patents, sample preparation, and the analyses. Besides, efforts were also made to discuss the possible uses of superficially porous (core-shell) columns in traditional and inexpensive high-performance liquid chromatography instruments. Additionally, the challenges and the future prospects are also highlighted. The present review will be useful for the academicians, scientists, and clinicians for the early detection of acute kidney injury biomarkers.

  12. Homochiral metal-organic framework used as a stationary phase for high-performance liquid chromatography.

    PubMed

    Kong, Jiao; Zhang, Mei; Duan, Ai-Hong; Zhang, Jun-Hui; Yang, Rui; Yuan, Li-Ming

    2015-02-01

    Metal-organic frameworks are promising porous materials. Chiral metal-organic frameworks have attracted considerable attention in controlling enantioselectivity. In this study, a homochiral metal-organic framework [Co(2) (D-cam)(2) (TMDPy)] (D-cam = D-camphorates, TMDPy = 4,4'-trimethylenedipyridine) with a non-interpenetrating primitive cubic net has been used as a chiral stationary phase in high-performance liquid chromatography. It has allowed the successful separation of six positional isomers and six chiral compounds. The good selectivity and baseline separation, or at least 60% valley separation, confirmed its excellent molecular recognition characteristics. The relative standard deviations for the retention time of run-to-run and column-to-column were less than 1.8 and 3.1%, respectively. These results demonstrate that [Co(2) (D-cam)(2) (TMDPy)] may represent a promising chiral stationary phase for use in high-performance liquid chromatography.

  13. Simultaneous high-performance liquid chromatographic determination of suxibuzone and its metabolites in plasma and urine.

    PubMed

    Marunaka, T; Shibata, T; Minami, Y; Umeno, Y; Shindo, T

    1980-11-01

    A high-performance liquid chromatographic method is described for the simultaneous determination of the anti-inflammatory agent suxibuzone and its metabolites, 4-hydroxymethylphenylbutazone, phenylbutazone, oxyphenbutazone, and gamma-hydroxyphenylbutazone, in plasma and urine. Acidified plasma or urine is extracted with benzenecyclohexane (1:1). The organic extract is reduced to dryness and the resulting residue is redissolved in methanol. Aliquots of this solution are chromatographed on a reversed-phase column using a mobile phase of methanol--0.5 M KH2PO4 (linear gradient from 0 to 100% methanol at 8% min with a flow rate of 2.0 ml/min) on a high-performance liquid chromatograph equipped with a UV absorbance detector (254 nm). Detection is limited to 0.10 microgram/ml for suxibuzone and 4-hydroxymethylphenylbutazone and to 0.05 microgram/ml for the other metabolites.

  14. High-performance liquid chromatographic determination of tilidine in pharmaceutical dosage forms.

    PubMed

    Zivanov-Stakić, D; Solomun, L J; Zivanović, L J

    1989-01-01

    A reversed-phase high performance liquid chromatographic method for the determination of tilidine in bulk drug and its liquid and solid dosage forms is described. The method uses reversed-phase column RP-8 with methanol -0.2% water solution of ammonium carbonate (75:25,v/v) as the mobile phase and UV detector. The time taken for separation is 6.17 min. The response is linear up to 3.6 mmol/l, with recovery levels ranging from 98.2 to 101.2%. The present method is rapid, simple and reproducible.

  15. Hydrocarbon group type determination in jet fuels by high performance liquid chromatography

    NASA Technical Reports Server (NTRS)

    Antoine, A. C.

    1977-01-01

    Thirty-two jet and diesel fuel samples of varying chemical composition and physical properties were prepared from oil shale and coal syncrudes. Hydrocarbon types in these samples were determined by a fluorescent indicator adsorption analysis, and the results from three laboratories are presented and compared. Two methods of rapid high performance liquid chromatography were used to analyze some of the samples, and these results are also presented and compared. Two samples of petroleum-based Jet A fuel are similarly analyzed.

  16. Determination of pentachlorophenol in water and aquifer sediments by high-performance liquid chromatography

    USGS Publications Warehouse

    Goerlitz, D.F.

    1981-01-01

    Methods for the determination of pentachlorophenol (PCP) in water and aquifer sediments are presented. Reverse-phase high-performance liquid chromotography employing ion suppression and gradient elution is used. PCP can be determined directly in water at a lower limit of detection Of 0.2 micrograms per liter. For extracts of sediment, PCP can be determined to a lower limit of 1.0 micrograms per kilogram.

  17. High-performance liquid chromatography analysis of plant saponins: An update 2005-2010

    PubMed Central

    Negi, Jagmohan S.; Singh, Pramod; Pant, Geeta Joshi Nee; Rawat, M. S. M.

    2011-01-01

    Saponins are widely distributed in plant kingdom. In view of their wide range of biological activities and occurrence as complex mixtures, saponins have been purified and separated by high-performance liquid chromatography using reverse-phase columns at lower wavelength. Mostly, saponins are not detected by ultraviolet detector due to lack of chromophores. Electrospray ionization mass spectrometry, diode array detector , evaporative light scattering detection, and charged aerosols have been used for overcoming the detection problem of saponins. PMID:22303089

  18. Determination of citrulline and homocitrulline by high-performance liquid chromatography with post-column derivatization.

    PubMed

    Koshiishi, I; Kobori, Y; Imanari, T

    1990-10-26

    A high-performance liquid chromatographic method was developed for the determination of citrulline and homocitrulline using a post-column colorimetric reaction with o-phthaladehyde and N-(1-naphthyl)-ethylenediamine. Citrulline and homocitrulline were determined with no interferences from protein amino acids. The results show that the level of citrulline in the plasma of patients with uremia on intermittent hemodialysis is higher than that in healthy human plasma, and that homocitrulline is excreted into the urine of healthy adults.

  19. RECENT ADVANCES IN ULTRA-HIGH PERFORMANCE LIQUID CHROMATOGRAPHY FOR THE ANALYSIS OF TRADITIONAL CHINESE MEDICINE

    PubMed Central

    Huang, Huilian; Liu, Min; Chen, Pei

    2014-01-01

    Traditional Chinese medicine has been widely used for the prevention and treatment of various diseases for thousands of years in China. Ultra-high performance liquid chromatography (UHPLC) is a relatively new technique offering new possibilities. This paper reviews recent developments in UHPLC in the separation and identification, fingerprinting, quantification, and metabolism of traditional Chinese medicine. Recently, the combination of UHPLC with MS has improved the efficiency of the analysis of these materials. PMID:25045170

  20. Determination of food preservatives and saccharin by high-performance liquid chromatography.

    PubMed

    Leuenberger, U; Gauch, R; Baumgartner, E

    1979-05-21

    The quantitative analysis of benzoic and sorbic acid, methyl, ethyl and propyl esters of p-hydroxybenzoic acid and saccharin in foodstuffs is described. These compounds are quantitatively extracted with disposable clean-up columns packed with Extrelut and simultaneously determined by high-performance liquid chromatography on reversed-phase columns. Complicated matrices such as cheese, cake, ketchup and chocolate were tested and recoveries were generally better than 95% in the concentration ranges normally used in the food industry.

  1. High performance liquid chromatography of benzalkonium chlorides--variation in commercial preparations.

    PubMed

    Euerby, M R

    1985-03-01

    High performance liquid chromatography (HPLC) has been used to identify and determine the various alkyl benzyldimethylammonium chloride homologues (C10 to C16) present in commercial benzalkonium chloride preparations. The assay is especially suited for routine quality control work since it has proved to be quick and easily reproducible. It has been found that there can be a large degree of variation in the quality of differing benzalkonium chloride sources.

  2. High-Performance Liquid Chromatography (HPLC) Measurements of Phytoplankton Pigment Distributions of Ocean Waters

    DTIC Science & Technology

    1988-11-01

    coccolithophorids 19. ABSTRACT (CanMyw on rviosfe Inhcesway aM den*t byblock nmber) Until the application of high-performance liquid chromatography (HPLC) to... phycocyanin , has a maximum 0 01 absorption peak. The spectra for the 008 chlorophyll degradation products (chlo- 0.06 rophyllides, phaeophorbides and...phaeo- phytins) which are not shown in Figure z I have similar absorption maxima as their associated chlorophylls, 002 , Until the application of high

  3. Isolation and purification of heroin from heroin street samples by preparative high performance liquid chromatography.

    PubMed

    Guo, Zhen; Zheng, Hui; Lu, Yanzhen; Wei, Yun

    2012-09-10

    The present study established a novel method using preparative high performance liquid chromatography to isolate and purify heroin·HCl from heroin street samples to be used as a reference standard. Different kinds of mobile phases and columns were used, ultimately the mobile phase consisting of hexane-isopropanol-methanol (65:28:7, v/v) and the SIL preparative column prepared in laboratory were selected as the final condition. Heroin was further purified by the drowning-out crystallization method using isopropanol-methanol (50:1, v/v) and hexane as drowning-out anti-solvents and salting-out agents, respectively. The purity was assessed by analytical high performance liquid chromatography and the confirmation of the chemical structure was performed by IR and NMR. About 110.7mg of heroin·HCl at a purity of over 99.52% was obtained from 180mg of heroin street samples which contained 156.15mg of heroin·HCl component by preparative high performance liquid chromatography. This method is suitable for preparing heroin standards in forensic science area.

  4. Determination of five antiarrhythmic drugs in human plasma by dispersive liquid-liquid microextraction and high-performance liquid chromatography.

    PubMed

    Jouyban, Abolghasem; Sorouraddin, Mohammad Hossein; Farajzadeh, Mir Ali; Somi, Mohammad Hossein; Fazeli-Bakhtiyari, Rana

    2015-03-01

    A fast and sensitive high-performance liquid chromatography (HPLC) method with ultraviolet (UV) detection was developed and validated for the simultaneous quantitation of five antiarrhythmic drugs (metoprolol, propranolol, carvedilol, diltiazem, and verapamil) in human plasma samples. It involves dispersive liquid-liquid microextraction (DLLME) of the desired drugs from 660 µL plasma and separation using isocratic elution with UV detection at 200 nm. The complete separation of all analytes was achieved within 7 min. Acetonitrile (as disperser solvent) resulting from the protein precipitation procedure was mixed with 100 µL dichloromethane (as an extraction solvent) and rapidly injected into 5 mL aqueous solution (pH 11.5) containing 1% (w/v), NaCl. After centrifugation, the sedimented phase containing enriched analytes was collected and evaporated to dryness. The residue was re-dissolved in 50 µL de-ionized water (acidified to pH 3) and injected into the HPLC system for analysis. Under the optimal conditions, the enrichment factors and extraction recoveries ranged between 4.4-10.8 and 33-82%, respectively. The suggested method was linear (r(2) ≥0.997) over a dynamic range of 0.02-0.80 µg mL(-1) in plasma. The intra- and inter-days relative standard deviation (RSD%) and relative error (RE%) values of the method were below 20%, which shows good precision and accuracy. Finally, this method was applied to the analysis of real plasma samples obtained from the patients treated with these drugs.

  5. Analysis of drugs of abuse in human plasma by dispersive liquid-liquid microextraction and high-performance liquid chromatography.

    PubMed

    Fernández, P; Regenjo, M; Bermejo, A M; Fernández, A M; Lorenzo, R A; Carro, A M

    2015-04-01

    Opioids and cocaine are widely used at present, both for recreational purposes and as drugs of abuse. This raises the need to develop new analytical methods specifically designed for the simultaneous detection of several drugs of abuse in biological samples. In this work, dispersive liquid-liquid microextraction (DLLME) was assessed as a new sample treatment for the simultaneous extraction of morphine (MOR), 6-acetylmorphine (6AM), cocaine (COC), benzoylecgonine (BZE) and methadone (MET) from human plasma. Preliminary assays were done before developing an experimental design based on a Uniform Network Doehlert which allowed the optimum extraction conditions to be identified, namely: a volume of extractant solvent (chloroform) and dispersant solvent (acetonitrile) of 220 µl and 3.2 ml, respectively; 0.2 g of NaCl as a salting-out additive; pH 10.6 and ultrasound stirring for 3.5 min. The resulting extracts were analyzed by high-performance liquid chromatography with photodiode array detection (HPLC-PDA), using an XBridge® RP18 column (250 × 4.6 mm i.d., 5 µm particle size). Calibration graphs were linear over the concentration range 0.1-10 µg ml⁻¹, and detection limits ranged from 13.9 to 28.5 ng ml⁻¹. Precision calculated at three different concentration levels in plasma was included in the range 0.1-6.8% RSD. Recoveries of the five drugs were all higher than 84% on average. Finally the proposed method was successfully applied to 22 plasma samples from heroin, cocaine and/or methadone users, and the most frequently detected drug was benzoylecgonine, followed by methadone, cocaine and morphine.

  6. Analysis of nitroguanidine in Aqueous Solutions by HPLC (High Performance Liquid Chromatography) with electrochemical Detection and Voltammetry

    DTIC Science & Technology

    1987-04-01

    The nitroguanidine was analyzed by high performance liquid chromatography (HPLC) with electrochemical detection at a hanging miercury drop electrode...previously reported on the application of solid sorbent collection techniques to the analysis of several explosives in water by high performance liquid chromatography (HPLC

  7. Determination of prostaglandin analogs in cosmetic products by high performance liquid chromatography with tandem mass spectrometry.

    PubMed

    Wittenberg, James B; Zhou, Wanlong; Wang, Perry G; Krynitsky, Alexander J

    2014-09-12

    A method was developed and validated for the determination of 16 prostaglandin analogs in cosmetic products. The QuEChERS (Quick, Easy, Cheap, Efficient, Rugged, Safe) liquid-liquid extraction method, typically used for pesticide residue analysis, was utilized as the sample preparation technique. The prostaglandin analogs were chromatographically separated and quantified using high performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS). Thirty-one cosmetic products were surveyed, and 13 products were determined to contain a prostaglandin analog with amounts ranging from 27.4 to 297μg/g. The calculated concentrations for the cosmetic products were in a similar range when compared to the concentrations of three different prostaglandin analog-containing prescription products.

  8. Ion pair-based dispersive liquid-liquid microextraction followed by high performance liquid chromatography as a new method for determining five folate derivatives in foodstuffs.

    PubMed

    Nojavan, Yones; Kamankesh, Marzieh; Shahraz, Farzaneh; Hashemi, Maryam; Mohammadi, Abdorreza

    2015-05-01

    A novel technique for simultaneous determination of five folate derivatives in various food matrices was developed by ion pair-based dispersive liquid-liquid microextraction (IP-DLLME) combined with high-performance liquid chromatography (HPLC). In the proposed method, N-methyl-N,N-dioctyloctan-1-ammonium chloride (aliquat-336) was used as an ion-pair reagent. Effective variables of microextraction process were optimized. Under optimum conditions, the method yielded a linear calibration curve ranging from 1-200 ng g(-1) with correlation coefficients (r(2)) higher than 0.98. The relative standard deviation for the seven analyses was 5.2-7.4%. Enrichment factors for the five folates ranged between 108-135. Limits of detection were 2-4.1 ng g(-1). A comparison of this method with other methods described that the new proposed method is rapid and accurate, and gives very good enrichment factors and detection limits for determining five folate derivatives. The newly developed method was successfully applied for the determination of five folate derivatives in wheat flour, egg yolk and orange juice samples.

  9. Analysis of some selected catechins and caffeine in green tea by high performance liquid chromatography.

    PubMed

    El-Shahawi, M S; Hamza, A; Bahaffi, S O; Al-Sibaai, A A; Abduljabbar, T N

    2012-10-15

    Green tea seems to have a positive impact on health due to the catechins-found as flavanols. Thus, the present study was aimed to develop a low cost reversed phase high performance liquid chromatographic (HPLC) method for simultaneous determination of flavanol contents, namely catechin (C), epicatechin (EC), epigallocatechin (EGC), epicatechin 3-gallate (ECG) and epigallocatechin 3-gallate (EGCG) and caffeine in 29 commercial green tea samples available in a Saudi Arabian local market. A C-18 reversed-phase column, acetonitrile-trifluoroacetic acid as a mobile phase, coupled with UV detector at 205 nm, was successfully used for precise analysis of the tested analytes in boiled water of digested tea leaves. The average values of N (No. of theoretical plates), HETP (height equivalent of theoretical plates) and R(s) (separation factor) (at 10 μg ml(-1) of the catechins EC, EGC, EGCG and ECG) were 2.6×10(3)±1.2×10(3), 1.7×10(-3)±4.7×10(-4) cm and 1.7±5.53×10(-2), respectively. The developed HPLC method demonstrated excellent performance, with low limits of detection (LOD) and quantification (LOQ) of the tested catechins of 0.004-0.05 μg ml(-1) and 0.01-0.17 μg ml(-1), respectively, and recovery percentages of 96-101%. The influence of infusion time (5-30 min) and temperature on the content of the flavanols was investigated by HPLC. After a 5 min infusion of the tea leaves, the average concentrations of caffeine, catechin, EC, EGC, ECG and EGCG were found to be in the ranges 0.086-2.23, 0.113-2.94, 0.58-10.22, 0.19-24.9, 0.22-13.9 and 1.01-43.3 mg g(-1), respectively. The contents of caffeine and catechins followed the sequence: EGCG>EGC>ECG>EC>C>caffeine. The method was applied satisfactorily for the analysis of (+)-catechin, even at trace and ultra trace concentrations of catechins. The method was rapid, accurate, reproducible and ideal for routine analysis.

  10. Determination of free amino acids in burley tobacco by high performance liquid chromatography

    PubMed Central

    Jing, Yanqiu; Zhang, Baolin; Yuan, Xiuxiu; Gao, Yuzhen; Lu, Ping; Wang, Weifeng; Xu, Min

    2015-01-01

    A reversed-phase high performance liquid chromatographic method was developed for determining free amino acids in burley tobacco. The test was done by OPA/3-mercaptopropionic acid as the pre-column derivatizing reagent. Chromatographic column was Elitte C18 column (4.6 mm × 250 mm i.d., 5 μm). Mobile phase A was 18 mol/l NaAc (pH7.2) including 0.002%(v/v) triethylamine and 0.3%(v/v) furanidine. Mobile phase B was 100 mol/l NaAc (pH7.2)–acetonitrile–methanol (v/v = 1:2:2). The column temperature was 40 °C and the flow rate was 1.0 ml/min. The fluorescence detector was used with 350 nm excitation wave length and 450 nm emission wave length. The average recoveries of the method ranged from 95.3–100.7% with the relative standard deviation of 2.32–9.24%. The method is simple, accurate and has good repeatability. The results of the determination of seventeen kinds of free amino acids in burley leaves were produced by the way of different ratios of cake fertilizer and inorganic fertilizer. The results show that Aspartic acid has the highest content however ratio of cake fertilizer and inorganic fertilizer. The contents of most of the free amino acids are increased and then gradually decreased with the increase in organic manure. The contents of most of the free amino acids are very close at 15:85% ratio and 30:70% ratio of cake fertilizer and inorganic fertilizer. The total amount of free amino acids is the highest at 30:70% ratio of cake fertilizer and inorganic fertilizer. Considering comprehensively, the quality of burley leaves is the best at 30:70% ratio of cake fertilizer and inorganic fertilizer. PMID:26858568

  11. Determination of nucleosides in Cordyceps sinensis and Ganoderma lucidum by high performance liquid chromatography method

    PubMed Central

    Khan, Masood Shah; Parveen, Rabea; Mishra, Kshipra; Tulsawani, Rajkumar; Ahmad, Sayeed

    2015-01-01

    Background: Nucleosides are supportive in the regulation and modulation of various physiological processes in body, they acts as precursors in nucleic acid synthesis, enhance immune response, help in absorption of iron and influence the metabolism of fatty acids. Cordyceps sinensis and Ganoderma lucidum are well-known for its use in traditional medicine of China, Nepal and India. They are rich in nucleosides such as adenine, adenosine, cordycepin, etc. Hence, a simple, economic and accurate high-performance liquid chromatography (HPLC) analytical method was proposed for determination of adenine and adenosine for the quality control of plants. Materials and Methods: Chromatographic experiments were conducted on YL9100 HPLC system (South Korea). Reversed-phase chromatography was performed on a C18 column with methanol and dihydrogen phosphate as the mobile phase in isocratic elution method at a flow rate of 1.0 mL/min. Detection was carried out at 254 nm, which gives a sharp peak of adenine and adenosine at a retention time of 6.53 ± 0.02 min and 12.41 ± 0.02, respectively. Results and Discussion: Linear regression analysis data for the calibration plot showed a good linear relationship between response and concentration in the range of 25–200 µg/mL for adenosine and 100–800 µg/mL for adenine with regression coefficient of 0.999 and 0.996, respectively. The adenine was found 0.16% and 0.71% w/w in G. lucidum and in C. sinensis, respectively, and adenosine was found to be 0.14% w/w in G. lucidum whereas absent in C. sinensis. Conclusion: The developed HPLC method for the quantification of adenosine and adenine can be used for the quality control and standardization of crude drug and for the different herbal formulations, in which adenine and adenosine are present as major constituents. The wide linearity range, sensitivity, accuracy, and simple mobile phase imply the method is suitable for routine quantification of adenosine and adenine with high precision and

  12. Stability-indicating High-performance Liquid Chromatography Method for Simultaneous Determination of Aminophylline and Chlorpheniramine Maleate in Pharmaceutical Formulations

    PubMed Central

    Ali, A.; Ahmed, M.; Mahmud, T.; Qadir, M. A.; Nadeem, K.; Saleem, A.

    2015-01-01

    The present work deals with the development and validation of method for simultaneous determination of antihistaminic drugs in pharmaceutical formulations. A precise, specific and accurate reverse phase-high-performance liquid chromatography method for the simultaneous measurement of aminophylline and chlorpheniramine maleate was developed. The separation of drugs was achieved on C-18 (5 μm, 250×4.6 mm) high-performance liquid chromatography column. The runtime for analysis was 10 min. Mobile phase is mixture containing dilute H2SO4:methanol (60:40% v/v) with flow rate adjusted at 1.5 ml/min. The detection of components was performed at a wavelength of 264 nm. Retention times of aminophylline and chlorphinramine maleate were found to be 2.00 and 3.25 min, respectively. Linearity was found in the range of 16-24 μg/ml for chlorpheniramine maleate and 102.4-153.6 μg/ml for aminophylline with a correlation coefficient of 0.9998 and 0.9996, respectively. High peak purity index of 99.99% indicated the complete separation of analytes in the presence of degradation products is justification of method stability. Linearity, accuracy, specificity, precision and robustness studies were performed for method validation. PMID:26798164

  13. Analysis of therapeutic proteins and peptides using multiangle light scattering coupled to ultra high performance liquid chromatography.

    PubMed

    Espinosa-de la Garza, Carlos E; Miranda-Hernández, Mariana P; Acosta-Flores, Lilia; Pérez, Néstor O; Flores-Ortiz, Luis F; Medina-Rivero, Emilio

    2015-05-01

    Analysis of the physical properties of biotherapeutic proteins is crucial throughout all the stages of their lifecycle. Herein, we used size-exclusion ultra high performance liquid chromatography coupled to multiangle light scattering and refractive index detection systems to determine the molar mass, mass-average molar mass, molar-mass dispersity and hydrodynamic radius of two monoclonal antibodies (rituximab and trastuzumab), a fusion protein (etanercept), and a synthetic copolymer (glatiramer acetate) employed as models. A customized instrument configuration was set to diminish band-broadening effects and enhance sensitivity throughout detectors. The customized configuration showed a performance improvement with respect to the high-performance liquid chromatography standard configuration, as observed by a 3 h column conditioning and a higher resolution analysis in 20 min. Analysis of the two monoclonal antibodies showed averaged values of 148.0 kDa for mass-average molar mass and 5.4 nm for hydrodynamic radius, whereas for etanercept these values were 124.2 kDa and 6.9 nm, respectively. Molar-mass dispersity was 1.000 on average for these proteins. Regarding glatiramer acetate, a molar mass range from 3 to 45 kDa and a molar-mass dispersity of 1.304 were consistent with its intrinsic peptide diversity, and its mass-average molar mass was 10.4 kDa. Overall, this method demonstrated an accurate determination of molar mass, overcoming the difficulties of size-exclusion chromatography.

  14. Stability-indicating High-performance Liquid Chromatography Method for Simultaneous Determination of Aminophylline and Chlorpheniramine Maleate in Pharmaceutical Formulations.

    PubMed

    Ali, A; Ahmed, M; Mahmud, T; Qadir, M A; Nadeem, K; Saleem, A

    2015-01-01

    The present work deals with the development and validation of method for simultaneous determination of antihistaminic drugs in pharmaceutical formulations. A precise, specific and accurate reverse phase-high-performance liquid chromatography method for the simultaneous measurement of aminophylline and chlorpheniramine maleate was developed. The separation of drugs was achieved on C-18 (5 μm, 250×4.6 mm) high-performance liquid chromatography column. The runtime for analysis was 10 min. Mobile phase is mixture containing dilute H2SO4:methanol (60:40% v/v) with flow rate adjusted at 1.5 ml/min. The detection of components was performed at a wavelength of 264 nm. Retention times of aminophylline and chlorphinramine maleate were found to be 2.00 and 3.25 min, respectively. Linearity was found in the range of 16-24 μg/ml for chlorpheniramine maleate and 102.4-153.6 μg/ml for aminophylline with a correlation coefficient of 0.9998 and 0.9996, respectively. High peak purity index of 99.99% indicated the complete separation of analytes in the presence of degradation products is justification of method stability. Linearity, accuracy, specificity, precision and robustness studies were performed for method validation.

  15. [Determination of sugars, organic acids and alcohols in microbial consortium fermentation broth from cellulose using high performance liquid chromatography].

    PubMed

    Jiang, Yan; Fan, Guifang; Du, Ran; Li, Peipei; Jiang, Li

    2015-08-01

    A high performance liquid chromatographic method was established for the determination of metabolites (sugars, organic acids and alcohols) in microbial consortium fermentation broth from cellulose. Sulfate was first added in the samples to precipitate calcium ions in microbial consortium culture medium and lower the pH of the solution to avoid the dissociation of organic acids, then the filtrates were effectively separated using high performance liquid chromatography. Cellobiose, glucose, ethanol, butanol, glycerol, acetic acid and butyric acid were quantitatively analyzed. The detection limits were in the range of 0.10-2.00 mg/L. The linear correlation coefficients were greater than 0.999 6 in the range of 0.020 to 1.000 g/L. The recoveries were in the range of 85.41%-115.60% with the relative standard deviations of 0.22% -4.62% (n = 6). This method is accurate for the quantitative analysis of the alcohols, organic acids and saccharides in microbial consortium fermentation broth from cellulose.

  16. Quantification of Quercetin and Rutin from Benincasa hispida Seeds and Carissa Congesta Roots by High-performance Thin Layer Chromatography and High-performance Liquid Chromatography

    PubMed Central

    Doshi, Gaurav Mahesh; Une, Hemant Devidas

    2016-01-01

    Objective: In Indian Ayurvedic system, Benincasa hispida (BH) and Carissa congesta (CC) are well-known plants used for major and minor ailments. BH has been regarded as Kushmanda, whereas CC has been used in immune-related disorders of the human system. Quercetin and rutin identified from the vast plethora of plant extracts have proved to possess ethnopharmacological relevance. Materials and Methods: In present studies, we have determined quercetin and rutin in terms of percentage in BH seeds and CC roots by high-performance thin layer chromatography (HPTLC) and high-performance liquid chromatography (HPLC). After extraction and phytochemical screening, the extracts were subjected to quantification for the presence of quercetin and rutin by HPTLC and HPLC. Results: HPTLC showed quercetin as 44.60, 27.13% and rutin as 32.00, 36.31% w/w, whereas HPLC revealed quercetin as 34.00, 35.00% and rutin as 21.99, 45.03% w/v in BH and CC extracts, respectively. Conclusion: The BH and CC extracts have elucidated peaks that were corresponding with standard peaks on undertaking chromatographic studies. SUMMARY Quercetin and rutin are isolated from BH seeds and CC roots by High Performance. Thin Layer Chromatography and High Performance Liquid Chromatography. HPTLC revealed presence of quercetin as 44.60, 27.13 % and rutin as 32.00, 36.31 % w/w. HPLC revealed presence of quercetin as 34.00, 35.00 % and rutin as 21.99, 45.03 % w/v. Abbreviation Used: HPTLC: High Performance Thin Layer Chromatography; HPLC: High Pressure Liquid Chromatography, UV: Ultraviolet, CC: Carissa congesta, BH: Benincasa hispida PMID:26941534

  17. Microwave-immobilized polybutadiene stationary phase for reversed-phase high-performance liquid chromatography.

    PubMed

    Lopes, Nilva P; Collins, Kenneth E; Jardim, Isabel C S F

    2004-03-19

    Polybutadiene (PBD) has been immobilized on high-performance liquid chromatography (HPLC) silica by microwave radiation at various power levels (52-663 W) and actuation times (3-60 min). Columns prepared from these reversed-phase HPLC materials, as well as from similar non-irradiated materials, were tested with standard sample mixtures and characterized by elemental analysis (%C) and infrared spectroscopy. A microwave irradiation of 20 min at 663 W gives a layer of immobilized PBD that presented good performance. Longer irradiation times give thicker immobilized layers having less favorable chromatographic properties.

  18. Anomalous properties of flavonoids in reversed phase high performance liquid chromatography

    NASA Astrophysics Data System (ADS)

    Zenkevich, I. G.; Gushchina, S. V.

    2011-09-01

    It is shown through reversed phase high performance liquid chromatography that a characteristic feature of such abundant natural flavonoids as flavon-3-ols is an anomalously strong antibate dependence of their retention indices ( RI) on the organic solvent concentration ( C) in the eluent, dRI/ dC < 0. In order to interpret this anomaly, the specific optical rotation values [α]{D/20} of natural (+)-(2 R,3 R)-dihydroquercetin in different solvents are compared, confirming the reverse formation of hydrated flavonoids in aqueous solutions.

  19. Fluorimetric assay for ornithine decarboxylase by high-performance liquid chromatography.

    PubMed

    Haraguchi, K; Kai, M; Kohashi, K; Ohkura, Y

    1980-12-05

    A highly sensitive method for the assay of ornithine decarboxylase in sample solutions prepared from rat tissue homogenate is described which employs high-performance liquid chromatography with fluorescence detection. Putrescine formed from ornithine under the optimal conditions for the enzyme reaction is treated by Cellex P column chromatography for clean-up and converted into the fluorescamine derivative in the presence of cupric ion which inhibits the reaction of interfering amines with fluorescamine. The derivative is separated by reversed-phase chromatography on LiChrosorb RP-18 with linear gradient elution. The lower limit of detection for putrescine formed enzymatically is 5 pmol.

  20. Determination of nadolol in serum by high-performance liquid chromatography with fluorimetric detection.

    PubMed

    Noguchi, H; Yoshida, K; Murano, M; Naruto, S

    1992-01-17

    A sensitive high-performance liquid chromatographic method for a routine assay of nadolol in serum is described. Serum samples spiked with atenolol (internal standard) were extracted with diethyl ether. After centrifugation, the organic layer was evaporated to dryness. The residue was redissolved in the mobile phase and injected onto an octadecyl silica column (150 mm x 4.6 mm I.D.). The mobile phase was 0.05 M ammonium acetate (pH 4.5)-acetonitrile (85:15, v/v). Fluorometric detection (excitation 230 nm, emission 300 nm) was used. The minimum detectable level of nadolol in serum was 1 ng/ml.

  1. Determination of rhoifolin and daidzin in human plasma by high-performance liquid chromatography.

    PubMed

    Ishii, K; Urano, S; Furuta, T; Kasuya, Y

    1994-05-13

    A method for determining flavonoids in human plasma is presented for application to pharmacokinetic studies of two flavonoids, rhoifolin and daidzin. Isocratic reversed-phase high-performance liquid chromatography (HPLC) was used with genistin as an internal standard and solid-phase extraction using a Sep-Pak C18 cartridge. The mobile phases were acetonitrile-0.1 M ammonium acetate solution (20:80, v/v) for rhoifolin and methanol-0.1 M ammonium acetate solution (33:67, v/v) for daidzin. The detection limits on-column were 2 ng for rhoifolin and 0.5 ng for daidzin.

  2. Study of Saiga Horn Using High-Performance Liquid Chromatography with Mass Spectrometry

    PubMed Central

    Mikulíková, Kateřina; Romanov, Oleg; Miksik, Ivan; Eckhardt, Adam; Pataridis, Statis; Sedláková, Pavla

    2012-01-01

    The saiga horns have been investigated the using of modern analytic methods. High-performance liquid chromatography (HPLC) with mass-spectrometric (MS and MS/MS) detection and polyacrylamide gel electrophoresis (PAGE) were used. It could be concluded that basic proteins of the saiga horns are keratins and collagen. The basic representation protein in all samples is keratin type I microfibrillar (from sheep), keratin type II microfibrillar (from sheep), collagen type I (α1) (from bovine) and collagen type I (α2) (from bovine). Free amino acids we determined in all samples are nontreated by enzyme. PMID:22629195

  3. Rapid determination of succinylcholine in human plasma by high-performance liquid chromatography with fluorescence detection.

    PubMed

    Lagerwerf, A J; Vanlinthout, L E; Vree, T B

    1991-10-04

    A high-performance liquid chromatographic method with fluorometric detection has been developed for the determination of succinylcholine in human plasma. Succinylcholine shows fluorescence at 282 nm with an excitation at 257 nm. The assay is sensitive, reproducible and linear for concentrations ranging from 100 ng/ml to 100 micrograms/ml of succinylcholine. In a pilot study the plasma concentration-time curve showed a triphasic elimination, with half-lives of 0.4, 1.2 and 8 min, respectively. In a clinical setting, drugs commonly administered during anaesthesia did not interfere with the assay. This method provides a simple and time-saving alternative to existing methods.

  4. High-performance liquid chromatographic determination of molluscicidal saponins from Phytolacca dodecandra (Phytolaccaceae).

    PubMed

    Slacanin, I; Marston, A; Hostettmann, K

    1988-09-02

    A high-performance liquid chromatographic method is described for the determination of oleanane saponins in Phytolacca dodecandra (Phytolaccaceae), a plant with potent molluscicidal properties. The molluscicidal monodesmosidic saponins of the berries were determined at 254 nm as their 4-bromophenacyl derivatives, whereas the non-derivatized bidesmosidic saponins, lacking a free carboxyl group, were determined at 206 nm. A comparison of different extraction procedures showed that with cold water predominantly monodesmosidic saponins were obtained, whereas hot water gave mainly bidesmosidic (non-molluscicidal) saponins.

  5. Separation of polyamines, conjugated to DNA, by reversed-phase high-performance liquid chromatography.

    PubMed

    Mateos, J L; Reyes, A; Vicente, C; Legaz, M E

    2000-02-18

    Genomic DNA was isolated from the lichen Evernia prunastri in order to analyze by high-performance liquid chromatography the occurrence of polyamines conjugated to the macromolecule. The acid-insoluble (PH) fraction of this DNA contained mainly conjugated spermidine, although small amounts of free putrescine and spermidine were also present. The PH fraction of DNA also contained conjugated evernic acid, the main phenol produced by this lichen species. Conjugation of polyamines to calf thymus DNA was carried out under in vitro conditions. Conjugation was to spermidine and mainly to spermine and produced DNA compactation. Evernic acid enhanced the action of polyamines in order to produce DNA aggregation.

  6. Quantitative high-performance liquid chromatographic determination of acrolein in plasma after derivatization with Luminarin 3.

    PubMed

    Paci, A; Rieutord, A; Guillaume, D; Traoré, F; Ropenga, J; Husson, H P; Brion, F

    2000-03-10

    A rapid, sensitive and specific high-performance liquid chromatographic method for the quantification of acrolein (1), one of the toxic metabolites of oxazaphosphorine alkylating agents (cyclophosphamide and ifosfamide) was developed. Condensation of acrolein with Luminarin 3 afforded a fluorescent derivative that could be specifically detected and quantified. Chromatographic conditions involved a C18 RP column Uptisphere and a gradient elution system to optimize resolution and time analysis. The method showed high sensitivity with a limit of detection of 100 pmol/ml and a limit of quantification of 300 pmol/ml. This technique is particularly suitable for pharmacokinetic studies on plasma of oxazaphosphorine-receiving patients.

  7. Analysis of doxylamine in plasma by high-performance liquid chromatography.

    PubMed

    Kohlhof, K J; Stump, D; Zizzamia, J A

    1983-08-01

    A rapid and sensitive high-performance liquid chromatographic (HPLC) assay for the quantitative determination of doxylamine in plasma is described. The drug levels of doxylamine in plasma were monitored after the oral administration of a single 25-mg tablet of doxylamine succinate to each of 20 male volunteers. The compound was extracted from the plasma samples, concentrated under a nitrogen stream, and analyzed by HPLC using normal-phase chromatography with detection at 254 nm. The detection limit is approximately 5 ng/ml.

  8. An enzymatic method for assaying sulbactam in human serum: comparison with high performance liquid chromatography.

    PubMed

    Sotto, A; Peray, P; Geny, F; Brunschwig, C; Carrière, C; Galtier, M; Ramuz, M; Jourdan, J

    1995-03-01

    An enzymatic method using nitrocefin as substrate was developed to assay sulbactam in human serum. Serum containing sulbactam was incubated with purified titrated TEM-1 beta-lactamase and nitrocefin was then added to the mixture to determine the remaining beta-lactamase activity and consequently the concentration of sulbactam. Assays were carried out on five patients with pulmonary infections receiving sulbactam plus amoxycillin iv. The values for serum sulbactam concentrations determined by the enzymatic method were compared with those determined by high performance liquid chromatography (HPLC). The correlation coefficient was 0.990 for serum sulbactam concentrations below 15 mg/L.

  9. Determination of nicotine, cotinine and caffeine in meconium using high-performance liquid chromatography.

    PubMed

    Baranowski, J; Pochopień, G; Baranowska, I

    1998-04-10

    A high-performance liquid chromatographic method with diode-array detection for the determination of nicotine and its metabolites, cotinine and caffeine, in meconium is described. This method is suitable to assess foetus exposure to tobacco smoke. The analytes were extracted by solid-phase extraction before chromatography. From among 30 meconium samples 11 were positive for cotinine (20-86 ng/g) and 27 for caffeine (10-45 ng/g). No nicotine was present in the samples because of its rapid metabolism into cotinine.

  10. Determination of benzalkonium chloride in aqueous ophthalmic preparations by high-performance liquid chromatography.

    PubMed

    Gomez-Gomar, A; Gonzalez-Aubert, M M; Garces-Torrents, J; Costa-Segarra, J

    1990-01-01

    A high-performance liquid chromatographic method is described for the determination of homologues of benzalkonium chloride in aqueous ophthalmic preparations. The technique involves direct injection of the sample on a 5-microns Spherisorb-CN column. The mobile phase is acetonitrile-triethylamine (0.1%, v/v) in water (pH 2.5; 40:60, v/v). Detection is carried out at 215 nm. The method is rapid, specific, reproducible and simple, and is especially useful for the assay of this preservative in stability studies and quality control procedures.

  11. High performance liquid chromatography and electron spin resonance studies of some sugar-nitroxide solutions

    SciTech Connect

    Angel, J.P.; Thiery, C.; Battesti, C.; Vincent, P.; Raffi, J.

    1985-01-01

    Radicals induced by gamma irradiation of alpha-D-glucose, 1-0-methyl-alpha-D-glucose and maltose, in the solid state, have been studied by the spin-trapping method. High performance liquid chromatography of sugar-nitroxide solutions, combined with electron spin resonance analysis, revealed nine, eight and twelve discernible radical species, the majority of them being indiscernible by the direct spin-trapping method. Tentative correlations and assignments of chemical structures are discussed. 9 references, 4 figures, 3 tables.

  12. Gold nanoparticle decorated graphene oxide/silica composite stationary phase for high-performance liquid chromatography.

    PubMed

    Liang, Xiaojing; Wang, Xusheng; Ren, Haixia; Jiang, Shengxiang; Wang, Licheng; Liu, Shujuan

    2014-06-01

    In the initial phase of this study, graphene oxide (GO)/silica was fabricated by assembling GO onto the silica particles, and then gold nanoparticles (GNPs) were used to modify the GO/silica to prepare a novel stationary phase for high-performance liquid chromatography. The new stationary phase could be used in both reversed-phase chromatography and hydrophilic interaction liquid chromatography modes. Good separations of alkylbenzenes, isomerides, amino acids, nucleosides, and nucleobases were achieved in both modes. Compared with the GO/silica phase and GNPs/silica phase, it is found that except for hydrophilicity, large π-electron systems, hydrophobicity, and coordination functions, this new stationary phase also exhibited special separation performance due to the combination of 2D GO with zero-dimensional GNPs.

  13. High-performance liquid-catalyst fuel cell for direct biomass-into-electricity conversion.

    PubMed

    Liu, Wei; Mu, Wei; Deng, Yulin

    2014-12-01

    Herein, we report high-performance fuel cells that are catalyzed solely by polyoxometalate (POM) solution without any solid metal or metal oxide. The novel design of the liquid-catalyst fuel cells (LCFC) changes the traditional gas-solid-surface heterogeneous reactions to liquid-catalysis reactions. With this design, raw biomasses, such as cellulose, starch, and even grass or wood powders can be directly converted into electricity. The power densities of the fuel cell with switchgrass (dry powder) and bush allamanda (freshly collected) are 44 mW cm(-2) and 51 mW cm(-2) respectively. For the cellulose-based biomass fuel cell, the power density is almost 3000 times higher than that of cellulose-based microbial fuel cells. Unlike noble-metal catalysts, POMs are tolerant to most organic and inorganic contaminants. Therefore, almost any raw biomass can be used directly to produce electricity without prior purification.

  14. Preparation and evaluation of surface-bonded tricationic ionic liquid silica as stationary phases for high-performance liquid chromatography.

    PubMed

    Qiao, Lizhen; Shi, Xianzhe; Lu, Xin; Xu, Guowang

    2015-05-29

    Two tricationic ionic liquids were prepared and then bonded onto the surface of supporting silica materials through "thiol-ene" click chemistry as new stationary phases for high-performance liquid chromatography. The obtained columns of tricationic ionic liquids were evaluated respectively in the reversed-phase liquid chromatography (RPLC) mode and hydrophilic interaction liquid chromatography (HILIC) mode, and possess ideal column efficiency of 80,000 plates/m in the RPLC mode with naphthalene as the test solute. The tricationic ionic liquid stationary phases exhibit good hydrophobic and shape selectivity to hydrophobic compounds, and RPLC retention behavior with multiple interactions. In the HILIC mode, the retention and selectivity were evaluated through the efficient separation of nucleosides and bases as well as flavonoids, and the typical HILIC retention behavior was demonstrated by investigating retention changes of hydrophilic solutes with water volume fraction in mobile phase. The results show that the tricationic ionic liquid columns possess great prospect for applications in analysis of hydrophobic and hydrophilic samples.

  15. Determination of nifuroxazide in biological fluids by automated high-performance liquid chromatography with large-volume injection.

    PubMed

    Guinebault, P R; Broquaire, M; Braithwaite, R A

    1981-01-16

    A high-performance liquid chromatographic method for the measurement of nifuroxazide in plasma is described. The technique is based on the single extraction of the drug from buffered plasma with chloroform, using nifuratel as internal standard. The chromatographic system consisted of a 15 cm x 4.6 mm I.D. stainless-steel column packed with Spherisorb ODS, 5 micrometer, and the mobile phase was acetonitrile-orthophosphoric acid (pH 2.5) (30:70). The method was able to measure accurately plasma nifuroxazide concentrations down to 2 ng . ml-1 using 2 ml of sample with no interference from endogenous compounds. The coefficients of variation of the method at 200 and 2 ng . ml-1 were 3% and 15%, respectively, and the calibration graph was linear in this range. The use of automatic injection makes the method suitable for the routine analysis of large numbers of samples.

  16. Development and validation of a new high-performance liquid chromatographic method for the loperamid hydrochloride determination in drugs

    NASA Astrophysics Data System (ADS)

    Nikolić, G. S.; Savić, I.; Marinković, V.

    2009-09-01

    A selective, precise and new high-performance liquid chromatographic method for the analysis of loperamid hydrochloride in pharmaceutical formulations was developed and validated. The mobile phase consisting buffer (sodium-octansulphonate, triethylamine and ammonium hydroxide) in water: acetonitriie (45: 55, v/v) (pH 3.2). The absorbance was monitored with a DAD detector at 226 nm. The flow rate was 1.5 cm3 min-1. The linearity ( r = 0.9947) and the recovery (98.58-100.42%) were found to be satisfactory. The detection and quantitation limits were found to be 0.95 and 3.12 μg cm-3. The results demonstrated that the procedure was accurate, precise and reproducible. It can be suitably applied for the estimation of lopera-mid hydrochloride in pharmaceutical formulations.

  17. [Determination of antidangdruff agent salicylic acid, zinc pyrithione, octopirox, climbazole and ketoconazole in shampoo by high performance liquid chromatography].

    PubMed

    Yang, Yan-Wei; Zhu, Ying; Su, Xiao-Qing

    2005-09-01

    A high performance liquid chromatography method was established for determination of antidangdruff agent salicylic acid,zinc pyrithione, octopirox, climbazole and ketoconazole in shampoo on a C18 column using acetonitrile-metholaqueous solution (10 mmol/L KH2 PO4 and 5 mmol/L EDTANa2, pH is adjusted to 4.0 with H3 PO4) (50:10:40) as mobile phase at a flow rate of 1.0 ml/min, with the column temperature 25 degrees C and detection wave 230nm. The precision was less than 3.8% and recovery varied from 92.7% to 104.9%. The experimental results showed that the method was simple, precise and accurate.

  18. Unconventional High-Performance Laser Protection System Based on Dichroic Dye-Doped Cholesteric Liquid Crystals

    PubMed Central

    Zhang, Wanshu; Zhang, Lanying; Liang, Xiao; Le Zhou; Xiao, Jiumei; Yu, Li; Li, Fasheng; Cao, Hui; Li, Kexuan; Yang, Zhou; Yang, Huai

    2017-01-01

    High-performance and cost-effective laser protection system is of crucial importance for the rapid advance of lasers in military and civilian fields leading to severe damages of human eyes and sensitive optical devices. However, it is crucially hindered by the angle-dependent protective effect and the complex preparation process. Here we demonstrate that angle-independence, good processibility, wavelength tunability, high optical density and good visibility can be effectuated simultaneously, by embedding dichroic anthraquinone dyes in a cholesteric liquid crystal matrix. More significantly, unconventional two-dimensional parabolic protection behavior is reported for the first time that in stark contrast to the existing protection systems, the overall parabolic protection behavior enables protective effect to increase with incident angles, hence providing omnibearing high-performance protection. The protective effect is controllable by dye concentration, LC cell thickness and CLC reflection efficiency, and the system can be made flexible enabling applications in flexible and even wearable protection devices. This research creates a promising avenue for the high-performance and cost-effective laser protection, and may foster the development of optical applications such as solar concentrators, car explosion-proof membrane, smart windows and polarizers. PMID:28230153

  19. Unconventional High-Performance Laser Protection System Based on Dichroic Dye-Doped Cholesteric Liquid Crystals

    NASA Astrophysics Data System (ADS)

    Zhang, Wanshu; Zhang, Lanying; Liang, Xiao; Le Zhou; Xiao, Jiumei; Yu, Li; Li, Fasheng; Cao, Hui; Li, Kexuan; Yang, Zhou; Yang, Huai

    2017-02-01

    High-performance and cost-effective laser protection system is of crucial importance for the rapid advance of lasers in military and civilian fields leading to severe damages of human eyes and sensitive optical devices. However, it is crucially hindered by the angle-dependent protective effect and the complex preparation process. Here we demonstrate that angle-independence, good processibility, wavelength tunability, high optical density and good visibility can be effectuated simultaneously, by embedding dichroic anthraquinone dyes in a cholesteric liquid crystal matrix. More significantly, unconventional two-dimensional parabolic protection behavior is reported for the first time that in stark contrast to the existing protection systems, the overall parabolic protection behavior enables protective effect to increase with incident angles, hence providing omnibearing high-performance protection. The protective effect is controllable by dye concentration, LC cell thickness and CLC reflection efficiency, and the system can be made flexible enabling applications in flexible and even wearable protection devices. This research creates a promising avenue for the high-performance and cost-effective laser protection, and may foster the development of optical applications such as solar concentrators, car explosion-proof membrane, smart windows and polarizers.

  20. Unconventional High-Performance Laser Protection System Based on Dichroic Dye-Doped Cholesteric Liquid Crystals.

    PubMed

    Zhang, Wanshu; Zhang, Lanying; Liang, Xiao; Le Zhou; Xiao, Jiumei; Yu, Li; Li, Fasheng; Cao, Hui; Li, Kexuan; Yang, Zhou; Yang, Huai

    2017-02-23

    High-performance and cost-effective laser protection system is of crucial importance for the rapid advance of lasers in military and civilian fields leading to severe damages of human eyes and sensitive optical devices. However, it is crucially hindered by the angle-dependent protective effect and the complex preparation process. Here we demonstrate that angle-independence, good processibility, wavelength tunability, high optical density and good visibility can be effectuated simultaneously, by embedding dichroic anthraquinone dyes in a cholesteric liquid crystal matrix. More significantly, unconventional two-dimensional parabolic protection behavior is reported for the first time that in stark contrast to the existing protection systems, the overall parabolic protection behavior enables protective effect to increase with incident angles, hence providing omnibearing high-performance protection. The protective effect is controllable by dye concentration, LC cell thickness and CLC reflection efficiency, and the system can be made flexible enabling applications in flexible and even wearable protection devices. This research creates a promising avenue for the high-performance and cost-effective laser protection, and may foster the development of optical applications such as solar concentrators, car explosion-proof membrane, smart windows and polarizers.

  1. Feeding of liquid silicon for high performance multicrystalline silicon with increased ingot height and homogenized resistivity

    NASA Astrophysics Data System (ADS)

    Krenckel, Patricia; Riepe, Stephan; Schindler, Florian; Strauch, Theresa

    2017-04-01

    Feeding of liquid silicon during the directional solidification process is a promising opportunity for cost reduction by increased throughput and improved material homogeneity due to constant resistivity over ingot height. In this work, a liquid feeding apparatus was developed for an industrial type directional solidification furnace. One n-type G2 sized High Performance multicrystalline ingot with liquid feeding of additional 14 kg of undoped silicon feedstock was crystallized. The resistivity was kept within a range of ±0.1 Ω cm of the target resistivity during the feeding sequence. A smaller mean grain area growth was observed during feeding, whereas the area fraction of recombination active dislocation structures was as low as in a reference ingot. Increased interstitial oxygen and substitutional carbon concentrations were measured for the ingot with liquid feeding. The measured mean bulk lifetime of 190 μs for passivated wafers in the feeding sequence can probably be increased by further pre-melting crucible improvements. For this laboratory experiment, energy reductions of 2% per wafer and time savings of 16% per wafer were realized.

  2. New support for high-performance liquid chromatography based on silica coated with alumina particles.

    PubMed

    Silveira, José Leandro R; Dib, Samia R; Faria, Anizio M

    2014-01-01

    A new material based on silica coated with alumina nanoparticles was proposed for use as a chromatographic support for reversed-phase high-performance liquid chromatography. Alumina nanoparticles were synthesized by a sol-gel process in reversed micelles composed of sodium bis(2-ethylhexyl)sulfosuccinate, and the support material was formed by the self-assembly of alumina layers on silica spheres. Spectroscopic and (29)Si nuclear magnetic resonance results showed evidence of chemical bonds between the alumina nanoparticles and the silica spheres, while morphological characterizations showed that the aluminized silica maintained the morphological properties of silica desired for chromatographic purposes after alumina incorporation. Stability studies indicated that bare silica showed high dissolution (~83%), while the aluminized silica remained practically unchanged (99%) after passing one liter of the alkaline mobile phase, indicating high stability under alkaline conditions. The C18 bonded aluminized silica phase showed great potential for use in high-performance liquid chromatography to separate basic molecules in the reversed-phase mode.

  3. Hb A1c Separation by High Performance Liquid Chromatography in Hemoglobinopathies

    PubMed Central

    Chandrashekar, Vani

    2016-01-01

    Hb A1c measurement is subject to interference by hemoglobin traits and this is dependent on the method used for determination. In this paper we studied the difference between Hb A1c measured by HPLC in hemoglobin traits and normal chromatograms. We also studied the correlation of Hb A1c with age. Hemoglobin analysis was carried out by high performance liquid chromatography. Spearman's rank correlation was used to study correlation between A1c levels and age. Mann-Whitney U test was used to study the difference in Hb A1c between patients with normal hemoglobin and hemoglobin traits. A total of 431 patients were studied. There was positive correlation with age in patients with normal chromatograms only. No correlation was seen in Hb E trait or beta thalassemia trait. No significant difference in Hb A1c of patients with normal chromatograms and patients with hemoglobin traits was seen. There is no interference by abnormal hemoglobin in the detection of A1c by high performance liquid chromatography. This method cannot be used for detection of A1c in compound heterozygous and homozygous disorders. PMID:26989559

  4. High-performance liquid chromatography of histamine and 1-methylhistamine with on-column fluorescence derivatization.

    PubMed

    Saito, K; Horie, M; Nose, N; Nakagomi, K; Nakazawa, H

    1992-03-20

    An on-column fluorometric derivatization method was developed for the determination of histamine and 1-methylhistamine (HMs) by high-performance liquid chromatography. The system for the derivatization consisted only of a commercially available single-plunger pump and a reversed-phase C18 column supported on synthetic polymer with a mobile phase of acetonitrile and alkaline borate buffer solution containing o-phthalaldehyde as a derivatization reagent. It required no additional reaction system as for a post-column derivatization method. Injected HMs might be derivatized to a fluorophore on the inlet site of the high-performance liquid chromatographic column, followed by chromatography on the same column. Optimization of the on-column reaction conditions resulted in a simple and sensitive analytical method for the determination of HMs with excellent reproducibility and linearity of 0.05-5 micrograms/ml of both HMs. Application of this method to the determination of HMs in food samples resulted in a limit of quantification of 0.05 mg/100 g and in a greater than 95% overall mean recovery at a fortification of 0.1 mg/g of both HMs. This method was furthermore applicable to the determination of histamine released from rat peritoneal mast cells.

  5. High-performance liquid chromatography with electrospray ionization ion mobility spectrometry: Characterization, data management, and applications.

    PubMed

    Zühlke, Martin; Riebe, Daniel; Beitz, Toralf; Löhmannsröben, Hans-Gerd; Andreotti, Sandro; Reinert, Knut; Zenichowski, Karl; Diener, Marc

    2016-12-01

    The combination of high-performance liquid chromatography and electrospray ionization ion mobility spectrometry facilitates the two-dimensional separation of complex mixtures in the retention and drift time plane. The ion mobility spectrometer presented here was optimized for flow rates customarily used in high-performance liquid chromatography between 100 and 1500 μL/min. The characterization of the system with respect to such parameters as the peak capacity of each time dimension and of the 2D spectrum was carried out based on a separation of a pesticide mixture containing 24 substances. While the total ion current chromatogram is coarsely resolved, exhibiting coelutions for a number of compounds, all substances can be separately detected in the 2D plane due to the orthogonality of the separations in retention and drift dimensions. Another major advantage of the ion mobility detector is the identification of substances based on their characteristic mobilities. Electrospray ionization allows the detection of substances lacking a chromophore. As an example, the separation of a mixture of 18 amino acids is presented. A software built upon the free mass spectrometry package OpenMS was developed for processing the extensive 2D data. The different processing steps are implemented as separate modules which can be arranged in a graphic workflow facilitating automated processing of data.

  6. A simple and simultaneous identification method for aloe, catechu and gambir by high performance liquid chromatography.

    PubMed

    Zhao, Yan; Kim, Young Ho; Lee, Wonjae; Lee, Young Keun; Kim, Kyung Tae; Kang, Jong Seong

    2016-01-05

    An effective and rapid method was developed for the simultaneous identification of aloe, catechu and gambir by high performance liquid chromatography-diode array detector (HPLC-DAD). Identification of three maker compounds presented in three medicinal materials was performed on high performance liquid chromatography-mass spectrometry (HPLC-MS). Under the optimal HPLC chromatographic conditions, sixty-two samples were processed on an Optimapak C18 column using a solvent system of acetonitrile (from 10% to 35%) and 0.1% phosphoric acid solution (from 90% to 65%) at a total flow rate of 1.0 mL/min and detected at 270 nm. All calibration curves exhibited good linear relationship (r(2)>0.9992). The relative standard deviation values of intra-day and inter-day precision were less than 1% and 2%, respectively. The recoveries of three analytes ranged from 99.48 to 100.97% with low RSDs (<2%). For the first time, this study demonstrates that the processed aloe, catechu and gambir are sold in local material markets in China and Korea without their correct identification. It indicates the existent of high potential medicinal risk by misuse of three medicinal materials. The developed HPLC method can be applied to prevent unexpected biological activity due to misapplication of medicinal materials.

  7. Liquid-Crystal Thermosets, a New Generation of High-Performance Liquid-Crystal Polymers

    NASA Technical Reports Server (NTRS)

    Dingemans, Theo; Weiser, Erik; Hou, Tan; Jensen, Brian; St. Clair, Terry

    2004-01-01

    One of the major challenges for NASA's next-generation reusable-launch-vehicle (RLV) program is the design of a cryogenic lightweight composite fuel tank. Potential matrix resin systems need to exhibit a low coefficient of thermal expansion (CTE), good mechanical strength, and excellent barrier properties at cryogenic temperatures under load. In addition, the resin system needs to be processable by a variety of non-autoclavable techniques, such as vacuum-bag curing, resin-transfer molding (RTM), vacuum-assisted resin-transfer molding (VaRTM), resin-film infusion (RFI), pultrusion, and advanced tow placement (ATP). To meet these requirements, the Advanced Materials and Processing Branch (AMPB) at NASA Langley Research Center developed a new family of wholly aromatic liquid-crystal oligomers that can be processed and thermally cross-linked while maintaining their liquid-crystal order. All the monomers were polymerized in the presence of a cross-linkable unit by use of an environmentally benign melt-condensation technique. This method does not require hazardous solvents, and the only side product is acetic acid. The final product can be obtained as a powder or granulate and has an infinite shelf life. The obtained oligomers melt into a nematic phase and do not exhibit isotropization temperatures greater than the temperatures of decomposition (Ti > T(sub dec)). Three aromatic formulations were designed and tested and included esters, ester-amides, and ester-imides. One of the major advantages of this invention, named LaRC-LCR or Langley Research Center-Liquid Crystal Resin, is the ability to control a variety of resin characteristics, such as melting temperature, viscosity, and the cross-link density of the final part. Depending on the formulation, oligomers can be prepared with melt viscosities in the range of 10-10,000 poise (100 rad/s), which can easily be melt-processed using a variety of composite-processing techniques. This capability provides NASA with custom

  8. Accurate measure by weight of liquids in industry

    SciTech Connect

    Muller, M.R.

    1992-12-12

    This research's focus was to build a prototype of a computerized liquid dispensing system. This liquid metering system is based on the concept of altering the representative volume to account for temperature changes in the liquid to be dispensed. This is actualized by using a measuring tank and a temperature compensating displacement plunger. By constantly monitoring the temperature of the liquid, the plunger can be used to increase or decrease the specified volume to more accurately dispense liquid with a specified mass. In order to put the device being developed into proper engineering perspective, an extensive literature review was undertaken on all areas of industrial metering of liquids with an emphasis on gravimetric methods.

  9. Accurate measure by weight of liquids in industry. Final report

    SciTech Connect

    Muller, M.R.

    1992-12-12

    This research`s focus was to build a prototype of a computerized liquid dispensing system. This liquid metering system is based on the concept of altering the representative volume to account for temperature changes in the liquid to be dispensed. This is actualized by using a measuring tank and a temperature compensating displacement plunger. By constantly monitoring the temperature of the liquid, the plunger can be used to increase or decrease the specified volume to more accurately dispense liquid with a specified mass. In order to put the device being developed into proper engineering perspective, an extensive literature review was undertaken on all areas of industrial metering of liquids with an emphasis on gravimetric methods.

  10. Determination of Niacinamide in Lotions and Creams Using Liquid-Liquid Extraction and High-Performance Liquid Chromatography

    ERIC Educational Resources Information Center

    Usher, Karyn M.; Simmons, Carolyn R.; Keating, Daniel W.; Rossi, Henry F., III

    2015-01-01

    Chemical separations are an important part of an undergraduate chemistry curriculum. Sophomore students often get experience with liquid-liquid extraction in organic chemistry classes, but liquid-liquid extraction is not as often introduced as a quantitative sample preparation method in honors general chemistry or quantitative analysis classes.…

  11. EXTRACTION AND QUANTITATIVE ANALYSIS OF ELEMENTAL SULFUR FROM SULFIDE MINERAL SURFACES BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY. (R826189)

    EPA Science Inventory

    A simple method for the quantitative determination of elemental sulfur on oxidized sulfide minerals is described. Extraction of elemental sulfur in perchloroethylene and subsequent analysis with high-performance liquid chromatography were used to ascertain the total elemental ...

  12. Surveillance of the Army’s Propellant Stockpile: Analysis of Stabilizer Content by High Performance Liquid Chromatography

    DTIC Science & Technology

    1990-10-01

    high performance liquid chromatography to monitor the level of stabilizer and its daughter products in propellant. Three of those methods are presented along with statistics and some comments about their

  13. Flavonoid content and antioxidant capacity of spinach genotypes determined by high-performance liquid chromatography/mass spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flavonoids in different spinach genotypes were separated, identified, and quantified by a high-performance liquid chromatographic method with photodiode array and mass spectrometric detection. The antioxidant capacities of the genotypes were also measured using two antioxidant assays - oxygen radica...

  14. Liquid-liquid extraction procedure for trace determination of cyclophosphamide in human urine by high-performance liquid chromatography tandem mass spectrometry.

    PubMed

    Sottani, C; Turci, R; Perbellini, L; Minoia, C

    1998-01-01

    A sensitive, specific and accurate high performance liquid chromatography/ionspray-tandem mass spectrometry procedure (HPLC/MS/MS) has been developed to quantify cyclophosphamide in human urine from hospital personnel involved in drug preparation and administration of antineoplastic alkylating agents. This methodology, which includes liquid-liquid extraction with ethylacetate, requires no derivatization procedures, preventing cyclophosphamide (CP) from possible thermal and chemical decomposition reactions. We detected the excretion of this unmetabolized alkylating drug in 50% of all the study participants. The amount of CP ranged from 0.1 ng microL-1 to 1.9 ng microL-1 urine. This methodology was validated by the use of ifosfamide as internal standard. The assay was linear over the range 0 to 3.2 ng microL-1 urine, with a lower limit of quantification of 0.2 microL-1. The limit of detection was assessed at 0.05 ng microL-1 urine. This method is characterized by a coefficient of variation < 10%. Standard calibration curves, obtained on three different days, had correlation coefficients always greater than 0.998. The intra and interday precision were within 11%, and accuracy was in the range 99-103%. The mean extracted recovery assessed at three different concentrations (0.5, 0.8, 3.2 ng microL-1) was always more than 85%. The extraction efficiency of cyclophosphamide from urine samples was also studied at six different pH values (pH 4, 5, 6, 7, 8, 10). The maximum extraction efficiency was obtained when the pH of urine solutions was adjusted to 7.0

  15. [Determination of four phenolic endocrine disruptors in environmental water samples by high performance liquid chromatography-fluorescence detection using dispersive liquid-liquid microextraction coupled with derivatization].

    PubMed

    Wang, Xiaoyan; Qi, Weimei; Zhao, Xian'en; Lü, Tao; Wang, Xiya; Zheng, Longfang; Yan, Yehao; You, Jinmao

    2014-06-01

    To achieve accurate, fast and sensitive detection of phenolic endocrine disruptors in small volume of environmental water samples, a method of dispersive liquid-liquid microextraction (DLLME) coupled with fluorescent derivatization was developed for the determination of bisphenol A, nonylphenol, octylphenol and 4-tert-octylphenol in environmental water samples by high performance liquid chromatography-fluorescence detection (HPLC-FLD). The DLLME and derivatization conditions were investigated, and the optimized DLLME conditions for small volume of environmental water samples (pH 4.0) at room temperature were as follows: 70 microL chloroform as extraction solvent, 400 microL acetonitrile as dispersing solvent, vortex mixing for 3 min, and then high-speed centrifugation for 2 min. Using 2-[2-(7H-dibenzo [a, g] carbazol-7-yl)-ethoxy] ethyl chloroformate (DBCEC-Cl) as precolumn derivatization reagent, the stable derivatives of the four phenolic endocrine disruptors were obtained in pH 10.5 Na2CO3-NaHCO3 buffer/acetonitrile at 50 degrees C for 3 min, and then separated within 10 min by HPLC-FLD. The limits of detection (LODs) were in the range of 0.9-1.6 ng/L, and the limits of quantification (LOQs) were in the range of 3.8-7.1 ng/L. This method had perfect linearity, precision and recovery results, and showed obvious advantages and practicality comparing to the previously reported methods. It is a convenient and validated method for the routine analysis of phenolic endocrine disruptors in waste water of paper mill, lake water, domestic wastewater, tap water, etc.

  16. Cucurbit(6)uril immobilized on silica: a novel high-performance liquid chromatographic stationary phase.

    PubMed

    Ma, Liyun; Liu, Simin; Wang, Qing; Yao, Lin; Xu, Li

    2015-04-01

    In the present study, one of the new generation of host molecules, cucurbit(6)uril (CB(6)), was immobilized onto silica (CB(6)/SiO2 ) by a sol-gel approach. CB(6)/SiO2 was characterized by NMR spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and elemental analysis. It was used as a high-performance liquid chromatographic stationary phase and its chromatographic performance was systematically investigated with different types of analytes as probes. The results revealed that the CB(6)/SiO2 stationary phase exhibited weak hydrophobic and strong hydrophilic properties. Hence, the variables for hydrophilic interaction liquid chromatography, including components and pH of the mobile phase, were further investigated to explore the retention mechanism of this CB(6)/SiO2 stationary phase. For less polar analytes, both hydrophobic and hydrophilic interactions could contribute to the retention, while for polar analytes, hydrophilic interaction may be predominant. Compared to the tetraethoxylsilane-coated SiO2 stationary phases, the CB(6)/SiO2 stationary phase exhibited a different retention behavior toward basic analytes with excellent stability. It is a novel promising hydrophilic interaction liquid chromatography stationary phase.

  17. Ultrasound-assisted ionic liquid-based homogeneous liquid-liquid microextraction high-performance liquid chromatography for determination of tanshinones in Salvia miltiorrhiza Bge. root.

    PubMed

    Wang, Zhibing; Cao, Bocheng; Yu, Aimin; Zhang, Hanqi; Qiu, Fangping

    2015-02-01

    The ultrasound-assisted ionic liquid-based homogeneous liquid-liquid microextraction has been developed and applied to the extraction of four tanshinones, including dihydrotanshinone, tanshinone I, cryptotanshinone and tanshinone IIA in Salvia miltiorrhiza Bge. root. High performance liquid chromatography was applied to the separation and determination of the analytes. The ionic liquid was used as extraction solvent and target analytes were extracted with help of ultrasound. Then, ion-pairing agent was added into the sample solution, which resulted in the formation of water-insoluble ionic liquid in the solution. The phase separation was performed by centrifugation. The extraction, concentration and purification of target analytes were performed simultaneously. The experimental parameters, including type and volume of ionic liquid, sample amount, the size of sample particle, pH value of extraction medium, extraction temperature, extraction time, amount of ion-pairing agent and centrifuging time, were investigated and optimized. The calibration curves showed good linear relationship (r>0.9997). The limits of detection and quantification were in the range of 0.052-0.093 and 0.17-0.31 μg mL(-1), respectively. The recoveries were between 70.45% and 94.23% with relative standard deviations lower than 5.31%. The present method is free of volatile organic solvents, and represents lower expenditures of sample, extraction time and solvent, compared with UAE and HRE. There was no obvious difference in the extraction yields of active constitutions obtained by the three extraction methods.

  18. Isolation and purification of glycoconjugates from complex biological sources by recycling high-performance liquid chromatography.

    PubMed

    Alley, William R; Mann, Benjamin F; Hruska, Vlastimil; Novotny, Milos V

    2013-11-05

    Among of the most urgent needs of the glycobiology community is to generate libraries of pure carbohydrate standards. While many oligosaccharides have recently been synthesized, some glycans of biomedical importance are still missing in existing collections or are available in only limited amounts. To address this need, we demonstrate the use of the relatively unexplored technique of recycling high-performance liquid chromatography (R-HPLC) to isolate and purify glycoconjugates from several natural sources. We were able to routinely achieve purities greater than 98%. In several cases, we were able to obtain isomerically pure substances, particularly for glycans with different positional isomerism. These purified substances can then be used in different analytical applications, for example, as standards for mass spectrometry (MS) and capillary-based separations. Moreover, using a bifunctional aromatic amine, the same derivatization agent can be used to enable UV detection of oligosaccharides during their purification and link the isolated molecules to functionalized surfaces and potentially create glycan arrays.

  19. Determination of hexazinone in groundwater by direct-injection high-performance liquid chromatography.

    PubMed

    Perkins, L B; Bushway, R J; Katz, L E

    1999-01-01

    Hexazinone has been detected at levels ranging from 0.2 to 50 micrograms/L in many groundwater samples from eastern Maine over the past decade. A rapid and inexpensive direct-injection high-performance liquid chromatographic (HPLC) method has been developed to monitor contamination levels of the herbicide. The method is sensitive (limit of quantitation = 0.33 microgram/L) and is linear to 33.0 micrograms/L (R2 = 0.9995). Direct injection results from 50 field samples compared well (R2 = 0.98) with an HPLC method using solid-phase extraction for concentration and cleanup. The technique is very reproducible (coefficients of variation of 0-8.4% within day and 3.0-13.2% between day) and eliminates loss of analyte because of fewer steps in the procedure.

  20. [Analysis of amines in water samples by high performance liquid chromatography-laser induced fluorescence detection].

    PubMed

    Liu, Fan; Gao, Fangyuan; Tang, Tao; Sun, Yuanshe; Li, Tong; Zhang, Weibing

    2013-11-01

    A sensitive high performance liquid chromatography (HPLC)-laser induced fluorescence detection (LIFD) method was developed for the determination of amines. The derivatization and separation conditions were investigated. Under the optimized conditions, spermidine, putrescine and histamine were analyzed. The limits of detection (LODs) of the three biogenic amines (S/N = 3) were as low as 10(-10) mol/L. This method showed excellent stability. The RSDs of retention times and peak areas of the three biogenic amines were lower than 0.3% and 3%, respectively. This method was applied in biogenic amine analysis in water samples, and the average recoveries were in the range of 94.99%-104.7%. Furthermore, the amines in seven tea samples were analyzed by this method, and satisfactory results were achieved. The developed assay is of excellent sensitivity and good reproducibility, which can be used in the analysis of the amines in water samples.

  1. Hydrocarbon group type determination in jet fuels by high performance liquid chromatography

    NASA Technical Reports Server (NTRS)

    Antoine, A. C.

    1977-01-01

    Results are given for the analysis of some jet and diesel fuel samples which were prepared from oil shale and coal syncrudes. Thirty-two samples of varying chemical composition and physical properties were obtained. Hydrocarbon types in these samples were determined by fluorescent indicator adsorption (FIA) analysis, and the results from three laboratories are presented and compared. Recently, rapid high performance liquid chromatography (HPLC) methods have been proposed for hydrocarbon group type analysis, with some suggestion for their use as a replacement of the FIA technique. Two of these methods were used to analyze some of the samples, and these results are also presented and compared. Two samples of petroleum-based Jet A fuel are similarly analyzed.

  2. Methacrylate-bonded covalent-organic framework monolithic columns for high performance liquid chromatography.

    PubMed

    Liu, Li-Hua; Yang, Cheng-Xiong; Yan, Xiu-Ping

    2017-01-06

    Covalent-organic frameworks (COFs) are a newfangled class of intriguing microporous materials. Considering their unique properties, COFs should be promising as packing materials for high performance liquid chromatography (HPLC). However, the irregular shape and sub-micrometer size of COFs synthesized via the traditional methods render the main obstacles for the application of COFs in HPLC. Herein, we report the preparation of methacrylate-bonded COF monolithic columns for HPLC to overcome the above obstacles. The prepared COF bonded monolithic columns not only show good homogeneity and permeability, but also give high column efficiency, good resolution and precision for HPLC separation of small molecules including polycyclic aromatic hydrocarbons, phenols, anilines, nonsteroidal anti-inflammatory drugs and benzothiophenes. Compared with the bare polymer monolithic column, the COF bonded monolithic columns show enhanced hydrophobic, π-π and hydrogen bond interactions in reverse phase HPLC. The results reveal the great potential of COF bonded monoliths for HPLC and COFs in separation sciences.

  3. Determination of captopril by high-performance liquid chromatography with direct electrogenerated chemiluminescence

    NASA Astrophysics Data System (ADS)

    Sun, Yonghua; Zhang, Zhujun; Zhang, Xinfeng

    2013-03-01

    Captopril exhibit electrogenerated chemiluminescence (ECL) in NaNO3 solution when constant current is exerted. Based on this observation, a direct ECL method coupled with high-performance liquid chromatography (HPLC) separation is developed for determination of captopril in human serum. Factors affected the ECL emission are investigated. Under the optimal conditions, the ECL intensity has a linear relationship with the concentration of captopril in the range of 4.0 × 10-6-2.0 × 10-3 g mL-1 and the detection limit is 2 × 10-6 g mL-1 (S/N = 3). Compared with the common electrogenerated chemiluminescence experiments, the developed method need no any other fluorescence additives.

  4. High-performance liquid chromatographic analysis of anthraquinone compounds in the Laurera benguelensis

    NASA Astrophysics Data System (ADS)

    Manojlović, N.; Marković, Z.; Gritsanapan, W.; Boonpragob, K.

    2009-09-01

    A high-performance liquid chromatographic (HPLC) method has been developed for the characterization of anthraquinone metabolites in extracts of the lichen Laurera benguelensis. With this method four anthraquinone derivatives 1,8-dihydroxy-3-methoxy-6-methylanthraquinone, 1,8-dihydroxy-3-formyl-6-methoxyanthraquinone, 1,8-dihydroxy-3-hydroxymethyl-6-methoxy-anthraquinone and 1,3,8-trihyroxy-6-methylanthraquinone can be analyzed. Components of lichen were detected by characteristic ultraviolet spectra and relative retention times. This is first report of phytochemical analysis of L. benguelensis. Importance of this research is in recognizing some new source (lichen and its extracts) as a natural emplacement of antioxidants because oxidation with free radicals or autooxidation is big problem for preservation of food products.

  5. Reversed-phase high-performance liquid chromatography of protected peptide segments.

    PubMed

    Pedroso, E; Grandas, A; Amor, J C; Giralt, E

    1987-11-13

    There is little evidence that reversed-phase high-performance liquid chromatography can be successfully used in the analysis of protected peptide segments. The use of C18 and CN packings and mobile phases containing water-acetonitrile with or without propionic acid in the separation of complex mixtures of synthetic protected peptides is reported. CN packings show a lower efficiency and exhibit poorer resolution than C18 packings but provide different separations. The addition of propionic acid to the mobile phase increases the retention time of peptides but also provides dramatic and useful changes in selectivity. Retention is not related to the molecular mass of the protected peptides but mainly to their hydrophobicity.

  6. Semipermeable-surface reversed-phase media for high-performance liquid chromatography.

    PubMed

    Desilets, C P; Rounds, M A; Regnier, F E

    1991-05-17

    Polyoxyethylene was both adsorbed hydrophobically (through the use of non-ionic surfactants) and covalently bonded to reversed-phase high-performance liquid chromatographic packings, thereby establishing a semipermeable hydrophilic layer over the alkylsilane surface. This layer restricts proteins from adsorbing to the alkylsilane phase while permitting penetration and chromatographic separation of small molecules. Biological fluids containing low-molecular-weight analytes may be injected directly, without sample pretreatment or the use of micellar eluents. In the case of adsorbed coatings, surfactant loading was determined primarily by the surface area (over the reversed phase) occupied by the polyoxyethylene head group. Semipermeability of the hydrophilic layer was demonstrated by observing changes in retention of both small molecules and proteins with increasing eluent ionic strength. Coated column stability was evaluated with regard to cumulative eluent volume and repeated serum injections.

  7. [Determination of melamine in milk powder and milk by high performance liquid chromatography].

    PubMed

    He, Qiaosang; Liu, Minfang; Huang, Liying; Yang, Yuanyuan; Liao, Shangfu

    2008-11-01

    The analytical method of melamine in milk and milk powder by high performance liquid chromatography (HPLC) was established. The sample was purified by a cation exchange solid-phase extraction column, separated on a Diamonsil C18 column (4.6 mm x 200 mm, 5 microm) with acetonitrile-0.01 mol/L sodium heptanesulfonate (pH 3.3) (10:90, v/v) as mobile phase at a flow rate of 1.0 mL/min, and determined by a photodiode array detector. A linear calibration curve was obtained in the concentration range of 1 - 500 mg/L. The qualification limit was 0.2 mg/kg, and the quantification limit was 1 mg/kg. The recovery was 81.4% -83.7%.

  8. High Performance Liquid Chromatography of the Dansyl Derivatives of Putrescine, Spermidine, and Spermine 1

    PubMed Central

    Escribano, M. Isabel; Legaz, M. Estrella

    1988-01-01

    A high performance liquid chromatographic (HPLC) method, based on dansylation and fluorescence detection, is described for the estimation of putrescine, spermidine, and spermine in lichen (Evernia prunastri [L.]) samples. Because of the high concentrations of phenols and salts, dansylation was followed by a pre-HPLC purification step. Both flow rate and mobile phase (methanol:water) followed a gradient for optimum resolution on a reverse-phase column. Amounts as small as 0.3 picomole of standard polyamines could be detected. In applying the method to lichens, it was found that 5.45% (w/w) of the exogenous putrescine taken up by the thallus was unbound in the algal partner and that 60% (w/w) was conjugated in the thallus, perhaps to lichen phenolics. PMID:16666175

  9. High performance liquid chromatography of the dansyl derivatives of putrescine, spermidine, and spermine.

    PubMed

    Escribano, M I; Legaz, M E

    1988-06-01

    A high performance liquid chromatographic (HPLC) method, based on dansylation and fluorescence detection, is described for the estimation of putrescine, spermidine, and spermine in lichen (Evernia prunastri [L.]) samples. Because of the high concentrations of phenols and salts, dansylation was followed by a pre-HPLC purification step. Both flow rate and mobile phase (methanol:water) followed a gradient for optimum resolution on a reverse-phase column. Amounts as small as 0.3 picomole of standard polyamines could be detected. In applying the method to lichens, it was found that 5.45% (w/w) of the exogenous putrescine taken up by the thallus was unbound in the algal partner and that 60% (w/w) was conjugated in the thallus, perhaps to lichen phenolics.

  10. Enzymatic determination of phosphate in conjunction with high-performance liquid chromatography.

    PubMed

    Morgan, D K; Danielson, N D

    1983-06-24

    A selective assay for orthophosphate in complex matrices was developed based on the nucleoside phosphorylase catalyzed conversion of inosine and orthophosphate of hypoxanthine. The enzyme reaction was using only 0.28 units/assay was allowed to proceed for 30 min before quenching. Separation of inosine and hypoxanthine was performed by reversed-phase high-performance liquid chromatography. Quantitation of the hypoxanthine peak was found to be linear with orthophosphate up to 30 micrograms/g. A detection limit of 0.75 ppm could be obtained after dialysis of the commercial enzyme. Interference studies showed that the enzymatic assay unlike the colorimetric molybdate-blue technique was essentially unaffected by complex matrices such as serum, urine, polyphosphates, and phosphoesters.

  11. [Simultaneous determination of sulbactam sodium and cefoperazone sodium in sulperazon by high performance liquid chromatography].

    PubMed

    Li, F S; Xu, Z X; Xiao, H B; Liang, X M

    2000-11-01

    A reversed-phase, isocratic high performance liquid chromatographic method with acid mobile phase can separate sulbactam and cafoperazone within 12 minutes. Column packed with Hypersil ODS2(250 mm x 4.6 mm i.d., 5 microns) was manufactured by Dalian Elite Company. Mobile phase is composed of water (adjusted to pH 4.0 with 1% phosphoric acid) and acetonitrile (80:20, V/V). The detection was performed at 210 nm and the injection volume was 2 microL. Cefoperazone and sulbactam have good linearity in the ranges of 100 mg/L to 800 mg/L and 100 mg/L to 1,000 mg/L with the correlation coefficients of 0.9991 and 0.9997 respectively. This method is easily to be operated and can be applied for manufacturing and medicinal study.

  12. Multiresidue analysis of seven anticoagulant rodenticides by high-performance liquid chromatography/electrospray/mass spectrometry.

    PubMed

    Marek, LeEtta J; Koskinen, William C

    2007-02-07

    Mice and rat populations are commonly controlled by two classes of rodenticide anticoagulants, coumarins and indandiones. However, poisoning of nontarget animals also often occurs. For cases such as these, a rapid, multiresidue method, which provides positive confirmation for both classes of anticoagulant rodenticides, is needed by diagnostic laboratories. A method was developed for the determination of seven anticoagulant rodenticides, coumafuryl, pindone, warfarin, diphacinone, chlorophacinone, bromadiolone, and brodifacoum, in diverse matrices, animal feed, cooked beef, and fruit-flavored beverages using high-performance liquid chromatography/electrospray/mass spectrometry. Detection was by MS/MS with electrospray ionization in negative mode. Confirmation was by retention time, m/z of molecular ion, and two parent-daughter transitions. Recoveries from selected the matrices ranged from 61 to 117%. Limits of quantitation were as low as 1.5-4.5 ng g-1. The developed method was rapid and provided the simultaneous confirmation and quantification of the seven anticoagulant rodenticides.

  13. Core-Shell Columns in High-Performance Liquid Chromatography: Food Analysis Applications

    PubMed Central

    Preti, Raffaella

    2016-01-01

    The increased separation efficiency provided by the new technology of column packed with core-shell particles in high-performance liquid chromatography (HPLC) has resulted in their widespread diffusion in several analytical fields: from pharmaceutical, biological, environmental, and toxicological. The present paper presents their most recent applications in food analysis. Their use has proved to be particularly advantageous for the determination of compounds at trace levels or when a large amount of samples must be analyzed fast using reliable and solvent-saving apparatus. The literature hereby described shows how the outstanding performances provided by core-shell particles column on a traditional HPLC instruments are comparable to those obtained with a costly UHPLC instrumentation, making this novel column a promising key tool in food analysis. PMID:27143972

  14. Development of high performance liquid chromatography method for miconazole analysis in powder sample

    NASA Astrophysics Data System (ADS)

    Hermawan, D.; Suwandri; Sulaeman, U.; Istiqomah, A.; Aboul-Enein, H. Y.

    2017-02-01

    A simple high performance liquid chromatography (HPLC) method has been developed in this study for the analysis of miconazole, an antifungal drug, in powder sample. The optimized HPLC system using C8 column was achieved using mobile phase composition containing methanol:water (85:15, v/v), a flow rate of 0.8 mL/min, and UV detection at 220 nm. The calibration graph was linear in the range from 10 to 50 mg/L with r 2 of 0.9983. The limit of detection (LOD) and limit of quantitation (LOQ) obtained were 2.24 mg/L and 7.47 mg/L, respectively. The present HPLC method is applicable for the determination of miconazole in the powder sample with a recovery of 101.28 % (RSD = 0.96%, n = 3). The developed HPLC method provides short analysis time, high reproducibility and high sensitivity.

  15. [Quantitative analysis of deacylgymnemic acid by high-performance liquid chromatography].

    PubMed

    Suzuki, K; Ishihara, S; Uchida, M; Komoda, Y

    1993-04-01

    A method of the quantitative analysis was established for the determination of deacylgymnemic acid (DAGA) in the alkaline hydrolysate of the sample containing gymnemic acids which are ingredients of Gymnema sylvestre R. BR. leaves, by means of high-performance liquid chromatography. This method was used for comparing the contents of gymnemic acids in various samples. The amount of gymnemic acids analyzed as DAGA in 70% ethanol extract of dry leaves was about twice that in hot water extract. The commercial health-supplemental foods of five companies were investigated for the contents of gymnemic acids as DAGA and there were large differences from 38 to 251 mg in the dosage per day recommended by each company.

  16. High-performance liquid chromatography measurement of hyperforin and its reduced derivatives in rodent plasma.

    PubMed

    Rozio, M; Fracasso, C; Riva, A; Morazzoni, P; Caccia, S

    2005-02-25

    A reverse-phase high-performance liquid chromatography method was developed for the determination of hyperforin and its reduced derivatives octahydrohyperforin and tetrahydrohyperforin in rodent plasma. The procedure includes solid-phase extraction from plasma using the Baker 3cc C8 cartridge, resolution on the Symmetry Shield RP8 column (150 mm x 4.6 mm, i.d. 3.5 microm) and UV absorbance detection at 300 nm. The assay was linear over a wide range, with an overall coefficient of variation less than 10% for all compounds. The precision and accuracy were within acceptable limits and the limit of quantitation was sufficient for studies preliminarily assessing the disposition of tetrahydrohyperforin and octahydrohyperforin in the mouse and rat.

  17. Determination of lipid hydroperoxides in serum iodometry and high performance liquid chromatography compared.

    PubMed

    Wieland, E; Schettler, V; Diedrich, F; Schuff-Werner, P; Oellerich, M

    1992-06-01

    It is postulated that lipid peroxidation plays a role in the pathogenesis of a variety of diseases. Efforts have therefore been made to develop reliable and practicable procedures for quantifying lipid peroxidation products such as lipid hydroperoxides in biological specimens. An iodometric cholesterol colour reagent (Merck, Darmstadt, Germany) can be used to measure lipid hydroperoxides in isolated low density lipoproteins without lipid extraction. This method has been validated with respect to its analytical performance and suitability for serum samples by comparing it with a high performance liquid chromatography technique. The method was found to have acceptable performance characteristics with aqueous fatty acid hydroperoxide solutions (linoleic acid) and isolated low density lipoproteins, but it cannot be applied to native serum samples without extraction of lipids.

  18. A simple assay for lipid hydroperoxides based on triphenylphosphine oxidation and high-performance liquid chromatography.

    PubMed

    Nakamura, T; Maeda, H

    1991-09-01

    A simple and sensitive method was developed to measure total hydroperoxides. After the reduction of hydroperoxides with triphenylphosphine (TP) in cyclohexane at 30°C, the amount of triphenylphosphine oxide (TPO) produced is determined by reverse-phase or normal-phase high-performance liquid chromatography (HPLC) in combination with an ultraviolet (UV)-detector by measuring absorption at 220 or 260 nm. TPO was shown to be gener-ated stoichiometrically by reduction of known amounts of either cumene hydroperoxide or methyl 13-hydroper-oxyoctadecadienoate. For various lipids at low levels of oxidation, the peroxide values determined by this method were in good agreement with those obtained by conventional iodometry. The detection limit of TPO in HPLC using absorption at 220 nm was less than 10 pmol. Consequently, total hydroperoxides in lipids at levels corresponding to less than a peroxide value of 1 can be estimated by the TP method on a 10-mg sample.

  19. High performance liquid chromatography study of complex oxygenated alkane mixtures from organic aerosols

    NASA Astrophysics Data System (ADS)

    Kalafut-Pettibone, Alicia J.; Klems, Joseph P.; McGivern, W. Sean

    2013-05-01

    The composition of secondary organic aerosol particles is of primary importance both in identifying particle sources and in determining physical parameters, such as cloud condensation nucleus propensity. Further, measurements of composition are valuable in determining the chemistry of formation and aging. In this work, we describe the application of a recently-developed derivatization technique to a complex synthetic organic aerosol derived from the photolysis of 1-iodooctane. The technique utilizes high-performance liquid chromatography (HPLC) coupled to both ultravioletvisible (UV/VIS) spectroscopy and tandem mass spectrometry (MS-MS) to determine the overall distribution of hydroxyl (OH), non-acid carbonyl (C=O), and carboxylic acid (COOH) moieties as well as the specific identities of chromatographically separated products. This composition data will then be used to constrain models of the particle formation mechanisms.

  20. Analysis of lipophilic pigments from a phototrophic microbial mat community by high performance liquid chromatography

    NASA Technical Reports Server (NTRS)

    Palmisano, A. C.; Cronin, S. E.; Des Marais, D. J.

    1988-01-01

    As assay for lipophilic pigments in phototrophic microbial mat communities using reverse phase-high performance liquid chromatography was developed which allows the separation of 15 carotenoids and chloropigments in a single 30 min program. Lipophilic pigments in a laminated mat from a commercial salina near Laguna Guerrero Negro, Baja California Sur, Mexico reflected their source organisms. Myxoxanthophyll, echinenone, canthaxanthin, and zeaxanthin were derived from cyanobacteria; chlorophyll c, and fucoxanthin from diatoms; chlorophyll a from cyanobacteria and diatoms; bacteriochlorophylls a and c, bacteriophaeophytin a, and gamma-carotene from Chloroflexus spp.; and beta-carotene from a variety of phototrophs. Sensitivity of detection was 0.6-6.1 ng for carotenoids and 1.7-12 ng for most chloropigments. This assay represents a significant improvement over previous analyses of lipophilic pigments in microbial mats and promises to have a wider application to other types of phototrophic communities.

  1. Measurement of serum pralidoxime methylsulfate (Contrathion) by high-performance liquid chromatography with electrochemical detection.

    PubMed

    Houzé, Pascal; Borron, Stephen W; Scherninski, François; Bousquet, Bernard; Gourmel, Bernard; Baud, Frédéric

    2005-01-05

    Pralidoxime methylsulfate (Contrathion) is widely used to treat organophosphate poisoning. Despite animal and human studies, the usefulness of Contrathion therapy remains a matter of debate. Therapeutic dosage regimens need to be clarified and availability of a reliable method for plasma pralidoxime quantification would be helpful in this process. We here describe a high-performance liquid chromatography technique with electrochemical detection to measure pralidoxime concentrations in human serum using guanosine as an internal standard. The assay was linear between 0.25 and 50 microg mL(-1) with a quantification limit of 0.2 microg mL(-1). The analytical precision was satisfactory, with variation coefficients lower 10%. This assay was applied to the analysis of a serum from an organophosphorate poisoned patient and treated by Contrathion infusions (100 and 200 mg h(-1)) after a loading dose (400 mg).

  2. Analysis of beechwood creosote by gas chromatography-mass spectrometry and high-performance liquid chromatography.

    PubMed

    Ogata, N; Baba, T

    1989-12-01

    Compounds in beechwood creosote were analyzed by gas chromatography-mass spectrometry, and 22 major constituents were identified. Of these, 19 were phenolic compounds, i. e., guaiacol, phenol, two cresol isomers, four methylguaiacol (creosol) isomers, six xylenol isomers, two trimethylphenol isomers, 4-ethylguaiacol, 4-ethyl-5-methylguaiacol, and 4-propylguaiacol. The remaining three were hitherto unpredicted five-membered ring compounds, i. e., 3-methyl-2-hydroxy-2-cyclopenten-1-one, 3,5-dimethyl-2-hydroxy-2-cyclopenten-1-one, and 3-ethyl-2-hydroxy-2-cyclopenten-1-one. The relative quantities of these compounds were also compared with those obtained by high-resolution high-performance liquid chromatography. This report probably represents the first extensive analysis of beechwood creosote.

  3. Determination of artificial sweeteners in beverages and special nutritional products using high performance liquid chromatography.

    PubMed

    Serdar, Maja; Knežević, Zorka

    2011-06-01

    This paper presents two high performance liquid chromatographic (HPLC) methods used for the separation and determination of artificial sweeteners aspartame, acesulphame K, sodium saccharin, and sodium cyclamate in beverages and special nutritional products (special food intended for specific population groups). All four compounds are soluble in aqueous solutions and can easily be separated and determined by HPLC with a diode array detector (DAD). The first method involved separation of aspartame, acesulphame K, and sodium saccharin on a C18 column with an isocratic elution of phosphate buffer and acetonitrile as mobile phase. The second method was used to separate sodium cyclamate on a C18 column with methanol and water as mobile phase. Under optimum conditions, both methods showed good analytical performance, such as linearity, precision, and recovery. The methods were successfully applied for the analysis of real samples of soft drinks and special nutritional products.

  4. Determination of ketorolac in blood and plasma samples by high-performance liquid chromatography.

    PubMed

    Flores-Murrieta, F J; Granados-Soto, V; Hong, E

    1994-10-01

    A new method for determination of ketorolac in blood or plasma samples by reversed-phase high-performance liquid chromatography has been developed. The method includes a double extraction with diethyl ether and detection by absorbance at 313 nm. Quantitation was performed by height ratios of ketorolac and the internal standard (sodium tolmetin). Detection limit of the method was 3 ng/ml using 1 ml of plasma and 10 ng/ml using 0.2 ml of blood. The method is linear in the range of concentrations typically obtained after therapeutic doses of the drug, has the advantages of using low volume of body fluid and the internal standard used is commercially available. Those characteristics allow us to conclude that this method is suitable for pharmacokinetic or drug monitoring studies.

  5. Separation of some platinum metal 8-hydroxyquinolinates by normal phase high-performance liquid chromatography.

    PubMed

    Alimarinod, I P; Basova, E M; Malykhin, A Y; Bol'shova, T A

    1990-05-01

    The method of normal phase high-performance liquid chromatography has been applied to the separation and determination of Pd(II), Pt(II), Rh(III), Ir(IV), Ru(III) and Os(IV) as chelates with 8-hydroxyquinoline on a 62 x 2 mm column packed with Silasorb 600 5 mu silica gel by elution with methylene chloride-isopropyl alcohol mixture (97:3 v/v). The detection limits (ng per 5 mul), were Pd 0.3, Pt 1.0, Rh 1.0, Ir 5.0, Ru 1.5, Os 25. The separation time was 12 min at a flow-rate of 0.1 ml/min.

  6. A high performance liquid chromatography method for determination of furfural in crude palm oil.

    PubMed

    Loi, Chia Chun; Boo, Huey Chern; Mohammed, Abdulkarim Sabo; Ariffin, Abdul Azis

    2011-09-01

    A modified steam distillation method was developed to extract furfural from crude palm oil (CPO). The collected distillates were analysed using high performance liquid chromatography (HPLC) coupled with an ultraviolet diode detector at 284nm. The HPLC method allowed identification and quantification of furfural in CPO. The unique thermal extraction of CPO whereby the fresh fruit bunches (FFB) are first subjected to steam treatment, distinguishes itself from other solvent-extracted or cold-pressed vegetable oils. The presence of furfural was also determined in the fresh palm oil from FFB (without undergoing the normal extraction process), palm olein, palm stearin, olive oil, coconut oil, sunflower oil, soya oil and corn oil. The chromatograms of the extracts were compared to that of standard furfural. Furfural was only detected in CPO. The CPO consignments obtained from four mills were shown to contain 7.54 to 20.60mg/kg furfural.

  7. High-performance liquid chromatographic determination of vertilmicin in rat plasma using sensitive fluorometric derivatization.

    PubMed

    Liu, Zhen; Sha, Yunfei; Huang, Taomin; Yang, Bei; Duan, Geng-Li

    2005-12-15

    A sensitive and reliable high-performance liquid chromatographic method was developed for the determination of vertilmicin in rat plasma. Derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl) followed by C(18) reversed-phase chromatography allowed the fluorimetric detection of vertilmicin. Optimal conditions for the derivatization of vertilmicin are described. The limit of quantification was 0.02 mg/L. The pharmacokinetics of vertilmicin was studied in 24 rats following intramuscular injection (i.m.) of different doses (4, 8, 16, 32 mg/kg of body weight). The pharmacokinetic parameter values were estimated by use of 3P97 program. In this study, we assessed the dose proportionality of vertilmicin after single intramuscular injection doses and obtained new information on the pharmacokinetics of the compound.

  8. Gas chromatography and high-performance liquid chromatography of natural steroids.

    PubMed

    Shimada, K; Mitamura, K; Higashi, T

    2001-11-23

    This review article underlines the importance of gas chromatography (GC), high-performance liquid chromatography (HPLC) and their hyphenated techniques using mass spectrometry (MS) for the determination of natural steroids, especially in human biological fluids. Steroids are divided into eight categories based on their structures and functions, and recent references using the above methodologies for the analysis of these steroids are cited. GC and GC-MS are commonly used for the determination of volatile steroids. Although HPLC is a widely used analytical method for the determination of steroids including the conjugated type in biological fluids, LC-MS is considered to be the most promising one for this purpose because of its sensitivity, specificity and versatility.

  9. Improved high-performance liquid chromatographic analysis of terazosin in human plasma.

    PubMed

    Cheah, P Y; Yuen, K H; Liong, M L

    2000-08-18

    A simple, sensitive and reproducible high-performance liquid chromatography (HPLC) method was developed for the determination of terazosin in human plasma. The method involves a one-step single solvent extraction procedure using dichloromethane with a 0.25 ml plasma sample. Recovery values were all greater than 90% over the concentration range 0.25-100 ng/ml. Terazosin was found to adsorb to glass or plastic tubes, but this could be circumvented by using disposable plastic tubes. Also, rinsing the injector port with methanol after each injection helped to prevent any carry-over effect. The internal standard, prazosin, did not exhibit this problem. The method has a quantification limit of 0.25 ng/ml. The within- and between-day coefficient of variation and accuracy values were all less than 7% over the concentration range 0.25-100 ng/ml and hence the method is suitable for use in pharmacokinetic studies of terazosin.

  10. Direct determination of benzamides in serum by column-switching high-performance liquid chromatography.

    PubMed

    Chiba, Ryoko; Ogasawara, Ayako; Kubo, Teppei; Yamazaki, Hiroyuki; Umino, Masuo; Ishizuka, Yoichi

    2003-05-01

    A column-switching high-performance liquid chromatographic method with fluorescence detection was developed for the simultaneous determination of four benzamide-type anti-psychotic drugs: sulpiride, tiapride, sultopride and metoclopramide in human serum. In this method, a TSKgel Super-ODS column was used as an analytical column, and a TSKgel G 2000SW was prepared as a pretreatment column. Under the optimized analytical conditions, four benzamide-type anti-psychotic drugs were eluted within 18 min. The detection limits (S/N = 3) for sulpiride, tiapride, sultopride and metoclopramide are 1 ng/ml, 4 ng/ml, 2 ng/ml and 0.5 ng/ml, respectively. Finally, the method was applied to the determination of sulpiride in human serum samples obtained after a single oral dose of sulpiride.

  11. Multiresidue analysis of neonicotinoids by solid-phase extraction technique using high-performance liquid chromatography.

    PubMed

    Mohan, Chander; Kumar, Yogesh; Madan, Jyotsana; Saxena, Navneet

    2010-06-01

    For routine monitoring of pesticides, a multiresidue analysis through solid-phase extraction technique and using high-performance liquid chromatography (HPLC) in cotton seed cake (CSC) has been developed. Extraction of fortified samples was carried out with aqueous acetone under vacuum. The concentrated extract was loaded onto the solid-phase extraction units, preconditioned with acetonitrile. The extraction units were then washed with hexane and finally eluted with acetonitrile. The pesticide residues were determined using a multiresidue method by reversed-phase HPLC. The average percentage recoveries were found to range between 65.47% and 110% at spiking levels of 10 to 40 mg/kg. The method developed shows a healthy rate of recovery and can successfully be utilized for the extraction and screening of neonicotinoid residues in CSC. The detection limits for imidacloprid, acetamiprid, and thiacloprid using this method were found to be 5, 10, and 20 mg/kg, respectively.

  12. An optical rotatory detector for high-performance liquid chromatography using polarization modulation.

    PubMed

    Yamamoto, Atsushi; Kawai, Mio; Sakamoto, Mitsunori; Kodama, Shuji; Hayakawa, Kazuichi

    2008-03-01

    A sensitive and variable-wavelength optical rotatory (OR) detector for high-performance liquid chromatography is presented. This design is entirely different from that of conventional OR detectors consisting of a crossed polarizer pair. By placing a polarizing prism and a retardation plate into a commercial circular dichroism (CD) detector, the OR signal was obtained. The Mueller matrix approach was used to prove the principle of the OR signal appearance. Sugars and 4-androstene-3,17-dione were chosen as test compounds. The limit of detection was below 0.5 microg of injected sucrose at 260 nm, which was superior to that obtained with a conventional OR detector. For 4-androstene-3,17-dione, which is CD active, and shows a large anomalous OR dispersion curve, our detector gave a large OR signal with approximately half the intensity of the CD signal at 340 nm.

  13. Determination of efavirenz in human plasma by high-performance liquid chromatography with ultraviolet detection.

    PubMed

    Saras-Nacenta, M; López-Púa, Y; Lípez-Cortés, L F; Mallolas, J; Gatell, J M; Carné, X

    2001-11-05

    Efavirenz is a non-nucleoside reverse transcriptase inhibitor for the treatment of the HIV infection. A simple, high-performance liquid chromatographic method has been developed and validated for the quantitative determination of efavirenz in human plasma. The method involved solid-phase extraction of the drug and the internal standard (L-737,354) from 300 microl of human plasma. The analysis was via UV detection at 250 nm using a reversed-phase C8 analytical column and a isocratic mobile phase consisting of phosphate buffer (pH 5.75)-acetonitrile that resolved the drug and internal standard from endogenous matrix components and potential coadministered drugs. Within- and between-day precisions were less than 8.6% for all quality control samples. The lower limit of quantification was 0.1 microg/ml. Recovery of efavirenz from human plasma was greater than 83%. This validated assay is being used in pharmacokinetic studies with efavirenz.

  14. Separation and quantitation of metallothioneins by high-performance liquid chromatography coupled with atomic absorption spectrophotometry

    SciTech Connect

    Lehman, L.D.; Klaassen, C.D.

    1986-03-01

    A rapid, reproducible, and sensitive high-performance liquid chromatography (HPLC) method for the determination of the concentrations of metallothionein-I (MT-I) and metallothionein-II (MT-II) in rat liver has been developed. Metallothioneins (MTs) were separated and quantitated by anion-exchange high-performance liquid chromatography coupled with atomic absorption spectrophotometry (AAS). Purified rat liver MT-I and MT-II, used as standards for developing the method, were easily resolved, eluting at 7.5 and 10.4 min, respectively. To establish standard curves, protein concentrations of solutions of the purified MTs were determined by the Kjeldahl method for the determination of nitrogen, after which the standards were saturated with Cd (final concentration of 50 ppm Cd). Rat liver cytosols obtained from untreated and Cd- or Zn-treated rats were prepared for HPLC-AAS analysis by saturation with Cd (50 ppm Cd) followed by heat denaturation (placing in a boiling water bath for 1 min). Based on the method of standard additions, recovery of MTs exceeded 95% and repeated injection of a sample yielded a coefficient of variance of approximately 2%. A detection limit of 5 ..mu..g MT/g liver was established for the method. Only MT-II was detected in untreated rats, whereas following exposure to Cd or Zn, both forms of MTs were detected. Concentrations of total MTs in liver of untreated and Cd- or Zn-treated rats were also determined by the Cd/hemoglobin radioassay (which fails to distinguish MT-I from MT-II) and indicated that results obtained with the HPLC-AAS method compared favorably to the Cd/hemoglobin radioassay.

  15. [Determination of five triazine herbicides in infant milk powder by high performance liquid chromatography coupled with ionic liquid-based homogeneous liquid-liquid microextraction].

    PubMed

    Zhang, Liyuan; Yao, Di; Li, Na; Zhang, Hanqi; Yu, Aimin

    2015-07-01

    A high performance liquid chromatography coupled with homogeneous liquid-liquid microextraction was developed for the determination of five triazine herbicides in infant milk powders. The ionic liquid was used as microextraction solvent. The separation of the herbicides was performed on an Eclipse XDB-C18 column using acetonitrile and water as mobile phases in gradient mode. The effects of homogeneous liquid-liquid extraction conditions on the experimental results were investigated in detail. Under the optimized experimental conditions, the calibration curves for determining the analytes were linear and the correlation coefficients were ≥ 0.9992. The limits of detection for cyanazine, desmetryn, terbumeton, terbuthylazine and dimethametryn were 12.1, 13.8, 11.8, 14.6 and 13.7 μg/kg, respectively. The recoveries of the analytes spiked in four infant milk powders ranged from 92.2% to 103.2% and the relative standard deviations were lower than 6%. This method is sensitive, simple, and suitable for the determination of triazine herbicides in milk powder samples.

  16. Microwave-assisted ionic liquid homogeneous liquid-liquid microextraction coupled with high performance liquid chromatography for the determination of anthraquinones in Rheum palmatum L.

    PubMed

    Wang, Zhibing; Hu, Jianxue; Du, Hongxia; He, Shuang; Li, Qing; Zhang, Hanqi

    2016-06-05

    The microwave-assisted ionic liquid homogeneous liquid-liquid microextraction (MA-IL-HLLME) coupled with high performance liquid chromatography with diode array detection (HPLC-DAD) was developed for the determination of anthraquinones, including aloe-emodin, emodin, chrysophanol and physcion in root of Rheum palmatum L. Several experimental parameters influencing the extraction efficiency, including amount of sample, type and volume of ionic liquid, volume and pH value of extraction medium, microwave power and extraction time, concentration of NH4PF6 as well as centrifugal condition were optimized. When 140μL of ionic liquid ([C8MIM][BF4]) was used as an extraction solvent, target analytes can be extracted from sample matrix in one minute with the help of microwave irradiation. The MA-IL-HLLME is simple and quick. The calibration curves exhibited good linear relationship (r>0.9984). The limits of detection and quantification were in the range of 0.015-0.026 and 0.051-0.088μgmL(-1), respectively. The spiked recovery for each analyte was in the range of 81.13-93.07% with relative standard deviations lower than 6.89%. The present method is free of volatile organic solvents, and represents lower expenditures of sample, extraction time and solvent, compared with ultrasonic and heat reflux extraction. The results indicated that the present method can be successfully applied to the determination of anthraquinones in medicinal plant.

  17. Fully automated high-performance liquid chromatographic assay for the analysis of free catecholamines in urine.

    PubMed

    Said, R; Robinet, D; Barbier, C; Sartre, J; Huguet, C

    1990-08-24

    A totally automated and reliable high-performance liquid chromatographic method is described for the routine determination of free catecholamines (norepinephrine, epinephrine and dopamine) in urine. The catecholamines were isolated from urine samples using small alumina columns. A standard automated method for pH adjustment of urine before the extraction step has been developed. The extraction was performed on an ASPEC (Automatic Sample Preparation with Extraction Columns, Gilson). The eluate was collected in a separate tube and then automatically injected into the chromatographic column. The catecholamines were separated by reversed-phase ion-pair liquid chromatography and quantified by fluorescence detection. No manual intervention was required during the extraction and separation procedure. One sample may be run every 15 min, ca. 96 samples in 24 h. Analytical recoveries for all three catecholamines are 63-87%, and the detection limits are 0.01, 0.01, and 0.03 microM for norepinephrine, epinephrine and dopamine, respectively, which is highly satisfactory for urine. Day-to-day coefficients of variation were less than 10%.

  18. Flavonoid profiling of a traditional Chinese medicine formula of Huangqin Tang using high performance liquid chromatography

    PubMed Central

    Li, Tao; Zhuang, Shuaixing; Wang, Yiwei; Wang, Yanli; Wang, Weihao; Zhang, Huihui; Chen, Li; Wang, Dunfang; Zhou, Zhongming; Yang, Weipeng

    2016-01-01

    The quality control processes for herbal medicines have been problematic. Flavonoids are the major active components of Huangqin Tang (HQT, a traditional Chinese medicine formula). In this study, we used a combinative method approach consisting of chromatographic fingerprinting (high performance liquid chromatography; HPLC), quantitative methods and a pharmacodynamic evaluation model to analyze the flavonoids of HQT obtained from different sources. Ten batches of HQT were analyzed by the HPLC fingerprinting method and 26 common peaks were detected, of which 23 peaks corresponded with the chemical profile of HQT. In addition, 11 major compounds were identified by LC–MS analysis (liquid chromatography–tandem mass spectrometer; LC–MSn) and quantified by the HPLC quantitative method approach. The studied 10 batches of HQT were found to be homogeneous in their composition with a similarity between 0.990 and 1.000. The distribution of the 11 identified compounds was found to be very similar among the batches. Only slight pharmacodynamic differences were detected between the different batches, confirming the homogeneity of HQT. The results of this study prove that the combination of chromatographic fingerprinting and quantitative analysis can be readily used for comprehensive quality control of herbal medicines. PMID:27006899

  19. A straightforward means of coupling preparative high-performance liquid chromatography and mass spectrometry.

    PubMed

    Cai, Hong; Kiplinger, Jeffrey P; Goetzinger, Wolfgang K; Cole, Roderic O; Laws, Kathrine A; Foster, Marc; Schrock, Audrey

    2002-01-01

    Flow splitting to a mass spectrometer is a common way of coupling a highly specific detector to preparative or semi-preparative high-performance liquid chromatography (HPLC) purification of combinatorial libraries, drug metabolites, and characterizable impurities. The sensitive mass spectrometer consumes only a small fraction of the analyte while providing online structure-specific detection, and its output can thus be used to trigger collection of the desired fraction. Coupling mass spectrometry to preparative HPLC is difficult due to the susceptibility of the detector to fouling under conditions of high analyte concentration or solute amount, or to changes in solvent composition. We report here on a device, the mass rate attenuator (MRA), which automatically produces split ratios over a range of 100:1 to 100 000:1 under programmable user control. The MRA is a flow-control device that periodically gates a small aliquot from one liquid stream into another. The design allows the user to set the frequency of the gating without interruption of the HPLC flow stream. The MRA also allows control of the volume of the aliquot that is transferred between the flow streams. This additional control, compared to passive splitting devices, facilitates optimization of the tubing connecting the separation, detection and collection events. We demonstrate that such optimization can reduce the volume of the collected fraction without compromising recovery, thus reducing the time spent in evaporating solvents to reclaim purified products.

  20. Reversed-phase high-performance liquid chromatography of tenuazonic acid and related tetramic acids.

    PubMed

    Shephard, G S; Thiel, P G; Sydenham, E W; Vleggaar, R; Marasas, W F

    1991-05-03

    A reversed-phase high-performance liquid chromatographic system for the determination of the fungal toxin, tenuazonic acid, (5S,8S)-3-acetyl-5-sec.-butyltetramic acid, is described. The system utilizes a column packed with deactivated end-capped C18 silica with a high carbon load to overcome the problem of poor chromatographic performance of this beta-diketone on reversed-phase liquid chromatography which previously necessitated the use of anion-exchange, ligand-exchange or ion-pairing methods. The reversed-phase system allows the separation of tenuazonic acid from its (5R,8S)-diastereomer, allo-tenuazonic acid and was applied to the detection of tenuazonic acid in cultures of Alternaria alternata and Phoma sorghina. By means of diode-array ultraviolet detection, (5S)-3-acetyl-5-isopropyltetramic acid was observed in extracts of culture material. This metabolite was purified using the analytical reversed-phase system and was identified by 1H and 13C nuclear magnetic resonance spectroscopy.

  1. Analysis of urine for cysteine, cysteinylglycine, and homocysteine by high-performance liquid chromatography.

    PubMed

    Kuśmierek, K; Głowacki, R; Bald, E

    2006-07-01

    A new analytical method is proposed for simultaneous determination, by liquid chromatography, of the three main urinary thiols-cysteine, cysteinylglycine, and homocysteine. To measure the total amount of these thiols urine is reduced with sodium borohydride, to convert disulfides to thiols which are then derivatized with 2-chloro-1-methylquinolinium tetrafluoroborate. Separation and quantitation of the 2-S-quinolinium thiol derivatives formed were achieved by high-performance liquid chromatography with detection at 355 nm. Validation showed the method enabled reliable simultaneous determination of these aminothiols in urine. The calibration graphs for each analyte, obtained by use of normal urine spiked with increasing amounts of cysteine, cysteinylglycine, and homocysteine, were linear (R2 > or = 0.997) over the range covering most practical situations. The recovery of the assay was 98-100% and sensitivity was 0.12-0.25 micromol L(-1). The method was applied to 91 different samples of normal urine to establish reference values for the aminothiols, normalized on creatinine.

  2. A high-performance liquid chromatographic determination of major phenolic compounds in tobacco smoke

    SciTech Connect

    Risner, C.H.; Cash, S.L. )

    1990-05-01

    A high-performance liquid chromatographic (HPLC) method is developed that simultaneously quantifies the dihydroxy compounds hydroquinone, resorcinol, and catechol and the monohydroxy compounds phenol, m + p-cresol and o-cresol in cigarette smoke. Particulate matter samples collected on Cambridge pads and in impingers by conventional trapping techniques are simply (no derivatization required) subjected to reversed-phase gradient liquid chromatography. Samples of both mainstream and sidestream smoke can be analyzed. Selective fluorescence detection is used to monitor the mobile phase effluent, by which these phenolic compounds are detected in the nanogram range. The detector response is linear, overall precision is good, and recoveries are greater than 95 percent. The total run time, excluding extraction, is one hour. The procedure has been applied to tobacco products whose smoke contains varying amounts of these phenols. Kentucky Reference Cigarette 1R4F was found to contain substantially more of these compounds than a new cigarette that heats but does not burn tobacco (New Cigarette). The method is compared with other procedures used to determine phenolics in cigarette smoke.

  3. Determination of swainsonine in the endophytic Undifilum fungi by high-performance liquid chromatography with evaporative light-scattering detector.

    PubMed

    Yang, Guo-Dong; Gao, Rui; Wang, Yan; Li, Jin-Cheng; Hu, Yan-Chun; Kang, Dan-Ju; Li, Yan-Hong; Li, Hai-Li; Geng, Guo-Xia; Wang, Jian-Hua

    2012-07-01

    Endophytic Undifilum oxytropis found within toxic locoweeds (Astragalus and Oxytropis spp.) produces the indolizidine alkaloid swainsonine, which is responsible for locoism in grazing animals. The aim of the current study is to establish an easy and accurate method for the determination of swainsonine in the endophytic Undifilum fungi. High-performance liquid chromatography (HPLC) with evaporative light-scattering detector (ELSD) was used for the assay of swainsonine in this study for the first time. The HPLC conditions were Waters XBridge hydrophilic interaction liquid chromatography column using acetonitrile-5 mM ammonium acetate (1:1, vol/vol) containing 0.02% (vol/vol) aqueous ammonium hydroxide as mobile phase at a flow rate of 0.5 mL/min. ELSD conditions were optimized at nebulizer-gas flow rate of 25 psi and drift tube temperature of 55 °C. The method was validated to achieve the satisfactory precision and recovery, and the calibration range was 15.625-250 μg/mL. Application of the developed analytical procedure to determine swainsonine content in the endophytic Undifilum fungi samples ensured its suitability for the routine analysis of swainsonine.

  4. Quantitative Determination of Saturates, Olefins, and Aromatics in Hydrocarbon Distillate Products Using High-Performance Liquid Chromatography with Dielectric Constant Detection (HPLC-DC).

    DTIC Science & Technology

    high - performance liquid chromatography (HPLC) is the basis of a rapid and accurate hydrocarbon group-type analysis. This novel method can determine saturates, olefins, and total aromatics in hydrocarbon liquids with distillation endpoints of at least 400 deg C. The HPLC separation is achieved using a single, 5-micron olefin-selective column, a backflush valve, and Freon 123 as the mobile phase. The DC detector ensures a genuine uniformity of response (less than 2.5% RSD) for each hydrocarbon group type, independent of the carbon number distribution of

  5. Direct injection isocratic high-performance liquid chromatographic analysis of mitomycin C in plasma.

    PubMed

    Song, D; Au, J L

    1996-02-09

    A direct injection high-performance liquid chromatography method is described for the determination of mitomycin C (MMC) in human plasma. The stationary phase consisted of hydrophilic and hydrophobic functional groups covalently bound to silicone-coated silica beads (CAPCELL PAK MF Ph-1, 150x4.6 mm I.D., 5 microns). A mobile phase using 100% water gave a better separation of MMC from endogenous interferences as compared to a mobile phase with 12.5% acetonitrile and 2.5 mM phosphate buffer (pH 6.9). Using water as the eluent (1 ml/min) and UV detection at 365 nm, MMC was found to elute at 5.0 min with a peak width of 0.3 min, whereas endogenous interferences eluted before 3 min. Total assay time per sample was 6 min. Internal standard was not required because the recovery of MMC was nearly complete, about 90% from 20 to 5000 ng/ml. The standard curve was linear from 20 to 5000 ng/ml in plasma, and the intra-and inter-day variation was between 3 to 6%. The lower detection limit was 5 ng/ml with a 25 microliters sample, which represents a two- to four-fold improvement over the 10 ng/ml detection limit by previous methods using liquid-liquid extraction and comparable sample size. The simplicity of this method, i.e., no sample extraction, no internal standard, 100% aqueous mobile phase, isocratic elution and short analysis time (6 min/sample), makes it suitable for large scale routine sample analysis, whereas its small sample volume requirement and high sensitivity are useful for pharmacokinetic studies in small animals where limited sample is available.

  6. [Measurement of 11 benzophenone ultraviolet-filters in cosmetics by high performance liquid chromatography].

    PubMed

    Qu, Baocheng; Bian, Haitao; Mao, Xiqin; Li, Jin

    2015-12-01

    A sample preparation and analytical method with liquid-liquid extraction (LLE) and high performance liquid chromatography (HPLC) was developed to detect 11 benzophenone ultraviolet-filters in cosmetics. The target compounds were extracted by the mixed solutions of tetrahydrofuran (TH)/methanol/water or dichloromethane/water at proper ratios. The extracts were centrifuged and filtered to remove matrix compounds, and then analyzed by HPLC. The separation of analytes was carried out on a Diamonsil-C18 column (150 mm x 4.6 mm, 5 μm) with 0.1% (v/v) formic acid aqueous solution (containing 10 mmol/L ammonium acetate) as mobile phase A and methanol containing 0.1% (v/v) formic acid as mobile phase B. The spiked recoveries of the method (n = 7) were 93.4%-103.8% with the relative standard deviations of 0.1%-4.2%. The limits of detection (LODs) were in the range of 4.0-30 μg/g and the limits of quantitation (LOQs) ranged from 15 to 100 μg/g. The method was applied to the determination of 42 cosmetic samples randomly purchased from the supermarket in Dalian. Five benzophenone series were always detected, in which the content of benzophenone-3 in sunscreen cream and the content of benzophenone-2 in perfume were very high and reached 2 785 μg/g and 2 106 μg/g, respectively. The results showed that the developed method is efficient, reliable and sensitive, which can be applied to the determination of benzophenones in cosmetics.

  7. [Determination of urinary trans, trans-muconic acid by high performance liquid chromatography].

    PubMed

    Liu, Liwen; Song, Shizhen; Hu, Xiamin; Ye, Fangli

    2006-05-01

    A method for the determination of urinary trans, trans-muconic acid (tt-MA) (benzene metabolite) by high performance liquid chromatography (HPLC) was developed. The separation was carried out on a C18 column (Spherisorb C18, 150 mm x 4.6 mm i. d. , 5 microm) at 25 degrees C with glacial acetic acid-tetrahydrofuran-methanol-water (1 : 2 : 10: 87, v/v) as mobile phase. Urinary sample was acidified by 2 mol/L hydrochloric acid and pretreated by liquid-liquid extraction using diethyl ether. After removal of diethyl ether with a stream of nitrogen, the residue was re-dissolved in 1 mL of mobile phase for HPLC injection. Good linearity was observed within the range from 0.10 mg/L to 10.00 mg/L (r =0.9999) and the detection limit was 0.10 mg/L. The average recoveries for tt-MA were 95.1%-100.5%. Relative standard deviations (RSD) for intra-day and inter-day determinations were 4.0%-9.0% and 6.2%-8.8%, respectively. The method was applied to 56 benzene-exposed workers and 24 controll workers. Urinary tt-MA in benzen-exposed workers were significantly higher than that in the control group. They can be correlated with benzene exposure concentrations (P <0.01). This analytical method for tt-MA is sensitive, rapid, and convenient. It is suitable for monitoring of occupational exposure to benzene and toxic kinetics studies.

  8. Ionic-liquid-based dispersive liquid-liquid microextraction combined with high-performance liquid chromatography for the determination of multiclass pesticide residues in water samples.

    PubMed

    Tadesse, Bezuayehu; Teju, Endale; Gure, Abera; Megersa, Negussie

    2015-03-01

    Ionic-liquid-based dispersive liquid-liquid microextraction in combination with high-performance liquid chromatography and diode array detection has been proposed for the simultaneous analysis of four multiclass pesticide residues including carbaryl, methidathion, chlorothalonil, and ametryn from water samples. The major experimental parameters including the type and volume of ionic liquid, sample pH, type, and volume of disperser solvent and cooling time were investigated and optimum conditions were established. Under the optimum experimental conditions, limits of detection and quantification of the method were in the range of 0.1-1.8 and 0.4-5.9 μg/L, respectively, with satisfactory enrichment factors ranging from 10-20. The matrix-matched calibration curves, which were constructed for lake water, as a representative matrix were linear over wide range with coefficients of determination of 0.996 or better. Intra- and interday precisions, expressed as relative standard deviations, were in the range of 1.1-9.7 and 3.1-7.8%, respectively. The relative recoveries of the spiked environmental water samples at one concentration level were in the range of 77-102%. The results of the present study revealed that the proposed method is simple, fast, and uses environmentally friendly extraction solvent for the analysis of the target pesticide residues in environmental water samples.

  9. Determination of phenylurea and triazine herbicides in milk by microwave assisted ionic liquid microextraction high-performance liquid chromatography.

    PubMed

    Gao, Shiqian; You, Jingyan; Zheng, Xia; Wang, Ying; Ren, Ruibing; Zhang, Rui; Bai, Yuping; Zhang, Hanqi

    2010-09-15

    The determination of phenylurea and triazine herbicides in milk based on microwave assisted ionic liquid microextraction (MAILME) coupled with high-performance liquid chromatographic separation was described. The experimental parameters of the MAILE, including type and amount of ionic liquid, microwave extraction power, extraction time and salt concentration in sample, were evaluated by a univariate method and orthogonal screening. When 60 microL of [C(6)MIM][PF(6)] was used as extraction solvent the target compounds can be isolated from the 4 mL of milk. The MAILME is quick (7 min) and simple. The detection limits for isoproturon, monolinuron, linuron, propazine, prometryne, terbutryn and trietazine are 0.46, 0.78, 1.00, 1.21, 1.96, 0.84 and 1.28 microg L(-1), respectively. The proposed method was applied to the analysis of milk samples and the recoveries of the analytes ranged from 88.4 to 117.9% and relative standard deviations were lower than 7.43%.

  10. A sensitive high performance liquid chromatography assay for the quantification of doxorubicin associated with DNA in tumor and tissues.

    PubMed

    Lucas, Andrew T; O'Neal, Sara K; Santos, Charlene M; White, Taylor F; Zamboni, William C

    2016-02-05

    Doxorubicin, a widely used anticancer agent, exhibits antitumor activity against a wide variety of malignancies. The drug exerts its cytotoxic effects by binding to and intercalating within the DNA of tumor and tissue cells. However, current assays are unable to accurately determine the concentration of the intracellular active form of doxorubicin. Thus, the development of a sample processing method and a high-performance liquid chromatography (HPLC) methodology was performed in order to quantify doxorubicin that is associated with DNA in tumors and tissues, which provided an intracellular cytotoxic measure of doxorubicin exposure after administration of small molecule and nanoparticle formulations of doxorubicin. The assay uses daunorubicin as an internal standard; liquid-liquid phase extraction to isolate drug associated with DNA; a Shimadzu HPLC with fluorescence detection equipped with a Phenomenex Luna C18 (2μm, 2.0×100mm) analytical column and a gradient mobile phase of 0.1% formic acid in water or acetonitrile for separation and quantification. The assay has a lower limit of detection (LLOQ) of 10ng/mL and is shown to be linear up to 3000ng/mL. The intra- and inter-day precision of the assay expressed as a coefficient of variation (CV%) ranged from 4.01 to 8.81%. Furthermore, the suitability of this assay for measuring doxorubicin associated with DNA in vivo was demonstrated by using it to quantify the doxorubicin concentration within tumor samples from SKOV3 and HEC1A mice obtained 72h after administration of PEGylated liposomal doxorubicin (Doxil(®); PLD) at 6mg/kg IV x 1. This HPLC assay allows for sensitive intracellular quantification of doxorubicin and will be an important tool for future studies evaluating intracellular pharmacokinetics of doxorubicin and various nanoparticle formulations of doxorubicin.

  11. Ionic-liquid-based dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography for the forensic determination of methamphetamine in human urine.

    PubMed

    Wang, Ruifeng; Qi, Xiujuan; Zhao, Lei; Liu, Shimin; Gao, Shuang; Ma, Xiangyuan; Deng, Youquan

    2016-07-01

    Determination of methamphetamine in forensic laboratories is a major issue due to its health and social harm. In this work, a simple, sensitive, and environmentally friendly method based on ionic liquid dispersive liquid-liquid microextraction combined with high-performance liquid chromatography was established for the analysis of methamphetamine in human urine. 1-Octyl-3-methylimidazolium hexafluorophosphate with the help of disperser solvent methanol was selected as the microextraction solvent in this process. Various parameters affecting the extraction efficiency of methamphetamine were investigated systemically, including extraction solvent and its volume, disperser solvent and its volume, sample pH, extraction temperature, and centrifugal time. Under the optimized conditions, a good linearity was obtained in the concentration range of 10-1000 ng/mL with determination coefficient >0.99. The limit of detection calculated at a signal-to-noise ratio of 3 was 1.7 ng/mL and the relative standard deviations for six replicate experiments at three different concentration levels of 100, 500, and 1000 ng/mL were 6.4, 4.5, and 4.7%, respectively. Meanwhile, up to 220-fold enrichment factor of methamphetamine and acceptable extraction recovery (>80.0%) could be achieved. Furthermore, this method has been successfully employed for the sensitive detection of a urine sample from a suspected drug abuser.

  12. Quantitation of antioxidants in water samples using ionic liquid dispersive liquid-liquid microextraction followed by high-performance liquid chromatography-ultraviolet detection.

    PubMed

    Sobhi, Hamid Reza; Kashtiaray, Amir; Farahani, Hadi; Farahani, Mohammad Reza

    2011-01-01

    A simple and efficient method, ionic liquid-based dispersive liquid-liquid microextraction combined with high-performance liquid chromatography-ultraviolet detection (HPLC-UV), has been applied for the extraction and determination of some antioxidants (Irganox 1010, Irganox 1076 and Irgafos 168) in water samples. The microextraction efficiency factors were investigated and optimized: 1-hexyl-3-methylimidazolium hexafluorophosphate [C(6)MIM][PF(6)] (0.06 g) as extracting solvent, methanol (0.5 mL) as disperser solvent without salt addition. Under the selected conditions, enrichment factors up to 48-fold, limits of detection (LODs) of 5.0-10.0 ng/mL and dynamic linear ranges of 25-1500 ng/mL were obtained. A reasonable repeatability (RSD≤11.8%, n=5) with satisfactory linearity (r(2)≥0.9954) of the results illustrated a good performance of the presented method. The accuracy of the method was tested by the relative recovery experiments on spiked samples, with results ranging from 85 to 118%. Finally, the method was successfully applied for determination of the analytes in several real water samples.

  13. Determination of formaldehyde in beverages using microwave-assisted derivatization and ionic liquid-based dispersive liquid-liquid microextraction followed by high-performance liquid chromatography.

    PubMed

    Xu, Xu; Su, Rui; Zhao, Xin; Liu, Zhuang; Li, Dan; Li, Xueyuan; Zhang, Hanqi; Wang, Ziming

    2011-10-15

    A simple method based on simultaneous microwave-assisted derivatization and ionic liquid-based dispersive liquid-liquid microextraction (IL-based DLLME) is proposed for the derivatization, extraction and preconcentration of formaldehyde in beverage samples prior to the determination by high-performance liquid chromatography (HPLC). Formaldehyde was in situ derivatized with 2,4-dinitrophenylhydrazine (DNPH) and simultaneously extracted and preconcentrated by using microwave-assisted derivatization and IL-based DLLME in a single step. Several experimental parameters, including type and volume of extraction solvent, type and volume of disperser, microwave power and irradiation time, volume of DNPH, pH of sample solution, and ionic strength were evaluated. When the microwave power was 120 W, formaldehyde could be derivatized and extracted simultaneously only within 90 s. Under optimal experimental conditions, good linearity was observed in the range of 0.5-50 ng/mL with the correlation coefficient of 0.9965, and the limit of detection was 0.12 ng/mL. The proposed method was applied to the analysis of different beverage samples, and the recoveries of formaldehyde obtained were in the range of 84.9-95.1% with the relative standard deviations lower than 8.4%. The results showed that the proposed method was a rapid, convenient and feasible method for the determination of formaldehyde in beverage samples.

  14. Chemotaxonomic study of Chrysobalanus icaco Linnaeus (Chrysobalanaceae) using ultra high performance liquid chromatography coupled with diode array detection fingerprint in combination with multivariate analysis.

    PubMed

    Paracampo, Nádia Elígia Nunes Pinto; Prance, Ghillean Tolmie; Poppi, Ronei Jesus; da Silva, José Alberto Fracassi

    2017-03-29

    We investigated a strategy for the chemotaxonomy study of Chrysobalanus icaco Linnaeus (Chrysobalanaceae) based on ultra high performance liquid chromatography coupled with diode array detection fingerprint in combination with multivariate analysis. Two models using principal component analysis and partial least squares discriminant analysis were developed, and the samples could be successfully classified into two classes: Class 1 (red morphotype) and Class 2 (white and black morphotypes). Furthermore, ultra high performance liquid chromatography coupled with diode array and electrospray ionization tandem mass spectrometry was used to identify the main compounds responsible for class separation. The partial least squares discriminant analysis model accurately classified the C. icaco samples using an external validation subset with prediction ability of 100% and revealed the existence of two chemotypes. The most important finding obtained in this study is that the three morphotypes distinguished by the mature fruit color (white, red and black) are not all phytoequivalent to each other. This article is protected by copyright. All rights reserved.

  15. A simple high-performance liquid chromatographic assay for ciprofloxacin in human serum.

    PubMed

    Jim, L K; el-Sayed, N; al-Khamis, K I

    1992-04-01

    A simple and selective high-performance liquid chromatographic (HPLC) method for the determination of ciprofloxacin in serum has been developed and evaluated. Serum protein was precipitated with acetonitrile. The drug and the internal standard (quinine) were evaluated from a 10 microns U-Bondapack C-18 cartridge at ambient temperature with a mobile phase consisting of acetonitrile: 0.1 M sodium dihydrogen phosphate (20:80%, v/v) adjusted to pH 3.9 with phosphoric acid, and at a flow rate of 2.5 ml/min. The effluent was monitored on a fluorescence detector using an excitation and emission wavelength of 280 and 455 nm, respectively. Each analysis required no longer than 6 min. Quantification was achieved by the measurement of the peak-height ratio and the limit of quantification for ciprofloxacin in serum is 25 ng/ml. The intraday coefficient of variation (CV) ranged from 0.4 to 5.8%, and interday CV from 4.6 to 8.8% at three different concentrations. Relative recovery ranged from 98 to 100.2% at three different concentrations. Preliminary stability tests show that ciprofloxacin is stable for at least 3 weeks in serum after freezing.

  16. High-performance liquid chromatographic determination of triclosan and triclocarban in cosmetic products.

    PubMed

    Liu, T; Wu, D

    2012-10-01

    A high-performance liquid chromatographic (HPLC) method for the determination of triclosan and triclocarban in cosmetic products was developed. Triclosan and triclocarban quantities in 168 of cosmetics were investigated and statistical analyzed with this method. The optimal condition are as follows: An Agilent SB-C8 analytical column (250 × 4.6 mm, 5μm) was utilized, and mixed buffer solution of methanol and 0.01 mol L(-1) phosphate (pH 3.0) (72 : 28, V/V) were used for isocratic elution at a total flow rate of 1.0 mL min(-1) . It is found the calibration curves had a good linear regression with UV detection (280 nm) within test range of 0-110 μg mL(-1) with the correlation coefficients of 0.999 in all cases. This method is simple, selective, convenient, and reproducible for the determination of triclosan and triclocarban in commercial cosmetic products.

  17. Determination of mitomycin C in human aqueous humor and serum by high-performance liquid chromatography.

    PubMed

    Li, W Y; Seah, S K; Koda, R T

    1993-09-08

    Mitomycin C (MMC) is used in the treatment of disseminated adenocarcinoma of the stomach and pancreas and is used in ophthalmology as adjunctive therapy in trabeculectomy. Since only small volumes of aqueous humor are available for analysis, a sensitive method requiring limited sample preparation was developed. An internal standard, 4-aminoacetophenone, was added to aqueous humor specimens, and the solution was directly injected into the high-performance liquid chromatographic (HPLC) column. The use of a short 50-mm C18 reversed-phase column gave adequate resolution of peaks with improved sensitivity. The method was applicable for determination of MMC in serum, although solid-phase extraction for sample clean-up was required prior to injection into the HPLC column, and analytical columns of 150-250 mm were necessary for adequate resolution of peaks. The method has been validated and is linear from 6.25 to 50 ng/ml in aqueous humor and from 10 to 500 ng/ml in serum.

  18. Reversed-phase high-performance liquid chromatographic determination of mitomycin C in human serum.

    PubMed

    Buice, R G; Sidhu, P; Gurley, B J; Niell, H B

    1984-01-01

    A reversed-phase high-performance liquid chromatographic method is presented by which the cancer chemotherapeutic agent, mitomycin C, may be measured in human serum. A mobile phase of methanol:water (35:65) passed through a mu-Bondapak C-18 column at a rate of 1.0 ml/min produced a sharp, symmetrical band for mitomycin C. An improved serum extraction procedure, using a reversed-phase sample preparation cartridge, proved to be efficient and reproducible. Recovery over a concentration range of 10-100 ng/ml was 81.6% with a between-day coefficient of variation of 4.6% (n = 5). The within-day coefficient of variation at 50 ng/ml was 5.6% (n = 10). Ultraviolet detection at a wavelength of 365 nm was sensitive to serum concentrations of 10 ng/ml. Serum concentration-time course data from lung cancer patients receiving mitomycin C by rapid intravenous injection are presented.

  19. Determination of fexofenadine enantiomers in human plasma with high-performance liquid chromatography.

    PubMed

    Miura, Masatomo; Uno, Tsukasa; Tateishi, Tomonori; Suzuki, Toshio

    2007-01-17

    A simple and sensitive high-performance liquid chromatography (HPLC) method was developed as an assay for fexofenadine enantiomers in human plasma. Fexofenadine enantiomers were separated using a mobile phase of 0.5% KH(2)PO(4)-acetonitrile (65:35, v/v) on a Chiral CD-Ph column at a flow rate of 0.5 ml/min and measurement at 220 nm. Analysis required 400 microl of plasma and involved solid-phase extraction with an Oasis HLB cartridge, which gave recoveries for both enantiomers from 67.4 to 71.8%. The lower limit of quantification was 25 ng/ml for (R)- and (S)-fexofenadine. The linear range of this assay was between 25 and 625 ng/ml (regression line r(2)>0.993). Inter- and intra-day coefficients of variation were less than 13.6% and accuracies were within 8.8% over the linear range for both analytes. This method can be applied effectively to measure fexofenadine enantiomer concentrations in clinical samples.

  20. [Determination of histamine in canned fish by high performance liquid chromatography with pre-column derivatization].

    PubMed

    Jin, Gaowa; Cai, Youqiong; Yu, Huijuan; Qian, Beilei

    2010-11-01

    A pre-column derivatization-high performance liquid chromatographic (HPLC) method has been developed for the determination of histamine in canned fish. The homogenated samples were ultrasonically extracted with perchloric acid aqueous solution, derivatized with dansyl chloride and diluted with acetonitrile to a desired volume. The samples were determined by HPLC with ultraviolet detector and quantified by external standard method. Adopting a C18 column with 1.8 microm stationary phase particles, the analysis time for each sample was smaller than 5 min with the flow rate of 0.3 mL/min. It can decrease the consumption of the mobile phase and save the cost. The linear range was 0.08-8.00 mg/L for histamine. The correlation coefficient was 0.999 98. The average recoveries of histamine at different concentration levels in spiked samples were greater than 96% and the relative standard deviations (RSDs) were smaller than 2.5%. The quantitation limit was 5.00 mg/kg for histamine in canned fish by HPLC. The results indicated that this HPLC method is fast, sensitive, reproducible and practical for the routine analysis of histamine in canned fish.

  1. Determination of multiple human arsenic metabolites employing high performance liquid chromatography inductively coupled plasma mass spectrometry

    PubMed Central

    Stice, Szabina; Liu, Guangliang; Matulis, Shannon; Boise, Lawrence H.; Cai, Yong

    2016-01-01

    During the metabolism of different arsenic-containing compounds in human, a variety of metabolites are produced with significantly varying toxicities. Currently available analytical methods can only detect a limited number of human metabolites in biological samples during one run due to their diverse characteristics. In addition, co-elution of species is often unnoticeable with most detection techniques leading to inaccurate metabolic profiles and assessment of toxicity. A high performance liquid chromatography inductively coupled mass spectrometry (HPLC-ICP-MS) method was developed that can identify thirteen common arsenic metabolites possibly present in human with special attention dedicated to thiolated or thiol conjugated arsenicals. The thirteen species included in this study are arsenite (AsIII), arsino-glutathione (As(GS)3), arsenate (AsV), monomethylarsonous acid (MMAIII), monomethylarsino-glutathione (MMAIII(GS)2), monomethylarsonic acid (MMAV), dimethylarsinous acid (DMAIII (from DMAIIII)), S-(dimethylarsinic)cysteine (DMAIII(Cys)), dimethylarsino-glutathione (DMAIII(GS)), dimethylarsinic acid (DMAV), dimethylmonothioarsinic acid (DMMTAV), dimethyldithioarsinic acid (DMDTAV), dimethylarsinothioyl glutathione (DMMTAV(GS)). The developed method was applied for the analysis of cancer cells that were incubated with Darinaparsin (DMAIII(GS)), a novel chemotherapeutic agent for refractory malignancies, and the arsenic metabolic profile obtained was compared to results using a previously developed method. This method provides a useful analytical tool which is much needed in unequivocally identifying the arsenicals formed during the metabolism of environmental arsenic exposure or therapeutic arsenic administration. PMID:26708625

  2. The MAREDAT global database of high performance liquid chromatography marine pigment measurements

    NASA Astrophysics Data System (ADS)

    Peloquin, J.; Swan, C.; Gruber, N.; Vogt, M.; Claustre, H.; Ras, J.; Uitz, J.; Barlow, R.; Behrenfeld, M.; Bidigare, R.; Dierssen, H.; Ditullio, G.; Fernandez, E.; Gallienne, C.; Gibb, S.; Goericke, R.; Harding, L.; Head, E.; Holligan, P.; Hooker, S.; Karl, D.; Landry, M.; Letelier, R.; Llewellyn, C. A.; Lomas, M.; Lucas, M.; Mannino, A.; Marty, J.-C.; Mitchell, B. G.; Muller-Karger, F.; Nelson, N.; O'Brien, C.; Prezelin, B.; Repeta, D.; Smith, W. O., Jr.; Smythe-Wright, D.; Stumpf, R.; Subramaniam, A.; Suzuki, K.; Trees, C.; Vernet, M.; Wasmund, N.; Wright, S.

    2012-12-01

    A global pigment database consisting of 37 103 pigment suites measured by high performance liquid chromatography was assembled in support of the MARine Ecosytem DATa (MAREDAT) initiative. These data originate from 136 field surveys within the global ocean, were solicited from investigators and databases, compiled, and then quality controlled. Nearly one quarter of the data originates from the Laboratoire d'Océanographie de Villefranche (LOV), with an additional 20% and 17% stemming from the US JGOFS and LTER programs, respectively. The MAREDAT pigment database provides high quality measurements of the major taxonomic pigments including chlorophyll a and b, 19'butanoyloxyfucoxanthin, 19'hexanoyloxyfucoxanthin, alloxanthin, divinyl chlorophyll a, fucoxanthin, lutein, peridinin, prasinoxanthin, violaxanthin and zeaxanthin, which may be used in varying combinations to estimate phytoplankton community composition. Quality control measures consisted of flagging samples that had a total chlorophyll a concentration of zero, had fewer than four reported accessory pigments, or exceeded two standard deviations of the log-linear regression of total chlorophyll a with total accessory pigment concentrations. We anticipate the MAREDAT pigment database to be of use in the marine ecology, remote sensing and ecological modeling communities where it will support model validation and advance our global perspective on marine biodiversity. The original dataset together with quality control flags as well as the gridded MAREDAT pigment data may be downloaded from PANGAEA: doi:10.1594/PANGAEA.793246.

  3. Analysis of Fluconazole in Human Urine Sample by High Performance Liquid Chromatography Method

    NASA Astrophysics Data System (ADS)

    Hermawan, D.; Ali, N. A. Md; Ibrahim, W. A. Wan; Sanagi, M. M.

    2013-04-01

    A method for determination of fluconazole, antifungal drug in human urine by using reversed-phased high performance liquid chromatography (RP-HPLC) with ultraviolet (UV) detector was developed. Optimization HPLC conditions were carried out by changing the flow rate and composition of mobile phase. The optimum separation conditions at a flow rate 0.85 mL/min with a composition of mobile phase containing methanol:water (70:30, v/v) with UV detection at a wavelength 254 nm was able to analyze fluconazole within 3 min. The excellent linearity was obtained in the range of concentration 1 to 10 μg/mL with r2 = 0.998. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.39 μg/mL and 1.28 μg/mL, respectively. Solid phase extraction (SPE) method using octadecylsilane (C18) as a sorbent was used to clean-up and pre-concentrated of the urine sample prior to HPLC analysis. The average recoveries of fluconazole in spiked urine sample was 72.4% with RSD of 3.21% (n=3).

  4. Spectrophotometric and high performance liquid chromatographic methods for sensitive determination of bisphenol A

    NASA Astrophysics Data System (ADS)

    Zhuang, Yafeng; Zhou, Meng; Gu, Jia; Li, Xiangmei

    2014-03-01

    A new spectrophotometric method for the determination of trace amounts of bisphenol A based on a diazotization-coupling reaction was developed. In acidic solution, clenbuterol was first diazotized with sodium nitrite, then coupled with bisphenol A to from an azo-compound [I] in NH3-NH4Cl buffer, which shows a maximum absorption at 410 nm. The effects of the amount of sodium nitrite, diazo reaction time, the amount of clenbuterol, coupling reaction time and coupling reaction temperature have been examined. Under the optional conditions, the determination of the linear range of bisphenol A is 0.24-8.4 μg/mL, correlation coefficient is 0.9905 and detection limit of this method is 0.15 μg/mL. The spectrophotometric method is simple, rapid, high sensitivity with better accuracy. High performance liquid chromatography (HPLC) technique combined with this new spectrophotometric method has been also developed for the measurement of bisphenol A. The analysis was achieved on a C18 column using water and methanol as a mobile phase and the detection was done spectrophotometrically at 410 nm. These reported methods were applied to the determination of bisphenol A in hot water in contact with commercially available table-water bottle samples.

  5. Detection of HEMA in self-etching adhesive systems with high performance liquid chromatography

    NASA Astrophysics Data System (ADS)

    Panduric, V.; Tarle, Z.; Hameršak, Z.; Stipetić, I.; Matosevic, D.; Negovetić-Mandić, V.; Prskalo, K.

    2009-04-01

    One of the factors that can decrease hydrolytic stability of self-etching adhesive systems (SEAS) is 2-hydroxymethylmethacrylate (HEMA). Due to hydrolytic instability of acidic methacrylate monomers in SEAS, HEMA can be present even if the manufacturer did not include it in original composition. The aim of the study was to determine the presence of HEMA because of decomposition by hydrolysis of methacrylates during storage, resulting with loss of adhesion strength to hard dental tissues of the tooth crown. Three most commonly used SEAS were tested: AdheSE ONE, G-Bond and iBond under different storage conditions. High performance liquid chromatography analysis was performed on a Nucleosil C 18-100 5 μm (250 × 4.6 mm) column, Knauer K-501 pumps and Wellchrom DAD K-2700 detector at 215 nm. Data were collected and processed by EuroCrom 2000 HPLC software. Calibration curves were made related eluted peak area to known concentrations of HEMA (purchased from Fluka). The elution time for HEMA is 12.25 min at flow rate 1.0 ml/min. Obtained results indicate that no HEMA was present in AdheSE ONE because methacrylates are substituted with methacrylamides that seem to be more stable under acidic aqueous conditions. In all other adhesive systems HEMA was detected.

  6. AB063. Prevalence of thalassemias and hemoglobinopathies detected via high performance liquid chromatography in Filipinos

    PubMed Central

    Silao, Catherine Lynn; Fabella, Terence Diane; Yuson, Ernesto; Naranjo, Maria Liza; Padilla, Carmencita

    2015-01-01

    Background The thalassemias and hemoglobinopathies are groups of autosomal recessive inherited blood disorders affecting the quantity and quality of hemoglobin. Patients with the disease can vary from clinically asymptomatic to transfusion dependent individuals. It is considered prevalent in many parts of the world particularly in Southeast Asia. Thus, screening and prevalence determination of these diseases are important in the Filipino population. The study aims to determine the prevalence of thalassemias and hemoglobinopathies in the Philippines using high performance liquid chromatography. Methods Referred patients by hematologists from different parts of the country from October 2008 to December 2014 were included. Peripheral blood extracted from the subjects, were hemolyzed and screened for thalassemias and hemoglobinopathies using VariantTM HPLC. Data interpretations were based on levels of the HbA2 Fetal Hb and HbA detected. Results Majority of the patients were beta thalassemics followed by alpha-thalassemics. Hemoglobin E was found in 1% of the population tested while 2% of the patients have beta thalassemia with HbE interaction. Conclusions A significant proportion of thalassemias and hemoglobinopathies were determined from the 6-year screening of Filipinos using VariantTM HPLC. The results of this study provide not only confirmation of the occurrence and prevalence of these growing and diverse groups of genetic blood diseases but also suggest that the use of HPLC is a useful screening tool.

  7. The MAREDAT global database of high performance liquid chromatography marine pigment measurements

    NASA Astrophysics Data System (ADS)

    Peloquin, J.; Swan, C.; Gruber, N.; Vogt, M.; Claustre, H.; Ras, J.; Uitz, J.; Barlow, R.; Behrenfeld, M.; Bidigare, R.; Dierssen, H.; Ditullio, G.; Fernandez, E.; Gallienne, C.; Gibb, S.; Goericke, R.; Harding, L.; Head, E.; Holligan, P.; Hooker, S.; Karl, D.; Landry, M.; Letelier, R.; Llewellyn, C. A.; Lomas, M.; Lucas, M.; Mannino, A.; Marty, J.-C.; Mitchell, B. G.; Muller-Karger, F.; Nelson, N.; O'Brien, C.; Prezelin, B.; Repeta, D.; Smith, W. O., Jr.; Smythe-Wright, D.; Stumpf, R.; Subramaniam, A.; Suzuki, K.; Trees, C.; Vernet, M.; Wasmund, N.; Wright, S.

    2013-03-01

    A global pigment database consisting of 35 634 pigment suites measured by high performance liquid chromatography was assembled in support of the MARine Ecosytem DATa (MAREDAT) initiative. These data originate from 136 field surveys within the global ocean, were solicited from investigators and databases, compiled, and then quality controlled. Nearly one quarter of the data originates from the Laboratoire d'Océanographie de Villefranche (LOV), with an additional 17% and 19% stemming from the US JGOFS and LTER programs, respectively. The MAREDAT pigment database provides high quality measurements of the major taxonomic pigments including chlorophylls a and b, 19'-butanoyloxyfucoxanthin, 19'-hexanoyloxyfucoxanthin, alloxanthin, divinyl chlorophyll a, fucoxanthin, lutein, peridinin, prasinoxanthin, violaxanthin and zeaxanthin, which may be used in varying combinations to estimate phytoplankton community composition. Quality control measures consisted of flagging samples that had a total chlorophyll a concentration of zero, had fewer than four reported accessory pigments, or exceeded two standard deviations of the log-linear regression of total chlorophyll a with total accessory pigment concentrations. We anticipate the MAREDAT pigment database to be of use in the marine ecology, remote sensing and ecological modeling communities, where it will support model validation and advance our global perspective on marine biodiversity. The original dataset together with quality control flags as well as the gridded MAREDAT pigment data may be downloaded from PANGAEA: http://doi.pangaea.de/10.1594/PANGAEA.793246.

  8. Determination of sulphachloropyrazine-diaveridine residues by high performance liquid chromatography in broiler edible tissues

    PubMed Central

    LI, Yongjun; BU, Shijin

    2015-01-01

    Diaveridine (DVD) is used in combination with sulphachloropyrazine (SPZ) as an effective antibacterial agent and antiprotozoal agent, respectively, in humans and animals. To gain a better understanding of the metabolism of SPZ and DVD in the food-producing animals, a high performance liquid chromatography (HPLC) method to determine and quantify sulphachloropyrazine (SPZ) and diaveridine (DVD) suspension residues from broilers is reported. Thirty healthy chickens were orally administered with sulphachloropyrazine-diaveridine (SPZ-DVD) suspension in water of 300 mg/l (SPZ) per day for seven successive days. Six chickens per day were slaughtered at 0, 1, 3, 5 and 7 days after the last administration. This procedure permitted SPZ and DVD to be separated from muscle tissue, liver, kidneys and skin with fat after extraction with acetonitrile and acetone under slightly acidic conditions. From the detected residuals in different tissues, we found that SPZ was quickly eliminated in liver and muscle, and slowly eliminated in kidney and skin with fat. DVD was quickly eliminated in liver and slowly eliminated in kidney. The withdrawal period of SPZ was 3.26, 3.72, 4.39 and 5.43 days in muscle, liver, kidney and skin with fat, respectively. The withdrawal period of DVD was 4.77, 4.94, 6.74 and 4.58 days in muscle, liver, kidney and skin with fat, respectively. Therefore, the suggested withdrawal period for SPZ-DVD suspension should be 7 days after dosing for seven successive days. PMID:26212255

  9. Analysis of serotonin concentrations in human milk by high-performance liquid chromatography with fluorescence detection.

    PubMed

    Chiba, Takeshi; Maeda, Tomoji; Tairabune, Tomohiko; Tomita, Takashi; Sanbe, Atsushi; Takeda, Rika; Kikuchi, Akihiko; Kudo, Kenzo

    2017-03-25

    Serotonin (5-hydroxytryptamine, 5-HT) plays an important role in milk volume homeostasis in the mammary gland during lactation; 5-HT in milk may also affect infant development. However, there are few reports on 5-HT concentrations in human breast milk. To address this issue, we developed a simple method based on high-performance liquid chromatography with fluorescence detection (HPLC-FD) for measuring 5-HT concentrations in human breast milk. Breast milk samples were provided by four healthy Japanese women. Calibration curves for 5-HT in each sample were prepared with the standard addition method between 5 and 1000 ng/ml, and all had correlation coefficients >0.999. The recovery of 5-HT was 96.1%-101.0%, with a coefficient of variation of 3.39%-8.62%. The range of 5-HT concentrations estimated from the calibration curves was 11.1-51.1 ng/ml. Thus, the HPLC-FD method described here can effectively extract 5-HT from human breast milk with high reproducibility.

  10. High performance liquid chromatography resolution of ubiquitin pathway enzymes from wheat germ. [Triticum vulgare

    SciTech Connect

    Sullivan, M.L.; Callis, J.; Vierstra, R.D. )

    1990-10-01

    The highly conserved protein ubiquitin is involved in several cellular processes in eukaryotes as a result of its covalent ligation to a variety of target proteins. Here, we describe the purification of several enzymatic activities involved in ubiquitin-protein conjugate formation and disassembly from wheat germ (Triticum vulgare) by a combination of ubiquitin affinity chromatography and anion-exchange high performance liquid chromatography. Using this procedure, ubiquitin activating enzyme (E1), several distinct ubiquitin carrier proteins (E2s) with molecular masses of 16, 20, 23, 23.5, and 25 kilodaltons, and a ubiquitin-protein hydrolase (isopeptidase) were isolated. Purified E1 formed a thiol ester linkage with {sup 125}I-ubiquitin in an ATP-dependent manner and transferred bound ubiquitin to the various purified E2s. The ubiquitin protein hydrolase fraction was sensitive to hemin, and in an ATP-independent reaction, was capable of removing the ubiquitin moiety from both ubiquitin {sup 125}I-lysozyme conjugates ({epsilon}-amino or isopeptide linkage) and the ubiquitin 52-amino acid extension protein fusion ({alpha}-amino or peptide linkage). Using this procedure, wheat germ represents an inexpensive source from which enzymes involved in the ubiquitin pathway may be isolated.

  11. Detection of honey adulteration with starch syrup by high performance liquid chromatography.

    PubMed

    Wang, Shaoqing; Guo, Qilei; Wang, Linlin; Lin, Li; Shi, Hailiang; Cao, Hong; Cao, Baosen

    2015-04-01

    According to saccharide profile comparison between starch syrups and pure honeys analysed through high performance liquid chromatography (HPLC), a characteristic peak was found at 15.25 min retention time in HPLC chromatogram of syrup, but no peak was observed at the same retention time in chromatogram of pure honeys. This characteristic peak for syrup was identified as an overlapping peak of oligosaccharides with more than 5 degree of polymerisation (DP) based on HPLC chromatogram comparison between starch syrup and a series of standard mono-, di- and oligosaccharides of 3-7 DP. Additionally syrup content correlated linearly with the height of the characteristic peak of syrup under different slope in two ranges 2.5-7.5% and 10-100%, respectively. Therefore, the characteristic peak at 15.25 min retention time can serve as a syrup indicator in HPLC analysis of the adulterated honeys. This new HPLC method for honey adulteration detection was further applied in an authenticity inspection on more than 100 commercial honeys. In addition to the improved accuracy of honey adulteration detection, the proposed HPLC method was simple, low cost and easy practice for honey product quality control by government department considering the popularity of HPLC device and technology.

  12. Improved high-performance liquid chromatographic method for the determination of coenzyme Q10 in plasma.

    PubMed

    Grossi, G; Bargossi, A M; Fiorella, P L; Piazzi, S; Battino, M; Bianchi, G P

    1992-02-28

    Coenzyme (Co) Q10 was dissociated from lipoproteins in plasma by treatment with methanol and extraction with n-hexane. Subsequent clean-up on silica gel and C18 solid-phase extraction cartridges with complete recovery (99 +/- 1.2%) produced a clean extract. High-performance liquid chromatographic (HPLC) separation was performed on a C18 reversed-phase column. Three simple, rapid procedures are presented: HPLC with final UV (275 nm) detection, a microanalysis utilizing a three-electrode electrochemical detector and a microanalysis with column-switching HPLC and electrochemical detection. The methods correlate very well with classical ethanol-n-hexane extraction with UV detection. The identity and purity of the Co Q10 peak were investigated and the resulting methods were concluded to be suitable for total plasma Co Q10 determination. The average level in healthy subjects was 0.80 +/- 0.20 mg/l; the minimum detectable Co Q10 plasma level was 0.05 and 0.005 mg/l for UV and electrochemical detection, respectively. The methods were applied to many samples and the plasma Co Q10 reference values for healthy subjects, athletes, hyperthyroid, hypothyroid and hypercholesterolaemic patients are given.

  13. [Determination of three isothiazolinone biocides in water-borne adhesives by high performance liquid chromatography].

    PubMed

    Zhou, Xiao; Li, Xiaolan; Chen, Zhiyan; Ye, Changwen; Zhou, Yun; Meng, Dongling

    2015-01-01

    A rapid high performance liquid chromatography (HPLC) method was developed for the quantitative analysis of three isothiazolinone biocides (2-methyl-4-isothiazolin-3-one (MI), 5-chloro-2-methyl-4-isothiazolin-3-one (CMI) and 1, 2-benzylisothiazolin-3-one (BIT)) in water-borne adhesives. The sample was extracted with methanol-water (1:1, v/v), and purified by centrifugation and filtration. The isothiazolones were separated on a C18 column with methanol-water as mobile phases under gradient elution and detected with a diode array detector (DAD). The pretreatment factors such as extraction solvent, extraction method, dilution ratio, extraction time were optimized. Under the optimized conditions, the targets had good linearities (r2H > or = 0.9992) in the range of 0.25-10.0 mg/L. The recoveries were between 92% and 103% with the relative standard deviations not more than 4%. The limits of detection (LODs) were between 0.43 mg/kg and 1.14 mg/kg. The limits of quantification (LOQs) were between 1.44 mg/kg and 3.81 mg/kg. The results showed that the method can achieve the purpose of quantitative detection. The analyses of real samples verified the reliability of this method.

  14. 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.

  15. High performance liquid chromatographic determination of etofibrate and its hydrolysis products.

    PubMed

    el-Gindy, Alaa; Hadad, Ghada M; Mahmoud, Waleed M M

    2007-01-04

    High performance liquid chromatographic (HPLC) method is presented for the determination of etofibrate (EF) and its hydrolysis products. The method was based on HPLC separation of EF from its hydrolysis products using cyanopropyl column at ambient temperature with mobile phase consisting of acetonitrile-10 mM potassium dihydrogen phosphate, pH was adjusted to 4.1 using phosphoric acid (50:50, v/v). Quantitation was achieved with UV detection at 221 nm based on peak area. The flow rate was 1.5 ml min(-1). The proposed method was used to investigate the kinetics of acidic hydrolysis process of EF at different temperatures and the apparent pseudo first-order rate constant, half-life and activation energy were calculated. The kinetics of alkaline hydrolysis process of EF using 0.01 M sodium hydroxide at different temperatures cannot be studied as the drug is rapidly hydrolyzed in alkaline medium. The pH-rate profile of hydrolysis of EF in Britton-Robinson buffer solutions within the pH range 2-10 were studied.

  16. Determination of xanthohumol in beer based on cloud point extraction coupled with high performance liquid chromatography.

    PubMed

    Chen, Ligang; Zhao, Qi; Jin, Haiyan; Zhang, Xiaopan; Xu, Yang; Yu, Aimin; Zhang, Hanqi; Ding, Lan

    2010-04-15

    A method based on coupling of cloud point extraction (CPE) with high performance liquid chromatography separation and ultraviolet detection was developed for determination of xanthohumol in beer. The nonionic surfactant Triton X-114 was chosen as the extraction medium. The parameters affecting the CPE were evaluated and optimized. The highest extraction yield of xanthohumol was obtained with 2.5% of Triton X-114 (v/v) at pH 5.0, 15% of sodium chloride (w/v), 70 degrees C of equilibrium temperature and 10 min of equilibrium time. Under these conditions, the limit of detection of xanthohumol is 0.003 mg L(-1). The intra- and inter-day precisions expressed as relative standard deviations are 4.6% and 6.3%, respectively. The proposed method was successfully applied for determination of xanthohumol in various beer samples. The contents of xanthohumol in these samples are in the range of 0.052-0.628 mg L(-1), and the recoveries ranging from 90.7% to 101.9% were obtained. The developed method was demonstrated to be efficient, green, rapid and inexpensive for extraction and determination of xanthohumol in beer.

  17. [Determination of glycyrrhizic acid in glycyrrhiza preparations with capillary electrophoresis and high performance liquid chromatography].

    PubMed

    Peng, J; Wang, F; Zhu, M

    1999-01-01

    High performance liquid chromatography (HPLC), capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography(MECC) have been used to determine glycyrrhizic acid in glycyrrhiza preparations. By HPLC, mobile phase was V(methanol):V(water):V(acetic acid) = 75:23.5:1.5. By CZE, experiment was performed with 15 kV power, 0.075 mm i.d. x 800 mm fused-silica capillary column and UV detector. Samples were injected into the capillary by electromigration injection for 20 s. Absorbance detection was at 254 nm. The running buffer was made up of 0.02 mol/L dipotassium hydrogenphosphate and borax (pH 9.0). By MECC, the running buffer was made up of 0.025 mol/L sodium dodecyl sulfate (SDS), 0.02 mol/L dipotassium hydrogenphosphate and borax (pH 9.0). Each new capillary was washed with 0.1 mol/L NaOH, deionized water and buffer, each for 3 min, before use. Comparison of the results of analysis with HPLC, CZE and MECC has been made. It was found that result of MECC was very close to that of HPLC. MECC has been satisfactorily applied to plant drug analysis.

  18. High performance liquid chromatography analysis of canthinone alkaloids from Eurycoma longifolia.

    PubMed

    Choo, Chee-Yan; Chan, Kit-Lam

    2002-04-01

    A reversed phase-high performance liquid chromatography method with a photodiode array detector was developed for the simultaneous determination of three major alkaloids, 9-methoxycanthin-6-one (1), 3-methylcanthin-5,6-dione (2) and its 9-methoxy analogue (3) in Eurycoma longifolia Jack. These alkaloids were easily separated by a gradient elution protocol of 20 - 42 % acetonitrile in 0.1 % acetic acid. Compound 1 showed characteristic absorption at 350 nm only whereas its dione analogues, 2 and 3 displayed strong absorptions at both 350 and 451 nm. The linear calibration ranges were 0.7 - 50 microg x mL(-1) for 1, 1.5-50 microg x mL(-1) for 2 and 3.1 -100 microg x mL(-1) for 3. The recoveries of the three alkaloids were 90.8-101.0% with relative standard deviations from 0.35 to 6.31 % (n = 3). The limits of detection for all the alkaloids were within the range of 0.35 - 0.7 microg x mL(-1). This method was successfully applied to the phytochemical analysis of E. longifolia roots obtained from different sources.

  19. Detection of synthetic corticosteroids in bovine urine by chemiluminescence high-performance liquid chromatography.

    PubMed

    Vázquez, B I; Feás, X; Lolo, M; Fente, C A; Franco, C M; Cepeda, A

    2005-01-01

    The development of a black market of chemical cocktails for illegal growth promotion in food-producing animals includes substances that are potentially dangerous for human health, such as synthetic corticosteroids. The potential presence of these residues in food makes it necessary to develop rapid and sensitive analytical methodologies to detect such substances, preferably in live animals before they arrive at the market. A chemiluminescence (CL) detection method for the determination of four synthetic corticosteroids (prednisolone, betamethasone, dexamethasone and flumethasone) in bovine urine has been developed. The proposed system, which does not need any derivatization procedure, offers an easy method well suited for routine research. Urine samples were homogenized with methanol:water (50:50, v/v) and centrifuged. The upper layer was collected and Strata X cartridges were used for cleaning up. The purified residues were evaporated to dryness and then redissolved in the mobile phase. Analysis of the extracts was performed using high-performance liquid chromatography with chemiluminescence detection, employing luminol as the CL reagent. The recovery curves, obtained at four spiking levels (different for each corticosteroid), showed that recoveries of at least 70% could be obtained for urine. The chemiluminescence detection procedure afforded satisfactory results with respect to sensitivity and the LOD and LOQ, taken as the first point of the regression curve, ranged from 4 ppb to 65 ppb. The maximum mean RSD was below 13% and below 15% for intra- and inter-day assay, respectively, in all cases.

  20. A reversed phase high performance liquid chromatographic method for determination of rapamycin.

    PubMed

    Sobhani, Hamideh; Shafaati, Alireza; Nafissi-Varcheh, Nastaran; Aboofazeli, Reza

    2013-01-01

    Easily degradating and various isomeric forms of rapamycin (Sirolimus) face the determination of this compound to many challenges. In this study, we developed and validated the isocratic reversed phase high performance liquid chromatographic (RP-HPLC) method for rapamycin. Separation was performed on a C8 column (MZ, 15 × 4.6 mm, 5 μm particle size) using methanol:water (80:20 v/v) as the mobile phase with the flow rate of 1 mL/min. The column temperature was set at 57°C and the detection was carried out at the wavelength of 277 nm. The method was linear over a concentration range of 0.025-2 μg/mL. The coefficient of variation of intra- and inter-day, assessed at three concentration levels of 0.075, 0.3 and 0.900 μg/mL, was less than 2%. Limit of quantification (LOQ) was found 25 ng/mL. The method with high percent recovery and short retention time of rapamycin, was found to be simple, rapid and reproducible.

  1. Rapid determination of lamivudine in human plasma by high-performance liquid chromatography.

    PubMed

    Alebouyeh, Mahmoud; Amini, Hossein

    2015-01-15

    A simple and rapid high-performance liquid chromatographic method with spectrophotometric detection was developed for the determination of lamivudine in human plasma. Sample preparation was accomplished through protein precipitation with acetonitrile followed by aqueous phase separation using dichloromethane. Lamivudine and the internal standard acyclovir were well separated from endogenous plasma peaks on a Chromolith RP-18e column under isocratic elution with 50 mM sodium dihydrogen phosphate-triethylamine (996:4, v/v), pH 3.2 at 20 °C. Total run time at a flow-rate of 1.5 ml/min was less than 5 min. Detection was made at 278 nm. The method was specific and sensitive, with a lower quantification limit of 40 ng/ml and a detection limit of 10 ng/ml. The absolute recovery was 97.7%, while the within- and between-day coefficient of variation and percent error values of the assay method were all less than 7%. The linearity was assessed in the range of 40-2560 in plasma, with a correlation coefficient of greater than 0.999. The method was successfully applied to a bioequivalence study in healthy volunteers.

  2. High-performance liquid chromatography using electrochemical detection for the determination of prazosin in biological samples.

    PubMed

    Rathinavelu, A; Malave, A

    1995-08-04

    For the quantitation of prazosin a sensitive high-performance liquid chromatographic (HPLC) method was developed. This HPLC analysis method uses an electrochemical detection technique for the identification and quantitation of prazosin. In this assay the serum samples were deproteinized by using a simple acetonitrile precipitation technique that was followed by n-hexane extraction. Prazosin in the deproteinized serum sample was separated by an isocratic elution with an ODS Hypersil HPLC column (150 x 4.6 mm) using a mobile phase consisting of 0.05 M Na2HPO4-acetonitrile (60:40), pH 8.4. Prazosin that was eluted from the column was detected using a Coulochem II electrochemical detector. The precision of this assay method was assessed by performing inter- and intra-assay analyses by spiking prazosin free fetal bovine serum samples with 20 and 40 ng/ml concentrations of prazosin. In the intra-assay the recovery was 95.40 +/- 4.82% and 97.80 +/- 3.40%, respectively, for 20 and 40 ng/ml concentrations of prazosin that were used to spike the serum samples. This electrochemical detection HPLC assay method could be very useful in monitoring plasma levels of prazosin.

  3. Molecular authentication and quality control using a high performance liquid chromatography technique of Fructus Evodiae.

    PubMed

    Huang, Dan; Li, Shun Xiang; Cai, Guang Xian; Yue, Chun Hua; Wei, Li Jun; Zhang, Ping

    2008-02-01

    In present paper, the properties of molecular authentication combined with the fingerprints of high performance liquid chromatography (HPLC) were validated by analyzing ten batches of Fructus Evodiae samples (the dried nearly ripe fruit of Evodia rutaecarpa (JUSS.) BENTH., Evodia rutaecarpa (JUSS.) BENTH. var. officinalis (DODE) HUANG or Evodia rutaecarpa (JUSS.) BENTH. var. bodinieri (DODE) HUANG). The results of this investigation show that the similarities of internal transcribed spacer (ITS) sequences were almost 100% in Evodia rutaecarpa (JUSS.) BENTH. var. bodinieri (DODE) HUANG, 97% in Evodia rutaecarpa (JUSS.) BENTH., and 96% in Evodia rutaecarpa (JUSS.) BENTH. var. officinalis (DODE) HUANG. The percentage of identity between the two groups of Evodia rutaecarpa (JUSS.) BENTH. var. bodinieri (DODE) HUANG and Evodia rutaecarpa (JUSS.) BENTH. var. officinalis (DODE) HUANG is almost 96%, but the identity among the group of these three species is only 73%. The results show that Fructus Evodiae comes from three species respectively. The fingerprints of HPLC show that Fructus Evodiae revealed 20 major common peaks. And the three species have almost the same chemical constituents. ITS sequence fingerprint combining the fingerprint of HPLC can not only be developed to identify and distinguish the three species in detail, but also can be used for optimizing location where Fructus Evodiae has much higher bioactive constituents and yield.

  4. High-Performance Liquid Chromatography and Mass Spectrometry-Based Design of Proteolytically Stable Antimicrobial Peptides.

    PubMed

    Bagheri, Mojtaba; Hancock, Robert E W

    2017-01-01

    The emergence of multiresistant bacteria worldwide together with the shortage of effective antibiotics in the market emphasizes the need for the design and development of the promising agents for the treatment of superbug-associated infections. Antimicrobial peptides (AMPs) have been considered as excellent candidates to tackle this issue, and thousands of peptides of different lengths, amino acid compositions, and mode of action have been discovered and prepared to date. Nevertheless, it is of great importance to develop innovative formulation strategies for delivering these AMPs and to improve their low bioavailability and metabolic stability, particularly against proteases, if these peptides are to find applications in the clinic and administered orally or parenterally or used as dietary supplements. The purpose of this chapter is to describe basic experimental principles, based on analytical reversed-phase high-performance liquid chromatography (RP-HPLC) and mass spectrometry (MS), for the prospective design of orally bioavailable AMPs considering the structural characteristics of the peptides and the substrate specificity of proteases that abound in the body especially at sites of infection.

  5. Ultra-high performance liquid chromatography tandem mass spectrometry for comprehensive analysis of urinary acylcarnitines.

    PubMed

    Zuniga, Azeret; Li, Liang

    2011-03-09

    We report an enabling mass spectrometric method for the analysis of lipid metabolites in order to define better the lipid metabolome in terms of chemical diversity and generate fragment ion spectra of these metabolites as a potential resource for unknown metabolite identification. This work focuses on the analysis of one important class of lipid metabolites, the acylcarnitines. Current analytical methods have only detected and identified a limited number of these metabolites. The method described herein provides the most comprehensive acylcarnitine profile in urine of healthy individuals up to date. It involves an optimized solid phase extraction technique for selective analyte extraction using cartridges containing both lipophilic and cation-exchange properties. The captured analytes are then subjected to ultra-high performance liquid chromatography (UPLC) separation, followed by tandem mass spectrometry (MS/MS) analysis using information-dependent acquisitions and selected reaction monitoring (SRM). The urine of six healthy individuals was analyzed using this method. A total of 355 acylcarnitines were detected; only 43 of them have been previously reported in the urine of healthy individuals. Detection of this large number of acylcarnitines illustrates the great diversity of the lipid metabolome as well as the usefulness of the method for profiling acylcarnitines. Furthermore, the MS/MS spectra of the 355 acylcarnitines will be uploaded to a public human metabolome database as a mass spectrometric resource for unknown metabolite identification.

  6. Determination of pyrazinamide and its main metabolites in rat urine by high-performance liquid chromatography.

    PubMed

    Mehmedagic, A; Vérité, P; Ménager, S; Tharasse, C; Chabenat, C; André, D; Lafont, O

    1997-08-01

    A new high-performance liquid chromatograhic procedure for simultaneous determination of pyrazinamide (PZA) and its three metabolites 5-hydroxypyrazinamide (5-OH-PZA), pyrazinoic acid (PA), and 5-hydroxypyrazinoic acid (5-OH-PA), in rat urine was developed. 5-OH-PZA and 5-OH-PA standards were obtained by enzymatic synthesis (xanthine oxidase) and checked by HPLC and GC-MS. Chromatographic separation was achieved in 0.01 M KH2PO4 (pH 5.2), circulating at 0.9 ml/min, on a C18 silica column, at 22 degrees C. The limits of detection were 300 microg/l for PZA, 125 microg/l for PA, 90 microg/l for 5-OH-PZA and 70 microg/l for 5-OH-PA. Good linearity (r2>0.99) was observed within the calibration ranges studied: 0.375-7.50 mg/l for PZA, 0.416-3.33 mg/l for PA, 0.830-6.64 mg/l for 5-OH-PZA and 2.83-22.6 mg/l for 5-OHPA. Accuracy was always lower than +/- 10.8%. Precision was in the range 0.33-5.7%. The method will constitute a useful tool for studies on the influence of drug interactions in tuberculosis treatment.

  7. Monosodium glutamate in chicken and beef stock cubes using high-performance liquid chromatography.

    PubMed

    Demirhan, Buket Er; Demirhan, Burak; Sönmez, Ceren; Torul, Hilal; Tamer, Uğur; Yentür, Gülderen

    2015-01-01

    In this survey monosodium glutamate (MSG) levels in chicken and beef stock cube samples were determined. A total number of 122 stock cube samples (from brands A, B, C, D) were collected from local markets in Ankara, Turkey. High-performance liquid chromatography with diode array detection (HPLC-DAD) was used for quantitative MSG determination. Mean MSG levels (±SE) in samples of A, B, C and D brands were 14.6 ± 0.2 g kg⁻¹, 11.9 ± 0.3 g kg⁻¹, 9.7 ± 0.1 g kg⁻¹ and 7.2 ± 0.1 g kg⁻¹, respectively. Differences between mean levels of brands were significant. Also, mean levels of chicken stock cube samples were lower than in beef stock cubes. Maximum limits for MSG in stock cubes are not specified in the Turkish Food Codex (TFC). Generally the limit for MSG in foods (except some foods) is established as 10 g kg⁻¹ (individually or in combination).

  8. High-performance liquid chromatography determination of hydrastine and berberine in dietary supplements containing goldenseal.

    PubMed

    Abourashed, E A; Khan, I A

    2001-07-01

    Goldenseal (Hydrastis canadensis L., Ranunculaceae) is an ingredient of various dietary supplements intended for enhancing general body immunity. Many goldenseal products are currently available in the United States, either alone or in combination with echinacea. In most products, the content of the main active alkaloids of goldenseal, hydrastine and berberine, is not indicated on the label. A high-performance liquid chromatography (HPLC) method has been developed for the detection and quantification of hydrastine and berberine in a number of products obtained from the United States market. The method uses a Phenomenex Luna C(18) column, a mobile phase consisting of solvent A (100 mM sodium acetate/acetic acid, pH 4.0) and solvent B (acetonitrile/methanol; 90/10, v/v). Elution was run at a flow rate of 1.0 mL/min, with a linear gradient of 80- 40% A in B over 20 min and ultraviolet detection at 290 nm. A wide range of content variation was observed for both alkaloids in the tested samples.

  9. Simultaneous determination of rifampicin and sulbactam in mouse plasma by high-performance liquid chromatography.

    PubMed

    Aparicio, Irene; Bello, Miguel Angel; Callejón, Manuel; Guiraúm, Alfonso

    2006-08-01

    A simple and rapid high-performance liquid chromatographic (HPLC) method with ultraviolet detection has been developed and validated for the simultaneous determination of rifampicin and sulbactam in mouse plasma. Plasma samples were deproteinized with acetonitrile and separated by HPLC on a RP-18 (125 x 4 mm, 5 microm) column and gradient elution with potassium dihydrogen phosphate solution (pH 4.5; 50 mm) and acetonitrile at a flow-rate of 1.0 mL/min. Rifampicin and sulbactam were monitored at 230 nm and confirmed by means of their UV spectra using a diode-array detector. The method was linear at plasma levels from 1 to 100 microg/mL for rifampicin and from 5 to 200 microg/mL for sulbactam. The limits of quantification were 0.6 microg/mL for rifampicin and 4.2 microg/mL for sulbactam. The intra- and inter-day precisions of the method (RSD) were lower than 5% for both compounds. Average recoveries of rifampicin and sulbactam from mice plasma were 98.2 and 89.3%, respectively. The developed method was successfully applied to the determination of the pharmacokinetic profile of both compounds in mice.

  10. Determination of benzalkonium chloride in viscous ophthalmic drops of azithromycin by high-performance liquid chromatography *

    PubMed Central

    Shen, Yan; Xu, Sheng-jie; Wang, Shi-chun; Tu, Jia-sheng

    2009-01-01

    A high-performance liquid chromatography (HPLC) system was used in the reversed phase mode for the determination of benzalkonium chloride (BKC) in azithromycin viscous ophthalmic drops. A Venusil-XBP(L)-C18 (150 mm×4.6 mm, 5 μm) column was used at 50 °C. The mobile phase consisted of a mixture of methanol-potassium phosphate (16:5, v/v). Two sample preparation methods were compared. The results suggested that, compared with an extraction procedure, a deproteinization procedure was much quicker and more convenient. Using the deproteinization procedure for sample preparation, calibration curves were linear in the range 5.0~50 μg/ml. The within-day and inter-day coefficients of variation were less than 10%. The average recoveries were determined as 96.70%, 98.52%, and 97.96% at concentrations of 10.0, 30.0, and 50.0 μg/ml, respectively. Variability in precision did not exceed 5%. In conclusion, this HPLC method using a simple sample treatment procedure appears suitable for monitoring BKC content in azithromycin viscous ophthalmic drops. PMID:19946951

  11. Chiral-phase high-performance liquid chromatography of rotenoid racemates

    USGS Publications Warehouse

    Abidi, S.L.

    1987-01-01

    The high-performance liquid chromatograhic (HPLC) behavior of parent rotenoids (type I) and the hydroxyl-analogues (type II) on three different chiral stationary phases (CSPs) was studied. Separations of optical isomers were achieved in various degrees depending largely upon the rotenoidal structures and the CSP types employed. Enantiomers of all but elliptone compounds were separable on β-cyclodextrin-bonded silica (CDS). Without exception, the 12a-hydroxyrotenoid antipodes were resolved on Pirkle's phenylglycine-bonded silica (PGS) despite unsuccessful attenmpts to resolve the type I rotenoidal racemates. Conversely, optical resolution of the latter rotenoids was accomplished by using a helical polytriphenylmethylacrylate-coated silica (TPS) column and the observed separation factors (α values) ranged from 1.14 to 1.90. The results from HPLC of type II rotenoids on TPS (α = 1.00–1.63) suggested that variations in E-ring structures had profound influence on the resolution outcome. Conjugated double bonds on the E-ring and the desisopropylation of the five-membered E-ring ot type II rotenoids appeared to be important structural features for chiral recognition involving the TPS substrate. In both reversed-phase (CDS) and normal-pahse (PGS and TPS) HPLC modes, the less polar enantiomers were the 6aβ,12aβ-rotenoids as observed in most cases, though this relationship was reversed in the cases of deguelin and hydroxyelliptone probably due to conformational effects of rotenoidal ring systems.

  12. Taking into account both preparation and injection in high-performance liquid chromatography linearity studies

    PubMed

    Vial; Jardy

    2000-05-01

    As mentioned in International Conference on Harmonisation publications, linearity is a principal parameter in method validation. The most popular statistical tool used is linear least-squares regression. Contrary to what is still very often practiced, the correlation coefficient can in no way be considered as an indicator of the fit quality. There is in fact a test called the "lack-of-fit test" that enables one to answer the question, "Is the linear model adapted to the calibration curve?". However, this test can give erroneous conclusions when, at each level, several sources of variation for the response are influent. It often occurs in high-performance liquid chromatography, as shown in a following example, where the calibration curve is obtained from repeated injections of repeated dilutions of a parent solution. The lack-of-fit test rejected linearity, although it was at least questionable. In fact, the reason for a discrepancy of this kind lies in the presence of a double source of variation: injection and dilution. It is possible to overcome the problem by mixing a nested ANOVA with the standard least-square linear regression. As shown in an example, implementing this methodology for data processing allows one not only to carry out an unbiased lack-of-fit test but also give estimates of the dispersion introduced respectively by the preparation and the injection.

  13. Analysis of protein-glutathione mixed disulfides by high performance liquid chromatography.

    PubMed

    Meredith, M J

    1983-06-01

    After precipitation of proteins; serum, hepatocytes, or glutathione-derivatized bovine serum albumin, by perchloric acid, dithiothreitol was used to reduce glutathione-protein mixed disulfides in the ether-washed, resuspended pellet. Following neutralization and S-carboxymethylation of free sulfhydral groups in the acid soluble fraction by iodoacetic acid. 2,4-dinitrophenyl derivatives of released compounds were produced by addition of ethanolic fluorodinitrobenzene. The 2,4-dinitrophenyl derivative of S-carboxymethylglutathione was measured by high-performance liquid chromatography. The method was found to be reproducible and limited only by the sensitivity of the glutathione analysis (about 10 pmol/sample). Quantitation of protein-bound glutathione was shown to be independent of the ratio of bound to soluble glutathione as well as the protein concentration in the sample. This method was found to produce glutathione values identical to those measured after borohydride reduction without the problems of foaming, sample loss, and the need of continuous pH adjustment during reduction.

  14. Dispersion of SiO2-based nanocomposites with high performance liquid chromatography.

    PubMed

    Wang, Jun; White, William B; Adair, James H

    2006-03-16

    Core-shell structured Ag/SiO2 nanocomposite has been synthesized by a cyclohexane/Igepal/water reverse micelle system. The spherical nanocomposite particles were washed and concentrated with high performance liquid chromatography (HPLC) to remove the surfactant added during synthesis. Spherical SiO2 micrometer-scale particles were packed in the HPLC column as a stationary phase for the washing and dispersing of Ag/SiO2 nanocomposite particles. Surface modification of Ag/SiO2 nanocomposite particles and SiO2 microspheres with silane coupling agent enhanced the surface charge of the particles and improved the efficiency of washing with HPLC. Well-dispersed Ag/SiO2 stable suspensions were successfully attained in ethanol/water mixed solvents after HPLC washing. The state of dispersion for the Ag/SiO2 nanocomposite suspension was systematically assessed using dynamic light scattering (DLS) and transmission electron microscope (TEM) and spin coat/atomic force microscope (AFM) analyses. The mechanism of the enabling HPLC washing protocol for SiO2-based nanoparticles is discussed.

  15. Quantitative determination of eleutheroside B and E from Acanthopanax species by high performance liquid chromatography.

    PubMed

    Kang, J S; Linh, P T; Cai, X F; Kim, H S; Lee, J J; Kim, Y H

    2001-10-01

    Reversed-phase high performance liquid chromatographic method was applied for the determination of eleutheroside B and E in the various Acanthopanax species collected in Korea. The stationary phase used was Zorbax 300 SB C18 and a mobile phase program was used, which started at 6% acetonitrile for 2 min, and then a linear gradient was operated for the next 18 min to 17% acetonitrile at a flow rate of 1.0 ml/min. The column effluent was monitored at UV 210 nm. Identification was carried out by comparing the retention time and the LC/MS spectrum of each peak corresponding to eleutheroside B and E from sample with those of standards. In general, the contents of eleutheroside B and E in stems were higher than those in roots. Acanthopanax species could be classified into two groups based upon the contents of eleutheroside B and E: one group contains no or very little eleutheroside B and another contains both eleutheroside B and E.

  16. High-performance liquid chromatography of quinoidal imminium compounds derived from triphenylmethanes

    USGS Publications Warehouse

    Abidi, S.L.

    1983-01-01

    A series of eleven p-aminotriphenylmethane dyes have been studied by high-performance liquid chromatography (HPLC). The combined use of HPLC and spectrophotometry permits specific detection of these compounds in the visible range around 600 nm. As the high affinity of the imminium cations for the active sites of the hydrocarbonaceous stationary phase has presented difficulties for reversed-phase HPLC with pure solvents, organic electrolytes were added to the mobile phase to facilitate the elution of the components with improved selectivity, sensitivity (minimum detection limit, 0.1 μg/ml), and peak symmetry. The effects of chromatographic variables on the component retentivity were investigated. Retention times of the dye analytes decreased with increasing concentration of the added ionic reagent and with decreasing number of the hydrophobic alkyl substituents on the nitrogen atom. The influence of pH on the retention parameters appears to parallel that observed previously for cationic quaternary ammonium compounds. Among the acidic reagents employed, naphthalenesulfonic acid yielded the most satisfactory results. The use of binary electrolyte systems invariably improved the chromatographic behavior of the imminium solutes analyzed. Results obtained with two different octadecylsilica columns have been compared.

  17. Spectrophotometric and high performance liquid chromatographic methods for sensitive determination of bisphenol A.

    PubMed

    Zhuang, Yafeng; Zhou, Meng; Gu, Jia; Li, Xiangmei

    2014-03-25

    A new spectrophotometric method for the determination of trace amounts of bisphenol A based on a diazotization-coupling reaction was developed. In acidic solution, clenbuterol was first diazotized with sodium nitrite, then coupled with bisphenol A to from an azo-compound [I] in NH3-NH4Cl buffer, which shows a maximum absorption at 410 nm. The effects of the amount of sodium nitrite, diazo reaction time, the amount of clenbuterol, coupling reaction time and coupling reaction temperature have been examined. Under the optional conditions, the determination of the linear range of bisphenol A is 0.24-8.4 μg/mL, correlation coefficient is 0.9905 and detection limit of this method is 0.15 μg/mL. The spectrophotometric method is simple, rapid, high sensitivity with better accuracy. High performance liquid chromatography (HPLC) technique combined with this new spectrophotometric method has been also developed for the measurement of bisphenol A. The analysis was achieved on a C18 column using water and methanol as a mobile phase and the detection was done spectrophotometrically at 410 nm. These reported methods were applied to the determination of bisphenol A in hot water in contact with commercially available table-water bottle samples.

  18. [Simultaneous determination of 11 aminophenols in hair dyes by high performance liquid chromatography].

    PubMed

    Zhu, Weixia; Wang, Caijuan; Yang, Jizhou; Wei, Wei; Sun, Zhuanlian; Zhang, Shusheng

    2012-09-01

    An analytical method was developed for the simultaneous determination of 11 aminophenols in direct and oxidized hair dyes by high performance liquid chromatography (HPLC). The samples were extracted with methanol using sodium bisulfite for anti-oxidation. The purification was carried out with the high speed frozen centrifugation. The separation was performed on an Agilent Zorbax SB C18 column with the mobile phases of acetonitrile and an ion pair system of sodium heptanesulfonate and phosphate under a gradient elution. The analytes were detected at three different wavelengths of 230, 270 and 400 nm. In the concentration range of 0.05 - 500 mg/L, the correlation coefficients for the 11 aminophenols were not less than 0.9992. The limits of quantification including 4-amino-3-nitrophenol, 2-amino-5-nitrophenol, and 4-(2-hydroxyethyl) amino-3-nitrophenol were 5 mg/kg. Other aminophenols including 4-aminophenol, 4-methyl aminophenol, 3-aminophenol, 2-aminophenol, 5-amino-o-cresol, 4-amino-3-methylphenol, 5-(2-hydroxyethyl) amino-o-cresol and 2-amino-4-nitrophenol were 20 mg/kg. The recoveries of the aminophenols spiked at different levels ranged from 88.5% to 109. 5% with the relative standard deviations (RSDs) within the range of 2.2% - 8.3%. The commercially available hair dye samples were analyzed for the aminophenols and the results showed that the method was suitable for the determination of the 11 aminophenols in direct and oxidized hair dyes.

  19. An Advanced, Interactive, High-Performance Liquid Chromatography Simulator and Instructor Resources

    PubMed Central

    Stoll, Dwight R.; Carr, Peter W.; Nagel, Megan L.; Vitha, Mark F.; Mabbott, Gary A.

    2013-01-01

    High-Performance Liquid Chromatography (HPLC) simulation software has long been recognized as an effective educational tool, yet we found that existing HPLC simulators are either too expensive, out-dated, or lack many important features we deemed necessary to make them widely useful for educational purposes. Here we describe a free, open-source HPLC simulator we developed that we believe meets this need. The web-based simulator is uniquely sophisticated, yet accessible to a diverse user group with varied expertise in HPLC. It features intuitive controls and indicators for a wide range of experimental conditions, and it displays a graphical chromatogram to provide immediate feedback when conditions are changed. The simulator can be found at hplcsimulator.org. At that website, we also provide a number of example problem sets that can be used by educators to more easily incorporate the simulator into their curriculum. Comments from students who used the simulator in an undergraduate Analytical Chemistry class were very positive. PMID:23543870

  20. An Advanced, Interactive, High-Performance Liquid Chromatography Simulator and Instructor Resources.

    PubMed

    Boswell, Paul G; Stoll, Dwight R; Carr, Peter W; Nagel, Megan L; Vitha, Mark F; Mabbott, Gary A

    2013-02-12

    High-Performance Liquid Chromatography (HPLC) simulation software has long been recognized as an effective educational tool, yet we found that existing HPLC simulators are either too expensive, out-dated, or lack many important features we deemed necessary to make them widely useful for educational purposes. Here we describe a free, open-source HPLC simulator we developed that we believe meets this need. The web-based simulator is uniquely sophisticated, yet accessible to a diverse user group with varied expertise in HPLC. It features intuitive controls and indicators for a wide range of experimental conditions, and it displays a graphical chromatogram to provide immediate feedback when conditions are changed. The simulator can be found at hplcsimulator.org. At that website, we also provide a number of example problem sets that can be used by educators to more easily incorporate the simulator into their curriculum. Comments from students who used the simulator in an undergraduate Analytical Chemistry class were very positive.

  1. Rapid estimation of concentration of aromatic classes in middistillate fuels by high-performance liquid chromatography

    NASA Technical Reports Server (NTRS)

    Otterson, D. A.; Seng, G. T.

    1985-01-01

    An high performance liquid chromatography (HPLC) method to estimate four aromatic classes in middistillate fuels is presented. Average refractive indices are used in a correlation to obtain the concentrations of each of the aromatic classes from HPLC data. The aromatic class concentrations can be obtained in about 15 min when the concentration of the aromatic group is known. Seven fuels with a wide range of compositions were used to test the method. Relative errors in the concentration of the two major aromatic classes were not over 10 percent. Absolute errors of the minor classes were all less than 0.3 percent. The data show that errors in group-type analyses using sulfuric acid derived standards are greater for fuels containing high concentrations of polycyclic aromatics. Corrections are based on the change in refractive index of the aromatic fraction which can occur when sulfuric acid and the fuel react. These corrections improved both the precision and the accuracy of the group-type results.

  2. New high-performance liquid chromatographic method for plasma/serum analysis of lamotrigine.

    PubMed

    Croci, D; Salmaggi, A; de Grazia, U; Bernardi, G

    2001-12-01

    Lamotrigine is an anticonvulsant drug recently approved in Italy for clinical use. Therapeutic monitoring of lamotrigine is relevant for patient management and avoidance of toxicity. The authors describe a simple, sensitive, and highly selective high-performance liquid chromatography method that does not involved extraction for analysis of serum lamotrigine. Serum (20 microL) with internal standard (BW 725 C) was injected directly into a column (25 cm x 4.6 mm) with an internal surface reversed phase (ISRP). The mobile phase consisted of 0.01 mol/L potassium phosphate bibasic (pH 6.0) and acetonitrile (82:18), the flow rate was 1.0 mL/min, and UV detection was optimized at 330 nm. The overall between-run coefficient of variance ranged from 1.89% to 3.25% and the lowest limit of detection was 0.05 mg/L. High linearity (r = 0.9996) in a wide range of concentrations (0.1-20.0 mg/L) and no interference with other antiepileptic drugs, benzodiazepines, and tricyclic antidepressants were the other characteristics of the method. The innovation of this method is the use of ISRP column and the choice of detection wavelength, which allow a shorter analysis time (5-6 minutes). The possibility of direct injection of plasma samples into the column permits a reduction in reagent consumption and in analytic steps, and hence in analytic error.

  3. New oxo-bridged calix[2]arene[2]triazine stationary phase for high performance liquid chromatography.

    PubMed

    Zhao, Wenjie; Hu, Kai; Wang, Caijuan; Liang, Song; Niu, Bailin; He, Lijun; Lu, Kui; Ye, Baoxian; Zhang, Shusheng

    2012-02-03

    A new oxo-bridged calix[2]arene[2]triazine bonded stationary phase (OCATS) for high performance liquid chromatography (HPLC) was prepared using 3-aminopropyltriethoxysilane as coupling reagent. The structure of new material was characterized by infrared spectroscopy, elemental analysis and thermogravimetric analysis. The chromatographic performance and retention mechanism of the new stationary phase were evaluated in reversed-phase mode compared with ODS using different solute probes including polycyclic aromatic hydrocarbons (PAHs), mono-substituted benzenes, disubstituted benzene isomers. The new OCATS stationary phase could provide various interactions for different solutes, such as hydrophobic, hydrogen bonding, ππ and inclusion interactions. The synergistic effects resulting from aromatic rings, bridging oxygen atoms and triazine nitrogen atoms and alkyl linkers in the new material improved the separation selectivity by multiple retention mechanisms. The retention behaviors of the analytes on OCATS column were explained with the assistance of quantum chemistry calculation results using DFT-B3LYP/STO-3G* base group. The OCATS column was successfully employed for the analysis of melamine in infant formula.

  4. Development of a decaaza-cyclophane stationary phase for high-performance liquid chromatography.

    PubMed

    Hu, Kai; Deng, Zhifen; Wang, Bei; Cui, Yongxia; Miao, Mingsan; Liu, Wei; Jiang, Qiong; Zhao, Wenjie; Huang, Yanjie; Zhang, Shusheng

    2015-01-01

    A new stationary phase for high-performance liquid chromatography was prepared by covalently bonding a heteroatom-bridged cyclophane onto silica gel using 3-aminopropyltriethoxysilane as the coupling reagent. The structure of the new material was characterized by infrared spectroscopy, elemental analysis, and thermogravimetric analysis. The linear solvation energy relationship method was successfully employed to evaluate the new phase with a set of 25 solutes, and compared with octadecylsilyl and p-tert-butyl-calix[4]arene bonded stationary phases. The retention characteristics of the new phase are similar to the octadecylsilyl and conventional calixarene phases, and it also has distinctive features. In addition, the chromatographic behavior of the phase was illustrated by eluting alkylbenzenes and inorganic anions in the reversed-phase mode and anion-exchange mode, respectively. Thus, multi-interaction mechanisms and mixed-mode separation of the new phase can very likely guarantee its promising application in the analysis of complex samples. The column has been successfully employed for the analysis of triazines in milk, and it is demonstrated to be a competitive alternative analytical method for the determination of triazine herbicide residues.

  5. Preparation and characterization, using high-performance liquid chromatography, of an enzyme forming glucosides of cytokinins.

    PubMed

    Entsch, B; Parker, C W; Letham, D S; Summons, R E

    1979-09-12

    Cytokinins can occur naturally as glycosides with beta-D-glucose as the sugar substituent. From radish (Raphanus sativus) cotyledons, an enzyme has been partly purified which synthesizes the 7-glucopyranoside of zeatin [6-(4-hydroxy-3-methylbut-trans-2-enylamino)purine], a compound known to occur in this species. High-performance reverse-phase liquid chromatography was uniquely useful as the analytical procedure for quantitative study of the minute amounts of enzyme available. The enzyme uses UDPglucose as the source of the sugar residue. A large number of derivatives of purine are glucosylated, but adenine derivatives with an alkyl side chain at least three carbon atoms in length at position N6 are preferentially glucosylated. This corresponds to the structural features required for high cytokinin activity. The 7-glucoside of zeatin is known to be very weakly active in cytokinin bioassays. Hence, this enzyme, and others catalyzing the same reaction, have a role in the regulation of cytokinin activity.

  6. Blind column selection protocol for two-dimensional high performance liquid chromatography.

    PubMed

    Burns, Niki K; Andrighetto, Luke M; Conlan, Xavier A; Purcell, Stuart D; Barnett, Neil W; Denning, Jacquie; Francis, Paul S; Stevenson, Paul G

    2016-07-01

    The selection of two orthogonal columns for two-dimensional high performance liquid chromatography (LC×LC) separation of natural product extracts can be a labour intensive and time consuming process and in many cases is an entirely trial-and-error approach. This paper introduces a blind optimisation method for column selection of a black box of constituent components. A data processing pipeline, created in the open source application OpenMS®, was developed to map the components within the mixture of equal mass across a library of HPLC columns; LC×LC separation space utilisation was compared by measuring the fractional surface coverage, fcoverage. It was found that for a test mixture from an opium poppy (Papaver somniferum) extract, the combination of diphenyl and C18 stationary phases provided a predicted fcoverage of 0.48 and was matched with an actual usage of 0.43. OpenMS®, in conjunction with algorithms designed in house, have allowed for a significantly quicker selection of two orthogonal columns, which have been optimised for a LC×LC separation of crude extractions of plant material.

  7. High-performance liquid-chromatographic separation of subcomponents of antimycin-A

    USGS Publications Warehouse

    Abidi, S.L.

    1988-01-01

    Using a reversed-phase high-performance liquid chromatographic (HPLC) technique, a mixture of antimycins A was separated into eight hitherto unreported subcomponents, Ala, Alb, A2a, A2b, A3a, A3b, A4a, and A4b. Although a base-line resolution of the known four major antimycins Al, A2, A3, and A4 was readily achieved with mobile phases containing acetate buffers, the separation of the new antibiotic subcomponents was highly sensitive to variation in mobile phase conditions. The type and composition of organic modifiers, the nature of buffer salts, and the concentration of added electrolytes had profound effects on capacity factors, separation factors, and peak resolution values. Of the numerous chromatographic systems examined, a mobile phase consisting of methanol-water (70:30) and 0.005 M tetrabutylammonium phosphate at pH 3.0 yielded the most satisfactory results for the separation of the subcomponents. Reversed-phase gradient HPLC separation of the dansylated or methylated antibiotic compounds produced superior chromatographic characteristics and the presence of added electrolytes was not a critical factor for achieving separation. Differences in the chromatographic outcome between homologous and structural isomers were interpretated based on a differential solvophobic interaction rationale. Preparative reversed-phase HPLC under optimal conditions enabled isolation of pure samples of the methylated antimycin subcomponents for use in structural studies.

  8. High-performance liquid chromatographic analysis and pharmacokinetics of terazosin in healthy volunteers.

    PubMed

    Kang, B C; Yang, C Q; Rhee, J E; Suh, O K; Shin, W G

    2001-01-01

    A high-performance liquid chromatographic (HPLC) analysis of terazosin in 1 ml of human plasma was developed using prazosin as an internal standard. The plasma sample was extracted with dichloromethane and ethylether and a 100-microl aliquot was injected onto the reversed-phase column. The mobile phase, 0.02 M sodium phosphate buffer:acetonitrile:tetrahydrofuran = 720:220:60 (v/v/v), was run at a flow rate of 0.8 ml/min and the column effluent was monitored using a florescence detector set at 370 and 250 nm for the emission and excitation wave numbers, respectively. The retention times for terazosin and prazosin were approximately 6.4 and 9.8 min, respectively, and the coefficients of variation of terazosin were generally low, below 6.4%. The present HPLC method was successful for the pharmacokinetic study of terazosin in healthy volunteers. Following oral administration of terazosin, 2 mg, to 20 healthy male volunteers, the area under the plasma concentration-time curve from time zero to time infinity was 421 +/- 71.8 ng h/ml and terminal half-life was 9.83 +/- 1.29 h.

  9. High-performance liquid chromatography-fluorometric determination of selenium based on selenotrisulfide formation reaction

    SciTech Connect

    Nakagawa, T.; Aoyama, E.; Hasegawa, N.; Kobayashi, N.; Tanaka, H.

    1989-02-01

    A new high-performance liquid chromatography-fluorometric method has been developed for selective determination of selenium(IV). The method involves precolumn reaction of selenium(IV) with penicillamine (Pen) to produce stable selenotrisulfide (Pen-SSeS-Pen) and subsequent derivatization to a fluorophore by reaction with 7-fluoro-4-nitrobenz-2,1,3-oxadiazole. The fluorophore was separated by reversed-phase HPLC and selenium content was determined by fluorometric detection. The calibration plots showed a linear relationship in the range of 10-2000 ppb of selenium(IV) with a detection limit of 5 ppb (signal to noise ratio (S/N) > 2). The method could determine total content of selenium in biological and environmental samples after digestion of the samples and reduction of selenium(VI) to selenium(IV). The results from standard samples indicated satisfactory agreement with those obtained by other established methods and certified values with good reproducibility. This method is as sensitive as, but simpler in operation than, conventional fluorometry using diaminonaphthalene.

  10. High-performance liquid chromatography with conductimetric detection of perfluorocarboxylic acids and perfluorosulfonates.

    PubMed

    Hori, Hisao; Hayakawa, Etsuko; Yamashita, Nobuyoshi; Taniyasu, Sachi; Nakata, Fumiya; Kobayashi, Yoshimi

    2004-10-01

    A rapid and simple method for separating and determining various environmentally harmful perfluorocarboxylic acids and perfluorosulfonates was successfully developed using high- performance liquid chromatography with conductimetric detection, for product and waste management of these compounds at manufacturing and processing sites. Compounds having C(3)-C(8) perfluoroalkyl groups were separated using a Tosoh TSKgel Super-ODS column and a mobile phase consisting of a mixture of methanol and aqueous NaH(2)PO(4) at several mixing ratios. The best detection limits for the compounds ranged from 0.12 to 0.66 mg l(-1) (ppm), and linear calibration graphs were obtained up to 87-109 mg l(-1). The combination of this method with concentration of the sample by solid-phase extraction with cartridges based on styrene-divinylbenzene-copolymer enabled the determination of approximately 50 microg l(-1) (ppb) for compounds with C(4)-C(8) perfluoroalkyl groups. This method was successfully used to monitor the artificial decomposition of the perfluorocarboxylic acid n-C(4)F(9)COOH induced by a photocatalyst.

  11. [Determination of peroxides in environmental samples by high performance liquid chromatography with fluorescence detection].

    PubMed

    Xu, Jinrong; Chen, Zhongming

    2005-07-01

    A high performance liquid chromatographic (HPLC) method with fluorescence detection was developed for the determination of hydrogen peroxide and organic peroxides in environmental samples, and the method has been applied to peroxides detection in urban air and rain samples. The analytical sensitivity was improved. Post-column derivatization involved the oxidation of peroxides to a fluorescent dimer using p-hydroxyphenylacetic acid, a reaction catalyzed by hemin. The optimal excitation wavelength was 315 nm, while the emission wavelength was 400 nm. The temperature of the reaction coil was controlled at about 30 degrees C. Based on the ratio of signal to noise of 3, the detection limits were 4.0 x 10(-9) mol/L for hydroperoxide (H2O2), 4.1 x 10(-8) mol/L for methylhydroperoxide (MHP) and 6.7 x 10(-8) mol/L for ethylhydroperoxide (EHP) for aqueous samples. While the corresponding detection limits were 2.4 ng/m3 for H2O2, 35.2 ng/m3 for MHP, and 74.4 ng/m3 for EHP for air samples. Air samples were collected by Horibe cold trap at the temperature of about -90 degrees C. The results show that H2O2, hydroxymethyl hydroperoxide (HMHP), MHP, and EHP were the major peroxides in air, and that peroxyacetic acid (PAA) was occasionally detected. In rain samples, the two major peroxides were H2O2 and HMHP.

  12. Reversed-phase high-performance liquid chromatography of unsubstituted aminobenzoic acids

    USGS Publications Warehouse

    Abidi, S.L.

    1989-01-01

    High-performance liquid chromatographic (HPLC) characteristics of three position isomers of aminobenzoic acids (potential metabolites of important anesthetic drugs), were delineated with respect to their interactions with various mobile phases and stationary phases. HPLC with five hydrocarbonaceous phase, I?-cyclodextrin silica (CDS), macrophase MP-1 polymer (MP), macroporous polystyrene/divinylbenzene (MPD), octadecylsilica (ODS), and propylphenylsilica (PPS), yielded results explicable in terms of substituent effects derived from the bifunctional amino- and carboxy groups. For cases where mobile phases contained sulfonates or quaternary ammonium salts both having longer chain alkyls, retention of analytes on all but CDS appeared to proceed predominantly via an ion-pairing mechanism. The extent of the corresponding counter-ion effects decreased in the order: MPD > ODS > PPS > MP, while the analyte retention order paralleled thier pH2 values. On the other hand, an inverse relationship between the magnitude of capacity factors (k') and pK1 values of the title compounds was observed in experiments that produced retention data incompatible with ion-pair interaction rationales. The unique HPLC results obtained with the CDS phase are compared with those obtained with other phases.

  13. Determination of berberine in plasma, urine and bile by high-performance liquid chromatography.

    PubMed

    Chen, C M; Chang, H C

    1995-03-10

    A high-performance liquid chromatographic method for the determination of berberine in plasma, urine and bile samples is described. Plasma samples were pretreated by protein precipitation with acetonitrile and urine and bile samples were pretreated by organic solvent extraction using 5% 2-propanol in methylene chloride. Berberine was determined in all samples using an octyl reversed-phase column with a mobile phase of 60-63% acetonitrile in 0.1% phosphoric acid (pH 6.0) and with UV detection at 267 nm. The detection limits for berberine in plasma, urine and bile were 18.1 ng/ml, 2.3 ng/ml and 90.4 ng/ml, respectively. The recoveries of berberine by simple deproteinization of plasma and by solvent extraction of urine were 78.3 and 82.9%, respectively. The intra-day and inter-day accuracy and precision for plasma reported as coefficients of variation and relative errors were both less then 6%. The applicability of the assay to pharmacokinetic and bioavailability studies was demonstrated by the determination of berberine in plasma, urine and bile after intravenous and intramuscular administration to rabbits at a dose of 2 mg/kg.

  14. Determination of benzalkonium chloride in viscous ophthalmic drops of azithromycin by high-performance liquid chromatography.

    PubMed

    Shen, Yan; Xu, Sheng-jie; Wang, Shi-chun; Tu, Jia-sheng

    2009-12-01

    A high-performance liquid chromatography (HPLC) system was used in the reversed phase mode for the determination of benzalkonium chloride (BKC) in azithromycin viscous ophthalmic drops. A Venusil-XBP(L)-C(18) (150 mmx4.6 mm, 5 microm) column was used at 50 degrees C. The mobile phase consisted of a mixture of methanol-potassium phosphate (16:5, v/v). Two sample preparation methods were compared. The results suggested that, compared with an extraction procedure, a deproteinization procedure was much quicker and more convenient. Using the deproteinization procedure for sample preparation, calibration curves were linear in the range 5.0 to approximately 50 microg/ml. The within-day and inter-day coefficients of variation were less than 10%. The average recoveries were determined as 96.70%, 98.52%, and 97.96% at concentrations of 10.0, 30.0, and 50.0 microg/ml, respectively. Variability in precision did not exceed 5%. In conclusion, this HPLC method using a simple sample treatment procedure appears suitable for monitoring BKC content in azithromycin viscous ophthalmic drops.

  15. A simple high-performance liquid chromatographic practical approach for determination of flurbiprofen

    PubMed Central

    Akhlaq, Muhammad; Khan, Gul Majid; Wahab, Abdul; Khan, Arshad; Hussain, Abid; Nawaz, Asif; Abdelkader, Hamdy

    2011-01-01

    A simple, rapid, sensitive, and specific high-performance liquid chromatography (HPLC) assay for flurbiprofen has been developed and validated practically. The chromatography was conducted using Gemini C18 column (5 μm; 4.6 mm × 250 mm, Phenomenex, California, USA). The mobile phase containing disodium hydrogen phosphate solution (30 mM) pH 7.0 and acetonitrile (50:50); and the isocratic flow rate of 1.0 ml/min were used in the current study. Detection was made at 247 nm. The calibration curve was linear (r ≥ 0.9996) over the concentration range of 5-50 μm/ml. Mean percentage (%) recovery ± % relative standard deviation (RSD) ranged from 97.07 ± 0.008 to 103.66 ± 0.013. Within-day and between-day precision were also in acceptable range of 98.83 ± 0.004 to 104.56 ± 0.009. In order to confirm the practical applicability of the method developed, flurbiprofen controlled release matrix tablets were subjected to the dissolution studies and the release rate was analyzed. The reported HPLC for flurbiprofen provides several advantages of simplicity, high specificity, accuracy, and very short run-cycle time. It is suggested that the method should be used for the routine quality control analysis of flurbiprofen pure drug and its dosage forms. PMID:22171311

  16. A validated new method for nevirapine quantitation in human plasma via high-performance liquid chromatography.

    PubMed

    Silverthorn, Courtney F; Parsons, Teresa L

    2006-01-01

    A fully validated and clinically relevant assay was developed for the assessment of nevirapine concentrations in neonate blood plasma samples. Solid-phase extraction with an acid-base wash series was used to prepare subject samples for analysis. Samples were separated by high performance liquid chromatography and detected at 280 nm on a C8 reverse-phase column in an isocratic mobile phase. The retention times of nevirapine and its internal standard were 5.0 and 6.9 min, respectively. The method was validated by assessment of accuracy and precision (statistical values <15%), specificity, and stability. The assay was linear in the range 25-10,000 ng/mL (r2 > 0.996) and the average recovery was 93% (n = 18). The lower limit of quantification (relative standard deviation <20%) was determined to be 25 ng/mL for 50 microL of plasma, allowing detection of as little as 1.25 ng of nevirapine in a sample. This value represents an increase in sensitivity of up to 30-fold over previously published methods.

  17. [Simultaneous determination of 10 synthetic colorants in cosmetics by high performance liquid chromatography].

    PubMed

    Liu, Haishan; Qian, Xiaoyan; Lü, Chunhu; Zhu, Xiaoyu; Chen, Xiaomei; Mo, Weimin

    2013-11-01

    A high performance liquid chromatographic method was developed for the simultaneous determination of 10 synthetic colorants in cosmetics. The cosmetics were extracted by the ultrasonic technique with tetrahydrofuran (THF), dimethyl sulfoxide (DMSO) and methanol sequentially. Then the extracts were centrifuged for purification and separated on an Eclipse XDB-C18 column (150 mm x 4.6 mm, 5 microm) with gradient elution by acetonitrile and 0.02 mol/L ammonium acetate (pH 4.60, adjusted with acetic acid). A diode array detector was used to determine the colorants with the wavelengths ranging from 417 nm to 640 nm. The linear relationships of the 10 colorants between the peak areas and the mass concentrations were obtained in the range of 0.5-20.0 mg/L (r > 0.999). The limits of quantitation ranged from 10 to 20 mg/kg. The average recoveries at three concentration levels ranged from 92.9% to 108.8% with the relative standard deviations in the range of 0.5% to 6.1% (n = 6). The method is simple, rapid and sensitive. It is suitable for the simultaneous determination of the 10 colorants in the oil cosmetics, cream cosmetics and powder cosmetics.

  18. Simultaneous determination of 11 preservatives in cosmetics by high-performance liquid chromatography.

    PubMed

    Aoyama, Airin; Doi, Takahiro; Tagami, Takaomi; Kajimura, Keiji

    2014-10-01

    Preservatives prevent the growth of microorganisms in foods, pharmaceuticals and cosmetics. There exist numerous restrictions regarding the maximum allowable levels of preservatives in cosmetics. We analyzed 11 regulated preservatives in commercial cosmetics and manufacturers need to analyze their products for quality control purposes. However, methods used in previous studies to date have been inadequate for use by public institutions and manufacturers. Therefore, an effective, scalable method for the analysis of preservatives in cosmetics is required. We developed a novel method for the simultaneous determination of 11 regulated preservatives in cosmetics by high-performance liquid chromatography (HPLC). We applied the samples to a C18 column in a simple mobile phase (5 mmol/L ammonium formate solution and acetonitrile) with gradient elution at a flow rate of 1.0 mL/min at a single wavelength (230 nm). The correlation coefficients of the calibration curves were >0.997. The percent recoveries were 92.8-111.9% and the relative standard deviations were <4.3% (n = 6). The peak resolution for all preservatives was >1.9. Because of the simple conditions for isolation and complete separation, the HPLC method can be effectively applied to the analysis of preservatives in commercially retailed cosmetics.

  19. Analyte loss due to membrane filter adsorption as determined by high-performance liquid chromatography.

    PubMed

    Carlson, M; Thompson, R D

    2000-02-01

    The phenomenon of membrane filter adsorption in high-performance liquid chromatography (HPLC) is investigated utilizing 16 brands of filters representing 3 polymeric materials: cellulose acetate (CA), nylon, and polyvinylidene difluoride in a variety of diameters (3, 4, 7, 13, and 25 mm). Sixteen compounds commonly encountered in drug preparations are selected as sample analytes and classified as acidic, basic, and neutral in chemical behavior. Six mobile phase/sample solvent mixtures are included: 3 with methanol-water and 3 with acetonitrile-water as major constituents. When using methanol as the mobile phase organic component, CA, nylon, and polyvinylidene difluoride (PVDF) filters exhibit negligible to moderate adsorption levels with regard to the neutral and basic drug compounds. The acidic drug test compounds are adsorbed by 50% of all 3 filter materials tested in methanol-water. In acetonitrile, neutral compounds are affected by 31.4%, basic compounds are affected by 47.0%, and acidic compounds are affected by 53.6% of the nylon and PVDF filters. CA is incompatible with acetonitrile and is excluded from the study with this solvent.

  20. Arsenic speciation in soil using high performance liquid chromatography/inductively coupled plasma/mass spectrometry

    SciTech Connect

    Bass, D.A.; Yaeger, J.S.; Parish, K.J.; Crain, J.S.; Kiely, J.T.; Gowdy, M.J.; Mohrman, G.B.; Besmer, M.G.

    1996-08-01

    A method has been developed to identify and quantify As(III), As(V), and organoarsenic compounds in soil samples from the Rocky Mountain Arsenal (RMA) by high performance liquid chromatography/inductively coupled plasma/mass spectrometry (HPLC/ICP/MS). The soils were extracted using tetrabutylammonium hydroxide (TBAH) and sonication. The percentages of As(III), As(V), and organoarsenic species extracted from soil samples were 30, 50, and 100 respectively. The arsenic species were not altered during the extraction process. They were separated by reversed-phase, ion-pairing, HPLC using a microbore Inertsil-ODS{trademark} column. The HPLC column effluent was introduced into an ICP/MS system using a direct injection nebulizer (DIN). Detection limits of less than 1 pg were readily obtained for each arsenic species. Internal standards are recommended to increase accuracy and precision. Soil samples spiked with arsenic oxide, sodium arsenate, dimethylarsinic acid (DMAA), and chlorovinyl arsenious acid (CVAA) were extracted, identified and quantified with the HPLC/ICP/MS system. The soil samples were analyzed in support of the analytical needs of a thermal desorption treatability study being conducted at the RMA.

  1. Determination of capsaicin and dihydrocapsaicin in Capsicum fruit samples using high performance liquid chromatography.

    PubMed

    Al Othman, Zeid Abdullah; Ahmed, Yacine Badjah Hadj; Habila, Mohamed Abdelaty; Ghafar, Ayman Abdel

    2011-10-24

    The aim of the present study was to determine the content of capsaicin and dihydrocapsaicin in Capsicum samples collected from city markets in Riyadh (Saudi Arabia), calculate their pungency in Scoville heat units (SHU) and evaluate the average daily intake of capsaicin for the population of Riyadh. The investigated samples consisted of hot chillies, red chillies, green chillies, green peppers, red peppers and yellow peppers. Extraction of capsaicinoids was done using ethanol as solvent, while high performance liquid chromatography (HPLC) was used for separation, identification and quantitation of the components. The limit of detection (LOD) of the method was 0.09 and 0.10 µg/g for capsaicin and dihydrocapsaicin, respectively, while the limit of quantification (LOQ) was 0.30 and 0.36 µg/g for capsaicin and dihydrocapsaicin, respectively. Hot chillies showed the highest concentration of capsaicin (4249.0 ± 190.3 µg/g) and the highest pungency level (67984.60 SHU), whereas green peppers had the lowest detected concentration (1.0 ± 0.9 µg/g); green peppers, red peppers and yellow peppers were non pungent. The mean consumption of peppers for Riyadh city population was determined to be 15.5 g/person/day while the daily capsaicin intake was 7.584 mg/person/day.

  2. High-performance liquid chromatographic separation of subcomponents of antimycin A.

    PubMed

    Abidi, S L

    1988-08-05

    Using a reversed-phase high-performance liquid chromatographic (HPLC) technique, a mixture of antimycins A was separated into eight hitherto unreported subcomponents, A1a, A1b, A2a, A2b, A3a, A3b, A4a, and A4b. Although a base-line resolution of the known four major antimycins A1, A2, A3, and A4 was readily achieved with mobile phases containing acetate buffers, the separation of the new antibiotic subcomponents was highly sensitive to variation in mobile phase conditions. The type and composition of organic modifers, the nature of buffer salts, and the concentration of added electrolytes had profound effects on capacity factors, separation factors, and peak resolution values. Of the numerous chromatographic systems examined, a mobile phase consisting of methanol-water (70:30) and 0.005 M tetrabutylammonium phosphate at pH 3.0 yielded the most satisfactory results for the separation of the subcomponents. Reversed-phase gradient HPLC separation of the dansylated or methylated antibiotic compounds produced superior chromatographic characteristics and the presence of added electrolytes was not a critical factor for achieving separation. Differences in the chromatographic outcome between homologous and structural isomers were interpreted based on a differential solvophobic interaction rationale. Preparative reversed-phase HPLC under optimal conditions enabled isolation of pure samples of the methylated antimycin subcomponents for use in structural studies.

  3. Determination of polycyclic aromatic hydrocarbons in marine samples by high-performance liquid chromatography

    SciTech Connect

    Obana, H.; Hori, S.; Kashimoto, T.

    1981-05-01

    It has been reported that polycyclic aromatic hydrocarbons (PAHs) are widely distributed in the environment, although their concentrations are quite low. Some PAHs, benzo(a)pyrene, dibenz(a,h)anthracene and 3-methycholanthrene, are carcinogenic to mammals after in vivo hydroxylation by mixed function oxidases. PAHs originate largely from smoke, soot, and exhaust gas produced by combustion and from petroleum oil spilled into the sea, so that the quantity of PAHs in the environment is broadly related to the level of contamination in a given region. Although PAHs have been determined by a TLC-fluorescence method, these methods suffer from complex pretreatment. On the other hand, the development of high-performance liquid chromatography (HPLC) has made it possible to analyze PAHs with good separation and high sensitivity and to simplify the pretreatment processes. In this study, ten PAHs in sediments, oyster, and wakame seaweed were determined by HPLC with a fluorescence detector (HPLC-FD). The contents and the patterns of PAHs found in sediments and marine samples may be used as an indicator of petroleum contamination in the sea.

  4. Isolation and quantification of tuliposides and tulipalins in tulips (Tulipa) by high-performance liquid chromatography.

    PubMed

    Christensen, L P; Kristiansen, K

    1999-06-01

    The content of tuliposides and tulipalins were determined in Tulipa species and cultivars by reversed-phase high-performance liquid chromatography (RP-HPLC), using a water:methanol gradient as mobile phase. The compounds were detected by a diode array detector employed at 208 nm. The investigation revealed, in addition to 1- and 6-tuliposide A, tuliposide D and the lactonized aglycones tulipalin A and (-)-tulipalin B, the new tuliposide F and 6-tuliposide B, the latter being a new acyl derivative of the known 1-tuliposide B. All compounds were isolated by preparative RP-HPLC and identified by NMR and mass spectroscopy. The predominant compounds were 6-tuliposide A and B present in amounts up to 1.5% and 1.3% of fresh weight, respectively. 6-Tuliposide A and tulipalin A seem to be the major allergens in tulips, although tuliposide D and F may also contribute to the allergenic properties. Tulipalin A and (-)-tulipalin B occur in intact tulips and are not only produced in response to fungal attack or after excision of the plants. A few species were found to have very low allergen content and a relatively high level of tuliposide B, indicating it should be possible to breed non-allergenic and disease-resistant tulips.

  5. A molecular nematic liquid crystalline material for high-performance organic photovoltaics

    PubMed Central

    Sun, Kuan; Xiao, Zeyun; Lu, Shirong; Zajaczkowski, Wojciech; Pisula, Wojciech; Hanssen, Eric; White, Jonathan M.; Williamson, Rachel M.; Subbiah, Jegadesan; Ouyang, Jianyong; Holmes, Andrew B.; Wong, Wallace W.H.; Jones, David J.

    2015-01-01

    Solution-processed organic photovoltaic cells (OPVs) hold great promise to enable roll-to-roll printing of environmentally friendly, mechanically flexible and cost-effective photovoltaic devices. Nevertheless, many high-performing systems show best power conversion efficiencies (PCEs) with a thin active layer (thickness is ~100 nm) that is difficult to translate to roll-to-roll processing with high reproducibility. Here we report a new molecular donor, benzodithiophene terthiophene rhodanine (BTR), which exhibits good processability, nematic liquid crystalline behaviour and excellent optoelectronic properties. A maximum PCE of 9.3% is achieved under AM 1.5G solar irradiation, with fill factor reaching 77%, rarely achieved in solution-processed OPVs. Particularly promising is the fact that BTR-based devices with active layer thicknesses up to 400 nm can still afford high fill factor of ~70% and high PCE of ~8%. Together, the results suggest, with better device architectures for longer device lifetime, BTR is an ideal candidate for mass production of OPVs. PMID:25586307

  6. Simultaneous determination of linear alkylbenzenesulfonates, alkylphenol polyethoxylates, and nonylphenol by high-performance liquid chromatography

    SciTech Connect

    Marcomini, A.; Giger, W.

    1987-07-01

    Linear 4-alkylbenzenesulfonates (LAS), 4-alkylphenol polyethoxylates (APEO) (i.e., 4-octylphenol polyethoxylates (OPEO) and 4-nonylphenol polyethoxylates (NPEO), and 4-nonylphenol (NP) are simultaneously determined by reversed-phase high-performance liquid chromatography (HPLC) using octylsilica columns and water/acetonitrile gradient elution. LAS are separated according to their alkyl chain lengths and coelution of NPEO and NP is observed in contrast to the separation of OPEO and NPEO. The determination of oligomer distributions of APEO and quantitation of NP,NP1EO, and NP2EO require additional information attainable by normal-phase HPLC. Recoveries of 85-100% were found for LAS, APEO, and NP isolated by Soxhlet extraction under basic conditions from laundry detergent powders, sewage sludges, sludge-amended soils, and river sediments. Relative standard deviations for all analytes in the different matrices did not exceed 6%. Detection limits with UV fluorescence detection are 95 ng for NP, 80 ng for LAS, and 65 ng for NPEO with respect to injected amounts.

  7. Stroboscopic sampling in comprehensive high-performance liquid chromatography-capillary electrophoresis via a pneumatic sampler.

    PubMed

    Ehala, Sille; Kaljurand, Mihkel; Kudrjashova, Marina; Vaher, Merike

    2004-04-01

    A new approach is presented to solve the problem of a long separation time in the second dimension of comprehensive two-dimensional chromatography. The need for a rapid separation in the second column is overcome by repeating analysis of a sample many times. In each of these individual analysis cases the sample is injected into the first dimension column and after a delay a low amount of the effluent at the end of the first column is sampled to the second-dimensional column. The time interval between the samplings from the first column to the second column is constantly increased. Thus, the system enables a comprehensive analysis of the effluent emerging from the first into the second column. This approach, which we call stroboscopic sampling, is tested for coupling high-performance liquid chromatography (HPLC) to capillary electrophoresis (CE) by an interface which operates on the principle of transporting the effluent from the HPLC column to the capillary inlet by small pressure pulses (0.5 MPa). The performance of the interface for accomplishing the comprehensive HPLC-CE analysis was demonstrated for an on-line connection of a short ion-exchange column and an ion-exclusion column to the CE capillary.

  8. Binary electroosmotic-pump nanoflow gradient generator for miniaturized high-performance liquid chromatography.

    PubMed

    Zhou, Lei; Lu, Joann Juan; Gu, Congying; Liu, Shaorong

    2014-12-16

    High-performance liquid chromatography (HPLC) plays an important role in biotechnology, and a majority of chromatographic separations use gradient elution. While gradient generators can be built in different formats, binary pumps or quaternary pumps are most frequently used for gradient generator constructions. We have recently developed a high-pressure electroosmotic pump (EOP); the pump can be manufactured at a cost of a few hundred dollars. However, it is challenging to use this pump to deliver a gradient eluent directly. In this study, we first improve the monolith preparation by applying a pressure to the monomer solution during polymerization. We assemble a binary EOP gradient generator and discuss the relationship between the gradient profile and voltage applied to the EOP. We demonstrate the feasibility of the binary EOP gradient generator for generating a smooth and reproducible nanoflow gradient. After integration of the gradient generator into a miniaturized HPLC system, we use the HPLC system for separating peptide mixtures from trypsin-digested proteins. The performance comparison between the above miniaturized HPLC system and an Agilent 1200 HPLC system exhibits comparable efficiencies, resolutions, and peak capacities.

  9. Enantioselective high-performance liquid chromatographic determination of nicardipine in human plasma.

    PubMed

    Uno, T; Ohkubo, T; Sugawara, K

    1997-09-26

    A sensitive method for the enantioselective high-performance liquid chromatography (HPLC) determination of nicardipine in human plasma is described. (+)-Nicardipine, (-)-nicardipine and (+)-barnidipine as an internal standard are detected by an ultraviolet detector at 254 nm. Racemic nicardipine in human plasma was extracted by a rapid and simple procedure based on C18 bonded-phase extraction. The extraction samples were purified and concentrated on a pre-column using a C1 stationary phase and the enantiomers of nicardipine are quantitatively separated by HPLC on a Sumichiral OA-4500 column, containing a chemically modified Pirkle-type stationary phase. Determination of (+)- and (-)-nicardipine was possible in a concentration range of 5-100 ng ml(-1) and the limit of detection in plasma was 2.5 ng ml(-1). The recoveries of (+)- and (-)-nicardipine added to plasma were 91.4-98.4% and 93.3-96.7%, respectively, with coefficients of variation of less than 9.0 and 9.4% respectively. The method was applied to low level monitoring of (+)- and (-)-nicardipine in plasma from healthy volunteers.

  10. Indirect chiral separation of tryptophan enantiomers by high performance liquid chromatography with indirect chemiluminiscence detection.

    PubMed

    Zhou, Jie; Chen, Shanshan; Sun, Fang; Luo, Pei; Du, Qiuzheng; Zhao, Suzhen

    2015-12-01

    In recent years, the study of chiral compounds in vivo has received much attention. In this study, a novel method based on high performance liquid chromatography (HPLC) coupled with chemiluminescence (CL) detection was developed for the separation of tryptophan (Trp) enantiomers. o-Phthalaldehyde and N-acetyl-l-cysteine were used as chiral derivatization reagents for Trp before it can be detected by HPLC-CL method. The separation was carried out on an ODS column using a mobile phase composed of methanol-0.01mol/L phosphate buffer (40/60, v/v). Under the optimum conditions, satisfactory results were obtained, including complete separation, good relative standard deviations and low detection limits. The applicability of the proposed method has been validated by determining Trp in biological samples. Linear responses (r>0.9990) were observed over the range of 2.5×10(-7) to 1.2×10(-5)g/mL of Trp enantiomers, with quantitation limit of 2.5×10(-7)g/mL. The assay method shows good specificity to Trp enantiomers, and thus it will have great potential application in clinical diagnosis. The mean extraction efficiency of Trp enantiomers in mice plasma samples were 98.48% and 97.40%, respectively. The mean relative standard deviation (RSD) of Trp enantiomers were <3%.

  11. Enantioselective high performance liquid chromatography and supercritical fluid chromatography separation of spirocyclic terpenoid flavor compounds.

    PubMed

    Schaffrath, Mathias; Weidmann, Verena; Maison, Wolfgang

    2014-10-10

    Chiral spirocyclic terpenoids are abundant natural flavors with significant impact particularly on the food industry. Chromatographic methods for analytical and preparative separation of these compounds are therefore of high interest to natural product chemists in academia and industry. Gas chromatography on chiral stationary phases is currently the standard method for the separation of volatile terpenoids, limiting the scale to analytical quantities. We report herein high performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC) protocols for the chiral separation of several racemic spirocyclic terpenoids such as the important flavors theaspirane and vitispirane. A screening of mobile phases and 16 commercially available chiral stationary phases (CSPs) largely based on polysaccharides led to identification of protocols for the separation of all terpenoids tested. SFC methods were found to be particularly useful for the separation of these spirocyclic flavors due to the volatility and low polarity of the compounds. The reported chiral HPLC and SFC protocols are scalable alternatives to gas chromatographic separations of volatile terpenoid flavors.

  12. Determination of 5-methylcytosine from plant DNA by high-performance liquid chromatography.

    PubMed

    Wagner, I; Capesius, I

    1981-06-26

    The relative amounts of the five nucleosides (deoxycytidine, 5-methyldeoxycytidine, deoxyadenosine, deoxyguanosine and thymidine) in the DNA of nine plant species, one plant satellite DNA, and one animal species were determined by high performance liquid chromatography. The method allows the clean separation of the nucleosides from 10 microgram samples with 15 min. The following values for the proportion of methylated cytosines among all cytosines were obtained: Lobularia maritima 18.5%, Nicotiana tabacum 32.6%, Pisum sativum 23.2%, Rhinanthus minor 29.2%, Sinapsis alba 12.2%, Vicia faba 30.5%, Viscum album 23.2%, Cymbidium pumilum 18.8%, Cymbidium pumilum AT-rich satellite DNA 15.8%, Triticum aestivum 22.4%. DNA of an animal, the gerbil, Meriones unguiculatus, had a methylation percentage of 3.1%. An estimate of the GC content based on the buoyant density of DNA tends to be lower than the actual value, an estimate based on the melting temperature tends to be higher. This supports the finding by other authors that DNA methylation decreases the buoyant density and may increase the melting temperature at high m5C concentration.

  13. Determination of hexamethylenetetramine in foods by high-performance liquid chromatography (HPLC).

    PubMed

    Lim, HoSoo; Kim, JungIm; Ko, KyungYuk; Kim, Meehye

    2014-01-01

    A simple and rapid method was developed and validated for the determination of hexamethylenetetramine (HMT) in foods. Samples were homogenised and extracted with methanol, followed by centrifugation. The resulting solution was filtered and injected into the high-performance liquid chromatograph (HPLC). HMT was separated using a Zorbax SCX-300 column coupled to a photodiode array detector. The calibration curve was linear in the range of 1.0-100 μg ml(-1), with good correlation coefficients (r(2) = 0.9992). The recoveries of HMT from foods spiked at levels of 10, 50 and 100 mg kg(-1) ranged from 91.6% to 103.8%, with relative standard deviations (RSDs) between 0.9% and 5.3%. The limit of detection and the limit of quantification of HMT were 0.3 and 1.0 mg kg(-1) based on three food matrixes (provolone cheese, glass noodle and tofu snack), respectively. Uncertainty associated with accuracy contributed mostly to the expanded uncertainty. No detectable levels of HMT were found in any of the samples retailed in Korea. The method was successful in determining HMT in foods.

  14. [Simultaneous determination of seven compounds in Lonicera japonica by high performance liquid chromatography].

    PubMed

    Niu, Xiaoxue; Cui, Xusheng; Su, He; Guo, Yuhai; Dong, Xuehui

    2012-02-01

    A high performance liquid chromatographic (HPLC) method was developed to determine the contents of seven compounds in Lonicera japonica and Folium Lonicerae with maximum wavelength conversion program, and analyze the content differences between them. The separation was performed on an Agilent Eclipse Plus C18 column (250 mm x 4.6 mm, 5 microm) operated at normal temperature with the gradient elution by two mobile phases of water (including 0.3% (v/v) formic acid) (A) and acetonitrile (B) at a flow rate of 1 mL/min. The maximum detection wavelength was set at 330 nm and 350 nm by conversion. The contents of chlorogenic acid and caffeic acid in Lonicera new leaves were 2.572% and 1.498 per thousand respectively, both higher than those cited in Chinese Pharmacopoeia, indicating that Lonicera new leaves have the necessity to be further studied and developed. This method is simple, rapid and highly sensitive. It is suitable for the simultaneous determination of the seven compounds and the quality control of Lonicera japonica.

  15. An application of high performance liquid chromatography to analysis of lipids in archaeological samples.

    PubMed

    Passi, S; Rothschild-Boros, M C; Fasella, P; Nazzaro-Porro, M; Whitehouse, D

    1981-07-01

    Five samples from three different types of 1500-year-old Mediterranean amphorae, as well as from a contemporary oil lamp found in the same deposit, were analyzed for the presence of lipid residues. Each sample of finely ground amphorae powder weighed 1-2 g. The abundance of interfering secondary products makes thin-layer chromatography (TLC) an essential step of the procedure. The fractionation of the extract into its various lipid components by means of TLC was followed by quantitative recovery of the triglyceride (TG) and free fatty acid (FFA) fractions from the plates and by the measurement of their components by high performance liquid chromatography (HPLC) after esterification. The minimum detectable level is 1 ng. The amphorae samples revealed a more abundant FFA fraction than a TG fraction, which is the reverse of what we know about the composition of fresh oil. Despite the considerable age of the amphorae and their preservation under non-ideal conditions, the lipid residues have retained certain identifiable characteristics that enable one to make valid suggestions as to the type of commodity originally transported in the amphorae. The results of these experiments yield important information that enables the biochemist to observe an aging process irreproducible in the laboratory and provides the archaeologist with previously unavailable information about trade 15 centuries ago.

  16. High-performance liquid chromatography with photodiode array detection and chemometrics method for the analysis of multiple components in the traditional Chinese medicine Shuanghuanglian oral liquid.

    PubMed

    Li, Bao Qiong; Chen, Jing; Li, Jiao Jiao; Wang, Xue; Zhai, Hong Lin; Zhang, Xiao Yun

    2015-12-01

    Shuanghuanlian oral liquid, a traditional Chinese medicine preparation, is a mixture of three herbs (Flos Lonicerae, Radix Scutellariae and Fructus Forsythiae). In this study, the quantitative analysis of three main active compounds, chlorogenic acid, forsythin and baicalin in samples from different manufacturers was performed rapidly by high-performance liquid chromatography coupled with photodiode array detection followed by Contour Projection coupled to stepwise regression treatment of the obtained three-dimensional spectra in which the partial overlap between adjacent target components existed. The method was validated for linearity (R>0.9940), precision (RSD<1.25%), recovery (92.20-102.50%), limit of detection (0.01-0.02 μg/mL) and limit of quantification (0.03-0.07 μg/mL). The results indicated that the combination of the three-dimensional spectra of traditional Chinese medicine and Contour Projection-stepwise regression offered an accurate, simple, low-cost and eco-friendly way for the rapid quantitative analysis of Shuanghuanlian oral liquid samples.

  17. Determination of acrylamide in potato chips and crisps by high-performance liquid chromatography.

    PubMed

    Gökmen, Vural; Senyuva, Hamide Z; Acar, Jale; Sarioğlu, Kemal

    2005-09-23

    A simple and rapid method using liquid chromatography coupled to diode array detection (LC-DAD) was developed for the determination of acrylamide in potato-based foods at low levels. The method entails extraction of acrylamide with methanol, purification with Carrez I and II solutions, evaporation and solvent change to water, and cleanup with a Oasis HLB solid-phase extraction (SPE) cartridge. The final extract was analyzed by LC-DAD for quantification and by liquid chromatography coupled to mass spectrometry (LC-MS) for confirmation. The chromatographic separations were performed on a hydrophilic and a hydrophobic interaction columns having good retention of acrylamide under 100% aqueous flow conditions (k' 3.67 and 2.54, respectively). The limit of quantitation was estimated to be 4.0 microg/kg based on the signal-to-noise ratio of 3 recorded at 226 nm. Recoveries of acrylamide from potato chips samples spiked at levels of 250, 500 and 1000 (n = 4 for each level) microg/kg ranged between 92.8 and 96.2% with relative standard deviations of less than 5%. The results of this study revealed that a conventional LC instrument coupled to DAD can also be used accurately and precisely, as an alternative to tandem LC-MS methods for the determination of acrylamide in potato-based foods.

  18. Determination of diflubenzuron and chlorbenzuron in fruits by combining acetonitrile-based extraction with dispersive liquid-liquid microextraction followed by high-performance liquid chromatography.

    PubMed

    Ruan, Chunqiang; Zhao, Xiang; Liu, Chenglan

    2015-09-01

    In this study, a simple and low-organic-solvent-consuming method combining an acetonitrile-partitioning extraction procedure followed by "quick, easy, cheap, effective, rugged and safe" cleanup with ionic-liquid-based dispersive liquid-liquid microextraction and high-performance liquid chromatography with diode array detection was developed for the determination of diflubenzuron and chlorbenzuron in grapes and pears. Ionic-liquid-based dispersive liquid-liquid microextraction was performed using the ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate as the extractive solvent and acetonitrile extract as the dispersive solvent. The main factors influencing the efficiency of the dispersive liquid-liquid microextraction were evaluated, including the extractive solvent type and volume and the dispersive solvent volume. The validation parameters indicated the suitability of the method for routine analyses of benzoylurea insecticides in a large number of samples. The relative recoveries at three spiked levels ranged between 98.6 and 109.3% with relative standard deviations of less than 5.2%. The limit of detection was 0.005 mg/kg for the two insecticides. The proposed method was successfully used for the rapid determination of diflubenzuron and chlorbenzuron residues in real fruit samples.

  19. Enzyme-assisted extraction and ionic liquid-based dispersive liquid-liquid microextraction followed by high-performance liquid chromatography for determination of patulin in apple juice and method optimization using central composite design.

    PubMed

    Mohammadi, Abdorreza; Tavakoli, Rouya; Kamankesh, Marzieh; Rashedi, Hamid; Attaran, Abdolmohammad; Delavar, Mostafa

    2013-12-04

    A simple and highly sensitive analytical methodology for isolation and determination of patulin in apple-juice samples, based on enzyme-assisted extraction (EAE) and ionic liquid-based dispersive liquid-liquid microextraction (IL-DLLME) was developed and optimized. Enzymes play essential roles in eliminating interference and increasing the extraction efficiency of patulin. Apple-juice samples were treated with pectinase and amylase. A mixture of 80 μL ionic liquid and 600 μL methanol (disperser solvent) was used for the IL-DLLME process. The sedimented phase was analyzed by high-performance liquid chromatography (HPLC). Experimental parameters controlling the performance of DLLME, were optimized using response surface methodology (RSM) based on central composite design (CCD). Under optimum conditions, the calibration curves showed high levels of linearity (R(2)>0.99) for patulin in the range of 1-200 ng g(-1). The relative standard deviation (RSD) for the seven analyses was 7.5%. The limits of detection (LOD) and limits of quantification (LOQ) were 0.15 ng g(-1) and 0.5 ng g(-1), respectively. The merit figures, compared with other methods, showed that new proposed method is an accurate, precise and reliable sample-pretreatment method that substantially reduces sample matrix interference and gives very good enrichment factors and detection limits for investigation trace amount of patulin in apple-juice samples.

  20. Evaluation between ultrahigh pressure liquid chromatography and high-performance liquid chromatography analytical methods for characterizing natural dyestuffs.

    PubMed

    Serrano, Ana; van Bommel, Maarten; Hallett, Jessica

    2013-11-29

    An evaluation was undertaken of ultrahigh pressure liquid chromatography (UHPLC) in comparison to high-performance liquid chromatography (HPLC) for characterizing natural dyes in cultural heritage objects. A new UHPLC method was optimized by testing several analytical parameters adapted from prior UHPLC studies developed in diverse fields of research. Different gradient elution programs were tested on seven UHPLC columns with different dimensions and stationary phase compositions by applying several mobile phases, flow rates, temperatures, and runtimes. The UHPLC method successfully provided more improved data than that achieved by the HPLC method. Indeed, even though carminic acid has shown circa 146% higher resolution with HPLC, UHPLC resulted in an increase of 41-61% resolution and a decrease of 91-422% limit of detection, depending on the dye compound. The optimized method was subsequently assigned to analyse 59 natural reference materials, in which 85 different components were ascribed with different physicochemical properties, in order to create a spectral database for future characterization of dyes in cultural heritage objects. The majority of these reference samples could be successfully distinguished with one single method through the examination of these compounds' retention times and their spectra acquired with a photodiode array detector. These results demonstrate that UHPLC analyses are extremely valuable for the acquisition of more precise chromatographic information concerning natural dyes with complex mixtures of different and/or closely related physicochemical properties, essential for distinguishing similar species of plants and animals used to colour cultural heritage objects.

  1. High-performance liquid chromatography using pressurized liquid extraction for the determination of seven tetracyclines in egg, fish and shrimp.

    PubMed

    Liu, Yu; Yang, Hailan; Yang, Sheng; Hu, Qiwei; Cheng, Hongbo; Liu, Huiyu; Qiu, Yinsheng

    2013-02-15

    A simple and especially rapid method, pressurized liquid extraction, has been developed and applied to the quantitative determination of oxytetracycline, tetracycline, chlortetracycline, minocycline, methacycline, demeclocycline and doxycycline in egg, fish and shrimp. The procedure consisted of a trichloracetic acid/methanol extraction conducted at elevated temperature (60°C) and pressure (65bar), without further clean-up, the extraction solution was concentrated and finally for high-performance liquid chromatography analysis. The limits of detection were 5.0-10.0μg/kg and the limits of quantification were 10.0-15.0μg/kg for tetracyclines in egg, fish and shrimp using UV detection. The analytical limits CCα and CCβ were also calculated. The recoveries of tetracyclines spiked at levels of 15-300μg/kg, averaged 75.6-103.5% with the relative standard deviation values less than 11%. The optimized procedure has been successfully applied to real samples in our laboratories. It demonstrated that the new method was robust and useful for monitoring and quantification of 7 tetracycline residues in food of animal origin.

  2. Ionic liquid-based ultrasound-assisted dispersive liquid-liquid microextraction followed high-performance liquid chromatography for the determination of ultraviolet filters in environmental water samples.

    PubMed

    Zhang, Yufeng; Lee, Hian Kee

    2012-10-31

    In the present study, a rapid, highly efficient and environmentally friendly sample preparation method named ionic liquid-based ultrasound-assisted dispersive liquid-liquid microextraction (IL-USA-DLLME), followed by high performance liquid chromatography (HPLC) has been developed for the extraction and preconcentration of four benzophenone-type ultraviolet (UV) filters (viz. benzophenone (BP), 2-hydroxy-4-methoxybenzophenone (BP-3), ethylhexyl salicylate (EHS) and homosalate (HMS)) from three different water matrices. The procedure was based on a ternary solvent system containing tiny droplets of ionic liquid (IL) in the sample solution formed by dissolving an appropriate amount of the IL extraction solvent 1-hexyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate ([HMIM][FAP]) in a small amount of water-miscible dispersive solvent (methanol). An ultrasound-assisted process was applied to accelerate the formation of the fine cloudy solution, which markedly increased the extraction efficiency and reduced the equilibrium time. Various parameters that affected the extraction efficiency (such as type and volume of extraction and dispersive solvents, ionic strength, pH and extraction time) were evaluated. Under optimal conditions, the proposed method provided good enrichment factors in the range of 354-464, and good repeatability of the extractions (RSDs below 6.3%, n=5). The limits of detection were in the range of 0.2-5.0 ng mL(-1), depending on the analytes. The linearities were between 1 and 500 ng mL(-1) for BP, 5 and 500 ng mL(-1) for BP-3 and HMS and 10 and 500 ng mL(-1) for EHS. Finally, the proposed method was successfully applied to the determination of UV filters in river, swimming pool and tap water samples and acceptable relative recoveries over the range of 71.0-118.0% were obtained.

  3. Identification of synthetic by-products in combinatorial libraries using high performance liquid chromatography-electrospray ionization mass spectrometry.

    PubMed

    Aubagnac, J L; Amblard, M; Enjalbal, C; Subra, G; Martinez, J; Durand, P; Renaut, P

    1999-10-01

    High performance liquid chromatography (HPLC), electrospray ionization mass spectrometry (ESI) and high performance liquid chromatography coupled to mass spectrometry (LC-MS) were used to analyze randomly chosen samples from parallel syntheses carried out on derivatized polypropylene crowns compatible with a Multipin solid support system. Side-reactions and by-products were clearly identified, and the yields of the expected molecules were unexpectedly low for most samples. LC-MS was superior to HPLC with absorbance detection or electrospray mass spectrometry alone for determining the identity and purity of each desired combinatorial compounds.

  4. Vortex-assisted surfactant-enhanced-emulsification liquid-liquid microextraction of biogenic amines in fermented foods before their simultaneous analysis by high-performance liquid chromatography.

    PubMed

    Donthuan, Jaruwan; Yunchalard, Sirinda; Srijaranai, Supalax

    2014-11-01

    A simple, rapid, sensitive, and environmentally friendly method, based on modified dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography was developed for the simultaneous determination of five biogenic amines in fermented food samples. Biogenic amines were derivatized with 9-fluorenylmethyl chloroformate, extracted by vortex-assisted surfactant-enhanced emulsification liquid-liquid microextraction, and then analyzed by high-performance liquid chromatography. Five biogenic amine compounds were separated within 30 min using a C18 column and gradient elution with acetonitrile and 1% acetic acid. Factors influencing the derivatization and extraction efficiency such as type and volume of extraction solvent, type, and concentration of surfactant, pH, salt addition, and vortex time were optimized. Under the optimum conditions, the method provided the enrichment factors in the range of 161-553. Good linearity was obtained from 0.002-0.5 mg/L for cadaverine and tyramine, 0.003-1 mg/L for tryptamine and histamine, and 0.005-1 mg/L for spermidine with coefficient of determination (R(2) ) > 0.992. The limits of detection ranged from 0.0010 to 0.0026 mg/L. The proposed method was successfully applied to analysis of biogenic amines in fermented foods such as fermented fish (plaa-som), wine and beer where good recoveries were obtained in the range of 83.2-112.5%

  5. Ultrasound-assisted dispersive liquid-liquid microextraction combined with high-performance liquid chromatography-fluorescence detection for sensitive determination of biogenic amines in rice wine samples.

    PubMed

    Huang, Ke-Jing; Wei, Cai-Yun; Liu, Wei-Li; Xie, Wan-Zhen; Zhang, Jun-Feng; Wang, Wei

    2009-09-18

    Ultrasound-assisted dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography-fluorescence detection was used for the extraction and determination of three biogenic amines including octopamine, tyramine and phenethylamine in rice wine samples. Fluorescence probe 2,6-dimethyl-4-quinolinecarboxylic acid N-hydroxysuccinimide ester was applied for derivatization of biogenic amines. Acetonitrile and 1-octanol were used as disperser solvent and extraction solvent, respectively. Extraction conditions including the type of extraction solvent, the volume of extraction solvent, ultrasonication time and centrifuging time were optimized. After extraction and centrifuging, analyte was injected rapidly into high-performance liquid chromatography and then detected with fluorescence. The calibration graph of the proposed method was linear in the range of 5-500 microg mL(-1) (octopamine and tyramine) and 0.025-2.5 microg mL(-1) (phenethylamine). The relative standard deviations were 2.4-3.2% (n=6) and the limits of detection were in the range of 0.02-5 ng mL(-1). The method was applied to analyze the rice wine samples and spiked recoveries in the range of 95.42-104.56% were obtained. The results showed that ultrasound-assisted dispersive liquid-liquid microextraction was a very simple, rapid, sensitive and efficient analytical method for the determination of trace amount of biogenic amines.

  6. Simultaneous determination of hypericin and hyperforin in human plasma and serum using liquid-liquid extraction, high-performance liquid chromatography and liquid chromatography-tandem mass spectrometry.

    PubMed

    Pirker, R; Huck, C W; Bonn, G K

    2002-09-25

    A method for the simultaneous extraction of hypericin and hyperforin from a St. John's Wort extract, which is used in case of moderate depressions and skin injuries, from human plasma and serum by liquid-liquid extraction (LLE) with n-hexane-ethylacetate (70:30, w/w) was developed. A reversed-phase high-performance liquid chromatographic (RP-HPLC) method with UV, fluorescence (FLD) and mass spectrometric (MS) detection using electrospray ionization (ESI) was used to identify and quantify hypericin and hyperforin in the extracts from blood samples. Linearity was obtained in the ranges 8.4-28.7 ng/ml (hypericin) and 21.6-242.6 ng/ml (hyperforin). Recoveries were between 32.2 and 35.6% for hypericin and 100.1 and 89.9% for hyperforin. Intra-day accuracy and precision for this method ranged between 3.2 and 4.3% and 2.6 and 2.8%, respectively. After validation of the LLE, the method was tested on real plasma samples which were obtained by ingestion of St. John's Wort extract capsules. Blood samples were taken 2, 4, and 6 h after ingestion. Finally, this method proved to be highly suitable for clinical and pharmacologically relevant studies.

  7. Ionic liquids for improving the extraction of NSAIDs in water samples using dispersive liquid-liquid microextraction by high performance liquid chromatography-diode array-fluorescence detection.

    PubMed

    Toledo-Neira, Carla; Álvarez-Lueje, Alejandro

    2015-03-01

    A rapid, sensitive and efficient analytical method based on the use of ionic liquids for determination of non-steroidal anti-inflammatory drugs (NSAIDs) in water samples was developed. High-performance liquid chromatography equipped with a diode array and fluorescence detector was used for quantification of ketoprofen, ibuprofen and diclofenac in tap and river water samples. This new method relies on the use of two ionic liquids with multiple functionalities: one functions as an extraction solvent (1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), and the other changes the polarity in the aqueous medium (1-butyl-3-methylimidazolium tetrafluoroborate, ([BMIM][BF4]). Factors such as the type and volume of the ILs and dispersive solvent, sample volume, and centrifugation time were investigated and optimized. The optimized method exhibited good precision, with relative standard deviation values between 2% and 3%, for the three NSAIDs. Limits of detection achieved for all of the analytes were between 17 and 95 ng mL(-1), and the recoveries ranged from 89% to 103%. Furthermore, the enrichment factors ranged from 49 to 57. The proposed method was successfully applied to the analysis of NSAIDs in tap and river water samples.

  8. Development of an offline bidimensional high-performance liquid chromatography method for analysis of stereospecific triacylglycerols in cocoa butter equivalents.

    PubMed

    Kadivar, Sheida; De Clercq, Nathalie; Nusantoro, Bangun Prajanto; Le, Thien Trung; Dewettinck, Koen

    2013-08-21

    Acyl migration is a serious problem in enzymatic modification of fats and oils, particularly in production of cocoa butter equivalent (CBE) through enzymatic acidolysis reaction, which leads to the formation of non-symmetrical triacylglycerols (TAGs) from symmetrical TAGs. Non-symmetrical TAGs may affect the physical properties of final products and are therefore often undesired. Consequently, an accurate method is needed to determine positional isomer TAGs during the production of CBE. A bidimentional high-performance liquid chromatography (HPLC) method with combination of non-aqueous reversed-phase HPLC and silver ion HPLC joining with an evaporative light scattering detector was successfully developed for the analysis of stereospecific TAGs. The best separation of positional isomer standards was obtained with a heptane/acetone mobile-phase gradient at 25 °C and 1 mL/min. The developed method was then used in multidimensional determination of the TAG positional isomers in fat and oil blends and successfully identified the TAGs and possible isomers in enzymatically acidolyzed CBE.

  9. Effects of Hemoglobin Variants on Hemoglobin A1c Values Measured Using a High-Performance Liquid Chromatography Method

    PubMed Central

    De-La-Iglesia, Silvia; Ropero, Paloma; Nogueira-Salgueiro, Patricia; Santana-Benitez, Jesus

    2014-01-01

    Hemoglobin A1c (HbA1c) is routinely used to monitor long-term glycemic control and for diagnosing diabetes mellitus. However, hemoglobin (Hb) gene variants/modifications can affect the accuracy of some methods. The potential effect of Hb variants on HbA1c measurements was investigated using a high-performance liquid chromatography (HPLC) method compared with an immunoturbimetric assay. Fasting plasma glucose (FPG) and HbA1c levels were measured in 42 371 blood samples. Samples producing abnormal chromatograms were further analyzed to characterize any Hb variants. Fructosamine levels were determined in place of HbA1c levels when unstable Hb variants were identified. Abnormal HPLC chromatograms were obtained for 160 of 42 371 samples. In 26 samples HbS was identified and HbA1c results correlated with FPG. In the remaining 134 samples HbD, Hb Louisville, Hb Las Palmas, Hb N-Baltimore, or Hb Porto Alegre were identified and HbA1c did not correlate with FPG. These samples were retested using an immunoturbidimetric assay and the majority of results were accurate; only 3 (with the unstable Hb Louisville trait) gave aberrant HbA1c results. Hb variants can affect determination of HbA1c levels with some methods. Laboratories should be aware of Hb variants occurring locally and choose an appropriate HbA1c testing method. PMID:25355712

  10. Stability-Indicating High-Performance Liquid Chromatography Assay for the Determination of Sulthiame in Pharmaceutical Dosage Forms

    PubMed Central

    Haidar, Ammar; Kabiche, Sofiane; Majoul, Elyes; Balde, Issa-Bella; Fontan, Jean-Eudes; Cisternino, Salvatore; Schlatter, Joël

    2016-01-01

    A stability-indicating assay by reversed-phase high performance liquid chromatography method was developed and validated for the determination of sulthiame (STM). The chromatographic separation was achieved on a reversed-phase NovaPack C18 column and an isocratic mobile phase consisting of deionized water:methanol (70:30, v/v). The flow rate was 1.0 mL/min (ultraviolet detection at 210 nm). The STM was separated within 2.83 min. The linearity of the method was demonstrated in the range of 20.0–200.0 μg/mL and a coefficient of determination of r2 = 0.9999. The limits of detection and quantification were 4.2 and 9.5 μg/mL, respectively. The intraday and interday precisions were less than 1%. Accuracy of the method ranged from 98.3% to 101.7%, with a relative standard deviation of <1%. STM was degraded by accelerated breakdown in alkaline, acidic, or oxidative stress conditions. This method allows accurate and reliable determination of STM for drug stability assay in pharmaceutical studies. PMID:27625574

  11. [Determination of amygdalin content in Semen Armeniacae Amarum by high-performance liquid chromatography with evaporative light-scattering detection].

    PubMed

    Wu, Zhao-hui; You, Wen-wei; He, Feng

    2005-12-01

    High-performance liquid chromatography with evaporative light-scattering detection (HPLC-ELSD) was employed for determination of amygdalin content in Semen Armeniacae Amarum. The detection was performed with the column of Hypersil-ODS (4.6 mm x 250 mm, 5 microm) and column temperature of 25 degrees C. The mobile phase was methanol-water (70:30) with flow rate of 0.5 ml/min. Evaporative light-scattering detector was used and the drift tube temperature was set at 98 degrees Celsius with the gas flow rate of 3.2 L/min. A standard curve was generated, which was linear in the range of 1.0-15.1 microg for amygdalin content (r=0.999 9). The average recovery of amygdalin was 99.0% with RSD of 2.9% (n=5). Besides simplicity and rapidness, the method yields accurate and reproducible results and can therefore be used in the quality control of Semen Armeniacae Amarum.

  12. [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.

  13. [Simultaneous determination of migration amounts of antioxidants and ultraviolet absorbents by high performance liquid chromatography in food contact materials].

    PubMed

    Li, Chengfa; Li, Ying; Chen, Zhinan; Liang, Feng; Chen, Xuhui; Wu, Shaojing; Li, Yongtao; Sun, Xiaoying

    2014-06-01

    An efficient analytical method for the quantitative determination of migration levels of antioxidants and ultraviolet absorbents in food contact materials by high performance liquid chromatography (HPLC) has been developed. The analytical method showed good linearity with the correlation coefficients (r2) > or = 0.999 8 for all the compounds. The limits of detection were between 0.01 mg/L and 0.22 mg/L and the limits of quantification were in the range of 0.03 to 0.85 mg/L for the 23 analytes. According to the European Union Directive No 10/2011, five food simulants were investigated: 30 g/L acetic acid, 10% (v/v) ethanol, 20% (v/v) ethanol, 50% (v/v) ethanol, and fatty food simulant (isooctane). The recoveries were in the range of 92.8%-117.7%, with the relative standard deviations of 0.95%-9.72%. The effects of different experimental conditions on the recoveries of antioxidants and UV absorbents were studied. The results showed that the method is accurate and stable, and can meet the requirements of European Commission Regulation (EU) No 10/2011 and GB 9685-2008 for the specific migration limits (SML) of the antioxidants and ultraviolet absorbents in real food contact plastic materials and article samples. The method has been applied to determine the migration levels of antioxidants and ultraviolet absorbents in different simulants from the migration tests of 30 batches of food contact material samples.

  14. [Determination of apomorphine, sildenafil and alprostadil in medicines for erectile dysfunction by high performance liquid chromatography-mass spectrometry].

    PubMed

    Xu, Yuanjin; Xu, Guiping

    2005-11-01

    A high performance liquid chromatography-mass spectrometry (LC-MS) analytical method for illicit drugs, apomorphine, sildenafil and alprostadil, in medicines for erectile dysfunction has been developed. The samples were extracted with methanol using ultrasound-assisted extraction. The chromatographic separation was performed on a Zorbax Eclipse XDB-C18 column using acetonitrile-0.5% formic acid aqueous solution as mobile phase. The three compounds were identified by retention time and m/z and quantified by peak area. The results demonstrated that the linear ranges were 50.0 - 5 000.0 microg/L, 10.0 - 1 000.0 microg/L, 40.0 - 4 000.0 microg/L, with detection limits of 20.0, 4.0, 10.0 microg/L for apomorphine, sildenafil and alprostadil, respectively. The average recoveries and the relative standard deviations were 89% - 95% and 9.5% - 11%. The method is simple, rapid, accurate and suitable for the simultaneous determination of these drugs in medicines for erectile dysfunction.

  15. Development and validation of stability indicating method for the determination of exemestane by reverse phase high performance liquid chromatography.

    PubMed

    Konda, Bharath; Tiwari, Ravi N; Fegade, Harshal

    2011-09-01

    Exemestane is an aromatase inhibitor used in the treatment of breast cancer. A selective stability-indicating reversed-phase high performance liquid chromatography (RP-HPLC) method has been developed which can separate and accurately quantitate low levels of exemestane. The stability-indicating capability of the method was demonstrated by adequate separation of exemestane and all the degradation product peaks from exemestane peak and also from each other in stability samples of exemestane. Chromatographic separation of exemestane and its degraded products were achieved by using isocratic elution at a flow rate of 1.0 mL/min on a C18 reverse phase column (Phenomenex, size: 250 × 4.60 mm, particle size 5 μm) at ambient temperature. The mobile phase used for the analysis was acetonitrile-water (60:40, %v/v) with UV visible detection at 242 nm. The proposed method was used to study the degradation behavior of drug under various stress conditions as per ICH recommended guidelines.

  16. Evaluation of hemoglobin A1c measurement from filter paper using high-performance liquid chromatography and immunoturbidimetric assay.

    PubMed

    Wu, Yonghua; Yang, Xu; Wang, Haining; Li, Zhenrong; Wang, Tiancheng

    2017-04-01

    Glycated hemoglobin (HbA1c) measurement from whole blood (WB) samples is inconvenient for epidemic surveillance and self-monitoring of glycemic level. We evaluated HbA1c measurement from WB blotted on filter paper (FP), which can be easily transported to central laboratories, with high-performance liquid chromatography (HPLC) and immunoturbidimetric assay (ITA). WB was applied to Whatman filter paper. By using HPLC and WB samples as reference methods, these FP samples were evaluated on HPLC and ITA. Inter- and intra-assay variation, WB vs. FP agreement and sample stability at 20-25 °C and -70 °C were assessed by statistical analysis. Results showed that the coefficient of variation (CV, %) of FP samples for HPLC and ITA were 0.44-1.02% and 1.47-2.72%, respectively (intra-assay); 2.13-3.56% and 3.21-4.82%, respectively (inter-assay). The correlation of WB HPLC with FP analyzed using HPLC and ITA are both significant (p < 0.001). Sample stability showed that FP method up to 5 days at 20-25 °C and 5 weeks at -70 °C is accurate and reproducible. In conclusion, FP samples analyzed by HPLC and ITA can both provide an alternative to WB for HbA1c measurement, supporting the use of FP method in epidemic surveillance and healthcare units.

  17. Determination of Flavonoids and Anthocyanins in Nitraria tangutorum by High Performance Liquid Chromatography Coupled with Tandem Mass Spectrometry.

    PubMed

    Zhe, Gao; Ying-Chun, Wang; Yan-Xu, Chang

    2016-01-01

    Using high-performance liquid chromatography coupled with diode array detection and electrospray ionization tandem mass spectrometry (HPLC-DAD-MSn) method, qualitative and quantitative analysis of flavonoids of stems, leaves, fruits and seeds, and anthocyanidin of fresh fruits in Nitraria tangutorum were performed. A total of 14 flavonoid components were identified from the seeds of N. tangutorum including three quercetin derivatives, three kaempferol derivatives, and eight isorhamnetin derivatives. A total of 12, 10, and 7 flavonoid components were identified from leaves, stems, and fruits of N. tangutorum, respectively; all were present in seeds also. The total content of flavonoids in leaves was the highest, up to 42.43 mg/g·dry weight. A total of 12 anthocyanidin components were identified from the fresh fruits of N. tangutorum, belonging to five anthocyanidin. The total content of anthocyanidin in fresh fruits was up to 45.83 mg/100 g· fresh weight, of which the acylated anthocyanidin accounted for 65.7%. The HPLC-DAD-MS(n) method can be operated easily, rapidly, and accurately, and is feasible for qualitative and quantitative analysis of flavone glycosides in N. tangutorum.

  18. High-performance liquid chromatographic assay of sulbactam using pre-column reaction with 1,2,4-triazole.

    PubMed

    Haginaka, J; Wakai, J; Yasuda, H; Uno, T; Nakagawa, T

    1985-05-31

    A high-performance liquid chromatographic (HPLC) method for the determination of sulbactam in human and rat plasma and urine has been developed. Sulbactam was reacted with 1,2,4-triazole to yield a product having an ultraviolet absorption maximum at 326 nm. The product was separated using reversed-phase HPLC from the regular components of plasma and urine with an ion-pair buffer at 50 degrees C and detected at the ultraviolet maximum. The limits of accurate determination were 0.2 and 1.0 micrograms/ml in plasma and urine, respectively. The coefficients of variation of inter- and intra-assays in human plasma spiked at 4.0 micrograms/ml (n = 5) were 1.02 and 3.05%, respectively. Coexisting cefoperazone, penicillins, or the alkaline degradation product(s) of sulbactam did not interfere in the sulbactam assay. The pharmacokinetic behaviour of sulbactam and cefoperazone coadministered to rats was estimated by moment analysis.

  19. Optimisation of the separation of herbicides by linear gradient high performance liquid chromatography utilising artificial neural networks.

    PubMed

    Tran, Anh T K; Hyne, Ross V; Pablo, Fleur; Day, W Roy; Doble, P

    2007-02-28

    An artificial neural network (ANN) was employed to model the chromatographic response surface for the linear gradient separation of 10 herbicides that are commonly detected in storm run-off water in agricultural catchments. The herbicides (dicamba, simazine, 2,4-D, MCPA, triclopyr, atrazine, diuron, clomazone, bensulfuron-methyl and metolachlor) were separated using reverse phase high performance liquid chromatography and detected with a photodiode array detector. The ANN was trained using the pH of the mobile phase and the slope of the acetonitrile/water gradient as input variables. A total of nine experiments were required to generate sufficient data to train the ANN to accurately describe the retention times of each of the herbicides within a defined experimental space of mobile phase pH range 3.0-4.8 and linear gradient slope 1-4% acetonitrile/min. The modelled chromatographic response surface was then used to determine the optimum separation within the experimental space. This approach allowed the rapid determination of experimental conditions for baseline resolution of all 10 herbicides. Illustrative examples of determination of these components in Milli-Q water, Sydney mains water and natural water samples spiked at 0.5-1mug/L are shown. Recoveries were over 70% for solid-phase extraction using Waters Oasis((R)) HLB 6cm(3) cartridges.

  20. Separation and detection of plasmalogen in marine invertebrates by high-performance liquid chromatography with evaporative light-scattering detection.

    PubMed

    Yamashita, Shinji; Abe, Akihiro; Nakagawa, Kiyotaka; Kinoshita, Mikio; Miyazawa, Teruo

    2014-12-01

    We have developed a new method for determining ethanolamine plasmalogen contents in marine invertebrates. This quantification method involves derivatization of ethanolamine glycerophospholipid (EtnGpl) subclasses, alkenylacyl (plasmalogen), diacyl, and alkylacyl subclasses, by enzyme treatment and acetylation, followed by separation and detection by high-performance liquid chromatography (HPLC) with evaporative light-scattering detection (ELSD). This method enabled complete separation of the subclasses, and the limit of detection for plasmalogen was 200 ng (260 pmol). The peak area of plasmalogen by ELSD was unaffected by the degree of unsaturated fatty acids in EtnGpl, in contrast to ultraviolet (UV) detection. Thus, this method enables accurate determination of plasmalogen contents in various species containing marine products possessing abundant polyunsaturated fatty acids (PUFA). The method developed here was applied to marine invertebrates available in Japan. The examined marine invertebrates showed a wide range of plasmalogen contents ranging from 19 to 504 μmol/100 g wet wt. The plasmalogen levels in samples except those of class Cephalopoda and Crustacea were more than 60 mol% of EtnGpl.

  1. Determination of naphthalene-derived compounds in apples by ultra-high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Esparza, X; Moyano, E; Cosialls, J R; Galceran, M T

    2013-06-11

    Naphthylacetic acid, naphthyloxy acetic acid and naphthylacetamide belong to a group of synthetic substances known as "auxin-like" compounds which are used as growth regulators in vegetables and fruits due to their structure similarities with the indoleacetic acid, the most important plant auxin. This paper reports a selective, sensitive and fast ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the determination of naphthylacetamide (NAD) and the isomers (α and β) of naphthylacetic acid (NAA) and naphthyloxy acetic (NOA) acid in apple samples. A baseline separation between the respective isomers was achieved using an RP-Amide column with gradient elution. The UHPLC-MS/MS method developed, using electrospray and selected reaction monitoring (SRM) acquisition mode led to a reliable determination of these family of compounds in apple samples at low quantitation levels, down to 1.0 μg kg(-1) and 0.25 μg kg(-1) respectively. For confirmation of NAA accurate mass measurement is proposed giving at these conditions quantitation limits of 10 μg kg(-1) for this compound. The UHPLC-MS/MS method developed was used for the analysis of apple samples harvested in three different apple fields from Lleida (Spain) during the blooming period. NAD and NAA were found in samples collected during 4-5 weeks after application at concentrations between the quantification limits and 43 μg kg(-1) and 24 μg kg(-1), respectively.

  2. [Determination of fluorescent whitening agents in plastic food contact materials by high performance liquid chromatography with fluorescence detector].

    PubMed

    Jiao, Yanna; Ding, Li; Zhu, Shaohua; Fu, Shanliang; Gong, Qiang; Li, Hui; Wang, Libing

    2013-01-01

    A method for the determination of fluorescent whitening agents in plastic food contact materials by high performance liquid chromatography (HPLC) with fluorescence detector was developed. The samples were extracted with trichloromethane by sonication for 30 min at 40 degrees C. The HPLC method was performed on a column of Eclipse XDB-C18 (250 mm x 4.6 mm, 5 microm) by gradient elution using 5 mmol/L ammonium acetate and acetonitrile as the mobile phases, and detected by the fluorescence detector at an excitation wavelength of 350 nm and an emission wavelength of 430 nm. The experimental results indicated that the four fluorescent whitening agents were separated well. The limits of detection (LOD) (S/N = 3) were 0.3, 0.1, 0.05, 0.14 mg/L, and the limits of quantification (LOQ) (S/N = 10) were 1.0, 0.4, 0.2, 0.5 mg/L for 1,4-bis (4-cyanostyryl) benzene (C. I. 199), 1,4-bis (2-benzoxazolyl) naphthalene (C. I. 367), 4,4'-bis(2-methoxystyryl) biphenyl (C. I. 378) and 2,5-thiophenediylbis (5-tert-butyl-1,3-benzoxazole) (C. I. 184), respectively. Good linearities with correlation coefficients (r2) not less than 0.991 were obtained. The proposed method is simple, accurate, sensitive and can meet the requirements of the routine determination of fluorescent whitening agents in entry-exit products.

  3. High performance liquid chromatography coupled to mass spectrometry for profiling and quantitative analysis of folate monoglutamates in tomato.

    PubMed

    Tyagi, Kamal; Upadhyaya, Pallawi; Sarma, Supriya; Tamboli, Vajir; Sreelakshmi, Yellamaraju; Sharma, Rameshwar

    2015-07-15

    Folates are essential micronutrients for animals as they play a major role in one carbon metabolism. Animals are unable to synthesize folates and obtain them from plant derived food. In the present study, a high performance liquid chromatography coupled to mass spectrometric (HPLC-MS/MS) method was developed for the high throughput screening and quantitative analysis of folate monoglutamates in tomato fruits. For folate extraction, several parameters were optimized including extraction conditions, pH range, amount of tri-enzyme and boiling time. After processing the extract was purified using ultra-filtration with 10 kDa membrane filter. The ultra-filtered extract was chromatographed on a RP Luna C18 column using gradient elution program. The method was validated by determining linearity, sensitivity and recovery. This method was successfully applied to folate estimation in spinach, capsicum, and garden pea and demonstrated that this method offers a versatile approach for accurate and fast determination of different folate monoglutamates in vegetables.

  4. [Simultaneous determination of organic acids and saccharides in lactic acid fermentation broth from biomass using high performance liquid chromatography].

    PubMed

    Ma, Rui; Ouyang, Jia; Li, Xin; Lian, Zhina; Cai, Cong

    2012-01-01

    Abstract: A high performance liquid chromatographic method for the simultaneous determination of organic acids and saccharides in lactic acid fermentation broth from biomass was developed. A Bio-Rad Aminex HPX-87H column was used at 55 degrees C. The mobile phase was 5 mmol/L sulfuric acid solution at a flow rate of 0.6 mL/min. The samples were detected by a refractive index detector (RID). The results showed that six organic acids and three saccharides in fermentation broth were completely separated and determined in 17 min. The linear correlation coefficients were above 0.999 8 in the range of 0.15-5.19 g/L. Under the optimized conditions, the recoveries of the organic acids and saccharides in Rhizopus oryzae fermentation broth at two spiked levels were in the range of 96.91%-103.11% with the relative standard deviations (RSDs, n = 6) of 0.81%-4.61%. This method is fast and accurate for the quantitative analysis of the organic acids and saccharides in microbial fermentation broths.

  5. Advanced use of high-performance liquid chromatography for synthesis of controlled metal clusters

    NASA Astrophysics Data System (ADS)

    Niihori, Yoshiki; Matsuzaki, Miku; Uchida, Chihiro; Negishi, Yuichi

    2014-06-01

    Because the synthesis of metal clusters with multiple ligand types results in a distribution of ligands, high-resolution separation of each unique cluster from the mixture is required for precise control of the ligand composition. Reverse-phase high-performance liquid chromatography combined with appropriate transitioning of the mobile phase composition is an extremely effective means of separating ligand combinations when working with metal clusters protected by two different types of thiolates. We report herein advanced use of this method. The studies involving Au24Pd(SR1)18-x(SR2)x and Au24Pd(SR1)18-x(SeR2)x (SR1, SR2 = thiolate, SeR2 = selenolate) revealed the following. (1) In general, an increase in the difference between the polarities of the functional groups incorporated in the two types of ligands improves the separation resolution. A suitable ligand combination for separation can be predicted from the retention times of Au24Pd(SR1)18 and Au24Pd(SR2)18, which cause the terminal peaks in a series of peaks. (2) The use of a step-gradient program during the mobile phase substitution results in improved resolution compared to that achievable with the linear gradients applied in prior work. (3) This technique is also useful for the evaluation of the chemical compositions of metal clusters protected by two different types of ligands with similar molecular weights. These findings will provide clear design guidelines for the functionalization of metal clusters via control of the ligand composition, and will also improve our understanding of the high-resolution isolation of metal clusters.Because the synthesis of metal clusters with multiple ligand types results in a distribution of ligands, high-resolution separation of each unique cluster from the mixture is required for precise control of the ligand composition. Reverse-phase high-performance liquid chromatography combined with appropriate transitioning of the mobile phase composition is an extremely effective

  6. 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.

  7. Pharmacokinetics of mitomycin C in dogs: application of a high-performance liquid chromatographic assay.

    PubMed

    Barbhaiya, R H; Papp, E A; Van Harken, D R; Smyth, R D

    1984-09-01

    A normal-phase high-performance liquid chromatographic (HPLC) assay was developed for the determination of mitomycin C in plasma and urine. The method involves extraction of mitomycin C from plasma or urine into ethyl acetate-2-propanol-chloroform (70:15:15) with UV detection at 365 nm. Quantitation was performed with an internal standard (porfiromycin) by the peak height ratio method. Excellent correlation was obtained between the HPLC assay and the established microbiological cup-plate bioassay. The pharmacokinetics of mitomycin C were investigated in beagle dogs following a 1-mg/kg iv (22-mg/m2) bolus dose. The plasma mitomycin C concentration versus time data were analyzed by using an open three-compartment model. The average volume of distribution was 1.90 L or 17% of body weight for the central compartment and 7.7 L or 68% of body weight for the terminal elimination phase. The volumes of distribution at steady state, calculated by model-dependent and -independent methods, compared very well with each other and were 6.5 L or 58% of body weight. Total body clearance averaged 112 mL/min, and the mean terminal plasma half-life was 53 min. The 0-24-h urinary excretion of intact mitomycin C accounted for 19% of the dose. The terminal half-life and percent urinary recovery of mitomycin C in dogs is similar to that in humans. Based on these observations, the dog appears to be a good model for studying the disposition of mitomycin C.

  8. Determination of biogenic amines in beer with pre-column derivatization by high performance liquid chromatography.

    PubMed

    Tang, Tao; Shi, Tianyu; Qian, Kun; Li, Pingliang; Li, Jianqiang; Cao, Yongsong

    2009-02-15

    Eighteen samples of commercially available Chinese beer were analyzed in order to determine the content of biogenic amines. The method involves pre-column derivatization of the amines with 4-chloro-3,5-dinitrobenzotrifluoride (CNBF) and subsequent analysis by RP-HPLC (reversed phase-high performance liquid chromatography) with diode array detection. The labeled biogenic amines were separated on a Kromasil C18 column (250mmx4.6mm, 5microm) at room temperature and UV detection was applied at 254nm. The separation of seven labeled biogenic amines was achieved within 22min by elution acetonitrile and HAc-NaAc buffers. The method linearity, calculated for each biogenic amine, has a correlation coefficient higher than 0.9925, in concentrations ranging from 2.9micromolL(-1) to 565micromolL(-1). Detection limits of biogenic amines were 0.056-0.87micromolL(-1), at a signal-to-noise ratio of 3. The proposed method has been applied to the quantitative determination of spermine, phenethylamine, spermidine, histamine, tyramine, tryptamine and putrescine in beer with recoveries of 91.9-103.1% and R.S.D. of 2.86-5.63%. Quantitation is relative to external standards. The results showed that each kind of beer examined contained at least three biogenic amines. Putrescine, histamine and tyramine were detected in all samples. Spermidine was detected in 89% of the beers. Spermine, tryptamine and phenylethylamine occurred in 78%, 61% and 44% of the beers examined, respectively. These levels were below the level that may elicit direct adverse reactions for most consumers.

  9. Simultaneous determination of cyclodol and diprazin by thin layer chromatography and high performance liquid chromatography.

    PubMed

    Makharadze, R; Adeishvili, L; Chelidze, T; Imnadze, N; Nizharadze, N

    2009-11-01

    Ciklodol (trihexyphenidil)--the central and peripheral m-cholinoblocker is currently used with other antipsychotic drugs such as phenotiazines and tricycle antidepressants. For the purpose of simultaneous determination of ciklodol and diprazine, were selected two methods of analysis: Thin Layer Chromatography (TLC) and High Performance Liquid Chromatography (HPLC). During development of TLC method was studied the 10 visualizing system and 24 mobile systems. For individual or simultaneous determination of ciklodol and diprazine were recommended the following solvents' systems: 1. Toluene-acetone-ethanole-25%NH(4)OH (45:45: 7.5:2.5), 2. Hexane-ethyl acetate (15:5), 3. Chloroform-heptene-25%NH(4)OH (16:3:3), 4. Ethylacetate-hexane (10:10), 5. Acetonitrile-metanol (10:10) and 6.Heptene-chloroform-ethanol-25% NH(4)OH (5:10:3:1). As visualizing systems were chosen: Iodine vapors, blacklight (UV254) and reagent of FNP. Reagent of FNP gives colored spot just with diprazine and it is also could be used for separation of both objects in simultaneous analysis. Developed HPLC method of simultaneous determination of ciklodol and diprazine: like mobile phase is recommended: Acetonitril- 0.05M KH(2)PO4 (55:45) (v/v) +H(3)PO(4) (pH3.5), column EC250 x 4.6mm, with solid phase Nucleosil, flow rate 1ml/min, sample volume 40 microl. In given conditions, the retention time of ciklodol is 6.005min and diprazine 7.227min. Developed method of simultaneous determination and separation of ciklodol and diprazine in respective mixtures could be successfully applied as in the pharmaceutical, as well in the chemical-toxicological laboratories.

  10. Simultaneous determination of three sesquiterpene lactones in Aucklandia lappa Decne by high-performance liquid chromatography

    PubMed Central

    Seo, Chang-Seob; Shin, Hyeun-Kyoo

    2015-01-01

    Background: Aucklandia lappa Decne, a well-known traditional herbal medicine, is used for the treatment of asthma, rheumatism, coughs, tuberculosis, and many other diseases. Objective: We performed simultaneous analysis of three sesquiterpene lactones, costunolide (1), dehydrocostus lactone (2), and alantolactone (3), obtained from a 70% methanol extract of A. lappa using high-performance liquid chromatography–photodiode array (HPLC–PDA) techniques. Materials and Methods: The compounds 1–3 were separated using a reversed-phase SunFire™ C18 analytical column kept at 35°C by the isocratic elution with distilled water and acetonitrile as mobile phase. The flow rate was 1.0 mL/min, and the injection volume was 10 μL. Results: The established analytical method showed high linearity, with a correlation coefficient ≥0.9999. The limit of detection and the limit of quantification of compounds 1–3 were 0.06–0.13 μg/mL and 0.21–0.42 μg/mL, respectively. The recovery of the compounds 1–3 was 97.27–103.00%. The intra- and inter-day relative standard deviations were 0.09–0.97% and 0.09–1.06%, respectively. The amounts of the compounds 1–3 were 17.32, 28.26, and 0.01 mg/g, respectively. Conclusion: The established and validated HPLC–PDA method may be help for the quality control of herbal medicine, A. lappa. PMID:26246732

  11. Rayleigh light scattering detection of three α1-adrenoceptor antagonists coupled with high performance liquid chromatograph

    NASA Astrophysics Data System (ADS)

    Li, Ai Ping; Peng, Huanjun; Peng, Jing Dong; Zhou, Ming Qiong; Zhang, Jing

    2015-08-01

    Herein, a Rayleigh light-scattering (RLS) detection method combined with high performance liquid chromatograph (HPLC) without any post-column probe was developed for the separation and determination of three α1-adrenoceptor antagonists. The quantitative analysis is benefiting from RLS signal enhancement upon addition of methanol which induced molecular aggregation to form an hydrophobic interface between aggregates and water that produce a sort of superficial enhanced scattering effect. A good chromatographic separation among the compounds was achieved using a Gemini 5u C18 reversed phase column (250 mm × 4.6 mm; 4 μm) with a mobile phase consisting of methanol and ammonium acetate-formic acid buffer solution (25 mM; pH = 3.0) at the flow rate of 0.7 mL min-1. The RLS signal was monitored at λex = λem = 354 nm. A limit of detection (LOD) of 0.065-0.70 μg L-1 was reached and a linear range was found between peak height and concentration in the range of 0.75-15 μg L-1 for doxazosin mesylate (DOX), 0.075-3.0 μg L-1 for prazosin hydrochloride (PRH), and 0.25-5 μg L-1 for terazosin hydrochloride (TEH), with linear regression coefficients all above 0.999. Recoveries from spiked urine samples were 88.4-99.0% which is within acceptable limits. The proposed method is convenient, reliable and sensitive which has been used successfully in human urine samples.

  12. Stability-indicating high-performance liquid chromatographic assay of busulfan in aqueous and plasma samples.

    PubMed

    Chow, D S; Bhagwatwar, H P; Phadungpojna, S; Andersson, B S

    1997-12-19

    A sensitive, specific and stability-indicating high-performance liquid chromatographic (HPLC) assay, involving pre-column derivatization and solid-phase extraction (SPE), was developed and validated for the quantitation of busulfan (BU) in aqueous and plasma samples. The linearity of the assay was in the concentration ranges of 0.15-10 microg/ml and 0.15-3 microg/ml for aqueous and plasma samples, respectively. The within-day and between-day variations were 2.90 and 3.31%, respectively, for the aqueous samples, and 9.24 and 14.56%, respectively, for the plasma samples. The overall recovery, derivatization yield and SPE efficiency of BU from plasma samples were 82.03, 108.01 and 86.69%, respectively. Forced degraded samples, either in highly acidic, neutral or basic medium, produced no interfering peaks in the chromatogram. The reported assay requires only 0.2 ml of plasma for the analysis, and its sensitivity is 150 ng/ml by monitoring samples at a wavelength of 254 nm, sufficient to study the plasma pharmacokinetics of BU in rats after a clinically relevant oral dose. Moreover, the sensitivity of the assay can be significantly increased to 30 ng/ml by monitoring samples at a wavelength of 278 nm. The applications of the assay were demonstrated with BU solubility measurements in two aqueous systems and with plasma samples from a Sprague-Dawley rat for an in vivo pharmacokinetic study. In addition, the assay has been employed in the development of a patented intravenous formulation, and in evaluations of stability, preclinical pharmacokinetics in rats and dogs, and clinical phase I trial of the formulation. The assay is readily adaptable to clinical therapeutic drug monitoring.

  13. Determination of ferric iron chelators by high-performance liquid chromatography using luminol chemiluminescence detection.

    PubMed

    Ariga, Tomoko; Imura, Yuki; Suzuki, Michio; Yoshimura, Etsuro

    2016-03-01

    Iron is an essential element for higher plants, and its acquisition and transportation is one of the greatest limiting factors for plant growth because of its low solubility in normal soil pHs. Higher plants biosynthesize ferric iron [Fe(III)] chelator (FIC), which solubilizes the iron and transports it to the rhizosphere. A high-performance liquid chromatography (HPLC) post-column method has been developed for the analysis of FICs using the luminol/H2O2 system for chemiluminescence (CL) detection. A size-exclusion column was the most suited in terms of column efficiency and CL detection efficiency. Mixing of the luminol with H2O2 in a post-column reaction was feasible, and a two-pump system was used to separately deliver the luminol and H2O2 solutions. The luminol and H2O2 concentrations were optimized using Fe(III)-EDTA and Fe(III)-citrate (Cit) solutions as analytes. A strong CL intensity was obtained for Fe(III)-Cit when EDTA was added to the luminol solution, probably because of an exchange of Cit with EDTA after separation on the HPLC column; CL efficiency was much higher for Fe(III)-EDTA than for Fe(III)-Cit with the luminol/H2O2 system. The present method can detect minute levels of Fe(III)-FICs; the detection limits of Fe(III)-EDTA, Fe(III)-Cit and Fe(III)-nicotianamine were 0.77, 2.3 and 1.1pmol, respectively.

  14. Simultaneous determination of caffeine, theobromine, and theophylline by high-performance liquid chromatography.

    PubMed

    Bispo, Marcia S; Veloso, Márcia Cristina C; Pinheiro, Heloísa Lúcia C; De Oliveira, Rodolfo F S; Reis, José Oscar N; De Andrade, Jailson B

    2002-01-01

    This work relates the development of an analytical methodology to simultaneously determine three methylxanthines (caffeine, theobromine, and theophylline) in beverages and urine samples based on reversed-phase high-performance liquid chromatography. Separation is made with a Bondesil C18 column using methanol-water-acetic acid or ethanol-water-acetic acid (20:75:5, v/v/v) as the mobile phase at 0.7 mL/min. Identification is made by absorbance detection at 273 nm. Under optimized conditions, the detection limit of the HPLC method is 0.1 pg/mL for all three methylxanthines. This method is applied to urine and to 25 different beverage samples, which included coffee, tea, chocolate, and coconut water. The concentration ranges determined in the beverages and urine are: < 0.1 pg/mL to 350 microg/mL and 3.21 microg/mL to 71.2 microg/mL for caffeine; < 0.1 pg/mL to 32 microg mL and < 0.1 pg/mL to 13.2 microg/mL for theobromine; < 0.1 pg/mL to 47 microg/mL and < 0.1 pg/mL to 66.3 microg/mL for theophylline. The method proposed in this study is rapid and suitable for the simultaneous quantitation of methylxanthines in beverages and human urine samples and requires no extraction step or derivatization.

  15. Enantiomeric Separations of Pyriproxyfen and its Six Chiral Metabolites by High-Performance Liquid Chromatography.

    PubMed

    Zhang, Chuntao; Liu, Hui; Liu, Donghui; Wang, Liying; Gao, Jing; Zhou, Zhiqiang; Wang, Peng

    2016-03-01

    Pyriproxyfen is a chiral insecticide, and over 10 metabolites have been identified in the environment. In this work the separations of the enantiomers of pyriproxyfen and its six chiral metabolites were studied by high-performance liquid chromatography (HPLC). Both normal phase and reverse phase were applied using the chiral columns Chiralpak IA, Chiralpak IB, Chiralpak IC, Chiralcel OD, Chiralcel OD-RH, Chiralpak AY-H, Chiralpak AD-H, Chiracel OJ-H, (R,R)-Whelk-O 1, and Lux Cellulose-3. The effects of the chromatographic parameters such as mobile phase composition and temperature on the separations were investigated and the enantiomers were identified with an optical rotation detector. The enantiomers of these targets could obtain complete separations (resolution factor Rs > 1.5) on Chiralpak IA, Chiralpak IB, Chiralcel OD, Chiralpak AY-H, or Chiracel OJ-H under normal conditions. Chiralcel OJ-H showed the best chiral separation results with n-hexane as mobile phase and isopropanol (IPA) as modifier. The simultaneous enantiomeric separation of pyriproxyfen and four chiral metabolites was achieved on Chiralcel OJ-H under optimized condition: n-hexane/isopropanol = 80/20, 15°C, flow rate of 0.8 ml/min, and UV detection at 230 nm. The enantiomers of pyriproxyfen and the metabolites , , and obtained complete separations on Chiralpak IA, Chiralpak IC, and Lux Cellulose-3 under reverse phase using acetonitrile/water as the mobile phase. The retention factors (k) and selectivity factors (α) decreased with increasing temperature, and the separations were better under low temperature in most cases. The work is of significance for the investigation of the environmental behaviors of pyriproxyfen on an enantiomeric level.

  16. Advanced use of high-performance liquid chromatography for synthesis of controlled metal clusters.

    PubMed

    Niihori, Yoshiki; Matsuzaki, Miku; Uchida, Chihiro; Negishi, Yuichi

    2014-07-21

    Because the synthesis of metal clusters with multiple ligand types results in a distribution of ligands, high-resolution separation of each unique cluster from the mixture is required for precise control of the ligand composition. Reverse-phase high-performance liquid chromatography combined with appropriate transitioning of the mobile phase composition is an extremely effective means of separating ligand combinations when working with metal clusters protected by two different types of thiolates. We report herein advanced use of this method. The studies involving Au₂₄Pd(SR₁)₁₈-x(SR₂)x and Au₂₄Pd(SR₁)₁₈-x(SeR₂)x (SR₁, SR₂ = thiolate, SeR₂ = selenolate) revealed the following. (1) In general, an increase in the difference between the polarities of the functional groups incorporated in the two types of ligands improves the separation resolution. A suitable ligand combination for separation can be predicted from the retention times of Au₂₄Pd(SR₁)₁₈ and Au₂₄Pd(SR₂)₁₈, which cause the terminal peaks in a series of peaks. (2) The use of a step-gradient program during the mobile phase substitution results in improved resolution compared to that achievable with the linear gradients applied in prior work. (3) This technique is also useful for the evaluation of the chemical compositions of metal clusters protected by two different types of ligands with similar molecular weights. These findings will provide clear design guidelines for the functionalization of metal clusters via control of the ligand composition, and will also improve our understanding of the high-resolution isolation of metal clusters.

  17. Robust naphthyl methacrylate monolithic column for high performance liquid chromatography of a wide range of solutes.

    PubMed

    Jonnada, Murthy; El Rassi, Ziad

    2015-08-28

    An organic monolithic column based on the co-polymerization of 2-naphthyl methacrylate (NAPM) as the functional monomer and trimethylolpropane trimethacrylate (TRIM) as the crosslinker was introduced for high performance reversed-phase liquid chromatography (RPC). The co-polymerization was performed in situ in a stainless steel column of 4.6mm i.d. in the presence of a ternary porogen consisting of 1-dodecanol and cyclohexanol. This monolithic column (referred to as naphthyl methacrylate monolithic column or NMM column) showed high mechanical stability at relatively high mobile phase flow velocity indicating that the column has excellent hydrodynamic characteristics. To characterize the NMM column, different probe molecules including alkyl benzenes, and aniline, benzene, toluene and phenol derivatives were chromatographed on the column and the results in terms of k, selectivity and plate counts were compared to those obtained on an octadecyl silica (ODS) column in order to assess the presence of π-π and hydrophobic interactions on the NMM column under otherwise the same elution conditions. The NMM column offered additional π-π interactions with aromatic molecules in addition to hydrophobic interactions under RPC elution conditions. Run-to-run and column-to-column reproducibility of solute k values were evaluated, and percent relative standard deviation of <1% and ∼2-3.5%, respectively, were obtained. Six standard proteins were readily separated on the NMM column using shallow (30min at 1.0mL/min), steep (10min at 1.0mL/min) and ultra steep (1min at 3.0mL/min) linear gradient elution at increasing ACN concentration in the mobile phase using a 10cm×4.6mm i.d. column in case of shallow and steep linear gradients and a 3cm×4.6mm i.d. column for ultra steep linear gradient.

  18. Chiral stationary phases based on chitosan bis(methylphenylcarbamate)-(isobutyrylamide) for high-performance liquid chromatography.

    PubMed

    Tang, Sheng; Bin, Qin; Chen, Wei; Bai, Zheng-Wu; Huang, Shao-Hua

    2016-04-01

    A series of chitosan bis(methylphenylcarbamate)-(isobutyrylamide) derivatives were synthesized by carbamylating chitosan isobutyrylamide with different methylphenyl isocyanates. Then the prepared chitosan derivatives were coated onto 3-aminopropyl silica particles, resulting in a series of new chiral stationary phases (CSPs) for high-performance liquid chromatography. It was observed that the chiral recognition abilities of these coated-type CSPs depended very much on the substituents on the phenyl moieties of the chitosan derivatives, the eluent composition, as well as the structure of racemates. As a typical example, the eluent tolerance of the prepared CSP with the best enantioseparation ability was investigated in detail, and the results revealed that the CSP exhibited extraordinary solvent tolerance and could still work without significant loss in enantioseparation capability after being flushed with chloroform (100%), ethyl acetate (100%) and even THF/n-hexane (70/30, v/v), while the traditional coated-type CSPs based on the cellulose and amylose derivatives, such as cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC) and amylose tris(3,5-dimethylphenylcarbamate) (ADMPC), might be dissolved or highly swollen in these eluents. Therefore, the application of the resultant CSPs could address the problem of the dissolution and high swelling of traditional coated-type CSPs in some unusual eluents, broadening the possibility of eluent choice. In addition, a comparison of the prepared CSPs with the well known CDMPC- and ADMPC- based CSPs concerning the chiral recognition ability was also made. Separation performances achieved on the as-prepared CSPs in different eluents were found to be even superior to CDMPC- and ADMPC-based CSPs for the tested chiral compounds. In summary, we could safely draw the conclusion that the CSPs derived from chitosan isobutyrylamide derivatives were capable of excellent chiral recognition ability, and meanwhile possessed satisfactory

  19. [Saliva cotinine determination using high-performance liquid chromatography with diode - array detection].

    PubMed

    Kulza, Maksymilian; Woźniak, Anna; Seńczuk-Przybyłowska, Monika; Czarnywojtek, Agata; Kurhańska-Flisykowska, Anna; Florek, Ewa

    2012-01-01

    The use of tobacco is a very serious threat to public health. Reducing the proportion of smokers easily leads to improved health of the general population. Smoking is a proven risk factor for respiratory disease, cardiovascular disease and cancer and complications during pregnancy. To verify the level of exposure to tobacco smoke in most patients used a simple test markers of exposure. The most commonly used marker in the evaluation of exposure to tobacco products is cotinine, which is a major metabolite of nicotine contained in tobacco smoke. Biological material most commonly used in this type of study is blood, urine and saliva. In the present study Sarstedt Salivette tubes were used to samples collection. In order to determine the concentration of cotinine in saliva samples analyzed with high performance liquid chromatography with diode array detection after extraction of cotinine from saliva by solid phase extraction. The method was linear of 10 to 400 ng/ml. The limit of detection was the value of the signal-to-noise ratio S/N=3, it amounted to 6 ng/ml, the limit of quantification was 10 ng/ml. The intraday repeatability was 8% for lowconcentrations, for high concentrations - 3.7%. Reproducibility interdays for low concentrations was 2.4%, for high concentrations - 4.1%. We analyzed 18 samples of saliva derived from patients smoking volunteers from the Department of Conservative Dentistry and Periodontology, University of Medical Sciences. University of Medical Sciences and the Chair and Department of Endocrinology, Metabolism and Internal Medicine, University of Medical Sciences. University of Medical Sciences. Mean concentrations of cotinine in patients was 240.9 ng/ml of saliva. In this study we demonstrated the usefulness of the saliva cotinine determination method in the assessment of patient exposure to tobacco smoke.

  20. Ultra-high-performance liquid chromatography profiling method for chemical screening of proanthocyanidins in Czech hops.

    PubMed

    Olšovská, J; Kameník, Z; Čejka, P; Jurková, M; Mikyška, A

    2013-11-15

    Hops represent an important natural source of bioactive polyphenols, particularly proanthocyanidins, which can contribute to prevention of several civilization diseases, owing to their antioxidant and radical scavenging activity. We have developed a high-throughput ultra-high-performance liquid chromatography time-of-flight mass spectrometry profiling method, which can be used for monitoring of bioactive proanthocyanidins in hops. The method was applied for analysis of hops of four Czech varieties (Saaz, Sladek, Preminat and Agnus) from the 2011 crop (9 localities, 11 samples) and the 2012 crop (24 localities, 40 samples). Hop samples were extracted by acetone and the analytes were separated on the Acquity UPLC BEH Shield RP18 column. Partial validation of the method revealed a satisfactory intra-day repeatability of the method for retention times (relative standard deviation within 1.39%) as well as areas under the peaks (within 9.89%). Experimental data were evaluated using principal component analysis and cluster analysis. Significant amounts of di-, tri- and tetramer proanthocyanidins consisting of (epi)catechin and (epi)gallocatechin were found in the hop samples. The dependence of the proantocyanidin composition on both the variety and the growing locality was observed. Specifically, the traditional Saaz variety contained more frequently oligomers formed by (epi)catechin units only, whereas the varieties Premiant and Agnus produced oligomers consisting of (epi)catechin as well as (epi)gallocatechin units. The relative abundance of proanthocyanidins in studied hop varieties from the two crops, 2011 and 2012, did correspond to each other. In the further perspective, the method may also be used for prediction of qualitative marks or authenticity verification of hops.

  1. High-Performance Liquid Chromatographic Method for Determination of Phenytoin in Rabbits Receiving Sildenafil

    PubMed Central

    Khedr, Alaa; Moustafa, Mohamed; Abdel-Naim, Ashraf B.; Alahdal, Abdulrahman; Mosli, Hisham

    2008-01-01

    A validated high-performance liquid chromatographic (HPLC) method for determination of phenytoin (PHN), para-hydroxy metabolite of phenytoin (POH) and sildenafil (SIL) in rabbit plasma is described. The method is based on extraction on Sep-Pak C18 solid support using ethyl acetate and ether as eluents and monitoring at 220 nm. The extracted samples were analyzed by HPLC using Agilent Zorbax Extended C18 column (150 mm × 4.6 mm internal diameter) and isocratic elution with a mobile phase consist of 29% acetonitrile and 71% sodium acetate solution (0.02 M, pH 4.6). The method was fully validated for linearity and range, selectivity, precision, stability, recovery, and robustness. The linearity of the method was in the range of 0.15 to 39 μg /ml for PHN and 0.15 to 33 μg/ml for both POH and SIL. Limits of detection (LOD) of PHN, POH, and SIL were 0.15 ± 0.01, 0.15 ± 0.01, and 0.15 ± 0.01 μg/ml, respectively. The % recovery of PHN, POH, and SIL from rabbit plasma were, 101.88 ± 0.12, 99.16 ± 0.25, and 99.49 ± 0.33, respectively. The method was applied on plasma collected from rabbits at different time intervals after receiving 30 mg/kg PHN-Na with (and without) 8 mg/kg SIL citrate. PMID:19609390

  2. Determination of formate in natural waters by a coupled enzymatic/high-performance liquid chromatographic technique

    SciTech Connect

    Kieber, D.J.; Vaughan, G.M.; Mopper, K.

    1988-09-01

    An enzymatic method was developed to quantify formic acid in natural water samples at submicromolar concentrations. The method is based on the oxidation of formate by formate dehydrogenase with corresponding reduction of ..beta..-nicotinamide adenine dinucleotide (..beta..-NAD/sup +/) to reduced ..beta..-NAD/sup +/ (..beta..-NADH); ..beta..-NADH is quantified by reversed-phase high-performance liquid chromatography with fluorometric detection. An important feature of this method is that the enzymatic reaction occurs directly in aqueous media, even sea water, and does not require sample pretreatment other than sample filtration. The reaction proceeds at room temperature at a slightly alkaline pH (7.5 - 8.5) and is specific for formate with a detection limit of 0.5 ..mu..M (S/N = 4) for a 200-..mu..L injection. The precision of the method was 4.6% relative standard deviation (n = 6) for a 0.6 ..mu..M standard addition of formate to Sargasso sea water. Average recoveries of 2 ..mu..M additions of formate to sea water, pore water, or rain were 103, 103, and 87%, respectively. Intercalibration with a Dionex ion chromatographic system showed an excellent agreement of 98%. Concentrations of formate present in natural samples ranged from 0.2 to 0.8 ..mu..M for Biscayne Bay sea water, 0.4 to 10.0 ..mu..M for Miami rain, and 0.9 to 8.4 ..mu..M for Biscayne Bay sediment pore water.

  3. Quantification of free formaldehyde in carrageenan and processed Eucheuma seaweed using high-performance liquid chromatography.

    PubMed

    Hornshøj, Bettina Høj; Kobbelgaard, Sara; Blakemore, William R; Stapelfeldt, Henrik; Bixler, Harris J; Klinger, Markus

    2015-01-01

    In 2010 the European Commission placed a limit on the amount of free formaldehyde in carrageenan and processed Eucheuma seaweed (PES) of 5 mg kg(-1). Formaldehyde is not used in carrageenan and PES processing and accordingly one would not expect free formaldehyde to be present in carrageenan and PES. However, surprisingly high levels up to 10 mg kg(-1) have been found using the generally accepted AOAC and Hach tests. These findings are, per proposed reaction pathways, likely due to the formation of formaldehyde when sulphated galactose, the backbone of carrageenan, is hydrolysed with the strong acid used in these conventional tests. In order to minimise the risk of false-positives, which may lead to regulatory non-compliance, a new high-performance liquid chromatography (HPLC) method has been developed. Initially, carrageenan or PES is extracted with 2-propanol and subsequently reacted with 2,4-dinitrophenylhydrazine (DNPH) to form the chromophore formaldehyde-DNPH, which is finally quantified by reversed-phase HPLC with ultraviolet light detection at 355 nm. This method has been found to have a limit of detection of 0.05 mg kg(-1) and a limit of quantification of 0.2 mg kg(-1). Recoveries from samples spiked with known quantities of formaldehyde were 95-107%. Using this more specific technique, 20 samples of carrageenan and PES were tested for formaldehyde. Only one sample had a detectable content of formaldehyde (0.40 mg kg(-1)), thus demonstrating that the formaldehyde content of commercial carrageenan and PES products are well below the European Commission maximum limit of 5 mg kg(-1).

  4. Thermal lens-circular dichroism detector for high-performance liquid chromatography.

    PubMed

    Xu, M R; Tran, C D

    1990-11-15

    A novel and ultrasensitive chiral detector for high-performance liquid chromatography has been developed. This detector is based on the measurement of circular dichroism of chiral effluents by the thermal lens effect. In this instrument, the chromatographic effluent was sequentially excited by left circularly polarized laser light (LCPL) and right circularly polarized laser light (RCPL); both of these excitation beams were derived from the same argon ion laser whose linearly polarized output was transformed into circularly polarized light by means of a Pockels cell. The heat generated as a consequence of the sample absorption of the LCPL and RCPL was measured by the probe laser beam collinearly overlapping with the two excitation beams. A lock-in amplifier was used to measure the thermal lens-circular dichroism (TL-CD) signal which corresponds to the difference in the thermal lens signals produced by the LCPL and RCPL excitation beams. In addition to its high sensitivity, the advantages of this TL-CD chiral detector include its ability to provide, directly and in real time, information on the chirality (i.e., circular dichroism) and optical purity of chiral samples. A detection limit of 7.2 ng was achieved for (-)-tris(ethylenediamine)cobalt(III) (k' = 0.45) as well as for the (+)-tris(ethylenediamine)cobalt(III) (k' = 1.40) when these two enantiomers were chromatographically separated from the corresponding racemic mixture through the use of bis(mu-d-tartrato)diantiomonate(III) ion pair reversed-phase chromatography. This limit of detection was found by using a 10-microL flow cell and having 5-mm path length and 6-mW excitation laser beam (lambda = 514.5 nm) modulated at 2 Hz.

  5. High-Performance Liquid-Chromatographic Analysis of Plasma Iohexol Concentrations.

    PubMed

    Schwertner, Harvey A; Weld, Kyle J

    2015-10-01

    In this study, a high-performance liquid-chromatographic (HPLC) method using photodiode array detection and isocratic conditions was developed for the analysis of plasma iohexol concentrations. Plasma proteins were precipitated with 1:1 volume of plasma and acetonitrile-ethanol-water (60:38.4:1.6, v/v/v). Iohexol concentrations in the supernatant phase were analyzed on a Waters Symmetry C-18 reversed-phase column under isocratic conditions at 245 nm. The extraction recoveries of iohexol from plasma were >95% and the plasma iohexol calibration curves were linear (R(2) ≥ 0.9998) from 10 to 1500 µg/mL. The within-day coefficients of variation (CVs) at plasma iohexol concentrations of 100, 375, 750 and 1500 µg/mL were 5.1, 3.5, 1.3 and 2.5%, respectively; the between-day CVs at 100, 375, 750 and 1500 µg/mL were 8.6, 4.2, 4.0 and 3.7%, respectively. The day-to-day accuracies of the method at plasma iohexol concentrations of 50, 100, 375, 750 and 1500 µg/mL were 89.0, 99.4, 108.4, 103.6 and 101.2%, respectively (n = 5). The lower limit of plasma iohexol quantitation was 10 µg/mL and no interferences >9 µg/mL were found in over 75 pre-dose porcine plasma samples. The applicability of the method was demonstrated by determining the glomerular filtration rates of iohexol in the porcine (Sus scrofa) model.

  6. Chromatographic behavior of small organic compounds in low-temperature high-performance liquid chromatography using liquid carbon dioxide as the mobile phase.

    PubMed

    Motono, Tomohiro; Nagai, Takashi; Kitagawa, Shinya; Ohtani, Hajime

    2015-07-01

    Low-temperature high-performance liquid chromatography, in which a loop injector, column, and detection cell were refrigerated at -35ºC, using liquid carbon dioxide as the mobile phase was developed. Small organic compounds (polyaromatic hydrocarbons, alkylbenzenes, and quinones) were separated by low-temperature high-performance liquid chromatography at temperatures from -35 to -5ºC. The combination of liquid carbon dioxide mobile phase with an octadecyl-silica (C18 ) column provided reversed phase mode separation, and a bare silica-gel column resulted in normal phase mode separation. In both the cases, nonlinear behavior at approximately -15ºC was found in the relationship between the temperature and the retention factors of the analytes (van't Hoff plots). In contrast to general trends in high-performance liquid chromatography, the decrease in temperature enhanced the separation efficiency of both the columns.

  7. Quantification of Influenza Neuraminidase Activity by Ultra-High Performance Liquid Chromatography and Isotope Dilution Mass Spectrometry.

    PubMed

    Solano, Maria I; Woolfitt, Adrian R; Williams, Tracie L; Pierce, Carrie L; Gubareva, Larisa V; Mishin, Vasiliy; Barr, John R

    2017-03-07

    Mounting evidence suggests that neuraminidase's functionality extends beyond its classical role in influenza virus infection and that antineuraminidase antibodies offer protective immunity. Therefore, a renewed interest in the development of neuraminidase (NA)-specific methods to characterize the glycoprotein and evaluate potential advantages for NA standardization in influenza vaccines has emerged. NA displays sialidase activity by cleaving off the terminal N-acetylneuraminic acid on α-2,3 or α-2,6 sialic acid containing receptors of host cells. The type and distribution of these sialic acid containing receptors is considered to be an important factor in transmission efficiency of influenza viruses between and among host species. Changes in hemagglutinin (HA) binding and NA specificity in reassortant viruses may be related to the emergence of new and potentially dangerous strains of influenza. Current methods to investigate neuraminidase activity use small derivatized sugars that are poor models for natural glycoprotein receptors and do not provide information on the linkage specificity. Here, a novel approach for rapid and accurate quantification of influenza neuraminidase activity is achieved utilizing ultra-high performance liquid chromatography (UPLC) and isotope dilution mass spectrometry (IDMS). Direct LC-MS/MS quantification of NA-released sialic acid provides precise measurement of influenza neuraminidase activity over a range of substrates. The method provides exceptional sensitivity and specificity with a limit of detection of 0.38 μM for sialic acid and the capacity to obtain accurate measurements of specific enzyme activity preference toward α-2,3-sialyllactose linkages, α-2,6-sialyllactose linkages, or whole glycosylated proteins such as fetuin.

  8. Incorporation of ionic liquid into porous polymer monoliths to enhance the separation of small molecules in reversed-phase high-performance liquid chromatography.

    PubMed

    Wang, Jiafei; Bai, Ligai; Wei, Zhen; Qin, Junxiao; Ma, Yamin; Liu, Haiyan

    2015-06-01

    An ionic liquid was incorporated into the porous polymer monoliths to afford stationary phases with enhanced chromatographic performance for small molecules in reversed-phase high-performance liquid chromatography. The effect of the ionic liquid in the polymerization mixture on the performance of the monoliths was studied in detail. While monoliths without ionic liquid exhibited poor resolution and low efficiency, the addition of ionic liquid to the polymerization mixture provides highly increased resolution and high efficiency. The chromatographic performances of the monoliths were demonstrated by the separations of various small molecules including aromatic hydrocarbons, isomers, and homologues using a binary polar mobile phase. The present column efficiency reached 27 000 plates/m, which showed that the ionic liquid monoliths are alternative stationary phases in the separation of small molecules by high-performance liquid chromatography.

  9. Determination of p-chloronitrobenzene and its metabolites in urine by reversed-phase high-performance liquid chromatography.

    PubMed

    Yoshida, T

    1993-03-05

    A simple, accurate and precise isocratic reversed-phase high-performance liquid chromatographic method (HPLC) using ultraviolet detection was developed for the determination of p-chloronitrobenzene (p-CNB) and seven of its metabolites in rat urine. Analysis was performed before and after hydrolysis of the urine samples with acid to determine both free and conjugate forms of the metabolites. An equal volume of methanol was added to the urine sample and after centrifugation the mixed solution was injected into a high-performance liquid chromatograph. A column packed with 5-microns octadecylsilane (ODS) spherical particles was used at 30 degrees C. The metabolites were divided into three groups, and each group was subjected to three different mobile phase and detection wavelength conditions as follows: water-methanol (60:40, v/v) and 250 nm for p-CNB and 2,4-dichloroaniline; 0.005 M phosphate buffer (pH 3.6)-methanol (76:24, v/v) containing 1.2 mM sodium 1-octanesulphonate and 240 nm for p-chloroaniline, 2-chloro-5-nitrophenol, 2-amino-5-chlorophenol, p-chloroacetanilide and 4-chloro-2-hydroxyacetanilide; and 0.005 M phosphate buffer (pH 6.0)-methanol (80:20, v/v) and 340 nm for N-acetyl-S-(4-nitrophenyl)-L-cysteine. The response was linear at concentrations less than 200.0 micrograms/ml (r = 0.9998) for all metabolites, and the detection limits of each metabolite were between 0.05 and 0.2 micrograms/ml in non-hydrolysed urine. Analysis of the spiked samples demonstrated good accuracy and precision of the method in both intra- and inter-day assays. Storage stabilities of p-CNB and its metabolites at -20 degrees C, 4 degrees C and room temperature were examined for both neutral and acidic urine samples. This method was also shown to be applicable to toxicokinetic study of p-CNB following administration to rats.

  10. Analysis of aromatic amines in water samples by liquid-liquid-liquid microextraction with hollow fibers and high-performance liquid chromatography.

    PubMed

    Zhao, Limian; Zhu, Lingyan; Lee, Hian Kee

    2002-07-19

    Liquid-liquid-liquid microextraction (LLLME) with hollow fibers in high-performance liquid chromatography (HPLC) has been applied as a rapid and sensitive quantitative method for the detection of four aromatic amines (3-nitroaniline, 4-chloroaniline, 4-bromoaniline and 3,4-dichloroaniline) in environmental water samples. The preconcentration procedure was induced by the pH difference inside and outside the hollow fiber. The target compounds were extracted from 4-ml aqueous sample (donor solution, pH approximately 13) through a microfilm of organic solvent (di-n-hexyl ether), immobilized in the pores of a hollow fiber (1.5 cm length x 0.6 mm I.D.), and finally into 4 microl of acid acceptor solution inside the fiber. After a prescribed period of time, the acceptor solution inside the fiber was withdrawn into the microsyringe and directly injected into the HPLC system for analysis. Factors relevant to the extraction procedure were studied. Up to 500-fold enrichment of analytes could be obtained under the optimized conditions (donor solution: 0.1 M sodium hydroxide solution with 20% sodium chloride and 2% acetone; organic phase: di-n-hexyl ether; acceptor solution: 0.5 M hydrochloric acid and 500 mM 18-crown-6 ether; extraction time of 30 min; stirring at 1,000 rev./min). The procedure also served as a sample clean-up step. The influence of humic acid on the extraction efficiency was also investigated, and more than 85% relative recoveries of the analytes at two different concentrations (20 and 100 microg/l) were achieved at various concentration of humic acid. This technique is a low cost, simple and fast approach to the analysis of polar compounds in aqueous samples.

  11. Rapid determination of phthalate esters in alcoholic beverages by conventional ionic liquid dispersive liquid-liquid microextraction coupled with high performance liquid chromatography.

    PubMed

    Fan, Yingying; Liu, Shuhui; Xie, Qilong

    2014-02-01

    A very simple, fast and environmentally friendly sample extraction method was proposed for the analysis of phthalate esters (PAEs, di-isobutyl phthalate (DIBP), dibutylphthalate (DBP), butylbenzylphthalate (BBP) and bis(2-ethylhexyl)phthalate (DEHP)) in alcoholic beverages by using conventional ionic liquid dispersive liquid-liquid microextraction. The samples were extracted by 160 μL 1-octyl-3-methylimidazolium hexafluorophosphate in the presence of appropriate amount of ethanol and 10% (w/v) sodium chloride solution; the enriched analytes in sedimented phases were analyzed by high performance liquid chromatography-diode array detector (HPLC-DAD). Under the optimum conditions, a satisfactory linearity (in the range of 0.02-1 μg mL(-1) for white spirits and 0.01-0.5 μg mL(-1) for red wines with the correlation coefficients (r) varying from 0.9983 to 1), acceptable recovery rates (88.5-103.5% for white spirits and 91.6-104.6% for red wines), good repeatability (RSD ≤ 8.0%) and low detection limits (3.1-4.2 ng mL(-1) for white spirits and 1.5-2.2 ng mL(-1) for red wines) were obtained. The developed method was successfully applied for the determination of the four PAEs in 30 white spirits and 11 red wines collected locally, and the DBP content in 63% (19:30) white spirits exceeded the specific migration limit of 0.3 mg kg(-1) established by international regulation.

  12. Ionic liquid-based dispersive liquid-liquid microextraction followed high-performance liquid chromatography for the determination of organophosphorus pesticides in water sample.

    PubMed

    He, Lijun; Luo, Xianli; Xie, Hongxue; Wang, Chunjian; Jiang, Xiuming; Lu, Kui

    2009-11-23

    Using 1-octyl-3-methylimidazolium hexafluorophosphate ([C(8)MIM][PF(6)]) ionic liquid as extraction solvent, organophosphorus pesticides (OPPs) (parathion, phoxim, phorate and chlorpyifos) in water were determined by dispersive liquid-liquid microextraction (DLLME) combined with high-performance liquid chromatography (HPLC). The extraction procedure was induced by the formation of cloudy solution, which was composed of fine drops of [C(8)MIM][PF(6)] dispersed entirely into sample solution with the help of disperser solvent (methanol). Parameters including extraction solvent and its volume, disperser solvent and its volume, extraction time, centrifugal time, salt addition, extraction temperature and sample pH were investigated and optimized. Under the optimized conditions, up to 200-fold enrichment factor of analytes and acceptable extraction recovery (>70%) were obtained. The calibration curves were linear in the concentration range of 10.5-1045.0 microg L(-1) for parathion, 10.2-1020.0 microg L(-1) for phoxim, 54.5-1089.0 microg L(-1) for phorate and 27.2-1089.0 microg L(-1) for chlorpyifos, respectively. The limits of detection calculated at a signal-to-noise ratio of 3 were in the range of 0.1-5.0 microg L(-1). The relative standard deviations for seven replicate experiments at 200 microg L(-1) concentration level were less than 4.7%. The proposed method was applied to the analysis of four different sources water samples (tap, well, rain and Yellow River water) and the relative recoveries of spiked water samples are 99.9-115.4%, 101.8-113.7% and 87.3-117.6% at three different concentration levels of 75, 200 and 1000 microg L(-1), respectively.

  13. Comparison of ultra-high performance supercritical fluid chromatography and ultra-high performance liquid chromatography for the separation of spirostanol saponins.

    PubMed

    Zhu, Ling-Ling; Zhao, Yang; Xu, Yong-Wei; Sun, Qing-Long; Sun, Xin-Guang; Kang, Li-Ping; Yan, Ren-Yi; Zhang, Jie; Liu, Chao; Ma, Bai-Ping

    2016-02-20

    Spirostanol saponins are important active components of some herb medicines, and their isolation and purification are crucial for the research and development of traditional Chinese medicines. We aimed to compare the separation of spirostanol saponins by ultra-high performance supercritical fluid chromatography (UHPSFC) and ultra-high performance liquid chromatography (UHPLC). Four groups of spirostanol saponins were separated respectively by UHPSFC and UHPLC. After optimization, UHPSFC was performed with a HSS C18 SB column or a Diol column and with methanol as the co-solvent. A BEH C18 column and mobile phase containing water (with 0.1% formic acid) and acetonitrile were used in UHPLC. We found that UHPSFC could be performed automatically and quickly. It is effective in separating the spirostanol saponins which share the same aglycone and vary in sugar chains, and is very sensitive to the number and the position of hydroxyl groups in aglycones. However, the resolution of spirostanol saponins with different aglycones and the same sugar moiety by UHPSFC was not ideal and could be resolved by UHPLC instead. UHPLC is good at differentiating the variation in aglycones, and is influenced by double bonds in aglycones. Therefore, UHPLC and UHPSFC are complementary in separating spirostanol saponins. Considering the naturally produced spirostanol saponins in herb medicines are different both in aglycones and in sugar chains, a better separation can be achieved by combination of UHPLC and UHPSFC. UHPSFC is a powerful technique for improving the resolution when UHPLC cannot resolve a mixture of spirostanol saponins and vice versa.

  14. High-Performance Liquid Chromatographic and High-Performance Thin-Layer Chromatographic Method for the Quantitative Estimation of Dolutegravir Sodium in Bulk Drug and Pharmaceutical Dosage Form.

    PubMed

    Bhavar, Girija B; Pekamwar, Sanjay S; Aher, Kiran B; Thorat, Ravindra S; Chaudhari, Sanjay R

    2016-01-01

    Simple, sensitive, precise, and specific high-performance liquid chromategraphic (HPLC) and high-performance thin-layer chromatographic (HPTLC) methods for the determination of dolutegravir sodium in bulk drug and pharmaceutical dosage form were developed and validated. In the HPLC method, analysis of the drug was carried out on the ODS C18 column (150 × 4.6 mm, 5 μm particle size) using a mixture of acetonitrile: water (pH 7.5) in the ratio of 80:20 v/v as the mobile phase at the flow rate 1 mL/min at 260 nm. This method was found to be linear in the concentration range of 5-35 μg/mL. The peak for dolutegravir sodium was observed at 3.0 ± 0.1 minutes. In the HPTLC method, analysis was performed on aluminum-backed plates pre-coated with silica gel G60 F254 using methanol: chloroform: formic acid in the proportion of 8:2:0.5 v/v/v as the mobile phase. This solvent system was found to give compact spots for dolutegravir sodium with the Rf value 0.77 ± 0.01. Densitometric analysis of dolutegravir sodium was carried out in the absorbance mode at 265 nm. Linear regression analysis showed good linearity with respect to peak area in the concentration range of 200-900 ng/spot. The methods were validated for precision, limit of detection (LOD), limit of quantitation (LOQ), accuracy, and specificity. Statistical analysis showed that both of the methods are repeatable and specific for the estimation of the said drug. The methods can be used for routine quality control analysis of dolutegravir sodium.

  15. Rapid quantitative analysis of individual anthocyanin content based on high-performance liquid chromatography with diode array detection with the pH differential method.

    PubMed

    Wang, Huayin

    2014-09-01

    A new quantitative technique for the simultaneous quantification of the individual anthocyanins based on the pH differential method and high-performance liquid chromatography with diode array detection is proposed in this paper. The six individual anthocyanins (cyanidin 3-glucoside, cyanidin 3-rutinoside, petunidin 3-glucoside, petunidin 3-rutinoside, and malvidin 3-rutinoside) from mulberry (Morus rubra) and Liriope platyphylla were used for demonstration and validation. The elution of anthocyanins was performed using a C18 column with stepwise gradient elution and individual anthocyanins were identified by high-performance liquid chromatography with tandem mass spectrometry. Based on the pH differential method, the high-performance liquid chromatography peak areas of maximum and reference absorption wavelengths of anthocyanin extracts were conducted to quantify individual anthocyanins. The calibration curves for these anthocyanins were linear within the range of 10-5500 mg/L. The correlation coefficients (r(2)) all exceeded 0.9972, and the limits of detection were in the range of 1-4 mg/L at a signal-to-noise ratio ≥5 for these anthocyanins. The proposed quantitative analysis was reproducible with good accuracy of all individual anthocyanins ranging from 96.3 to 104.2% and relative recoveries were in the range 98.4-103.2%. The proposed technique is performed without anthocyanin standards and is a simple, rapid, accurate, and economical method to determine individual anthocyanin contents.

  16. Fast and simultaneous determination of 12 polyphenols in apple peel and pulp by using chemometrics-assisted high-performance liquid chromatography with diode array detection.

    PubMed

    Wang, Tong; Wu, Hai-Long; Xie, Li-Xia; Zhu, Li; Liu, Zhi; Sun, Xiao-Dong; Xiao, Rong; Yu, Ru-Qin

    2017-02-20

    In this work, a smart chemometrics-enhanced strategy, high-performance liquid chromatography, and diode array detection coupled with second-order calibration method based on alternating trilinear decomposition algorithm was proposed to simultaneously quantify 12 polyphenols in different kinds of apple peel and pulp samples. The proposed strategy proved to be a powerful tool to solve the problems of coelution, unknown interferences, and chromatographic shifts in the process of high-performance liquid chromatography analysis, making it possible for the determination of 12 polyphenols in complex apple matrices within 10 min under simple conditions of elution. The average recoveries with standard deviations, and figures of merit including sensitivity, selectivity, limit of detection, and limit of quantitation were calculated to validate the accuracy of the proposed method. Compared to the quantitative analysis results from the classic high-performance liquid chromatography method, the statistical and graphical analysis showed that our proposed strategy obtained more reliable results. All results indicated that our proposed method used in the quantitative analysis of apple polyphenols was an accurate, fast, universal, simple, and green one, and it was expected to be developed as an attractive alternative method for simultaneous determination of multitargeted analytes in complex matrices.

  17. Comparison of ultra-high performance supercritical fluid chromatography and ultra-high performance liquid chromatography for the analysis of pharmaceutical compounds.

    PubMed

    Grand-Guillaume Perrenoud, Alexandre; Veuthey, Jean-Luc; Guillarme, Davy

    2012-11-30

    Currently, columns packed with sub-2 μm particles are widely employed in liquid chromatography but are scarcely used in supercritical fluid chromatography. The goal of the present study was to compare the performance, possibilities and limitations of both ultra-high performance liquid chromatography (UHPLC) and ultra-high performance supercritical fluid chromatography (UHPSFC) using columns packed with sub-2 μm particles. For this purpose, a kinetic evaluation was first performed, and van Deemter curves and pressure plots were constructed and compared for columns packed with hybrid silica stationary phases composed of 1.7 and 3.5 μm particles. As expected, the kinetic performance of the UHPSFC method was significantly better than that of the UHPLC. Indeed, the h(min) values were in the same range with both strategies and were between 2.2 and 2.8, but u(opt) was increased by a factor of >4 in UHPSFC conditions. Another obvious advantage of UHPSFC over UHPLC is related to the generated backpressure, which is significantly lower in the presence of a supercritical or subcritical fluid. However, the upper pressure limit of the UHPSFC system was only ∼400 bar vs. ∼1000 bar in the UHPLC system, which prevents the use of highly organic mobile phases at high flow rates in UHPSFC. Second, the impact of reducing the particle size (from 3.5 to 1.7 μm) was evaluated in both UHPLC and UHPSFC conditions. The effect of frictional heating on the selectivity was demonstrated in UHPLC and that of fluid density or decompression cooling was highlighted in UHPSFC. However, in both cases, a change in selectivity was observed for only a limited number of compounds. Third, various types of column chemistries packed with 1.7 μm particles were evaluated in both UHPLC and UHPSFC conditions using a model mixture of acidic, neutral and basic compounds. It has been shown that more drastic changes in selectivity were obtained using UHPSFC columns compared to those obtained by changing

  18. Can numerical simulations accurately predict hydrodynamic instabilities in liquid films?

    NASA Astrophysics Data System (ADS)

    Denner, Fabian; Charogiannis, Alexandros; Pradas, Marc; van Wachem, Berend G. M.; Markides, Christos N.; Kalliadasis, Serafim

    2014-11-01

    Understanding the dynamics of hydrodynamic instabilities in liquid film flows is an active field of research in fluid dynamics and non-linear science in general. Numerical simulations offer a powerful tool to study hydrodynamic instabilities in film flows and can provide deep insights into the underlying physical phenomena. However, the direct comparison of numerical results and experimental results is often hampered by several reasons. For instance, in numerical simulations the interface representation is problematic and the governing equations and boundary conditions may be oversimplified, whereas in experiments it is often difficult to extract accurate information on the fluid and its behavior, e.g. determine the fluid properties when the liquid contains particles for PIV measurements. In this contribution we present the latest results of our on-going, extensive study on hydrodynamic instabilities in liquid film flows, which includes direct numerical simulations, low-dimensional modelling as well as experiments. The major focus is on wave regimes, wave height and wave celerity as a function of Reynolds number and forcing frequency of a falling liquid film. Specific attention is paid to the differences in numerical and experimental results and the reasons for these differences. The authors are grateful to the EPSRC for their financial support (Grant EP/K008595/1).

  19. High-performance liquid chromatography separation of unsaturated organic compounds by a monolithic silica column embedded with silver nanoparticles.

    PubMed

    Zhu, Yang; Morisato, Kei; Hasegawa, George; Moitra, Nirmalya; Kiyomura, Tsutomu; Kurata, Hiroki; Kanamori, Kazuyoshi; Nakanishi, Kazuki

    2015-08-01

    The optimization of a porous structure to ensure good separation performances is always a significant issue in high-performance liquid chromatography column design. Recently we reported the homogeneous embedment of Ag nanoparticles in periodic mesoporous silica monolith and the application of such Ag nanoparticles embedded silica monolith for the high-performance liquid chromatography separation of polyaromatic hydrocarbons. However, the separation performance remains to be improved and the retention mechanism as compared with the Ag ion high-performance liquid chromatography technique still needs to be clarified. In this research, Ag nanoparticles were introduced into a macro/mesoporous silica monolith with optimized pore parameters for high-performance liquid chromatography separations. Baseline separation of benzene, naphthalene, anthracene, and pyrene was achieved with the theoretical plate number for analyte naphthalene as 36,000 m(-1). Its separation function was further extended to cis/trans isomers of aromatic compounds where cis/trans stilbenes were chosen as a benchmark. Good separation of cis/trans-stilbene with separation factor as 7 and theoretical plate number as 76,000 m(-1) for cis-stilbene was obtained. The trans isomer, however, is retained more strongly, which contradicts the long- established retention rule of Ag ion chromatography. Such behavior of Ag nanoparticles embedded in a silica column can be attributed to the differences in the molecular geometric configuration of cis/trans stilbenes.

  20. Using reversed phase high performance liquid chromatography to study the complexation of anthocyanins with β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Deineka, V. I.; Lapshova, M. S.; Deineka, L. A.

    2014-06-01

    It is shown by means of reversed phase high performance liquid chromatography (RP HPLC) with mobile phases containing additions of β-cyclodextrin that 5-glucosides of cyanidin and pelargonidin form stronger inclusion complexes than 3-glucosides; this is explained by the steric interference of the glucoside radical.

  1. Study of the metabolism of pyrazinamide using a high-performance liquid chromatographic analysis of urine samples.

    PubMed

    Yamamoto, T; Moriwaki, Y; Takahashi, S; Hada, T; Higashino, K

    1987-02-01

    A reversed-phase high-performance liquid chromatographic method was developed for the simultaneous determination of pyrazinamide and its metabolites in urine. Study of the metabolism of pyrazinamide by this method demonstrated that 5-hydroxypyrazinamide excretion was compatible with pyrazinoic acid excretion and allopurinol decreased in vivo conversion of pyrazinamide to 5-hydroxypyrazinamide and blocked that of pyrazinoic acid to 5-hydroxypyrazinoic acid.

  2. RAPID ANALYSIS OF CYANURIC ACID IN SWIMMING POOL WATERS BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY USING POROUS GRAPHITIC CARBON

    EPA Science Inventory

    An innovative approach is presented for reducing analysis times of cynuric acid in swimming pool waters by high performance liquid chromatography (HPLC). The HPLC method exploits the unique selectivity of porous graphitic carbon (PGC) to fully resolve within 10 minutes cyanuric ...

  3. RAPID ANALYSIS OF CYNANURIC ACID IN SWIMMING POOL WATERS BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY USING POROUS GRAPHITIC CARBON COLUMN

    EPA Science Inventory

    An innovative approach is presented for reducing analysis times of cyanuric acid in swimming pool waters by high performance liquid chromatography (HPLC). The HPLC method exploits the unique selectivity of porous graphitic carbon (PGC) to fully resolve cyanuric acid from other p...

  4. Simultaneous determination of estrogens and progestogens in honey using high performance liquid chromatography-tandem mass spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This work describes the development and validation of a method for the simultaneous determination of 13 estrogens and progestogens in honey by high performance liquid chromatography-tandem mass spectrometry. The target compounds were preconcentrated by solid phase extraction. Pretreatment variables ...

  5. Constructing a LabVIEW-Controlled High-Performance Liquid Chromatography (HPLC) System: An Undergraduate Instrumental Methods Exercise

    ERIC Educational Resources Information Center

    Smith, Eugene T.; Hill, Marc

    2011-01-01

    In this laboratory exercise, students develop a LabVIEW-controlled high-performance liquid chromatography system utilizing a data acquisition device, two pumps, a detector, and fraction collector. The programming experience involves a variety of methods for interface communication, including serial control, analog-to-digital conversion, and…

  6. Simultaneous Determination of Caffeine and Vitamin B6 in Energy Drinks by High-Performance Liquid Chromatography (HPLC)

    ERIC Educational Resources Information Center

    Leacock, Rachel E.; Stankus, John J.; Davis, Julian M.

    2011-01-01

    A high-performance liquid chromatography experiment to determine the concentration of caffeine and vitamin B6 in sports energy drinks has been developed. This laboratory activity, which is appropriate for an upper-level instrumental analysis course, illustrates the standard addition method and simultaneous determination of two species. (Contains 1…

  7. Preparation and Characterization of a Polymeric Monolithic Column for Use in High-Performance Liquid Chromatography (HPLC)

    ERIC Educational Resources Information Center

    Bindis, Michael P.; Bretz, Stacey Lowery; Danielson, Neil D.

    2011-01-01

    The high-performance liquid chromatography (HPLC) experiment, most often done in the undergraduate analytical instrumentation laboratory course, generally illustrates reversed-phase chromatography using a commercial C[subscript]18 silica column. To avoid the expense of periodic column replacement and introduce a choice of columns with different…

  8. Application of polymer based stationary phases in high performance liquid chromatography and capillary high performance liquid chromatography hyphenated to microcoil 1H nuclear magnetic resonance spectroscopy.

    PubMed

    Grynbaum, Marc David; Meyer, Christoph; Putzbach, Karsten; Rehbein, Jens; Albert, Klaus

    2007-07-13

    The increased demand for chromatographic materials that are able to achieve a fast separation of large quantities of structure analogues is a great challenge. It is known that polymer based chromatographic materials have a higher loadability, compared to silica based sorbents. Unfortunately these polymer materials cannot be used under high pressure which is necessary in order to obtain high flow rates, and hence long times are needed to perform a separation. However, by immobilizing a polymer on a mechanically stable porous silica core, this problem can be circumvented and higher flows become feasible on these materials. Especially for capillary liquid chromatography hyphenated with nuclear magnetic resonance a high loadability is of great importance in order to obtain sharp, resolved, and concentrated peaks thus resulting in a good signal to noise ratio in the NMR experiment. Therefore, a highly shape selective chromatographic sorbent was developed by covalently immobilizing a poly(ethylene-co-acrylic) acid copolymer (-CH(2)CH(2)-)(x)[CH(2)CH(CO(2)H)-](y) (x=119, y=2.4) with a mass fraction of acrylic acid of 5% as stationary phase on silica via a spacer molecule (3-glycidoxypropyltrimethoxysilane). First, the loadability of this sorbent compared to C(30) is demonstrated by the HPLC separation of two xanthophyll isomers. Subsequently, it has been successfully employed in the hyphenation of capillary HPLC with microcoil (1)H NMR spectroscopy by separating and identifying a highly concentrated solution of the tocopherol homologues.

  9. ICSH recommendations for assessing automated high-performance liquid chromatography and capillary electrophoresis equipment for the quantitation of HbA2.

    PubMed

    Stephens, A D; Colah, R; Fucharoen, S; Hoyer, J; Keren, D; McFarlane, A; Perrett, D; Wild, B J

    2015-10-01

    Automated high performance liquid chromatography and Capillary electrophoresis are used to quantitate the proportion of Hemoglobin A2 (HbA2 ) in blood samples order to enable screening and diagnosis of carriers of β-thalassemia. Since there is only a very small difference in HbA2 levels between people who are carriers and people who are not carriers such analyses need to be both precise and accurate. This paper examines the different parameters of such equipment and discusses how they should be assessed.

  10. Development and comparison of two dispersive liquid-liquid microextraction techniques coupled to high performance liquid chromatography for the rapid analysis of bisphenol A in edible oils.

    PubMed

    Liu, Shuhui; Xie, Qilong; Chen, Jie; Sun, Janzhi; He, Hui; Zhang, Xiaoke

    2013-06-21

    In this study, two novel sample extraction methods for the analysis of bisphenol A (BPA) in edible oils were developed by using liquid-liquid extraction followed by a dispersive liquid-liquid microextraction (LLE-DLLME) and reversed-phase dispersive liquid-liquid microextraction (RP-DLLME). RP-DLLME showed a superior characteristic over LLE-DLLME and other previously reported procedures because of its easy operation, short extraction time, high sensitivity, low organic solvent consumption and waste generation. The optimized extraction conditions of RP-DLLME for 1.0 g of edible oil diluted in 4 mL of n-hexane were: extractant, 100 μL 0.2 M sodium hydroxide solution (80% methanol, v/v); extraction time, 1 min; centrifugation, 3 min. The determination of BPA was carried out by high performance liquid chromatography coupled with a DAD detector. The method offered excellent linearity over a range of 0.010-0.5 μg g(-1) with a correlation coefficient of r>0.997. Intra-day and inter-day repeatability values expressed as relative standard deviation were 1.9% and 5.9%, respectively. The quantitation limit and detection limit were 6.3 and 2.5 ng g(-1). The target analyte was detected in 5 out of 16 edible oil samples. The recovery rates in real samples ranged from 89.5 to 99.7%.

  11. 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.

  12. High Performance Liquid Chromatography Tandem Mass Spectrometry Assay for the Determination of Cobinamide in Pig Plasma

    PubMed Central

    McCracken, Brent A.; Brittain, Matthew K.

    2015-01-01

    Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been widely utilized for the analysis of compounds in biological matrices due to its selectivity and sensitivity. This study describes the application of an LC-MS/MS-based approach toward the analysis of cobinamide in Yorkshire pig plasma. The selectivity, accuracy, precision, recovery, linearity, range, carryover, sensitivity, matrix effect, interference, stability, reproducibility, and ruggedness of the method were investigated in pig plasma. The accuracy and precision of the method was determined to be within 10% over three different days over a range of concentrations (25–10,000 ng/mL) that spanned more than two orders of magnitude. The lower limit of quantitation (LLOQ) for dicyanocobinamide was determined to be 25 ng/mL in pig plasma. Carryover was acceptable, as the area response of the carryover blanks were ≤15% of the area response of the nearest LLOQ standard for the analyte, while it was nonexistent for the internal standard. Specificity was ensured using six different lots of pig plasma. While the matrix effects of dicyanocobinamide in plasma were enhanced, ginsenoside Rb1 experienced signal suppression under the described conditions. The absolute recovery results for both compounds were consistent, precise, and reproducibly lower than expected at ~60% for dicyanocobinamide and ~22% for ginsenoside Rb1, confirming that a matrix standard curve was required for accurate quantitation. Cobinamide was shown to be very stable in matrix at various storage conditions including room temperature, refrigerated, and frozen at time intervals of 20 hours, 4 days, and 60 days respectively. This method was demonstrated to be sensitive, reproducible, stable, and rugged, and it should be applicable to the analysis of cobinamide in other biological matrices and species. PMID:26540437

  13. High-performance liquid chromatography-mass spectrometry analysis of plant metabolites in brassicaceae.

    PubMed

    De Vos, Ric C H; Schipper, Bert; Hall, Robert D

    2012-01-01

    The Brassicaceae family comprises a variety of plant species that are of high economic importance as -vegetables or industrial crops. This includes crops such as Brassica rapa (turnip, Bok Choi), B. oleracea (cabbages, broccoli, cauliflower, etc.), and B. napus (oil seed rape), and also includes the famous genetic model of plant research, Arabidopsis thaliana (thale cress). Brassicaceae plants contain a large variety of interesting secondary metabolites, including glucosinolates, hydroxycinnamic acids, and flavonoids. These metabolites are also of particular importance due to their proposed positive effects on human health. Next to these well-known groups of phytochemicals, many more metabolites are of course also present in crude extracts prepared from Brassica and Arabidopsis plant material.High-pressure liquid chromatography coupled to mass spectrometry (HPLC-MS), especially if combined with a high mass resolution instrument such as a QTOF MS, is a powerful approach to separate, detect, and annotate metabolites present in crude aqueous-alcohol plant extracts. Using an essentially unbiased procedure that takes into account all metabolite mass signals from the raw data files, detailed information on the relative abundance of hundreds of both known and, as yet, unknown semipolar metabolites can be obtained. These comprehensive metabolomics data can then be used to, for instance, identify genetic markers regulating metabolic composition, determine effects of (a)biotic stress or specific growth conditions, or establish metabolite changes occurring upon food processing or storage.This chapter describes in detail a procedure for preparing crude extracts and performing comprehensive HPLC-QTOF MS-based profiling of semi-polar metabolites in Brassicaceae plant material. Compounds present in the extract can be (partially or completely) annotated based on their accurate mass, their MS/MS fragments and on other specific chemical characteristics such as retention time and UV

  14. Low Density Solvent-Based Dispersive Liquid-Liquid Microextraction for the Determination of Synthetic Antioxidants in Beverages by High-Performance Liquid Chromatography

    PubMed Central

    Çabuk, Hasan; Köktürk, Mustafa

    2013-01-01

    A simple and efficient method was established for the determination of synthetic antioxidants in beverages by using dispersive liquid-liquid microextraction combined with high-performance liquid chromatography with ultraviolet detection. Butylated hydroxy toluene, butylated hydroxy anisole, and tert-butylhydroquinone were the antioxidants evaluated. Experimental parameters including extraction solvent, dispersive solvent, pH of sample solution, salt concentration, and extraction time were optimized. Under optimal conditions, the extraction recoveries ranged from 53 to 96%. Good linearity was observed by the square of correlation coefficients ranging from 0.9975 to 0.9997. The relative standard deviations ranged from 1.0 to 5.2% for all of the analytes. Limits of detection ranged from 0.85 to 2.73 ng mL−1. The method was successfully applied for determination of synthetic antioxidants in undiluted beverage samples with satisfactory recoveries. PMID:23853535

  15. Determination of three estrogens and bisphenol A by functional ionic liquid dispersive liquid-phase microextraction coupled with ultra-high performance liquid chromatography and ultraviolet detection.

    PubMed

    Jiang, Yuehuang; Tang, Tingting; Cao, Zhen; Shi, Guoyue; Zhou, Tianshu

    2015-06-01

    A hydroxyl-functionalized ionic liquid, 1-hydroxyethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, was employed in an improved dispersive liquid-phase microextraction method coupled with ultra high performance liquid chromatography for the enrichment and determination of three estrogens and bisphenol A in environmental water samples. The introduced hydroxyl group acted as the H-bond acceptor that dispersed the ionic liquid effectively in the aqueous phase without dispersive solvent or external force. Fourier transform infrared spectroscopy indicated that the hydroxyl group of the cation of the ionic liquid enhanced the combination of extractant and analytes through the formation of hydrogen bonds. The improvement of the extraction efficiency compared with that with the use of alkyl ionic liquid was proved by a comparison study. The main parameters including volume of extractant, temperature, pH, and extraction time were investigated. The calibration curves were linear in the range of 5.0-1000 μg/L for estrone, estradiol, and bisphenol A, and 10.0-1000 μg/L for estriol. The detection limits were in the range of 1.7-3.4 μg/L. The extraction efficiency was evaluated by enrichment factor that were between 85 and 129. The proposed method was proved to be simple, low cost, and environmentally friendly for the determination of the four endocrine disruptors in environmental water samples.

  16. Relationship between High-Performance Liquid Chromatography Fingerprints and Uric Acid-Lowering Activities of Cichorium intybus L.

    PubMed

    Zhu, Chun-Sheng; Zhang, Bing; Lin, Zhi-Jian; Wang, Xue-Jie; Zhou, Yue; Sun, Xiao-Xia; Xiao, Ming-Liang

    2015-05-22

    This study aimed to explore the spectrum-effect relationships between high-performance liquid chromatography fingerprints and the uric acid-lowering activities of chicory. Chemical fingerprints of chicory samples from ten different sources were determined by high-performance liquid chromatography, and then investigated by similarity analysis and hierarchical clustering analysis. Pharmacodynamics experiments were conducted in animals to obtain the uric acid-lowering activity information of each chicory sample. The spectrum-effect relationships between chemical fingerprints and the uric acid-lowering activities of chicory were established by canonical correlation analysis. The structures of potential effective peaks were identified by liquid chromatography with tandem mass spectrometry. The results showed that a close correlation existed between the spectrum and effect of chicory. Aesculin, chlorogenic acid, chicoric acid, isochlorogenic acid A/B/C and 13,14-seco-stigma5(6),14(15)-diene-3α-ol might be the main effective constituents. This work provides a general model of the combination of high-performance liquid chromatography and uric acid-lowering activities to study the spectrum-effect relationships of chicory, which can be used to discover the principle components responsible for the bioactivity.

  17. [Simultaneous determination of eight derivatives of propranolol in cornea perfusate in vitro by high performance liquid chromatography].

    PubMed

    Wu, Haitao; Chen, Chuanbing; Wang, Ningsheng; Mi, Suiqing; Liao, Nanying

    2012-11-01

    A high performance liquid chromatographic method was developed for the simultaneous determination of eight derivatives of propranolol. Cassette dosing method was used in the epithelium side of cornea in vitro to get the effect of penetrant, and the perfusate was collected in the side of endothelium. The protein in the sample was precipitated and discarded by high speed centrifugation before injection. An Agilent Zorbax Extend column (150 mm x 3 mm, 5 microm) was used at 30 degrees C. The mobile phase system contained acetonitrile and 0.03% (v/v) phosphoric acid aqueous solution and the percentage of acetonitrile changed between 3% and 20% (v/v) in a linear gradient elution. The samples were detected by an ultraviolet (UV) detector at 205 nm. The results showed that the eight derivatives of propranolol were completely separated and determined in 31 min. The correlation coefficients were above 0.9970 and good linear relationships were obtained in the range of 0.2 (0.1)-40.0 micromol/L. Under the optimized conditions, the recoveries of the derivatives were in the range of 91.12%-105.73%. The intra-day relative standard deviations (RSDs) were in the range of 1.00%-11.63%, and the inter-day RSDs were in the range of 1.18%-18.58%. The sample showed stability under room temperature, freeze and three cycles of freeze-thaw conditions. This method is fast and accurate for the quantitative analysis of the derivatives of propranolol in transmembrane absorption such as cornea perfusion in vitro or transwell cell system.

  18. Collection and determination of nucleotide metabolites in neonatal and adult saliva by high performance liquid chromatography with tandem mass spectrometry.

    PubMed

    Al-Shehri, S; Henman, M; Charles, B G; Cowley, D; Shaw, P N; Liley, H; Tomarchio, A; Punyadeera, C; Duley, J A

    2013-07-15

    Saliva contains a number of biochemical components which may be useful for diagnosis/monitoring of metabolic disorders, and as markers of cancer or heart disease. Saliva collection is attractive as a non-invasive sampling method for infants and elderly patients. We present a method suitable for saliva collection from neonates. We have applied this technique for the determination of salivary nucleotide metabolites. Saliva was collected from 10 healthy neonates using washed cotton swabs, and directly from 10 adults. Two methods for saliva extraction from oral swabs were evaluated. The analytes were then separated using high performance liquid chromatography (HPLC) with tandem mass spectrometry (MS/MS). The limits of detection for 14 purine/pyrimidine metabolites were variable, ranging from 0.01 to 1.0μM. Recovery of hydrophobic purine/pyrimidine metabolites from cotton tips was consistently high using water/acetonitrile extraction (92.7-111%) compared with water extraction alone. The concentrations of these metabolites were significantly higher in neonatal saliva than in adults. Preliminary ranges for nucleotide metabolites in neonatal and adult saliva are reported. Hypoxanthine and xanthine were grossly raised in neonates (49.3±25.4; 30.9±19.5μM respectively) compared to adults (4.3±3.3; 4.6±4.5μM); nucleosides were also markedly raised in neonates. This study focuses on three essential details: contamination of oral swabs during manufacturing and how to overcome this; weighing swabs to accurately measure small saliva volumes; and methods for extracting saliva metabolites of interest from cotton swabs. A method is described for determining nucleotide metabolites using HPLC with photodiode array or MS/MS. The advantages of utilising saliva are highlighted. Nucleotide metabolites were not simply in equilibrium with plasma, but may be actively secreted into saliva, and this process is more active in neonates than adults.

  19. [Determination of 14 sulfonamide residues in shrimps by high performance liquid chromatography coupled with post-column derivatization].

    PubMed

    Huang, Dongmei; Huang, Xuanyun; Gu, Runrun; Hui, Yunhua; Tian, Liangliang; Feng, Bing; Zhang, Xuan; Yu, Huijuan

    2014-08-01

    A method for the determination of 14 sulfonamide residues in shrimps by high performance liquid chromatography coupled with post-column derivatization was established. The sulfonamide residues were extracted with ethyl acetate after adding sulfapyridine as internal standard. The extracts were vacuum-concentrated and reverse-extracted by 2 mol/L hydrochloric acid solution for clean-up, and then the hydrochloric acid solution was defatted with n-hex- ane. The solution after filtration was blended with a mixed solution of methanol, acetonitrile and 3. 5 mol/L sodium acetate solution (5:5:20, v/v/v). The sulfonamides were separated on a C18 column by RP-HPLC and on-line derivatized with a fluorescamine and detected with a fluorescence detector. The standard addition method was used for quantitative analysis. The parameters of post-column derivatization system, such as concentration of fluorescamine solution, velocity of reagent solution and reaction temperature, were optimized. The calibration curves of the method showed good linearity in the range of 5 - 200 μg/L. The limits of quantification (LOQ, S/N= 10) were 1.0-5.0 μg/kg for the 14 sulfonamides. The recoveries were 77.8%- 103. 6% in the spiked range of 1. 0-100.0 μg/kg in shrimps with the relative standard deviations of 2.9%-9.1% (n= 6). The results indicated that the method is sensitive, efficient and more accurate. It is suitable for the simultaneous determination of the 14 sulfonamide residues in shrimps.

  20. Isolation and identification of the metolachlor stereoisomers using high-performance liquid chromatography, polarimetric measurements, and enantioselective gas chromatography.

    PubMed

    Müller, M D; Poiger, T; Buser, H

    2001-01-01

    Because of the presence of two chiral elements (an asymmetrically substituted carbon and a chiral axis), the herbicide metolachlor consists of four stereoisomers stable at ambient temperature with aSS-, aRS-, aSR-, and aRR-configurations (aSS, the isomer with aS,1'S-configuration, etc.). Metolachlor, initially introduced into the market as the racemic product containing all four stereoisomers, is currently being replaced worldwide by S-metolachlor, the product enantiomerically enriched with the herbicidally active 1'S-isomers (aSS, aRS). The isomer-specific analysis of metolachlor requires not only enantioselective ("chiral") analytical techniques but also suitable reference compounds. In this study, two of the four metolachlor isomers were isolated from rac-metolachlor in enantio- (ee > 98%) and diastereomerically pure forms by a combination of achiral and chiral high-performance liquid chromatography (HPLC). The two isomers were identified as the aSS- and the aRR-isomers by polarimetric measurements, in reference to previous data. The two isomers were then thermally equilibrated to 1:1 mixtures of the aSS/aRS and aRR/aSR diastereomers, respectively, so that analytical data of all four metolachlor isomers became available; they were then used to identify these isomers in technical products by chiral high-resolution gas chromatography (HRGC). The kinetics of the thermally induced interconversion of the atropisomers was studied and the consequences, such as for GC analysis, are discussed. A comparison of on-column and split/splitless injection indicated that the latter technique results in significant isomerization prior to separation and, therefore, cannot be used for accurate isomer analysis.

  1. Development and application of methods for determination of residual monomer in dental acrylic resins using high performance liquid chromatography.

    PubMed

    Urban, V M; Cass, Q B; Oliveira, R V; Giampaolo, E T; Machado, A L

    2006-04-01

    Two high-performance liquid chromatographic methods for determination of residual monomer in dental acrylic resins are described. Monomers were detected by their UV absorbance at 230 nm, on a Nucleosil C18 (5 microm particle size, 100 A pore size, 15 x 0.46 cm i.d.) column. The separation was performed using acetonitrile-water (55:45 v/v) containing 0.01% triethylamine (TEA) for methyl methacrylate and butyl methacrylate, and acetonitrile-water (60:40 v/v) containing 0.01% TEA for isobutyl methacrylate and 1,6-hexanediol dimethacrylate as mobile phases, at a flow rate of 0.8 mL/min. Good linear relationships were obtained in the concentration range 5.0-80.0 microg/mL for methyl methacrylate, 10.0-160.0 microg/mL for butyl methacrylate, 50.0-500.0 microg/mL for isobutyl methacrylate and 2.5-180.0 microg/mL for 1,6-hexanediol dimethacrylate. Adequate assay for intra- and inter-day precision and accuracy was observed during the validation process. An extraction procedure to remove residual monomer from the acrylic resins was also established. Residual monomer was obtained from broken specimens of acrylic disks using methanol as extraction solvent for 2 h in an ice-bath. The developed methods and the extraction procedure were applied to dental acrylic resins, tested with or without post-polymerization treatments, and proved to be accurate and precise for the determination of residual monomer content of the materials evaluated.

  2. Validation of high-performance liquid chromatography-boron-doped diamond detection for assessing hepatic glutathione redox status.

    PubMed

    Park, Hea Jin; Mah, Eunice; Bruno, Richard S

    2010-12-15

    Glutathione redox status is a commonly used oxidative stress biomarker. High-performance liquid chromatography-ultraviolet (HPLC-UV) and HPLC-electrochemical detection (HPLC-ECD) have been used to assess glutathione status but have potential limitations due to challenging sample preparation procedures or electrochemical signal degradation. Thus, this study aimed to validate an HPLC-ECD approach using boron-doped diamond (BDD), a novel electrode material exhibiting excellent electrochemical stability. Liver homogenates from obese (ob/ob) mice and their lean littermates (n=4/genotype) as well as from rats fed high- or low-fat diets (n=8/treatment) were analyzed in parallel by HPLC-BDD and -UV. HPLC-BDD responses for reduced glutathione (GSH) and oxidized glutathione (GSSG) were linear over more than four orders of magnitude at 1475 mV, the optimal oxidation potential. Within- and between-day precision values of GSH, GSSG, and GSH/GSSG were 2.1% to 7.9%, and accuracy values of GSH and GSSG were 96% and 105%, respectively. Electrochemical responses were stable up to 48 h of continuous system use. Using HPLC-BDD and -UV, hepatic GSH, GSSG, and GSH/GSSG from mice (r=0.64-0.94) and rats (r=0.79-0.92) were well correlated (P<0.05), and no significant differences in thiol levels were observed between detection methods. Collectively, our findings support HPLC-BDD as a relatively simple, accurate, and validated approach for evaluating hepatic glutathione redox status.

  3. Determination of multiple phytohormones in fruits by high-performance liquid chromatography with fluorescence detection using dispersive liquid-liquid microextraction followed by precolumn fluorescent labeling.

    PubMed

    Li, Guoliang; Lu, Shuaimin; Wu, Hongliang; Chen, Guang; Liu, Shucheng; Kong, Xiaojian; Kong, Weiheng; You, Jinmao

    2015-01-01

    Plant hormone determination in food matrices has attracted more and more attention because of their potential risks to human health. However, analytical methods for the analysis of multiple plant hormones remain poorly investigated. In the present study, a convenient, selective, and ultrasensitive high-performance liquid chromatography method for the simultaneous determination of multiple classes of plant hormones has been developed successfully using dispersive liquid-liquid microextraction followed by precolumn fluorescent labeling. Eight plant hormones in fruits including jasmonic acid, 12-oxo-phytodienoic acid, indole-3-acetic acid, 3-indolybutyric acid, 3-indolepropionic acid, gibberellin A3 , 1-naphthylacetic acid, and 2-naphthaleneacetic acid were analyzed by this method. The conditions employed for dispersive liquid-liquid microextraction were optimized systematically. The linearity for all plant hormones was found to be >0.9993 (R(2) values). This method offered low detection limits of 0.19-0.44 ng/mL (at a signal-to-noise ratio of 3), and method accuracies were in the range of 92.32-103.10%. The proposed method was applied to determine plant hormones in five kinds of food samples, and this method can achieve a short analysis time, low threshold levels of detection, and a high specificity for the analysis of targeted plant hormones present at trace level concentrations in complex matrices.

  4. Rapid determination of some psychotropic drugs in complex matrices by tandem dispersive liquid-liquid microextraction followed by high performance liquid chromatography.

    PubMed

    Asghari, Alireza; Fahimi, Ebrahim; Bazregar, Mohammad; Rajabi, Maryam; Boutorabi, Leila

    2017-03-15

    Simple and rapid determinations of some psychotropic drugs in some pharmaceutical wastewater and human plasma samples were successfully accomplished via the tandem dispersive liquid-liquid microextraction combined with high performance liquid chromatography-ultraviolet detection (TDLLME-HPLC-UV). TDLLME of the three psychotropic drugs clozapine, chlorpromazine, and thioridazine was easily performed through two consecutive dispersive liquid-liquid microextractions. By performing this convenient method, proper sample preconcentrations and clean-ups were achieved in just about 7min. In order to achieve the best extraction efficiency, the effective parameters involved were optimized. The optimal experimental conditions consisted of 100μL of CCl4 (as the extraction organic solvent), and the pH values of 13 and 2 for the donor and acceptor phases, respectively. Under these optimum experimental conditions, the proposed TDLLME-HPLC-UV technique provided a good linearity in the range of 5-3000ngmL(-1) for the three psychotropic drugs with the correlation of determinations (R(2)s) higher than 0.996. The limits of quantification (LOQs) and limits of detection (LODs) obtained were 5.0ngmL(-1) and 1.0-1.5ngmL(-1), respectively. Also the proper enrichment factors (EFs) of 96, 99, and 88 for clozapine, chlorpromazine, and thioridazine, respectively, and good extraction repeatabilities (relative standard deviations below 9.3%, n=5) were obtained.

  5. Preconcentration and determination of ceftazidime in real samples using dispersive liquid-liquid microextraction and high-performance liquid chromatography with the aid of experimental design.

    PubMed

    Razmi, Rasoul; Shahpari, Behrouz; Pourbasheer, Eslam; Boustanifar, Mohammad Hasan; Azari, Zhila; Ebadi, Amin

    2016-11-01

    A rapid and simple method for the extraction and preconcentration of ceftazidime in aqueous samples has been developed using dispersive liquid-liquid microextraction followed by high-performance liquid chromatography analysis. The extraction parameters, such as the volume of extraction solvent and disperser solvent, salt effect, sample volume, centrifuge rate, centrifuge time, extraction time, and temperature in the dispersive liquid-liquid microextraction process, were studied and optimized with the experimental design methods. Firstly, for the preliminary screening of the parameters the taguchi design was used and then, the fractional factorial design was used for significant factors optimization. At the optimum conditions, the calibration curves for ceftazidime indicated good linearity over the range of 0.001-10 μg/mL with correlation coefficients higher than the 0.98, and the limits of detection were 0.13 and 0.17 ng/mL, for water and urine samples, respectively. The proposed method successfully employed to determine ceftazidime in water and urine samples and good agreement between the experimental data and predictive values has been achieved.

  6. Recent advances in ultra-high performance liquid chromatography for the analysis of traditional chinese medicine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Traditional Chinese medicines (TCMs) have been widely used for the prevention and treatment of various diseases for thousands of years in China. Ultra Performance Liquid Chromatography (UHPLC) is a relatively new technique offering new possibilities in liquid chromatography. This paper reviews recen...

  7. Determination of methyldibromoglutaronitrile in cosmetic products by high performance liquid chromatography with electrochemical detection.

    PubMed

    Rooselaar, J; Weyland, J W

    1993-02-01

    Synopsis A method for the determination of methyldibromoglutaronitrile in cosmetic products is described. Reversed phase high performance liquid chromatography and reductive electrochemical detection is employed to provide for improved selectivity and detectability compared to alternative methods. The method detects 0.002% methyldibromoglutaronitrile in cosmetic products and has a linear range from 0.006 up to 0.06%, which can easily be extended to the legally allowed limit of 0.1% by means of a simple dilution step. At a level of 0.03% the coefficient of variation was estimated to be 1.7%. Recoveries measured were between 98 and 100%. The method has been subjected to a ruggedness test, which indicated that it was stable, but slightly sensitive for a decrease in the detection potential. More than 130 cosmetic products have been analysed using the method. In 19 samples methyldibromoglutaronitrile was detected in concentrations varying between 0.002% and 0.030%. Résumé Une méthode a été mise au point pour la détermination du methyldibromoglutaronitrile, un conservateur cosmétique dont l'utilisation est croissante. La méthode utilise la chromatographie liquide à haute performance avec détection électrochimique pour permettre une amélioration de la détection et de la spécificité. Selon une procédure simple, le methyldibromoglutaronitrile est séparé sur une colonne 100 RP8 (lichosphere MERCK) avec une phase mobile constituee d'eau et d'acétone (60/40 v/v) avec un ajout de sulfate de sodium et du chlorure de sodium pour obtenir des concentrations de 0.02 M et 0.002 M respectivement. Une électrode en or a été utilisée pour la détection avec un potentiel de fonctionnement de -0.6 V réductif. Une détection par pulsation a été nécessaire pour obtenir une réponse stable. Le détecteur a été programmé pourgarder l'électrode pour 10 ms à 1 V, 10 ms à-1 V (réductif) et à-0.6 V pour 100 ms, ce potentiel a été utilisé comme mesure. Des

  8. High performance discharges in the Lithium Tokamak eXperiment with liquid lithium walls

    SciTech Connect

    Schmitt, J. C.; Bell, R. E.; Boyle, D. P.; Esposti, B.; Kaita, R.; Kozub, T.; LeBlanc, B. P.; Lucia, M.; Maingi, R.; Majeski, R.; Merino, E.; Punjabi-Vinoth, S.; Tchilingurian, G.; Capece, A.; Koel, B.; Roszell, J.; Biewer, T. M.; Gray, T. K.; Kubota, S.; Beiersdorfer, P.; and others

    2015-05-15

    The first-ever successful operation of a tokamak with a large area (40% of the total plasma surface area) liquid lithium wall has been achieved in the Lithium Tokamak eXperiment (LTX). These results were obtained with a new, electron beam-based lithium evaporation system, which can deposit a lithium coating on the limiting wall of LTX in a five-minute period. Preliminary analyses of diamagnetic and other data for discharges operated with a liquid lithium wall indicate that confinement times increased by 10× compared to discharges with helium-dispersed solid lithium coatings. Ohmic energy confinement times with fresh lithium walls, solid and liquid, exceed several relevant empirical scaling expressions. Spectroscopic analysis of the discharges indicates that oxygen levels in the discharges limited on liquid lithium walls were significantly reduced compared to discharges limited on solid lithium walls. Tokamak operations with a full liquid lithium wall (85% of the total plasma surface area) have recently started.

  9. Chemical constituents of Meconopsis horridula and their simultaneous quantification by high-performance liquid chromatography coupled with tandem mass spectrometry.

    PubMed

    Liu, Jiajia; Wu, Haimei; Zheng, Feng; Liu, Wenyuan; Feng, Feng; Xie, Ning

    2014-09-01

    Meconopsis horridula Hook.f. Thoms has been used as a traditional Tibetan medicine to clear away heat, relieve pain, and mobilize static blood. In this study, a reliable method based on high-performance liquid chromatography with diode array detection and electrospray ionization quadrupole time-of-flight tandem mass spectrometry was established for the identification of components in this herb. A total of 40 compounds (including 17 flavonoids, 15 alkaloids, and eight phenylpropanoids) were identified or tentatively identified. Among them, 17 components were identified in the herb for the first time. Compound 39 appears to be a novel compound, which is confirmed as 3-(kaempferol-8-yl)-2,3-epoxyflavanone by NMR spectroscopy and mass spectrometry. Moreover, seven major constituents were simultaneously quantified by the developed high-performance liquid chromatography with tandem triple-quadrupole mass spectrometry method. The quantitative method was validated and quality parameters were established. The study provides a comprehensive approach for understanding this herbal medicine.

  10. Quantification of urinary uric acid in the presence of thymol and thimerosal by high-performance liquid chromatography

    NASA Technical Reports Server (NTRS)

    Chen, Y.; Pietrzyk, R. A.; Whitson, P. A.

    1997-01-01

    A high-performance liquid chromatographic method was developed as an alternative to automated enzymatic analysis of uric acid in human urine preserved with thymol and/or thimerosal. Uric acid (tR = 10 min) and creatinine (tR = 5 min) were separated and quantified during isocratic elution (0.025 M acetate buffer, pH 4.5) from a mu Bondapak C18 column. The uric-acid peak was identified chemically by incubating urine samples with uricase. The thymol/thimerosal peak appeared at 31 min during the washing step and did not interfere with the analysis. We validated the high-performance liquid chromatographic method for linearity, precision and accuracy, and the results were found to be excellent.

  11. Detection of argan oil adulteration with vegetable oils by high-performance liquid chromatography-evaporative light scattering detection.

    PubMed

    Salghi, Rachid; Armbruster, Wolfgang; Schwack, Wolfgang

    2014-06-15

    Triacylglycerol profiles were selected as indicator of adulteration of argan oils to carry out a rapid screening of samples for the evaluation of authenticity. Triacylglycerols were separated by high-performance liquid chromatography-evaporative light scattering detection. Different peak area ratios were defined to sensitively detect adulteration of argan oil with vegetable oils such as sunflower, soy bean, and olive oil up to the level of 5%. Based on four reference argan oils, mean limits of detection and quantitation were calculated to approximately 0.4% and 1.3%, respectively. Additionally, 19 more argan oil reference samples were analysed by high-performance liquid chromatography-refractive index detection, resulting in highly comparative results. The overall strategy demonstrated a good applicability in practise, and hence a high potential to be transferred to routine laboratories.

  12. Determination of phosphatidylserine in milk-based nutritional products using online derivatization high-performance liquid chromatography.

    PubMed

    Lin, Qi; Zhang, Jie; Pei, Weijie; Zhang, Chunyan; Yew, Jia Le

    2015-02-13

    Phosphatidylserine (PS) has received interest for its ability to improve cognitive abilities and behaviors. A new method for determining PS in milk-based nutritional products has been developed. The method includes a quick and simple sample preparation procedure, followed by high-performance liquid chromatography (HPLC) fluorescence detection (FLD) with an on-line 9-fluorenylmethyloxycarbonyl (FMOC) derivatization. The method allows PS to be determined in raw materials, milk powder and liquid milk products. The day-to-day (n=3 days) average recovery of over spike-in (at 100% PS content level) was 100%, and the method quantification limit is 53 mg per kg milk powder.

  13. Reversed-phase high-performance liquid chromatography for the determination of steroid hormones in oral contraceptives.

    PubMed

    Bond, A M; Heritage, I D; Briggs, M H

    1984-12-19

    Reversed-phase high-performance liquid chromatography with UV detection is studied for the determination of both progestogenic and oestrogenic components of oral contraceptive formulations. The applicability of the assay is demonstrated for a number of different progestogen-oestrogen combinations in both conventional tablet and novel "paper" formulations. The results show that the method developed is a versatile technique for the routine assay of these pharmaceutical formulations.

  14. Enantiomeric high-performance liquid chromatography resolution and absolute configuration of 6β-benzoyloxy-3α-tropanol.

    PubMed

    Muñoz, Marcelo A; González, Natalia; Joseph-Nathan, Pedro

    2016-07-01

    The absolute configuration of the naturally occurring isomers of 6β-benzoyloxy-3α-tropanol (1) has been established by the combined use of chiral high-performance liquid chromatography with electronic circular dichroism detection and optical rotation detection. For this purpose (±)-1, prepared in two steps from racemic 6-hydroxytropinone (4), was subjected to chiral high-performance liquid chromatography with electronic circular dichroism and optical rotation detection allowing the online measurement of both chiroptical properties for each enantiomer, which in turn were compared with the corresponding values obtained from density functional theory calculations. In an independent approach, preparative high-performance liquid chromatography separation using an automatic fraction collector, yielded an enantiopure sample of OR (+)-1 whose vibrational circular dichroism spectrum allowed its absolute configuration assignment when the bands in the 1100-950 cm(-1) region were compared with those of the enantiomers of esters derived from 3α,6β-tropanediol. In addition, an enantiomerically enriched sample of 4, instead of OR (±)-4, was used for the same transformation sequence, whose high-performance liquid chromatography follow-up allowed their spectroscopic correlation. All evidences lead to the OR (+)-(1S,3R,5S,6R) and OR (-)-(1R,3S,5R,6S) absolute configurations, from where it follows that samples of 1 isolated from Knightia strobilina and Erythroxylum zambesiacum have the OR (+)-(1S,3R,5S,6R) absolute configuration, while the sample obtained from E. rotundifolium has the OR (-)-(1R,3S,5R,6S) absolute configuration.

  15. Protective properties of wine products and the role of high performance liquid chromatography in the study of these properties

    NASA Astrophysics Data System (ADS)

    Ulyanova, E. V.; Larionov, O. G.; Revina, A. A.; Andrievskaya, D. V.; Urusova, L. M.; Fenin, A. A.

    2013-12-01

    Data on the biologically active substances present in wines and wine products, the methods of their determination, and changes under chemical, radiation and other types of action are generalized. The role of high performance liquid chromatography in the studies of the protective properties of wines is demonstrated. Particular attention is devoted to problems of counterfeiting of wine products and the possibility to reveal it by using amperometric determination of the antioxidant activity. The bibliography includes 117 references.

  16. Determination of Catechol Estrogen Adducts by High-Performance Liquid Chromatography: Establishing Biomarkers for the Early Detection of Breast Cancer

    DTIC Science & Technology

    1999-07-01

    Catechol Estrogen Adducts by High- Performance Liquid Chromatography: Establishing Biomarkers for the Early Detection of Breast Cancer PRINCIPAL...DAMD17-98-1-8216 Chromatography: Establishing Biomarkers for the Early Detection of Breast Cancer 6. AUTHOR(S) Douglas E. Stack, Ph.D. 7. PERFORMING...ultimate goal of this research is the development of a biomarker for the early detection of breast cancer. 14. SUBJECT TERMS 15. NUMBER OF PAGES Breast

  17. Use of high-performance liquid chromatography to study the pharmacokinetics of colistin sulfate in rats following intravenous administration.

    PubMed

    Li, Jian; Milne, Robert W; Nation, Roger L; Turnidge, John D; Smeaton, Timothy C; Coulthard, Kingsley

    2003-05-01

    The pharmacokinetics of colistin was investigated using specific high-performance liquid chromatography (HPLC) to measure the concentrations of colistin and colistin A and B in plasma and urine in five rats after administration of an intravenous bolus of 1 mg of colistin sulfate/kg of body weight. There were differences in the pharmacokinetic behaviors of unbound colistin A and B. This is the first report of the use of HPLC to study the pharmacokinetics of colistin and its two major components.

  18. Identification of New Metabolites of Bacterial Transformation of Indole by Gas Chromatography-Mass Spectrometry and High Performance Liquid Chromatography

    PubMed Central

    Arora, Pankaj Kumar

    2014-01-01

    Arthrobacter sp. SPG transformed indole completely in the presence of an additional carbon source. High performance liquid chromatography and gas chromatography-mass spectrometry detected indole-3-acetic acid, indole-3-glyoxylic acid, and indole-3-aldehyde as biotransformation products. This is the first report of the formation of indole-3-acetic acid, indole-3-glyoxylic acid, and indole-3-aldehyde from indole by any bacterium. PMID:25548566

  19. Direct determination of benzalkonium chloride in ophthalmic systems by reversed-phase high-performance liquid chromatography.

    PubMed

    Ambrus, G; Takahashi, L T; Marty, P A

    1987-02-01

    High-performance liquid chromatography has been used to quantitate benzalkonium chloride (alkylbenzyldimethylammonium chloride) in complex ophthalmic formulations at or below concentration levels of 50 ppm. The method involves a one-step dilution for sample preparation and direct injection; therefore, recovery and/or conversion problems are nonexistent. The assay is quick, specific, reproducible, and simple. This new approach makes routine determinations far simpler than previous methods and is especially useful for product stability studies and quality control procedures.

  20. [Determination of congo red in beef by high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry and ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry].

    PubMed

    Lin, Hui; Xu, Chunxiang; Yan, Chunrong; Zhang, Zheng; Wang, Suilou

    2013-09-01

    A method was developed for the determination of congo red in beef. The analyte was identified by high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry (LC-QTOF MS) and quantitatively determined by ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry. After purified by liquid-liquid extraction, the congo red in the beef sample was separated on an Agilent ZORBAX Eclipse Plus C18 Rapid Resolution HD UPLC column (50 mm x 2.1 mm, 1.8 microm) HPLC , using 95% (volume percentage) methanol as the mobile phase at 0.2 mL/min. The detection was performed on an AB 4000 + triple quadrupole mass spectrometer utilizing electrospray ionization (ESI) interface operated in negative ion mode and multiple-reaction monitoring (MRM) mode. The results showed that the linear range of congo red mass concentration was 0.03 - 1 mg/L with the correlation coefficient of 0.999 8. The method had a good precision with the RSDs lower than 5% and the recoveries ranging from 88% to 91%. The limit of detection (LOD) of congo red was 0.01 mg/L. With good reproducibility, the method is simple, fast and effective for the determination of the illegally added congo red in beef and other meat products.

  1. EPA Method 8321B (SW-846): Solvent-Extractable Nonvolatile Compounds by High Performance Liquid Chromatography-Thermospray-Mass Spectrometry (HPLC-TS-MS) or Ultraviolet (UV) Detection

    EPA Pesticide Factsheets

    Method 8321B describes procedures for preparation and analysis of solid, aqueous liquid, drinking water and wipe samples using high performance liquid chromatography and mass spectrometry for extractable non-volatile compounds.

  2. Comparative analysis of steroidal saponins in four Dioscoreae herbs by high performance liquid chromatography coupled with mass spectrometry.

    PubMed

    Guo, Long; Zeng, Su-Ling; Zhang, Yu; Li, Ping; Liu, E-Hu

    2016-01-05

    Steroidal saponins, which exhibit multiple pharmacological effects, are the major bioactive constituents in herbal medicines from Dioscoreae species. In this study, a sensitive method based on high performance liquid chromatography-mass spectrometry (HPLC-MS) was established and validated for qualitative and quantitative analysis of steroidal saponins in four Dioscoreae herbs including Dioscoreae Nipponica Rhizome (DNR) and Dioscoreae Hypoglaucae Rhizome (DHR), Dioscoreae Spongiosae Rhizome (DSR) and Dioscoreae Rhizome (DR). A total of eleven steroidal saponins were identified by high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-QTOF/MS). Furthermore, seven major steroidal saponins was simultaneous quantified using a high performance liquid chromatography coupled with triple quadrupole mass spectrometry (HPLC-QQQ/MS). The qualitative and quantitative analysis results indicated that the chemical composition of DNR, DHR and DSR samples exhibited a high level of global similarity, while the ingredients in DR varied greatly from the other three herbs. Moreover, principal component analysis (PCA) and hierarchical clustering analysis (HCA) were performed to compare and discriminate the Dioscoreae herbs based on the quantitative data. The results demonstrated the qualitative and quantitative analysis of steroidal saponins based on HPLC-MS is a feasible method for quality control of Dioscoreae herbs.

  3. Determination of Aspartame, Caffeine, Saccharin, and Benzoic Acid in Beverages by High Performance Liquid Chromatography.

    ERIC Educational Resources Information Center

    Delaney, Michael F.; And Others

    1985-01-01

    Describes a simple and reliable new quantitative analysis experiment using liquid chromatography for the determinaiton of caffeine, saccharin, and sodium benzoate in beverages. Background information, procedures used, and typical results obtained are provided. (JN)

  4. The use of Element-Specific Detectors Coupled with High-Performance Liquid Chromatographs.

    DTIC Science & Technology

    1981-11-04

    approach to determining the amount of various chelating agents in solution, Jones and Manahan reacted the indicator metal, A 20 copper(II) with a...latter two cases, GFAA was employed as the element specific detector. Jones and Manahan employing a high performance absorption column directly...Chromatogr. Sci., 17: 395 (1979). 35. D. R. Jones, IV and S. E. Manahan , Anal. Chem., 48: 1897 (1976). 36. D. R. Jones, IV and S. E. Manahan , Anal. Chem

  5. Development and validation of ultra-high performance supercritical fluid chromatography method for determination of illegal dyes and comparison to ultra-high performance liquid chromatography method.

    PubMed

    Khalikova, Maria A; Šatínský, Dalibor; Solich, Petr; Nováková, Lucie

    2015-05-18

    A novel simple, fast and efficient ultra-high performance supercritical fluid chromatography (UHPSFC) method was developed and validated for the separation and quantitative determination of eleven illegal dyes in chili-containing spices. The method involved a simple ultrasound-assisted liquid extraction of illegal compounds with tetrahydrofuran. The separation was performed using a supercritical fluid chromatography system and CSH Fluoro-Phenyl stationary phase at 70°C. The mobile phase was carbon dioxide and the mixture of methanol:acetonitrile (1:1, v/v) with 2.5% formic acid as an additive at the flow rate 2.0 mL min(-1). The UV-vis detection was accomplished at 500 nm for seven compounds and at 420 nm for Sudan Orange G, Butter Yellow, Fast Garnet GBC and Methyl Red due to their maximum of absorbance. All eleven compounds were separated in less than 5 min. The method was successfully validated and applied using three commercial samples of chili-containing spices - Chili sauce (Indonesia), Feferony sauce (Slovakia) and Mojo sauce (Spain). The linearity range of proposed method was 0.50-9.09 mg kg(-1) (r ≥ 0.995). The detection limits were determined as signal to noise ratio of 3 and were ranged from 0.15 mg kg(-1) to 0.60 mg kg(-1) (1.80 mg kg(-1) for Fast Garnet) for standard solution and from 0.25 mg kg(-1) to 1.00 mg kg(-1) (2.50 mg kg(-1) for Fast Garnet, 1.50 mg kg(-1) for Sudan Red 7B) for chili-containing samples. The recovery values were in the range of 73.5-107.2% and relative standard deviation ranging from 0.1% to 8.2% for within-day precision and from 0.5% to 8.8% for between-day precision. The method showed potential for being used to monitor forbidden dyes in food constituents. The developed UHPSFC method was compared to the UHPLC-UV method. The orthogonality of Sudan dyes separation by these two methods was demonstrated. Benefits and drawbacks were discussed showing the reliability of both methods for monitoring of studied illegal dyes in real

  6. Development of a high-performance boiling heat exchanger by improved liquid supply to narrow channels.

    PubMed

    Ohta, Haruhiko; Ohno, Toshiyuki; Hioki, Fumiaki; Shinmoto, Yasuhisa

    2004-11-01

    A two-phase flow loop is a promising method for application to thermal management systems for large-scale space platforms handling large amounts of energy. Boiling heat transfer reduces the size and weight of cold plates. The transportation of latent heat reduces the mass flow rate of working fluid and pump power. To develop compact heat exchangers for the removal of waste heat from electronic devices with high heat generation density, experiments on a method to increase the critical heat flux for a narrow heated channel between parallel heated and unheated plates were conducted. Fine grooves are machined on the heating surface in a transverse direction to the flow and liquid is supplied underneath flattened bubbles by the capillary pressure difference from auxiliary liquid channels separated by porous metal plates from the main heated channel. The critical heat flux values for the present heated channel structure are more than twice those for a flat surface at gap sizes 2 mm and 0.7 mm. The validity of the present structure with auxiliary liquid channels is confirmed by experiments in which the liquid supply to the grooves is interrupted. The increment in the critical heat flux compared to those for a flat surface takes a maximum value at a certain flow rate of liquid supply to the heated channel. The increment is expected to become larger when the length of the heated channel is increased and/or the gravity level is reduced.

  7. Monosaccharide composition analysis of immunomodulatory polysaccharides by on-line hollow fiber microextraction with high-performance liquid chromatography.

    PubMed

    Wang, Nani; Wang, Xuping; Huang, Xiaowen; Mao, Zhujun; Zhang, Yang; Yu, Yong; Shou, Dan

    2016-03-01

    The monosaccharide compositions of functional polysaccharides are essential for structure elucidation and biological activity determination. A sensitive method based on on-line hollow-fiber liquid-phase microextraction with high-performance liquid chromatography has been established for the analysis of ten monosaccharide compositions (two uronic acids, two amino sugars and six neutral sugars) of the immunomodulatory polysaccharides. After derivatization, the sample was injected into the lumen of a hollow fiber immersed in butyl ether and separated by liquid chromatography. Under optimized conditions, the calibration curves were linear (r ≥ 0.9996) in the range of 10-2000 μmol L(-1) . The limits of detection were in the range of 0.04-1.58 μmol L(-1) , and the recoveries were in the range of 92.1-99.6%, which shows that the method is applicable to the analysis of the monosaccharide composition of various polysaccharides.

  8. Quantification of polycyclic aromatic hydrocarbons in tea and coffee samples of Mumbai City (India) by high performance liquid chromatography.

    PubMed

    Bishnoi, Narsi R; Mehta, Urvashi; Sain, Umashanker; Pandit, G G

    2005-08-01

    This paper describes a method for quantification of sixteen polycyclic aromatic hydrocarbons (PAHs) in tea and coffee samples of Mumbai City with the help of reversed phase high performance liquid chromatography with UV-VIS detector. This method is based on liquid-liquid extraction followed by clean up with C-18 cartridge. Concentration of total PAHs in different brands of tea and coffee samples varied from 18.79 to 31.37 microg/L and from 16.47 to 18.24 microg/L, respectively. Mean concentration of total PAHs was 27.56 microg/L in tea and 17.20 microg/L in coffee. Recoveries at different concentration levels were higher than 68% in samples of tea and coffee. Detection limit was found to be low (0.0006 ng) for anthracene and highest (0.174 ng) for naphthalene with relative standard deviation between 0.4%-7%.

  9. Sensitive and rapid high-performance liquid chromatography tandem mass spectrometry method for estimation of fulvestrant in rabbit plasma.

    PubMed

    Balaram, Varanasi Murali; Parmar, Dharmesh; Teja, Bulusu B; Rathnam, Shivprakash; Rao, Jangala Venkateswara; Dasandi, Bhavesh

    2010-08-01

    A rapid and sensitive high-performance liquid chromatography and electrospray tandem mass spectrometry method was developed and validated for estimation of fulvestrant in rabbit plasma using liquid-liquid extraction. The separation and quantification of fulvestrant were achieved by reverse-phase chromatography on a Sunfire C18 column (50 x 2.1. i.d., 3.5 microm) with isocratic elution at a flow rate of 300 microL/min using norethistrone as an internal standard from 500 microL plasma sample. The method was validated over the concentration range from 0.092 to 16.937 ng/mL with a lower limit of detection of 0.023 ng/mL. The intra-day and inter-day accuracy and precision were within 10%. The recovery was 85 and 90% for fulvestrant and norethistrone respectively. The chromatographic run time was only 2.5 min.

  10. Preliminary validation of high performance liquid chromatography method for detection of methyl-testosterone residue in carp muscle

    NASA Astrophysics Data System (ADS)

    Jiang, Jie; Lin, Hong; Fu, Xiaoting; Li, Mingming

    2005-07-01

    The use of synthetic anabolic steroid methyltestosterone (MT) as growth promoter is prohibited in China. Validations of analytical methods for MT residue in food and the results obtained have become indispensable. The high performance liquid chromatography (HPLC) method for the detection of MT with liquid-liquid extraction by trichloromethane-methanol in carp muscle tissue was preliminarily validated with reference to the following parameters: recovery (accuracy) at the 1, 5 and l0 mgkg-1 level, between-run and within-run CV values (repeatability, also called relative standard deviation (RSD)) and limit of detection. The recoveries were above 80% and the between-run and within-run CV values below 10% for muscle tissue. The limit of detection was 0.05 mgkg-1.

  11. Quantitative separation of tetralin hydroperoxide from its decomposition products by high performance liquid chromatography

    NASA Technical Reports Server (NTRS)

    Worstell, J. H.; Daniel, S. R.

    1981-01-01

    A method for the separation and analysis of tetralin hydroperoxide and its decomposition products by high pressure liquid chromatography has been developed. Elution with a single, mixed solvent from a micron-Porasil column was employed. Constant response factors (internal standard method) over large concentration ranges and reproducible retention parameters are reported.

  12. High Performance Liquid Chromatography of Some Analgesic Compounds: An Instrumental Analysis Experiment.

    ERIC Educational Resources Information Center

    Haddad, Paul; And Others

    1983-01-01

    Background information, procedures, and results are provided for an experiment demonstrating techniques of solvent selection, gradient elution, pH control, and ion-pairing in the analysis of an analgesic mixture using reversed-phase liquid chromatography on an octadecylsilane column. Although developed using sophisticated/expensive equipment, less…

  13. Compatiblitity of hydrophobic ionic liquids with high performance cathode materials for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Carnes-Mason, Ezekial Robert

    Lithium batteries are widely seen as the best choice for the future of energy storage but significant improvements are still required. One important area for improvement is searching for new cathode materials that incorporate lithium at higher capacities and voltages. This increases the energy and power available from an individual electrochemical cell, which reduces the number of cells required thereby reducing the size of a battery pack. While several high voltage cathode materials have been discovered, research has been hindered due to safety concerns with current standard electrolytes at high voltages. Ionic liquids are a new class of materials that exhibit excellent electrochemical and thermal stability as well as high ionic conductivity. These qualities make them excellent candidates to replace current battery electrolytes but difficulties in purification and the sheer number of possible chemistries have inhibited their study. In this study four hydrophobic ionic liquids based on pyrrolidinium and piperidinium cations paired with bis(trifluoromethylsulfonyl)imide anions were synthesized using bench top methods. These ionic liquids were successfully incorporated into working half-cells with LiNi1/3Mn1/3Co 1/3O2, a high capacity layered cathode and LiNi0.5Mn 1.5O4, a high voltage spinel type cathode. By comparing the behavior of the ionic liquids a clear relationship between cation size and rate capability was shown. The improved performance and safety at elevated temperatures was also demonstrated showing that ionic liquids are excellent candidates for use as battery electrolytes.

  14. Rapid determination of some beta-blockers in complicated matrices by tandem dispersive liquid-liquid microextraction followed by high performance liquid chromatography.

    PubMed

    Hemmati, Maryam; Asghari, Alireza; Bazregar, Mohammad; Rajabi, Maryam

    2016-11-01

    In this research work, an efficient tandem dispersive liquid-liquid microextraction (TDLLME) procedure coupled with high performance liquid chromatography-ultraviolet detection (HPLC-UV) was successfully applied for the determination of beta-blockers in human plasma and pharmaceutical wastewater samples. High clean-up and preconcentration factor are easily and rapidly feasible via this novel, cheap, and safe microextraction method, leading to high quality experimental data. It consists of two sequential dispersive liquid-liquid microextraction methods, accomplished via air/ultrasonic agitation and air agitation, respectively. In order to enrich the optimal values for the mentioned procedures, the Box-Behnken design (BBD) combined with the desirability function (DF) was used. The optimum values were found to be 11.0 % (w/v) of the salt amount, an initial pH value of 12.0, 103 μL of organic extractant phase, and 45 μL of aqueous extractant phase with pH value of 2.0, resulted in reasonable recovery percentages with a logical desirability. Under optimal experimental conditions, good linear ranges (3-2000 ng mL(-1) for metoprolol and 2.5-2500 ng mL(-1) for propranolol with the correlation of determinations (R (2)s) higher than 0.99) and low limits of detection (0.8 and 1.0 ng mL(-1) for propranolol and metoprolol, respectively) were obtainable. Also, TDLLME-HPLC-UV provided good proper repeatabilities (relative standard deviations (RSDs) below 5.7 %, n = 3) and high enrichment factors (EFs) of 75-100. Graphical abstract TDLLME of beta-blockers from complicated matrices.

  15. Dispersive liquid-liquid microextraction based on solidification of floating organic droplets followed by high performance liquid chromatography for the determination of duloxetine in human plasma.

    PubMed

    Suh, Joon Hyuk; Lee, Yun Young; Lee, Hee Joo; Kang, Myunghee; Hur, Yeoun; Lee, Sun Neo; Yang, Dong-Hyug; Han, Sang Beom

    2013-03-05

    A novel dispersive liquid-liquid microextraction method based on solidification of floating organic droplets (DLLME-SFO) technique was developed for the determination of duloxetine in human plasma samples by high performance liquid chromatography with fluorescence detection (HPLC-FLD). During the extraction procedure, plasma protein was precipitated by using a mixture of zinc sulfate solution and acetonitrile. After the protein precipitation step, duloxetine in an alkaline sample solution was quickly extracted by DLLME-SFO with 50 μL of 1-undecanol (extractant). Disperser was unnecessary because the small amount of remaining acetonitrile, which acts as a protein precipitating reagent, was also employed as a disperser; therefore, organic solvent consumption was reduced as much as possible. The emulsion was centrifuged and then fine droplets were floated to the top of the sample solution. The floated droplets were solidified in an ice bath and easily transferred. Various DLLME-SFO parameters such as extractant type, extractant amount, ionic strength, pH and extraction time were optimized. The chromatographic separation of duloxetine was carried out using ethanol as mobile phase. Validation of the method was performed with respect to linearity, intra- and inter-day accuracy and precision, limit of quantification (LOQ), and recovery. Calibration curves for duloxetine showed good linearity with correlation coefficients (r²) higher than 0.99. The method showed good precision and accuracy, with intra- and inter-assay coefficients of variation less than 15% (LOQ: less than 20%) at all concentrations. The recovery was carried out following the standard addition procedure with yields ranging from 59.6 to 65.5%. A newly developed environmentally friendly method was successfully applied to the pharmacokinetic study of duloxetine in human plasma and was shown to be an alternative green approach compared with the conventional solid-phase microextraction (SPME) and dispersive

  16. Accurate measurement of liquid transport through nanoscale conduits

    PubMed Central

    Alibakhshi, Mohammad Amin; Xie, Quan; Li, Yinxiao; Duan, Chuanhua

    2016-01-01

    Nanoscale liquid transport governs the behaviour of a wide range of nanofluidic systems, yet remains poorly characterized and understood due to the enormous hydraulic resistance associated with the nanoconfinement and the resulting minuscule flow rates in such systems. To overcome this problem, here we present a new measurement technique based on capillary flow and a novel hybrid nanochannel design and use it to measure water transport through single 2-D hydrophilic silica nanochannels with heights down to 7 nm. Our results show that silica nanochannels exhibit increased mass flow resistance compared to the classical hydrodynamics prediction. This difference increases with decreasing channel height and reaches 45% in the case of 7 nm nanochannels. This resistance increase is attributed to the formation of a 7-angstrom-thick stagnant hydration layer on the hydrophilic surfaces. By avoiding use of any pressure and flow sensors or any theoretical estimations the hybrid nanochannel scheme enables facile and precise flow measurement through single nanochannels, nanotubes, or nanoporous media and opens the prospect for accurate characterization of both hydrophilic and hydrophobic nanofluidic systems. PMID:27112404

  17. Pipette vial dispersive liquid-liquid microextraction combined with high-performance liquid chromatography for the determination of benzoylurea insecticide in fruit juice.

    PubMed

    Xi, Xuefei; Yang, Miyi; Shen, Ganni; Wu, Xiaoling; Lu, Runhua; Zhou, Wenfeng; Zhang, Sanbing; Gao, Haixiang

    2016-01-01

    A simple, sensitive, and efficient method of using a pipette vial to perform dispersive liquid-liquid microextraction based on the solidification of floating organic droplets was coupled with high-performance liquid chromatography (HPLC) and a diode array detector for the preconcentration and analysis of four benzoylurea insecticides in fruit juice. In this method, 1-dodecanol was used as an extractant, and a snipped pipette was used as an experimental vial to simplify the procedure of collecting and separating solidified extractant. The experimental parameters were optimized using a Plackett-Burman design and one-factor-at-a-time method. Under the optimal conditions in the water model, the limits of detection for analytes varied from 0.03 to 0.28 μg/L, and the enrichment factors ranged from 147 to 206. Linearity was achieved for diflubenzuron and flufenoxuron in a range of 0.5-500 μg/L, for hexaflumuron in a range of 1-500 μg/L, and for triflumuron in a range of 5-500 μg/L. The correlation coefficients for the analytes ranged from 0.9986 to 0.9994 with recoveries of 91.4-110.9%. Finally, the developed technique was successfully applied to fruit juice samples with acceptable results. The relative standard deviations of the analytes at two spiking levels (50 and 200 μg/L) varied between 0.2 and 4.5%.

  18. Speciation of mercury in water samples by dispersive liquid-liquid microextraction combined with high performance liquid chromatography-inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Jia, Xiaoyu; Han, Yi; Liu, Xinli; Duan, Taicheng; Chen, Hangting

    2011-01-01

    The dispersive liquid-liquid microextraction (DLLME) combined with high performance liquid chromatography-inductively coupled plasma mass spectrometry for the speciation of mercury in water samples was described. Firstly methylmercury (MeHg +) and mercury (Hg 2+) were complexed with sodium diethyldithiocarbamate, and then the complexes were extracted into carbon tetrachloride by using DLLME. Under the optimized conditions, the enrichment factors of 138 and 350 for MeHg + and Hg 2+ were obtained from only 5.00 mL sample solution. The detection limits of the analytes (as Hg) were 0.0076 ng mL -1 for MeHg + and 0.0014 ng mL -1 for Hg 2+, respectively. The relative standard deviations for ten replicate measurements of 0.5 ng mL -1 MeHg + and Hg 2+ were 6.9% and 4.4%, respectively. Standard reference material of seawater (GBW(E)080042) was analyzed to verify the accuracy of the method and the results were in good agreement with the certified values. Finally, the developed method was successfully applied for the speciation of mercury in three environmental water samples.

  19. Extraction and determination of opium alkaloids in urine samples using dispersive liquid-liquid microextraction followed by high-performance liquid chromatography.

    PubMed

    Shamsipur, Mojtaba; Fattahi, Nazir

    2011-10-15

    A simple, rapid and sensitive method based on dispersive liquid-liquid microextraction (DLLME) combined with high-performance liquid chromatography-ultraviolet detection (HPLC-UV) was used to determine opium alkaloids in urine samples. Some effective parameters on extraction were studied and optimized. Under the optimum conditions, enrichment factors and recoveries for different opiates are in the range of 63.0-104.5 and 31.5-52.2%, respectively. The calibration graphs are linear in the range of 0.50-500 μg L(-1) and limit of detections (LODs) are in the range of 0.2-10 μg L(-1). The relative standard deviations (RSDs) for 200 μg L(-1) of morphine, codeine and thebaine, 5.0 μg L(-1) of papaverine and 10.0 μg L(-1) of noscapine in diluted urine sample are in the range of 2.8-6.1% (n=7). The relative recoveries of urine samples spiked with alkaloids are 84.3-106.0%. The obtained results show that DLLME combined with HPLC-UV is a fast and simple method for the determination of opium alkaloids in urine samples.

  20. Determination of 13 Organic Toxicants in Human Blood by Liquid-Liquid Extraction Coupling High-Performance Liquid Chromatography Tandem Mass Spectrometry.

    PubMed

    Song, Aiying

    2016-01-01

    Pesticides and antidepressants are frequently misused in drug-facilitated crime because of their toxicological effect and easy-availability. Therefore, it is essential for the development of a simple and reliable method for the determination of these organic toxicants in biological fluids. Here, we report on an applicable method by the combination of optimized liquid-liquid extraction (LLE) procedure and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) to identify and quantify dimethoate, omethoate, dichlorvos, carbofuran, fenpropathrin, diazepam, estazolam, alprazolam, triazolamm, chlorpromazine, phenergan, barbitone and phenobarbital in human blood. The method demonstrated a linear calibration curve in range of 20 - 500 μg/L (r > 0.994). The accuracy evaluated by recovery spiked at three different concentrations (50, 100 and 200 μg/L) was in the range of 58.8 - 83.1% with a relative standard deviations (RSD) of 3.7 - 7.4%. The limits of quantification ranged over 6.7 - 33.3 μg/L. This method was proved to be simple and reliable, and was thus successfully applied to forensic toxicology.

  1. Dispersive liquid-liquid microextraction combined with high-performance liquid chromatography for the determination of clozapine and chlorpromazine in urine.

    PubMed

    Chen, Jing; Xiong, Chaomei; Ruan, Jinlan; Su, Zou

    2011-04-01

    A simple method has been proposed for the determination of clozapine (CLZ) and chlorpromazine (CPZ) in human urine by dispersive liquid-liquid microextraction (DLLME) in combination with high-performance liquid chromatography-ultraviolet detector (HPLC-UV). All important variables influencing the extraction efficiency, such as pH, types of the extraction solvent and the disperser solvent and their volume, ionic strength and centrifugation time were investigated and optimized. Under the optimal conditions, the limit of detection (LODs) and quantification (LOQs) of the method were 13 and 39 ng/mL for CLZ, and 2 and 6 ng/mL for CPZ, respectively. The relative standard deviations (RSDs) of the targets were less than 5.1% (C=0.100 μg/mL, n=9). Good linear behaviors over the tested concentration ranges were obtained with the values of R (2)>0.999 for the targets. The absolute extraction efficiencies of CLZ and CPZ from the spiked blank urine samples were 98.3% and 97.8%, respectively. The applicability of the technique was validated by analyzing urine samples and the mean recoveries for spiked urine samples ranged from 93.3% to 105.0%. The method was successfully applied for the determination of CLZ and CPZ in real human urine.

  2. Intravascular Residence Time Determination for the Cyanide Antidote Dimethyl Trisulfide in Rat by Using Liquid-Liquid Extraction Coupled with High Performance Liquid Chromatography

    PubMed Central

    De Silva, Deepthika; Lee, Steven; Duke, Anna; Angalakurthi, Siva; Chou, Ching-En; Ebrahimpour, Afshin; Thompson, David E.

    2016-01-01

    These studies represent the first report on the intravascular residence time determinations for the cyanide antidote dimethyl trisulfide (DMTS) in a rat model by using high performance liquid chromatography coupled with ultraviolet absorption spectroscopy (HPLC-UV). The newly developed sample preparation included liquid-liquid extraction by cyclohexanone. The calibration curves showed a linear response for DMTS concentrations between 0.010 and 0.30 mg/mL with R2 = 0.9994. The limit of detection for DMTS via this extraction method was 0.010 mg/mL, and the limit of quantitation was 0.034 mg/mL. Thus this calibration curve provided a tool for determining DMTS in the range between 0.04 and 0.30 mg/mL. Rats were given 20 mg/kg DMTS dose (in 15% Polysorbate 80) intravenously, and blood samples were taken 15, 60, 90, 120, and 240 min after DMTS injections. The data points were plotted as DMTS concentration in RBCs versus time, and the intravascular residence time was determined graphically. The results indicated a half-life of 36 min in a rat model, suggesting that the circulation time is long enough to provide a reasonable time interval for cyanide antagonism. PMID:28053802

  3. Vortex-assisted extraction combined with dispersive liquid-liquid microextraction for the determination of polycyclic aromatic hydrocarbons in sediment by high performance liquid chromatography.

    PubMed

    Leng, Geng; Lui, Guibin; Chen, Yong; Yin, Hui; Dan, Dezhong

    2012-10-01

    A simple, rapid, and efficient method, vortex-assisted extraction followed by dispersive liquid-liquid microextraction (DLLME) has been developed for the extraction of polycyclic aromatic hydrocarbons (PAHs) in sediment samples prior to analysis by high performance liquid chromatography fluorescence detection. Acetonitrile was used as collecting solvent for the extraction of PAHs from sediment by vortex-assisted extraction. In DLLME, PAHs were rapidly transferred from acetonitrile to dichloromethane. Under the optimum conditions, the method yields a linear calibration curve in the concentration range from 10 to 2100 ng g(-1) for fluorene, anthracene, chrysene, benzo[k]fluoranthene, and benzo[a]pyrene, and 20 to 2100 ng g(-1) for other target analytes. Coefficients of determinations ranged from 0.9986 to 0.9994. The limits of detection, based on signal-to-noise ratio of three, ranged from 2.3 to 6.8 ng g(-1) . Reproducibility and recoveries was assessed by extracting a series of six independent sediment samples, which were spiked with different concentration levels. Finally, the proposed method was successfully applied in analyses of real nature sediment samples. The proposed method extended and improved the application of DLLME to solid samples, which greatly shorten the extraction time and simplified the extraction process.

  4. Vortex-assisted low density solvent based demulsified dispersive liquid-liquid microextraction and high-performance liquid chromatography for the determination of organophosphorus pesticides in water samples.

    PubMed

    Seebunrueng, Ketsarin; Santaladchaiyakit, Yanawath; Srijaranai, Supalax

    2014-05-01

    A simple, rapid, effective and eco-friendly preconcentration method, vortex-assisted low density solvent based solvent demulsified dispersive liquid-liquid microextraction (VLDS-SD-DLLME), followed by high performance liquid chromatography-diode array detector (HPLC-DAD) analysis, has been developed for the first time for the determination of four organophosphorus pesticides (OPPs) (e.g., azinphos-methyl, parathion-methyl, fenitrothion and diazinon) in environmental water samples. In this preconcentration procedure, an emulsion was obtained after the mixture of extraction solvent (1-dodecanol) and dispersive solvent (acetonitrile, ACN) was injected rapidly into 10 mL of the sample solution. The vortex agitator aided the dispersion of the extraction solvent into the sample solution. After the formation of an emulsion, the demulsifier (ACN) was added, resulting in the rapid separation of the mixture into two phases without centrifugation. Under optimal conditions, the proposed method provided high extraction efficiency (90-99%), good linearity range (0.5-500 ng mL(-1)), low limits of detection (0.25-1 ng mL(-1)) and good repeatability and recoveries were obtained.

  5. Vortex-assisted liquid-liquid micro-extraction and high-performance liquid chromatography for a higher sensitivity methyl methacrylate determination in biological matrices.

    PubMed

    Sousa, Tiago F A; Aniceto, Marta C; Amorim, Célia G; Souto-Lopes, Mariana; Pérez-Mongiovi, Daniel; Montenegro, Maria C B S M; Araújo, Alberto N

    2014-05-01

    A vortex-assisted liquid-liquid micro-extraction coupled with high-performance liquid chromatography, with UV-vis, is proposed to pre-concentrate methyl methacrylate and to improve separation in biological matrices. The use of 1-octanol as extracting phase, its volume, the need for a dispersant agent, the agitation conditions and the cooling time before phase separation were evaluated. In optimum conditions, enrichment factors of 20 (±0.5) and enrichment recovery of 99% were obtained. The straightforward association of this extraction process with the HPLC method, previously regulated by the International Organization for Standardization, afforded a detection limit of 122 ng/mL and a quantification limit of 370 ng/mL. The within-batch precision, relative standard deviation, was 3% for a sample with 1.49 µg/mL and 4% for a sample with 13.4 µg/mL. The results showed a between batch-precision of 21% for experiments performed on five different days, for a sample with a concentration of 1.10 µg/mL in methyl methacrylate.

  6. Vortex-assisted liquid-liquid microextraction coupled with high performance liquid chromatography for the determination of furfurals and patulin in fruit juices.

    PubMed

    Abu-Bakar, Nur-Bahiyah; Makahleh, Ahmad; Saad, Bahruddin

    2014-03-01

    A fast and simple solvent microextraction technique using salting out-vortex-assisted liquid-liquid microextraction (salting out-VALLME) was developed for the extraction of furfurals (2-furfural (2-F), 3-furfural (3-F), 5-methylfurfural (5-MF) and 5-hydroxymethylfurfural (5-HMF)) and patulin (PAT) in fruit juice samples. The optimum extraction conditions for 5 mL sample were: extraction solvent, 1-hexanol; volume of extractant, 200 µL; vortex time, 45 s; salt addition, 20%. The simultaneous determination of the furfurals and PAT were investigated using high performance liquid chromatography coupled with diode array detector (HPLC-DAD). The separation was performed using ODS Hypersil C18 column (4.6 mm i.d × 250 mm, 5 μm) under gradient elution. The detection wavelengths used for all compounds were 280 nm except for 3-F (210 nm). The furfurals and PAT were successfully separated in less than 9 min. Good linearities (r(2)>0.99) were obtained within the range 1-5000 μg L(-1) for all compounds except for 3-F (10-5000 µg L(-1)) and PAT (0.5-100 μg L(-1)). The limits of detection (0.28-3.2 µg L(-1)) were estimated at S/N ratio of 3. The validated salting out-VALLME-HPLC method was applied for the analysis of furfurals and PAT in fruit juice samples (apple, mango and grape).

  7. Sensitive determination of melamine in milk and powdered infant formula samples by high-performance liquid chromatography using dabsyl chloride derivatization followed by dispersive liquid-liquid microextraction.

    PubMed

    Faraji, M; Adeli, M

    2017-04-15

    A new and sensitive pre-column derivatization with dabsyl chloride followed by dispersive liquid-liquid microextraction was developed for the analysis of melamine (MEL) in raw milk and powdered infant formula samples by high performance liquid chromatography (HPLC) with visible detection. Derivatization with dabsyl chloride leads to improving sensitivity and hydrophobicity of MEL. Under optimum conditions of derivatization and microextraction steps, the method yielded a linear calibration curve ranging from 1.0 to 500μgL(-1) with a determination coefficient (R(2)) of 0.9995. Limit of detection and limit of quantification were 0.1 and 0.3μgL(-1), respectively. The relative standard deviation (RSD%) for intra-day (repeatability) and inter-day (reproducibility) at 25 and 100μgL(-1) levels of MEL was less than 7.0% (n=6). Finally, the proposed method was successfully applied for the preconcentration and determination of MEL in different raw milk and powdered infant formula, and satisfactory results were obtained (relative recovery ⩾94%).

  8. Intravascular Residence Time Determination for the Cyanide Antidote Dimethyl Trisulfide in Rat by Using Liquid-Liquid Extraction Coupled with High Performance Liquid Chromatography.

    PubMed

    De Silva, Deepthika; Lee, Steven; Duke, Anna; Angalakurthi, Siva; Chou, Ching-En; Ebrahimpour, Afshin; Thompson, David E; Petrikovics, Ilona

    2016-01-01

    These studies represent the first report on the intravascular residence time determinations for the cyanide antidote dimethyl trisulfide (DMTS) in a rat model by using high performance liquid chromatography coupled with ultraviolet absorption spectroscopy (HPLC-UV). The newly developed sample preparation included liquid-liquid extraction by cyclohexanone. The calibration curves showed a linear response for DMTS concentrations between 0.010 and 0.30 mg/mL with R(2) = 0.9994. The limit of detection for DMTS via this extraction method was 0.010 mg/mL, and the limit of quantitation was 0.034 mg/mL. Thus this calibration curve provided a tool for determining DMTS in the range between 0.04 and 0.30 mg/mL. Rats were given 20 mg/kg DMTS dose (in 15% Polysorbate 80) intravenously, and blood samples were taken 15, 60, 90, 120, and 240 min after DMTS injections. The data points were plotted as DMTS concentration in RBCs versus time, and the intravascular residence time was determined graphically. The results indicated a half-life of 36 min in a rat model, suggesting that the circulation time is long enough to provide a reasonable time interval for cyanide antagonism.

  9. Combination of saponification and dispersive liquid-liquid microextraction for the determination of tocopherols and tocotrienols in cereals by reversed-phase high-performance liquid chromatography.

    PubMed

    Shammugasamy, Balakrishnan; Ramakrishnan, Yogeshini; Ghazali, Hasanah M; Muhammad, Kharidah

    2013-07-26

    A simple sample preparation technique coupled with reversed-phase high-performance liquid chromatography was developed for the determination of tocopherols and tocotrienols in cereals. The sample preparation procedure involved a small-scale hydrolysis of 0.5g cereal sample by saponification, followed by the extraction and concentration of tocopherols and tocotrienols from saponified extract using dispersive liquid-liquid microextraction (DLLME). Parameters affecting the DLLME performance were optimized to achieve the highest extraction efficiency and the performance of the developed DLLME method was evaluated. Good linearity was observed over the range assayed (0.031-4.0μg/mL) with regression coefficients greater than 0.9989 for all tocopherols and tocotrienols. Limits of detection and enrichment factors ranged from 0.01 to 0.11μg/mL and 50 to 73, respectively. Intra- and inter-day precision were lower than 8.9% and the recoveries were around 85.5-116.6% for all tocopherols and tocotrienols. The developed DLLME method was successfully applied to cereals: rice, barley, oat, wheat, corn and millet. This new sample preparation approach represents an inexpensive, rapid, simple and precise sample cleanup and concentration method for the determination of tocopherols and tocotrienols in cereals.

  10. Automated dispersive liquid-liquid microextraction coupled to high performance liquid chromatography - cold vapour atomic fluorescence spectroscopy for the determination of mercury species in natural water samples.

    PubMed

    Liu, Yao-Min; Zhang, Feng-Ping; Jiao, Bao-Yu; Rao, Jin-Yu; Leng, Geng

    2017-04-14

    An automated, home-constructed, and low cost dispersive liquid-liquid microextraction (DLLME) device that directly coupled to a high performance liquid chromatography (HPLC) - cold vapour atomic fluorescence spectroscopy (CVAFS) system was designed and developed for the determination of trace concentrations of methylmercury (MeHg(+)), ethylmercury (EtHg(+)) and inorganic mercury (Hg(2+)) in natural waters. With a simple, miniaturized and efficient automated DLLME system, nanogram amounts of these mercury species were extracted from natural water samples and injected into a hyphenated HPLC-CVAFS for quantification. The complete analytical procedure, including chelation, extraction, phase separation, collection and injection of the extracts, as well as HPLC-CVAFS quantification, was automated. Key parameters, such as the type and volume of the chelation, extraction and dispersive solvent, aspiration speed, sample pH, salt effect and matrix effect, were thoroughly investigated. Under the optimum conditions, linear range was 10-1200ngL(-1) for EtHg(+) and 5-450ngL(-1) for MeHg(+) and Hg(2+). Limits of detection were 3.0ngL(-1) for EtHg(+) and 1.5ngL(-1) for MeHg(+) and Hg(2+). Reproducibility and recoveries were assessed by spiking three natural water samples with different Hg concentrations, giving recoveries from 88.4-96.1%, and relative standard deviations <5.1%.

  11. Simultaneous determination of six synthetic phenolic antioxidants in edible oils using dispersive liquid-liquid microextraction followed by high-performance liquid chromatography with diode array detection.

    PubMed

    Xu, Shuangjiao; Liu, Liangliang; Wang, Yanqin; Zhou, Dayun; Kuang, Meng; Fang, Dan; Yang, Weihua; Wei, Shoujun; Xiao, Aiping; Ma, Lei

    2016-08-01

    A simple, rapid, organic-solvent- and sample-saving pretreatment technique, called dispersive liquid-liquid microextraction, was developed for the determination of six synthetic phenolic antioxidants from edible oils before high-performance liquid chromatography with diode array detection. The entire procedure was composed of a two-step microextraction and a centrifugal process and could be finished in about 5 min, only consuming only 25 mg of sample and 1 mL of the organic solvent for each extraction. The influences of several important parameters on the microextraction efficiency were thoroughly investigated. Recovery assays for oil samples were spiked at three concentration levels, 50, 100 and 200 mg/kg, and provided recoveries in the 86.3-102.5% range with a relative standard deviation below 3.5%. The intra-day and inter-day precisions for the analysis were less than 3.8%. The proposed method was successfully applied for the determination of synthetic phenolic antioxidants in different oil samples, and satisfactory results were obtained. Thus, the developed method represents a viable alternative for the quality control of synthetic phenolic antioxidant concentrations in edible oils.

  12. Determination of six pyrethroid insecticides in fruit juice samples using dispersive liquid-liquid microextraction combined with high performance liquid chromatography.

    PubMed

    Boonchiangma, Suthasinee; Ngeontae, Wittaya; Srijaranai, Supalax

    2012-01-15

    Dispersive liquid-liquid microextraction (DLLME) coupled to high performance liquid chromatography (HPLC) with UV detection was applied for the determination of six pyrethroids (tetramethrin, fenpropathrin, cypermethrin, deltamethrin, fenvalerate and permethrin) in various fruit juices including apple, red grape, orange, kiwi, passion fruit, pomegranate and guava juice. Six pyrethroids were separated within 30 min using a Waters Atlantis T3 column under an isocratic elution of acetonitrile-water (72:28). The parameters affecting extraction efficiency of the DLLME method such as type of disperser and extraction solvent, volume of disperser and extraction solvent and centrifugation time were investigated. Under the optimum conditions, 5.00 mL of sample solution, 300 μL of chloroform as extraction solvent and 1.25 mL of methanol as dispersive solvent gave high enrichment factor in the range of 62-84. Good linearity was obtained from 2 to 1,500 μg/L (r(2)>0.995). The mean recoveries of the pyrethroids evaluated by fortification of real samples were in the range of 84-94%. The limits of detection ranging from 2 to 5 μg/L are sufficient to analyze pyrethroid residues at the maximum residue limits (MRLs) established by the European Union (EU) in fruit juices. The proposed method can be applied to direct determination of pyrethroid residues in fruit juices.

  13. Sensitive high-performance liquid chromatographic quantitation of gabapentin in human serum using liquid-liquid extraction and pre-column derivatization with 9-fluorenylmethyl chloroformate.

    PubMed

    Bahrami, Gholamreza; Kiani, Amir

    2006-05-01

    Most of the published methods for analysis of gabapentin, an antiepileptic agent, in human serum are based on the same approach, involving o-phthaldialdehyde derivatization of deproteinized serum samples. The present paper however, describes a new, simple and sensitive high-performance liquid chromatographic method for determination of gabapentin in human serum using liquid-liquid extraction and 9-fluorenylmethyl chloroformate (FMOC-Cl) as pre-column labeling agent. The drug and an internal standard (azithromycin) were extracted from serum by salting-out approach using a mixture of dichloromethane-2 propanol (1:1, v/v) as the extracting solvent. The extracted analytes were subjected to derivatization with FMOC-Cl in the presence of phosphate buffer (pH 7). A mobile phase consisting of methanol-0.05 M sodium phosphate buffer (73/27, v/v; pH of 3.9) containing 1 ml/l triethylamine was eluted and chromatographic separation was performed on a Shimpack CLC-C18 (150 mm x 4.6 mm) column. The standard curve was linear over the range of 0.03-20 microg/ml and limit of quantification was 0.03 microg/ml. The performance of analysis was studied and the validated method showed excellent performance in terms of selectivity, specificity, sensitivity, precision and accuracy. No interferences were found from commonly co-administered antiepileptic agents.

  14. Simultaneous determination of tetrahydropalmatine and tetrahydroberberine in rat urine using dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography.

    PubMed

    Zhang, Mingyong; Le, Jian; Wen, Jun; Chai, Yifeng; Fan, Guorong; Hong, Zhanying

    2011-11-01

    Dispersive liquid-liquid microextraction (DLLME) coupled with high-performance liquid chromatography (HPLC)-UV detection was applied in rat urine for the extraction and determination of tetrahydropalmatine (THP) and tetrahydroberberine (THB), both active components in Rhizoma corydalis. Various parameters affecting the extraction efficiency, such as the type and volume of extraction and dispersive solvent, pH, etc. were evaluated. Under the optimal conditions (extraction solvent: 37 μL of chloroform, dispersive solvent: 100 μL of methanol, alkaline with 100 μL of 1 mol/L NaOH, and without salt addition), the enrichment factors of THP and THB were more than 30. The extraction recoveries were 69.8-75.8% and 72.7-77.6% for THP and THB in rat urine, respectively. Both THP and THB showed good linearity in the range of 0.025-2.5 μg/mL, and the limit of quantification was 0.025 μg/mL (S/N=10, n=6). The intra-day and inter-day precision of THP and THB were <12.6%. The relative recoveries ranged from 95.5 to 107.4% and 96.8 to 100.9% for THP and THB in rat urine, respectively. The method has been successfully applied to rat urine samples. The results demonstrated that DLLME is a very simple, rapid and efficient method for the extraction and preconcentration of THP and THB from urine samples.

  15. Surfactant-assisted dispersive liquid-liquid microextraction of nitrazepam and lorazepam from plasma and urine samples followed by high-performance liquid chromatography with UV analysis.

    PubMed

    Molaei, Karam; Asgharinezhad, Ali Akbar; Ebrahimzadeh, Homeira; Shekari, Nafiseh; Jalilian, Niloofar; Dehghani, Zhara

    2015-09-10

    Surfactant-assisted liquid-liquid microextraction followed by high-performance liquid chromatography with UV detection has been developed for the simultaneous preconcentration and determination of lorazepam and nitrazepam in biological fluids. In this study, an ionic surfactant (cetyltrimethyl ammonium bromide) was used as an emulsifier. The predominant parameters affecting extraction efficiency such as the type and volume of extraction solvent, the type and concentration of surfactant, sample pH, and the concentration of salt added to the sample were investigated and opted. Under the optimum conditions (extraction solvent and its volume, 1-octanol, 70 μL; surfactant and its concentration, 1 mL of ultra-pure water containing 2 mmol L(-1) cetyltrimethyl ammonium bromide; sample pH = 9 and salt content of 10% NaCl w/v), the preconcentration factors were obtained in the range of 202-241 and 246-265 for nitrazepam and lorazepam, respectively. The limits of quantification for both drugs were 5 μg L(-1) in water sample and 10 μg L(-1) in biological fluids with R(2) values higher than 0.993. The suitability of the proposed method was successfully confirmed by the extraction and determination of the target drugs in human urine and plasma samples in the range of microgram per liter.

  16. Rapid determination of tetrabromobisphenol A and its main derivatives in aqueous samples by ultrasound-dispersive liquid-liquid microextraction combined with high-performance liquid chromatography.

    PubMed

    Wang, Xuemei; Liu, Jiyan; Liu, Qian; Du, Xinzhen; Jiang, Guibin

    2013-11-15

    A method of ultrasound-dispersive liquid-liquid microextraction (US-DLLME) combined with high-performance liquid chromatography/variable wavelength detection (HPLC-VWD) has been developed for rapid measuring tetrabromobisphenol A and its five derivatives in water. Parameters affecting the extraction efficiency including the extraction solvents and dispersive solvents and their volume, ionic strength of the sample, and ultrasound time were optimized, and further validated by orthogonal array design (OAD). The optimized conditions provided enrichment factors for analytes of 74-490. Most analytes had linear responses between 2 and 500 μg L(-1), with correlation coefficients (r(2)) of 0.9923-0.9994. Limits of detection were 0.13-0.63 μg L(-1). Relative standard deviations (RSDs) for five replicates ranged from 2.6% to 4.5% for all analytes. When applied to spiked samples of real water, the method provided recoveries of 88.6-106.3% for tap water, 87.8-108.5% for Mi River water, 82.7-113.5% for chemical wastewater, 45.5-115.3% for urine, and 46.4-126.2% for fruit juice, with RSDs (n=5) less than 4%, 6%, 8%, 10%, and 9% respectively.

  17. Rapid extraction and determination of amphetamines in human urine samples using dispersive liquid-liquid microextraction and solidification of floating organic drop followed by high performance liquid chromatography.

    PubMed

    Ahmadi-Jouibari, Toraj; Fattahi, Nazir; Shamsipur, Mojtaba

    2014-06-01

    A novel, rapid, simple and sensitive dispersive liquid-liquid microextraction method based on the solidification of floating organic drop (DLLME-SFO) combined with high-performance liquid chromatography-ultraviolet detection (HPLC-UV) was used to determine amphetamine and methamphetamine in urine samples. The factors affecting the extraction efficiency of DLLME-SFO such as the kind and volume of the extraction and the disperser solvents, effect of concentration of K2CO3 and extraction time were investigated and the optimal extraction conditions were established. Under the optimum conditions (extraction solvent: 30.0μl 1-undecanol; disperser solvent: 300μl acetonitrile; buffer concentration: 2% (w/v) K2CO3 and extraction time: 1min), calibration curves are linear in the range of 10-3000μgl(-1) and limit of detections (LODs) are in the range of 2-8μgl(-1). The relative standard deviations (RSDs) for 100μgl(-1) of amphetamine and methamphetamine in diluted urine are in the range of 6.2-7.8% (n=7). The method was successfully applied for the determination of amphetamine and methamphetamine in the actual urine samples. The relative recoveries of urine samples spiked with amphetamine and methamphetamine are 87.8-113.2%. The obtained results show that DLLME-SFO combined with HPLC-UV is a fast and simple method for the determination of amphetamine and methamphetamine in urine.

  18. Ionic liquid foam floatation coupled with ionic liquid dispersive liquid-liquid microextraction for the separation and determination of estrogens in water samples by high-performance liquid chromatography with fluorescence detection.

    PubMed

    Zhang, Rui; Wang, Chuanliu; Yue, Qiaohong; Zhou, Tiecheng; Li, Na; Zhang, Hanqi; Hao, Xiaoke

    2014-11-01

    An ionic liquid foam floatation coupled with ionic liquid dispersive liquid-liquid microextraction method was proposed for the extraction and concentration of 17-α-estradiol, 17-β-estradiol-benzoate, and quinestrol in environmental water samples by high-performance liquid chromatography with fluorescence detection. 1-Hexyl-3-methylimidazolium tetrafluoroborate was applied as foaming agent in the foam flotation process and dispersive solvent in microextraction. The introduction of the ion-pairing and salting-out agent NH4 PF6 was beneficial to the improvement of recoveries for the hydrophobic ionic liquid phase and analytes. Parameters of the proposed method including concentration of 1-hexyl-3-methylimidazolium tetrafluoroborate, flow rate of carrier gas, floatation time, types and concentration of ionic liquids, salt concentration in samples, extraction time, and centrifugation time were evaluated. The recoveries were between 98 and 105% with relative standard deviations lower than 7% for lake water and well water samples. The isolation of the target compounds from the water was found to be efficient, and the enrichment factors ranged from 4445 to 4632. This developing method is free of volatile organic solvents compared with regular extraction. Based on the unique properties of ionic liquids, the application of foam floatation, and dispersive liquid-liquid microextraction was widened.

  19. Quantification of tipranavir in human plasma by high-performance liquid chromatography with UV detection.

    PubMed

    Giraud, Emmanuelle; Rey, Elisabeth; Tréluyer, Jean-Marc; Pons, Gérard; Jullien, Vincent

    2006-01-02

    A simple method for the quantification of tipranavir, a new non-peptidic protease-inhibitor, was developed. An internal standard, prazepam, was added to 100 microl of plasma before a liquid-liquid extraction by 3 ml of tert-butyl methyl ether. The extracts were evaporated to dryness and reconstituted with 100 microl of mobile phase before being injected in the chromatographic system. The separation was made on a C8 column using sodium acetate buffer (pH 5):methanol:acetonitrile (35:30:35, v/v/v) as mobile phase. The detection was performed at a wavelength of 260 nm. The method was linear and has been validated over a concentration range of 2-80 mg/l. The mean precision and accuracy of the method were respectively, 10.5 and -9.1%. The mean recovery was 70.8%.

  20. Determination of nonylphenol polyethoxylates in household detergents by high-performance liquid chromatography.

    PubMed

    Cheng, Chin-Yuan; Ding, Wang-Hsien

    2002-08-30

    Preliminary survey results of the content of nonylphenol polyethoxylates (NPEOs) in various household detergents sold in Taiwan are presented. This survey was conducted to elucidate the concentration of NPEOs in household detergents and support pollution prevention and control programs. The concentrations of NPEOs in detergents and cleaners were determined by HPLC with a C8 reversed-phase column and equipped with fluorescence detection. The accuracy and precision of the method was validated and was successfully applied to determine concentrations of NPEOs in household detergents. The results show that NPEOs were detected in 41% of 90 household detergents at concentrations from 0.2 to 21%. The highest concentration of NPEOs (21%) was detected in a laundry liquid especially designed for washing socks. Reversed-phase liquid chromatography connected with electrospray mass spectrometry confirmed the results.

  1. High-performance liquid chromatographic determination of cotinine in urine in isocratic mode.

    PubMed

    Ceppa, F; El Jahiri, Y; Mayaudon, H; Dupuy, O; Burnat, P

    2000-09-15

    A simple procedure for the determination of cotinine, major metabolite of nicotine in urine, is described. The assay involved a liquid-liquid extraction with dichloromethane in alkaline environment. The extract was dried at ambient temperature under a gentle stream of nitrogen. The residue was dissolved in 300 microl of mobile phase and 30 microl aliquot was injected via an automatic sampler into the liquid chromatograph and eluted with the mobile phase (10-9%, v/v methanol and acetonitrile, respectively in potassium dihydrogenphosphate buffer adjusted to pH 3.4) at a flow rate of 1 ml/min on a C8 Symmetry cartridge column (5 microm, 150 mm x 3.9 mm, Waters) at 25 degrees C. The eluate was detected at 260 nm. Internal standard was 2-phenylimidazole. Sensitive and specific, this technique was performed to test urine of diabetic patients (smokers and non-smokers) admitted in an endocrinology service. Urinary cotinine seems to be a better marker of smoking status than thiocyanates.

  2. Identification, characterization, and high-performance liquid chromatography quantification of process-related impurities in vonoprazan fumarate.

    PubMed

    Liu, Lei; Cao, Na; Ma, Xingling; Xiong, Kaihe; Sun, Lili; Zou, Qiaogen

    2016-04-01

    High-performance liquid chromatography analysis of vonoprazan fumarate, a novel proton pump inhibitor drug revealed six impurities. These were identified by liquid chromatography with mass spectrometry. Further, the structures of the impurities were confirmed by synthesis followed by characterization by mass spectrometry, NMR spectroscopy, and infrared spectroscopy. On the basis of these data and knowledge of the synthetic scheme of vonoprazan fumarate, the previously unknown impurity was identified as 1-[5-(2-fluorophenyl)-1-(pyridin-3-ylsulfonyl)-1H-pyrrol-3-yl]-N-methyldimethylamine, which is a new compound. The possible mechanisms by which these impurities were formed were also discussed. A high-performance liquid chromatography method was optimized in order to separate, selectively detect, and quantify all process-related impurities of vonoprazan fumarate. The presented method has been validated in terms of linearity, limits of detection, and quantification, and response factors and, therefore, is highly suitable for routine analysis of vonoprazan fumarate related substances as well as stability studies.

  3. Improved high-performance liquid chromatographic analysis of some carboxylic acids in food and beverages as their p-nitrobenzyl esters.

    PubMed

    Badoud, R; Pratz, G

    1986-06-06

    An improved, straightforward and accurate method for the derivatization and quantitative high-performance liquid chromatographic analysis of carboxylic acids in food and beverages is presented. Thirty-two p-nitrobenzyl esters were prepared in high yields by direct reaction of the free acid with O-(4-nitrobenzyl)-N,N'-diisopropylisourea in dioxane-water (9:1). Benzylmalonic acid was used as a new internal standard. Excess of reagent was removed on a strong cation-exchange resin. The advantage of this original and very convenient procedure over the usual clean-up step involving filtration through a disposable silica cartridge is discussed. The p-nitrobenzyl ester derivatives were readily separated using a single linear gradient of solvent (acetonitrile in water). With a high-performance liquid chromatography column of conventional size (20-25 cm X 4.6 mm I.D.), the analysis lasted for less than 20 min. This analysis time was even shorter (less than 12 min) when using modern small-bore (100 X 2.1 mm I.D.) columns. Applications of the method to the analysis of the main carboxylic acids in coffee, wine and fruit juices are presented.

  4. Analysis of lignans in Magnoliae Flos by turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry.

    PubMed

    Zhou, Xuan; Chen, Cen; Ye, Xiaolan; Song, Fenyun; Fan, Guorong; Wu, Fuhai

    2016-04-01

    In this study, a method coupling turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry was developed for analyzing the lignans in Magnoliae Flos. By the online pretreatment of turbulent flow chromatography solid-phase extraction, the impurities removal and analytes concentration were automatically processed, and the lignans were separated rapidly and well. Seven lignans of Magnoliae Flos including epieudesmin, magnolin, 1-irioresinol-B-dimethyl ether, epi-magnolin, fargesin aschantin, and demethoxyaschantin were identified by comparing their retention behavior, UV spectra, and mass spectra with those of reference substances or literature data. The developed method was validated, and the good results showed that the method was not only automatic and rapid, but also accurate and reliable. The turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry method holds a high potential to become an effective method for the quality control of lignans in Magnoliae Flos and a useful tool for the analysis of other complex mixtures.

  5. Quantitative analysis of ripasudil hydrochloride hydrate and its impurities by reversed-phase high-performance liquid chromatography after precolumn derivatization: Identification of four impurities.

    PubMed

    Hui, Wenkai; Sun, Lili; Zhang, Hui; Zou, Liang; Zou, Qiaogen; Ouyang, Pingkai

    2016-09-01

    We report the development and validation of a stability-indicating reversed-phase high-performance liquid chromatography method with precolumn derivatization for the separation and identification of the impurities of ripasudil hydrochloride hydrate, a novel protein kinase inhibitor. 2,3,4,6-Tetra-O-acetyl-β-d-glucopyranosyl isothiocyanate was chosen as the derivatizing reagent and triethylamine was added as catalyst. 200 μL sample solution (1 mg/mL), 600 μL derivatizing reagent (1 mg/mL), and 200 μL triethylamine solution (1%, v/v) were mixed and reacted at 40°C for 30 min. The separation was achieved on an Inertsil C18 ODS-3 (250 mm × 4.6 mm, 5 μm) column using mobile phases including 10 mmol monopotassium phosphate buffer (pH 3.0) and methanol in gradient mode. The column temperature was adjusted at 25°C and the flow rate at 1 mL/min. The detection was carried out at 220 nm. Different precolumn derivatization conditions as well as the high-performance liquid chromatography conditions were optimized. Ripasudil hydrochloride hydrate and its four impurities were detected and quantitated, among which two new compounds were characterized. The proposed method was validated and proven to be selective, accurate, and precise and suitable for the quantitative analysis of ripasudil hydrochloride hydrate.

  6. High Performance Liquid Chromatography-Diode Array Detector Method for the Simultaneous Determination of Five Compounds in the Pulp and Seed of Sea Buckthorn

    PubMed Central

    Zhao, Lu; Wen, E; Upur, Halmuart; Tian, Shuge

    2017-01-01

    Context: Sea buckthorn (Hippophae rhamnoides L.) as a traditional Chinese medicinal plant has various uses in Xinjiang. Objective: A reversed-phase rapid-resolution liquid-chromatography method with diode array detector was developed for simultaneous determination of protocatechuic acid, rutin, quercetin, kaempferol, and isorhamnetin in the pulp and seed of sea buckthorn, a widely used traditional Chinese medicine for promoting metabolism and treating scurvy and other diseases. Settings and design: Compounds were separated on an Agilent ZORBAX SB-C18 column (4.6 mm × 250 mm, 5 μm; USA) with gradient elution using methanol and 0.4% phosphoric acid (v/v) at 1.0 mL/min. Detection wavelength was set at 280 nm. Materials and Methods: The fruits of wild sea buckthorn were collected from Wushi County in Aksu, Xinjiang Province. Statistical performances: The RSD of precision test of the five compounds were in the range of 0.60-2.22%, and the average recoveries ranged from 97.36% to 101.19%. Good linearity between specific chromatographic peak and component qualities were observed in the investigated ranges for all the analytes (R2 > 0.9997). Results: The proposed method was successfully applied to determine the levels of five active components in sea buckthorn samples from Aksu in Xinjiang. Conclusions: The proposed method is simple, fast, sensitive, accurate, and suitable for quantitative assessment of the pulp and seed of sea buckthorn. SUMMARY Quantitative analysis method of protocatechuic acid, rutin, quercetin, kaempferol, and isorhamnetin in the extract of sea buckthorn pulp and seed is developed by high-performance liquid chromatography (HPLC) diode array detection.This method is simple and accurate; has strong specificity, good precision, and high recovery rate; and provides a reliable basis for further development of the substances in the pulp and seed of sea buckthorn.The method is widely used for content determination of active ingredients or physiologically

  7. Determination of total phthalates in edible oils by high-performance liquid chromatography coupled with photodiode array detection.

    PubMed

    Xie, Qilong; Sun, Dekui; Han, Yangying; Jia, Litao; Hou, Bo; Liu, Shuhui; Li, Debao

    2016-03-01

    The previously reported procedure for the determination of the total phthalate in fatty food involved the extraction of phthalates using chloroform/methanol followed by the removal of the solvents before alkaline hydrolysis requiring 20 h and derivatization of phthalic acid. In this study, a phase-transfer catalyst (tetrabutylammonium chloride) was used in the liquid-liquid heterogeneous hydrolysis of phthalates in oil matrix shortening the reaction time to within 25 min. The resulting phthalic acid in the hydrolysate was extracted by a novel molecular complex based dispersive liquid-liquid microextraction method coupled with back-extraction before high-performance liquid chromatography coupled with photodiode array detection. Under the optimal experimental conditions, the linearity of the method was in the range of 0.5-12 nmol/g with the correlation coefficients (r) >0.997. The detection limit (S/N = 3) was 0.11 nmol/g. Intraday and interday repeatability values expressed as relative standard deviation were 3.9 and 7.1%, respectively. The recovery rates ranged from 82.4 to 99.0%. The developed method was successfully applied for the analysis of total phthalate in seven edible oils.

  8. Emerging approaches to estimate retention factors in high performance liquid chromatography.

    PubMed

    Bermúdez-Saldaña, José María; Escuder-Gilabert, Laura; Villanueva-Camañas, Rosa María; Medina-Hernández, María José; Sagrado, Salvador

    2005-11-11

    The retention factor is one of the most universally used parameters in chromatography. The errors associated with the conventional ways to determine the retention factor of compounds in liquid chromatography are studied and compared with those corresponding to new approaches. The later avoid the use of extra-column time and hold-up time values, which have proven to be tedious and ambiguous. Simulations and real data, used to examine the accuracy of four different approaches (two classic and two new), suggest that the new approaches could be considered more satisfactory than the classic ones.

  9. Rapid determination of beta-aminoisobutyric acid by reversed-phase high-performance liquid chromatography.

    PubMed

    Ladrón de Guevara, O; Cortinas de Nava, C; Padilla, P; Espinosa, J; Cebrian, M; García, L

    1990-06-08

    For the determination of beta-aminoisobutyric acid (BAIBA) in urine samples in which the beta-alanine concentrations are higher than those of BAIBA, the resolution between these two amino acids, separated by reversed-phase liquid chromatography on an octadecylsilane column, was optimized. The chromatographic analysis included precolumn derivatization of amino acids with o-phthalaldehyde, followed by a 15-min isocratic elution and detection at 340 nm. Because of its simplicity, this method should be useful for monitoring urinary excretion of BAIBA.

  10. Separation of Long and Short Chain Fatty Acids as Naphthacyl and Substituted Phenacyl Esters by High Performance Liquid Chromatography.

    DTIC Science & Technology

    High performance liquid chromatography of various C2 - C24 fatty acids was run on their p-bromophenacyl, p-nitrophenacyl, p-chlorophenacyl, and 2--naphthacyl esters. All the separations were accomplished using reversed phase columns with the eluent consisting of an acetonitrile:water gradient. For all derivatives tested the separations were well defined and analogous although certain esters eluted together as one peak. Quantitative results indicate that the limit of detection in the present study was two picograms of n-caproic acid and 10 picograms of

  11. Determination of sulfates and glucuronides of endogenic steroids in biofluids by high-performance liquid chromatography/orbitrap mass spectrometry

    NASA Astrophysics Data System (ADS)

    Semenistaya, E. N.; Virus, E. D.; Rodchenkov, G. M.

    2009-04-01

    the possibility of selective determination of testosterone and epitestosterone glucuronides in urine by high-performance liquid chromatography/high-resolution mass spectrometry using solid phase microextraction on a meps cartridge was studied. the effect of the biological matrix on the spectra of conjugated steroids can be taken into account by using the spectra of conjugates recorded for urine samples after hydrolysis as reference spectra. the conditions of fragmentation in the ion source were optimized for separate analytes. this method was used for analyzing real samples with different testosterone/epitestosterone ratios. variations in conjugate contents and qualitative changes in the steroid profile of endogenic compounds were observed.

  12. Investigation into the temporal stability of aqueous standard solutions of psilocin and psilocybin using high performance liquid chromatography.

    PubMed

    Anastos, N; Barnett, N W; Pfeffer, F M; Lewis, S W

    2006-01-01

    This paper reports an investigation into the temporal stability of aqueous solutions of psilocin and psilocybin reference drug standards over a period of fourteen days. This study was performed using high performance liquid chromatography utilising a (95:5% v/v) methanol: 10 mM ammonium formate, pH 3.5 mobile phase and absorption detection at 269 nm. It was found that the exclusion of light significantly prolonged the useful life of standards, with aqueous solutions of both psilocin and psilocybin being stable over a period of seven days.

  13. High-performance liquid chromatographic determination of free and total polyamines in human serum as fluorescamine derivatives.

    PubMed

    Kai, M; Ogata, T; Haraguchi, K; Ohkura, Y

    1979-06-11

    A highly sensitive and simple fluorimetric method for the determination of free and total polyamines, spermidine, spermine, putrescine and cadaverine, in human serum by high-performance liquid chromatography is described. The polyamines, obtained after clean-up of deproteinized serum by Cellex P column chromatography, are converted to their fluorescamine derivatives in the presence of nickel ion which inhibits the reaction of interfering amines with fluorescamine, and the derivatives are separated simultaneously by reversed-phase chromatography (LiChrosorb RP-18) with a linear gradient elution. The lower limits of detection are 10 and 15 pmole for spermine and the others in 0.5 ml of serum, respectively.

  14. Determination of oxytetracycline in milk samples by polymer inclusion membrane separation coupled to high performance liquid chromatography.

    PubMed

    Pérez-Silva, Irma; Rodríguez, José A; Ramírez-Silva, Ma Teresa; Páez-Hernández, Ma Elena

    2012-03-09

    The determination of oxytetracycline in milk samples using a polymer inclusion membrane concept with high performance liquid chromatography (HPLC) was studied. The membranes developed are composed by cellulose acetate as polymer base, Cyanex 923 as carrier and o-nitrophenyl octyl ether as plasticizer. In the optimal conditions, the method exhibits good linearity in the range 0.03-0.20 mg L(-1) with a limit of detection and quantification of 8.2 and 27.3 μg L(-1) respectively. The method was successfully applied to the analysis of milk samples with high selectivity.

  15. Improvement of the analysis of dansylated derivatives of polyamines and their conjugates by high-performance liquid chromatography.

    PubMed

    Fontaniella, B; Mateos, J L; Vicente, C; Legaz, M E

    2001-06-15

    The paper described a method for improving the hydrolysis of conjugated polyamines in PH fraction, isolated from the lichen Evernia prunastri, as well as the optimization of dansylation procedure of these polyamines on the basis of the pH value to which derivatization is achieved. Dansylated polyamines have been later separated by high-performance liquid chromatography (HPLC) using a gradient elution. Hydrolysis of conjugates requires acid treatment at room temperature rather than at 110 degrees C, as usually described. Dansylation is improved at high pH values, whereas removal of phenolics (mainly evernic acid), from the conjugates requires low pH values.

  16. Rapid determination of quinolones in cosmetic products by ultra high performance liquid chromatography with tandem mass spectrometry.

    PubMed

    Liu, Shao-Ying; Huang, Xi-Hui; Wang, Xiao-Fang; Jin, Quan; Zhu, Guo-Nian

    2014-05-01

    This study developed an improved analytical method for the simultaneous quantification of 13 quinolones in cosmetics by ultra high performance liquid chromatography combined with ESI triple quadrupole MS/MS under the multiple reaction monitoring mode. The analytes were extracted and purified by using an SPE cartridge. The limits of quantification ranged from 0.03 to 3.02 μg/kg. The precision for determining the quinolones was <19.39%. The proposed method was successfully developed for the determination of quinolones in real cosmetic samples.

  17. [Study on the reaction mechanism of chloroacetanilide herbicides with urease using fluorescence spectrum and high-performance liquid chromatography].

    PubMed

    Liu, Hui-jun; Zhan, Xiu-Ming; Li, Ke-bin; Liu, Wei-ping

    2005-03-01

    The relationship between excess thermodynamic function and binding to urease of four chloroacetanilide herbicides was studied using high-performance liquid chromatography and fluorescence spectrum. The linear relationship between the composition of mobile phase of RP-HPLC and the capacity factor of chloroacetanilide herbicides has been obtained. The excess thermodynamic enthalpy (deltaH* ) of acetochlor, pretilachlor, butachlor and metolachlor was determined, and the binding constant K and the number of binding sites with urease were calculated. The relationship between excess thermodynamic function and the binding constant K was suggested.

  18. High-performance liquid chromatographic determination of benzalkonium and naphazoline or tetrahydrozoline in nasal and ophthalmic solutions.

    PubMed

    Santoni, G; Medica, A; Gratteri, P; Furlanetto, S; Pinzauti, S

    1994-11-01

    A high-performance liquid chromatographic method is described for the determination of benzalkonium chloride homologues and naphazoline nitrate or tetrahydrozoline hydrochloride in ophthalmic and nasal solutions. The technique involves a one-step dilution (1:5) for sample preparation and direct injection onto a 5 mm RP C-8 column. The mobile phase is acetonitrile-diluted acetic acid (80:20, v/v) with 6 mM tetramethylammonium bromide. Detection is carried out at 260 nm with a diode array. The method is rapid, specific, reproducible and is especially useful for quality control procedures.

  19. Varietal differences among the flavonoid profiles of white grape cultivars studied by high-performance liquid chromatography.

    PubMed

    Masa, A; Vilanova, M; Pomar, F

    2007-09-14

    In order to develop a method that allows to distinguish between white grape cultivars, the flavonoid profiles of 10 white accessions from the "Misión Biológica de Galicia" germplasm collection were studied during years 2003, 2004 and 2005 by high-performance liquid chromatography (HPLC). Twenty-four flavonoids (15 flavonols and 9 dihydroflavonols) were totally or partly identified, and significant differences between the studied flavonoid markers were found. With this method all the cultivars examined could be easily distinguished from each other, and we may conclude that this has been proved to be of great value for white grape cultivar recognition.

  20. Use of High-Performance Liquid Chromatography To Study the Pharmacokinetics of Colistin Sulfate in Rats following Intravenous Administration

    PubMed Central

    Li, Jian; Milne, Robert W.; Nation, Roger L.; Turnidge, John D.; Smeaton, Timothy C.; Coulthard, Kingsley

    2003-01-01

    The pharmacokinetics of colistin was investigated using specific high-performance liquid chromatography (HPLC) to measure the concentrations of colistin and colistin A and B in plasma and urine in five rats after administration of an intravenous bolus of 1 mg of colistin sulfate/kg of body weight. There were differences in the pharmacokinetic behaviors of unbound colistin A and B. This is the first report of the use of HPLC to study the pharmacokinetics of colistin and its two major components. PMID:12709357

  1. High-performance liquid chromatography-tandem mass spectrometry validation of medroxyprogesterone acetate in products of pork origin and serum.

    PubMed

    Giannetti, Luigi; Barchi, Daniela; Fiorucci, Fulvia; Gennuso, Elisa; Sanna, Patrizia; Pallagrosi, Marco; Neri, Bruno

    2005-08-01

    Different extraction and purification methods are described here to determine medroxyprogesterone acetate (MPA) in pork meat and serum. Spiked samples are investigated over the concentration range of MPA 0.5-20 ng/g. Pork meat tissues are subjected to extraction using organic solvent, and pork serum is simply diluted with acetate buffer. Clean-up is performed using solid-phase extraction on a C18 cartridge, and MPA is eluted with ethanol. Aliquots are injected into a high-performance liquid chromatography-mass spectrometry system. MPA content is determined on the basis of m/z 387-327 and 387-123 transitions.

  2. Synthesis of novel glucose-based polymers and their applications as chiral stationary phases for high performance liquid chromatography.

    PubMed

    Ikai, Tomoyuki; Yamada, Takayuki

    2016-01-01

    Two novel polymers containing glucose units as the main-chain that only differ in terms of their regioregularity were synthesized to evaluate their chiral recognition abilities as chiral stationary phases (CSPs) for high performance liquid chromatography (HPLC). The regioregular polymer (poly-5) shows clear resolution ability for the racemate of cobalt (III) acetylacetonate (Co(acac)3), whereas the corresponding regioirregular polymer (poly-3) does not show any chiral recognition for Co (acac)3. The regioregular polymer main-chain seems to play an important role not only in providing an efficient interaction with the racemate but also in expressing the chiral recognition ability as a CSP for HPLC.

  3. Effects of boiling duration in processing of White Paeony Root on its overall quality evaluated by ultra-high performance liquid chromatography quadrupole/time-of-flight mass spectrometry based metabolomics analysis and high performance liquid chromatography quantification.

    PubMed

    Ming, Kong; Xu, Jun; Liu, Huan-Huan; Xu, Jin-Di; Li, Xiu-Yang; Lu, Min; Wang, Chun-Ru; Chen, Hu-Biao; Li, Song-Lin

    2017-01-01

    Boiling processing is commonly used in post-harvest handling of White Paeony Root (WPR), in order to whiten the herbal materials and preserve the bright color, since such WPR is empirically considered to possess a higher quality. The present study was designed to investigate whether and how the boiling processing affects overall quality of WPR. First, an ultra-high performance liquid chromatography quadrupole/time-of-flight mass spectrometry-based metabolomics approach coupled with multivariate statistical analysis was developed to compare the holistic quality of boiled and un-boiled WPR samples. Second, ten major components in WPR samples boiled for different durations were quantitatively determined using high performance liquid chromatography to further explore the effects of boiling time on the holistic quality of WPR, meanwhile the appearance of the processed herbal materials was observed. The results suggested that the boiling processing conspicuously affected the holistic quality of WPR by simultaneously and inconsistently altering the chemical compositions and that short-time boiling processing between 2 and 10 min could both make the WPR bright-colored and improve the contents of major bioactive components, which were not achieved either without boiling or with prolonged boiling. In conclusion, short-term boiling (2-10 min) is recommended for post-harvest handling of WPR.

  4. Peptide profiling of Internet-obtained Cerebrolysin using high performance liquid chromatography - electrospray ionization ion trap and ultra high performance liquid chromatography - ion mobility - quadrupole time of flight mass spectrometry.

    PubMed

    Gevaert, Bert; D'Hondt, Matthias; Bracke, Nathalie; Yao, Han; Wynendaele, Evelien; Vissers, Johannes Petrus Cornelis; De Cecco, Martin; Claereboudt, Jan; De Spiegeleer, Bart

    2015-09-01

    Cerebrolysin, a parenteral peptide preparation produced by controlled digestion of porcine brain proteins, is an approved nootropic medicine in some countries. However, it is also easily and globally available on the Internet. Nevertheless, until now, its exact chemical composition was unknown. Using high performance liquid chromatography (HPLC) coupled to ion trap and ultra high performance liquid chromatography (UHPLC) coupled to quadrupole-ion mobility-time-of-flight mass spectrometry (Q-IM-TOF MS), combined with UniProt pig protein database search and PEAKS de novo sequencing, we identified 638 unique peptides in an Internet-obtained Cerebrolysin sample. The main components in this sample originate from tubulin alpha- and beta-chain, actin, and myelin basic protein. No fragments of known neurotrophic factors like glial cell-derived neurotrophic factor (GDNF), neurotrophin nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and ciliary neurotrophic factor (CNTF) were found, suggesting that the activities reported in the literature are likely the result of new, hitherto unknown cryptic peptides with nootropic properties.

  5. Methods of analysis by the U.S. Geological Survey Organic Geochemistry Research Group; determination of chloroacetanilide herbicide metabolites in water using high-performance liquid chromatography-diode array detection and high-performance liquid chromatography/mass spectrometry

    USGS Publications Warehouse

    Zimmerman, L.R.; Hostetler, K.A.; Thurman, E.M.

    2000-01-01

    Analytical methods using high-performance liquid chromatography-diode array detection (HPLC-DAD) and high-performance liquid chromatography/mass spectrometry (HPLC/MS) were developed for the analysis of the following chloroacetanilide herbicide metabolites in water: acetochlor ethanesulfonic acid (ESA), acetochlor oxanilic acid (OXA), alachlor ESA, alachlor OXA, metolachlor ESA, and metolachlor OXA. Good precision and accuracy were demonstrated for both the HPLC-DAD and HPLC/MS methods in reagent water, surface water, and ground water. The mean HPLC-DAD recoveries of the chloroacetanilide herbicide metabolites from water samples spiked at 0.25, 0.50, and 2.0 mg/L (micrograms per liter) ranged from 84 to 112 percent, with relative standard deviations of 18 percent or less. The mean HPLC/MS recoveries of the metabolites from water samples spiked at 0.05, 0.20, and 2.0 mg/L ranged from 81 to 125 percent, with relative standard deviations of 20 percent or less. The limit of quantitation (LOQ) for all metabolites using the HPLC-DAD method was 0.20 mg/L, whereas the LOQ using the HPLC/MS method was 0.05 mg/L. These metabolite-determination methods are valuable for acquiring information about water quality and the fate and transport of the parent chloroacetanilide herbicides in water.

  6. High-performance liquid chromatography determination of direct and temporary dyes in natural hair colourings.

    PubMed

    Scarpi, C; Ninci, F; Centini, M; Anselmi, C

    1998-02-20

    A simple and reliable HPLC method is described for the simultaneous determination of nine direct and temporary hair dyes in hair colourings containing vegetal extracts. Detection was performed by a diode array detector and two different wavelengths, in the visible range (450 and 650 nm), were used for quantitation. The method does not involve any extraction procedure and it is sufficiently rapid and accurate for routine analyses. The method described was successfully applied to the identification of synthetic organic dyes in 13 direct and temporary hair dyeing formulations commercialized as 'natural'.

  7. Robotic sample preparation and high-performance liquid chromatographic analysis of verlukast in human plasma.

    PubMed

    Hsieh, J Y; Lin, C; Matuszewski, B K

    1994-11-18

    A fully automated HPLC assay has been developed and validated for the quantitation of verlukast, a leukotriene D4 antagonist, in human plasma. An upgraded Zymate I robotic system was utilized to perform protein precipitation and on-line injection followed by reversed-phase HPLC with fluorescence detection. Inter-day accuracy and precision were 100.8 and 4.6%, respectively, for the low quality control standards (0.125 microgram/ml). The automated robotic method was shown to be more efficient and accurate than the manual method.

  8. Quantification of zolpidem in human plasma by high-performance liquid chromatography with fluorescence detection.

    PubMed

    Nirogi, Ramakrishna V S; Kandikere, Vishwottam N; Shrivasthava, Wishu; Mudigonda, Koteshwara

    2006-10-01

    A simple, reliable HPLC method with fluorescence detection (excitation 320 and emission 388 nm) was developed and validated for quantitation of zolpidem in human plasma. Following a single-step liquid-liquid extraction, the analyte and internal standard (quinine) were separated using an isocratic mobile phase on a reversed-phase C(18) column. The lower limit of quantitation was 1.8 ng/mL, with a relative standard deviation of less than 5%. A linear dynamic range of 1.8-288 ng/mL was established. This HPLC method was validated with between-batch and within-batch precision of 1.7-4.8 and 1.2-2.3%, respectively. The between-batch and within-batch accuracy was 95.3-100.4 and 95.5-102.7%, respectively. Frequently coadministered drugs did not interfere with the described methodology. Stability of zolpidem in plasma was excellent, with no evidence of degradation during sample processing (autosampler) and 30 days storage in a freezer. This validated method is simple and repeatable enough to be used in pharmacokinetic studies.

  9. A monolithic functional film of nanotubes/cellulose/ionic liquid for high performance supercapacitors

    NASA Astrophysics Data System (ADS)

    Basiricò, Lucia; Lanzara, Giulia

    2014-12-01

    A novel monolithic, pre-fabricated, fully functional film made of a nanostructured free-standing layer is presented for a new and competitive class of easy-to-assemble flexible supercapacitors whose design is in-between the all solid state and the traditional liquid electrolyte. The film is made of two vertically aligned multi-walled carbon nanotube (VANT) electrodes that store ions, embedded-in, and monolithically interspaced by a solution of microcrystalline cellulose in a room temperature ionic liquid (RTIL) electrolyte (1-ethyl-3-methylimidazolium acetate-EMIM Ac). The fine tuning of VANTs length and electrolyte/cellulose amount leads, in a sole and continuous block, to ions storage and physical separation between the electrodes without the need of the additional separator layer that is typically used in supercapacitors. Thus, physical discontinuities that can induce disturbances to ions mobility, are fully eliminated significantly reducing the equivalent series resistance and increasing the knee frequency, hence outclassing the best supercapacitors based on VANTs and non-aqueous electrolytes. The excellent electrochemical response can also be addressed to the chosen electrolyte that, not only has the advantage of leading to a significantly simpler and more affordable fabrication procedure, but has higher ionic conductivity, lower viscosity and higher ions mobility than other electrolytes capable of dissolving cellulose.

  10. One-pot preparation of a novel monolith for high performance liquid chromatography applications.

    PubMed

    Jiao, Xiaoyan; Shen, Shigang; Shi, Tiesheng

    2015-12-15

    Various novel porous organic-based monoliths with the mode of hydrophobicity were synthesized by in situ free-radical crosslinking copolymerization and optimized for the separations of small molecules and high-performance reversed-phase chromatography (RP-chromatography). These monoliths contained co-polymers based on glycidyl methacrylate (GMA)/ethylene glycol dimethacrylate (EDMA)/tripropylene glycol diacrylate (TPGDA) or EDMA/TPGDA. A mixture of cetanol, methanol and poly (ethylene glycol) (PEG) was used as the porogen, with the ratio of these solvents being varied along with the polymerization temperature to generate a library of monoliths. The conditions were optimized and the resulting poly (GMA-co-TPGDA-co-EDMA) monolith was investigated by infrared spectrometer (IR), field emission scanning electron microscope (FESEM), and mercury intrusion porosimetry (MIP), respectively. The column performance was assessed by the separation of a series of neutral solutes of benzene derivatives. The result demonstrated that the prepared monolith exhibited an RP-chromatographic behavior and relatively homogeneous structure, good permeability and separation performance. Moreover, the relative standard deviations (RSDs) of the retention factor values for benzene derivatives were less than 1.5% (n=7, column-to-column). The approach used in this study was extended to the separation of anilines.

  11. Fast and comprehensive analysis of secondary metabolites in cocoa products using ultra high-performance liquid chromatography directly after pressurized liquid extraction.

    PubMed

    Damm, Irina; Enger, Eileen; Chrubasik-Hausmann, Sigrun; Schieber, Andreas; Zimmermann, Benno F

    2016-08-01

    Fast methods for the extraction and analysis of various secondary metabolites from cocoa products were developed and optimized regarding speed and separation efficiency. Extraction by pressurized liquid extraction is automated and the extracts are analyzed by rapid reversed-phase ultra high-performance liquid chromatography and normal-phase high-performance liquid chromatography methods. After extraction, no further sample treatment is required before chromatographic analysis. The analytes comprise monomeric and oligomeric flavanols, flavonols, methylxanthins, N-phenylpropenoyl amino acids, and phenolic acids. Polyphenols and N-phenylpropenoyl amino acids are separated in a single run of 33 min, procyanidins are analyzed by normal-phase high-performance liquid chromatography within 16 min, and methylxanthins require only 6 min total run time. A fourth method is suitable for phenolic acids, but only protocatechuic acid was found in relevant quantities. The optimized methods were validated and applied to 27 dark chocolates, one milk chocolate, two cocoa powders and two food supplements based on cocoa extract.

  12. Identification and quantification of cannabinoids in Cannabis sativa L. plants by high performance liquid chromatography-mass spectrometry.

    PubMed

    Aizpurua-Olaizola, Oier; Omar, Jone; Navarro, Patricia; Olivares, Maitane; Etxebarria, Nestor; Usobiaga, Aresatz

    2014-11-01

    High performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) has been successfully applied to cannabis plant extracts in order to identify cannabinoid compounds after their quantitative isolation by means of supercritical fluid extraction (SFE). MS conditions were optimized by means of a central composite design (CCD) approach, and the analysis method was fully validated. Six major cannabinoids [tetrahydrocannabinolic acid (THCA), tetrahydrocannabinol (THC), cannabidiol (CBD), tetrahydrocannabivarin (THCV), cannabigerol (CBG), and cannabinol (CBN)] were quantified (RSD < 10%), and seven more cannabinoids were identified and verified by means of a liquid chromatograph coupled to a quadrupole-time-of-flight (Q-ToF) detector. Finally, based on the distribution of the analyzed cannabinoids in 30 Cannabis sativa L. plant varieties and the principal component analysis (PCA) of the resulting data, a clear difference was observed between outdoor and indoor grown plants, which was attributed to a higher concentration of THC, CBN, and CBD in outdoor grown plants.

  13. Rapid and sensitive high-performance liquid chromatographic determination of nicotine and cotinine in nonsmoker human and rat urines.

    PubMed

    Oddoze, C; Pauli, A M; Pastor, J

    1998-04-24

    A simple reversed-phase high-performance liquid chromatographic method with paired-ion and UV detection has been developed for the rapid quantification of urinary nicotine and cotinine. A one-step solid-liquid extraction on Extrelut was used. Separation from endogenous substances was achieved with a decreasing flow-rate. With 20 ml of urine for extraction, the limit of quantification was 0.5 ng/ml for cotinine and 5 ng/ml for nicotine; linearity was obtained from 50 to 5000 ng/ml. The intra- and inter-day coefficients of variation were less than 9% for cotinine and 30% for nicotine. Average recoveries for cotinine were 92-100% and 47-86% for nicotine. The present method was applied to the urine analysis of smokers, nonsmoker children, and experimental animals.

  14. Self-immobilization of poly(methyloctylsiloxane) on high-performance liquid chromatographic silica.

    PubMed

    Collins, Kenneth E; Bottoli, Carla B G; Vigna, Camila R M; Bachmann, Stefan; Albert, Klaus; Collins, Carol H

    2004-03-12

    Poly(methyloctylsiloxane) (PMOS) was deposited on HPLC silica by a solvent evaporation procedure and this material was then extracted, using a good solvent for the PMOS, after different time periods, to remove unretained liquid polymer. Solvent extraction data reveal changes which occur at ambient temperature as a function of the time interval between particle loading and extraction. The quantity of PMOS remaining on the silica after extraction, as determined by elemental analysis for carbon, is attributed to strongly adsorbed polymer. This phenomenon is termed self-immobilization. Solid-state 29Si NMR spectra indicate the formation of a silicon species with a different chemical shift than the original PMOS. These new signals are attributed to a combination of different adsorbed and chemically bonded groups.

  15. Determination of abamectin residues in fruits and vegetables by high-performance liquid chromatography.

    PubMed

    Diserens, H; Henzelin, M

    1999-02-12

    A rapid and sensitive HPLC method has been developed and validated for the determination of abamectin residues (avermectin B1a and B1b, as well as the metabolite 8,9-Z-avermectin B1) in apples, pears and tomatoes. Residues are extracted with acetonitrile. The diluted extract is cleaned up on a C18 solid-phase extraction cartridge. Abamectin residues are derivatised with trifluoroacetic acid and 1-methylimidazole and determined by reversed-phase liquid chromatography with fluorescence detection (excitation: 365 nm and emission: 470 nm). High and consistent recoveries, ranging from 88 to 106%, were obtained, at spiking levels of 10, 20 and 50 micrograms/kg, when analysing apples, pears and tomatoes.

  16. Simultaneous determination of cefepime and grepafloxacin in human urine by high-performance liquid chromatography.

    PubMed

    Ocaña González, J A; Jiménez Palacios, F J; Callejón Mochón, M; Barragán de la Rosa, F J

    2004-09-21

    A liquid chromatographic method with UV detection for simultaneous determination of cefepime and grepafloxacin has been developed. The method uses a C18 column, equipped with a pre-column of the same material, and acetonitrile-0.1 M phosphoric acid/sodium hydroxide buffer (pH 3.0)-0.01 M n-octylamine (pH 3.0) as mobile phase in gradient mode. Mobile flow rate and sample volume injected were 1.3 mL min(-1) and 20 microL, respectively. Detection wavelengths were 259 nm for cefepime and 278 nm for grepafloxacin. The retention times were 4.03 min for cefepime and 8.85 min for grepafloxacin, with detection limits of 1.0 and 1.1 microg mL(-1), respectively. The method was applied to the determination of both antibiotics in spiked samples of human urine.

  17. Phytochemical analysis of Hibiscus caesius using high performance liquid chromatography coupled with mass spectrometry.

    PubMed

    Ain, Quratul; Naveed, Muhammad Na; Mumtaz, Abdul Samad; Farman, Muhammad; Ahmed, Iftikhar; Khalid, Nauman

    2015-09-01

    Various species in genus Hibiscus are traditionally known for their therapeutic attributes. The present study focused on the phytochemical analysis of a rather unexplored species Hibiscus caesius (H. caesius), using high-pressure liquid chromatography coupled with mass spectrometry (HPLC-MS). The analysis revealed five major compounds in the aqueous extract, viz. vanillic acid, protocatechoic acid, quercetin, quercetin glucoside and apigenin, being reported for the first time in H. caesius. Literature suggests that these compounds have important pharmacological traits such as anti-cancer, anti-inflammatory, anti-bacterial and hepatoprotective etc. however, this requires further pharmacological investigations at in vitro and in vivo scale. The above study concluded the medicinal potential of H. caesius.

  18. Systematic toxicological analysis by high-performance liquid chromatography with diode array detection (HPLC-DAD).

    PubMed

    Pragst, Fritz; Herzler, Matthias; Erxleben, Björn-Thoralf

    2004-01-01

    In recent years, photodiode array detectors (DADs) have been much improved with respect to wavelength accuracy and resolution, sensitivity, linearity and software operation. UV spectra of drugs measured with up-to-date DADs from different manufacturers are in excellent agreement, have the same quality as measured by a conventional UV spectrometer and are highly reproducible. The calculation of similarity parameters by the DAD software includes the entire range of the spectra compared and allows recognition of very small differences. It was shown in a systematic study of more than 2500 toxicologically relevant substances that UV spectra have a very high specificity with respect to substance structure. Therefore, HPLC-DAD in combination with a comprehensive database of UV spectra and retention parameters is one of the most efficient techniques used in systematic toxicological analysis (STA). Furthermore, the method is advantageous for the identification of metabolites, since in many cases they have the same or very similar UV spectra compared with their respective parent substances and their retention times on reversed-phase columns are shifted in a manner typical of the particular biotransformation reaction. Beside these general aspects, practical applications of HPLC-DAD for STA are reviewed with respect to sample preparation and chromatographic conditions. The efficiency of the method is demonstrated for an example of a routine procedure using liquid-liquid extraction with CH 2 Cl 2 and protein precipitation for sample preparation, a system of three isocratic mobile phases with different acetonitrile/phosphate buffer ratios and RP8 columns for chromatography and a database of 2682 UV spectra and relative retention times for substance identification.

  19. Quantification of ACE inhibiting peptides in human plasma using high performance liquid chromatography-mass spectrometry.

    PubMed

    van Platerink, Chris J; Janssen, Hans-Gerd M; Horsten, Roos; Haverkamp, Johan

    2006-01-02

    An HPLC-MRM-MS method was developed for the quantification of 17 small ACE inhibiting (ACEI) peptides in plasma samples collected from human volunteers after the consumption of a peptide-enriched drink. The assay shows the high selectivity and sensitivity necessary to monitor small changes in the levels of the ACEI peptides after consumption of drinks developed to effect lowering of the blood pressure. Four different sample preparation methods were tested and evaluated. The final sample preparation method selected is simple and effective and consists mainly of the removal of proteins by acidification and heating, followed by a large volume injection. Additional sample preparation steps such as solid phase extraction and liquid/liquid partitioning were studied. Although they resulted in cleaner extracts, losses of specific peptides such as SAP were frequently seen. The isotope labeled form of one of the peptides to be quantified, [U(13)C]IPP, was used as an internal standard. The limit of detection of the assay is below 0.01 ng ml(-1). The limit of quantification is between 0.05 and 0.2 ng ml(-1), which is approximately 10% of the expected peptide concentration in plasma based on a normal diet. The intra- and inter-day relative standard deviations for all peptides have shown to be below 25% and the method has an accuracy of better than 75%. The long-term stability is good. At least 200 samples could be analysed before the system had to be cleaned. The assay has been successfully applied to blood samples collected from volunteers during a human trial.

  20. High-performance liquid chromatographic determination of tianeptine in plasma applied to pharmacokinetic studies.

    PubMed

    Gaulier, J M; Marquet, P; Lacassie, E; Desroches, R; Lachatre, G

    2000-10-10

    An improved analytical method for the quantitative measurement of tianeptine and its main metabolite MC5 in human plasma was designed. Extraction involved ion-paired liquid-liquid extraction of the compounds from 1.0 ml of human plasma adjusted to pH 7.0. HPLC separation was performed using a Nucleosil C18, 5 microm column (150x4.6 mm I.D.) and a mixture of acetonitrile and pH 3, 2.7 g l(-1) solution of sodium heptanesulfonate in distilled water (40:60, v/v) as mobile phase. UV detection was performed using a diode array detector in the 200-400 nm passband, and quantification of the analytes was made at 220 nm. For both tianeptine and MC5 metabolite, the limit of quantitation was 5 microg l(-1) and the calibration curves were linear from 5 to 500 microg l(-1). Intra- and inter-assay precision and accuracy fulfilled the international requirements. The recovery of tianeptine and its metabolite from plasma was, respectively, 71.5 and 74.3% at 20 microg l(-1), 71.2 and 70.8% at 400 microg l(-1). The selectivity of the method was checked by verifying the absence of chromatographic interference from pure solutions of the most commonly associated therapeutic drugs. This method, validated according to the criteria established by the Journal of Chromatography B, was applied to the determination of tianeptine and MC5-metabolite in human plasma in pharmacokinetic studies.