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

PubMed

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

2015-12-04

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

Stereochemistry of C18 monounsaturated cork suberin acids determined by spectroscopic techniques including (1) H-NMR multiplet analysis of olefinic protons.

PubMed

Santos, Sara; Graça, José

2014-01-01

Suberin is a biopolyester responsible for the protection of secondary plant tissues, and yet its molecular structure remains unknown. The C18:1 ω-hydroxyacid and the C18:1 α,ω-diacid are major monomers in the suberin structure, but the configuration of the double bond remains to be elucidated. To unequivocally define the configuration of the C18:1 suberin acids. Pure C18:1 ω-hydroxyacid and C18:1 α,ω-diacid, isolated from cork suberin, and two structurally very close C18:1 model compounds of known stereochemistry, methyl oleate and methyl elaidate, were analysed by NMR spectroscopy, Fourier transform infrared (FTIR) and Raman spectroscopy, and GC-MS. The GC-MS analysis showed that both acids were present in cork suberin as only one geometric isomer. The analysis of dimethyloxazoline (DMOX) and picolinyl derivatives proved the double bond position to be at C-9. The FTIR spectra were concordant with a cis-configuration for both suberin acids, but their unambiguous stereochemical assignment came from the NMR analysis: (i) the chemical shifts of the allylic (13) C carbons were shielded comparatively to the trans model compound, and (ii) the complex multiplets of the olefinic protons could be simulated only with (3) JHH and long-range (4) JHH coupling constants typical of a cis geometry. The two C18:1 suberin acids in cork are (Z)-18-hydroxyoctadec-9-enoic acid and (Z)-octadec-9-enedoic acid. Copyright © 2013 John Wiley & Sons, Ltd.

MS(n) , LC-MS-TOF and LC-PDA studies for identification of new degradation impurities of bupropion.

PubMed

Bansal, Rohit; Saini, Balraj; Bansal, Yogita; Bansal, Gulshan

2013-11-01

Three new degradation impurities of bupropion were characterized through high performance liquid chromatography coupled to photodiode array detection and to time-of-flight mass spectrometry. Bupropion was subjected to the ICH prescribed stress conditions. It degraded to seven impurities (I-VII) in alkaline hydrolytic conditions which were optimally resolved on an XTerra C18 column (250 × 4.6 mm, 5 µm) with a ternary mobile phase comprising ammonium formate (20 mm, pH 4.0), methanol and acetonitrile (75:10:15, v/v). The degradation impurities (III-V and VII) were characterized on the basis of mass fragmentation pattern of drug, accurate mass spectral and photodiode array data of the drug and degradation impurities. Compound V was found to be a known degradation impurity [1-hydroxy-1-(3-chlorophenyl)propan-2-one], whereas III, IV and VII were characterized as 2-hydroxy-2-(3'-chlorophenyl)-3,5,5-trimethylmorpholine, (2,4,4-trimethyl-1,3-oxazolidin-2-yl)(3-chlorophenyl)-methanone and 2-(3'-chlorophenyl)-3,5,5-trimethylmorphol-2-ene, respectively. Compound III was a known metabolite of the drug. This additional information on the degradation impurities can help in the development of a new stability-indicating assay method to monitor the stability of the drug product during its shelf-life as well as in development of a drug product with increased shelf-life. Copyright © 2013 John Wiley & Sons, Ltd.

40 CFR 721.10297 - Tin, C16-18 and C18-unsatd. fatty acids castor-oil fatty acids complexes.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Tin, C16-18 and C18-unsatd. fatty... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10297 Tin, C16-18 and C18-unsatd... to reporting. (1) The chemical substance identified as tin, C16-18 and C18-unsatd. fatty acids castor...

40 CFR 721.10297 - Tin, C16-18 and C18-unsatd. fatty acids castor-oil fatty acids complexes.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Tin, C16-18 and C18-unsatd. fatty... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10297 Tin, C16-18 and C18-unsatd... to reporting. (1) The chemical substance identified as tin, C16-18 and C18-unsatd. fatty acids castor...

40 CFR 721.10297 - Tin, C16-18 and C18-unsatd. fatty acids castor-oil fatty acids complexes.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Tin, C16-18 and C18-unsatd. fatty... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10297 Tin, C16-18 and C18-unsatd... to reporting. (1) The chemical substance identified as tin, C16-18 and C18-unsatd. fatty acids castor...

Quantitative determination of cyclic phosphatidic acid and its carba analog in mouse organs and plasma using LC-MS/MS.

PubMed

Shimizu, Yoshibumi; Ishikawa, Masaki; Gotoh, Mari; Fukasawa, Keiko; Yamamoto, Shinji; Iwasa, Kensuke; Yoshikawa, Keisuke; Murakami-Murofushi, Kimiko

2018-02-15

Cyclic phosphatidic acid (cPA), an analog of lysophosphatidic acid, is involved in the regulation of many cellular processes. A sensitive and specific method to quantify the molecular species of cPA is important for studying the physiological and pathophysiological roles of cPA. Here, we developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based quantification method for the simultaneous detection of cPA species having various fatty acids (16:0, 18:0, 18:1, and 18:2) as well as 2-carba-cPA, a chemically synthesized analog of cPA. Chromatography was performed using a reversed-phase C18 column. cPA species were detected using a triple quadrupole mass spectrometer. cPA 17:0 was used as an internal standard. Intra- and interday precision values (CV%) were within 10%. The linear range of detection for each cPA species was 0.01 μg/mL to 5 μg/mL, with correlation coefficients of 0.998 or higher. The developed method was applied to the quantification of cPA species in mouse plasma and organs. The concentrations of cPA 16:0, 18:0, and 18:1 were revealed to be significantly reduced in the brains of cuprizone-treated mice, a model of multiple sclerosis, compared with control mice. These findings could be important for understanding the roles of cPA in the neurodegenerative processes associated with multiple sclerosis. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Identification of chemical markers in Cordyceps sinensis by HPLC-MS/MS.

PubMed

Hu, Hankun; Xiao, Ling; Zheng, Baogen; Wei, Xin; Ellis, Alexis; Liu, Yi-Ming

2015-10-01

Authentication and quality assessment of Cordyceps sinensis, a precious and pricey natural product that offers a variety of health benefits, is highly significant. To identify effective chemical markers, authentic C. sinensis was thoroughly screened by using HPLC-MS/MS. In addition to many previously reported ingredients, two glycosides, i.e., cyclo-Ala-Leu-rhamnose and Phe-o-glucose, were detected for the first time in this material. Six ingredients detected, including cordycepin, D-mannitol, Phe, Phe-o-glucose, cyclo-Gly-Pro, and cyclo-Ala-Leu-rhamnose, were selected as a collection of chemical markers. An HPLC-MS/MS method was developed to simultaneously quantify them with sensitivity and specificity. The method had limits of detection ranging from 0.008 μg mL(-1) for cordycepin to 0.75 μg mL(-1) for cyclo-Gly-Pro. Recovery was found between 96 and 103 % in all tests. To evaluate the effectiveness of the marker collection proposed, five authentic C. sinensis samples and five samples of its substitutes were analyzed. Cordycepin, D-mannitol, and Phe were found present in all samples. The contents ranged from 0.0076 to 0.029 % (w/w) for cordycepin, 0.33 to 18.9 % for mannitol, and 0.0013 to 0.642 % for Phe. Interestingly, the two glycosides, Phe-o-glucose and cyclo-Ala-Leu-rhamnose, were detected only in authentic C. sinensis samples. These results indicated that the proposed protocol based on HPLC-MS/MS quantification of the markers might have a great potential in authentication and quality assessment of C. sinensis. Graphical abstract Chemical markers of C. sinensis identified in this work.

Identification of alkyl dimethylbenzylammonium surfactants in water samples by solid-phase extraction followed by ion trap LC/MS and LC/MS/MS

USGS Publications Warehouse

Ferrer, I.; Furlong, E.T.

2001-01-01

A novel methodology was developed for the determination of alkyl (C12, C14, and C16) dimethylbenzylammonium chloride (benzalkonium chloride or BAC, Chemical Abstract Service number: 8001-54-5) in water samples. This method is based on solid-phase extraction (SPE) using polymeric cartridges, followed by high-performance liquid chromatography/ion trap mass spectrometry (LC/MS) and tandem mass spectrometry(MS/MS) detection, equipped with an electrospray interface in positive ion mode. Chromatographic separation was achieved for three BAC homologues by using a C18 column and a gradient of acetonitrile/10 millimolar aqueous ammonium formate. Total method recoveries were higher than 71% in different water matrices. The main ions observed by LC/MS were at mass-to-charge ratios (m/z) of 304, 332, and 360, which correspond to the molecular ions of the C12, C14, and C16 alkyl BAC, respectively. The unequivocal structural identification of these compounds in water samples was performed by LC/MS/MS after isolation and subsequent fragmentation of each molecular ion. The main fragmentation observed for the three different homologues corresponded to the loss of the toluyl group in the chemical structure, which leads to the fragment ions at m/z 212, 240, and 268 and a tropylium ion, characteristic of all homologues, at m/z 91. Detection limits for the methodology developed in this work were in the low nanogram-per-liter range. Concentration levels of BAC - ranging from 1.2 to 36.6 micrograms per liter - were found in surface-water samples collected downstream from different wastewater-treatment discharges, thus indicating its input and persistence through the wastewater-treatment process.

Sensitivity of GC-EI/MS, GC-EI/MS/MS, LC-ESI/MS/MS, LC-Ag(+) CIS/MS/MS, and GC-ESI/MS/MS for analysis of anabolic steroids in doping control.

PubMed

Cha, Eunju; Kim, Sohee; Kim, Ho Jun; Lee, Kang Mi; Kim, Ki Hun; Kwon, Oh-Seung; Lee, Jaeick

2015-01-01

This study compared the sensitivity of various separation and ionization methods, including gas chromatography with an electron ionization source (GC-EI), liquid chromatography with an electrospray ionization source (LC-ESI), and liquid chromatography with a silver ion coordination ion spray source (LC-Ag(+) CIS), coupled to a mass spectrometer (MS) for steroid analysis. Chromatographic conditions, mass spectrometric transitions, and ion source parameters were optimized. The majority of steroids in GC-EI/MS/MS and LC-Ag(+) CIS/MS/MS analysis showed higher sensitivities than those obtained with other analytical methods. The limits of detection (LODs) of 65 steroids by GC-EI/MS/MS, 68 steroids by LC-Ag(+) CIS/MS/MS, 56 steroids by GC-EI/MS, 54 steroids by LC-ESI/MS/MS, and 27 steroids by GC-ESI/MS/MS were below cut-off value of 2.0 ng/mL. LODs of steroids that formed protonated ions in LC-ESI/MS/MS analysis were all lower than the cut-off value. Several steroids such as unconjugated C3-hydroxyl with C17-hydroxyl structure showed higher sensitivities in GC-EI/MS/MS analysis relative to those obtained using the LC-based methods. The steroids containing 4, 9, 11-triene structures showed relatively poor sensitivities in GC-EI/MS and GC-ESI/MS/MS analysis. The results of this study provide information that may be useful for selecting suitable analytical methods for confirmatory analysis of steroids. Copyright © 2015 John Wiley & Sons, Ltd.

A method of coupling the Paternò-Büchi reaction with direct infusion ESI-MS/MS for locating the C[double bond, length as m-dash]C bond in glycerophospholipids.

PubMed

Stinson, Craig A; Xia, Yu

2016-06-21

Tandem mass spectrometry (MS/MS) coupled with soft ionization is established as an essential platform for lipid analysis; however, determining high order structural information, such as the carbon-carbon double bond (C[double bond, length as m-dash]C) location, remains challenging. Recently, our group demonstrated a method for sensitive and confident lipid C[double bond, length as m-dash]C location determination by coupling online the Paternò-Büchi (PB) reaction with nanoelectrospray ionization (nanoESI) and MS/MS. Herein, we aimed to expand the scope of the PB reaction for lipid analysis by enabling the reaction with infusion ESI-MS/MS at much higher flow rates than demonstrated in the nanoESI setup (∼20 nL min(-1)). In the new design, the PB reaction was effected in a fused silica capillary solution transfer line, which also served as a microflow UV reactor, prior to ESI. This setup allowed PB reaction optimization and kinetics studies. Under optimized conditions, a maximum of 50% PB reaction yield could be achieved for a standard glycerophosphocholine (PC) within 6 s of UV exposure over a wide flow rate range (0.1-10 μL min(-1)). A solvent composition of 7 : 3 acetone : H2O (with 1% acid or base modifier) allowed the highest PB yields and good lipid ionization, while lower yields were obtained with an addition of a variety of organic solvents. Radical induced lipid peroxidation was identified to induce undesirable side reactions, which could be effectively suppressed by eliminating trace oxygen in the solution via N2 purge. Finally, the utility of coupling the PB reaction with infusion ESI-MS/MS was demonstrated by analyzing a yeast polar lipid extract where C[double bond, length as m-dash]C bond locations were revealed for 35 glycerophospholipids (GPs).

Design of five-layer gold nanoparticles self-assembled in a liquid open tubular column for ultrasensitive nano-LC-MS/MS proteomic analysis of 80 living cells.

PubMed

Shao, Xi; Zhang, Xiangmin

2017-04-01

In this work, for the first time, a liquid open tubular column modified by five-layer gold nanoparticles and linked with C 18 (GNPs@C 18 ) was designed and fabricated for nano-LC-MS/MS analysis of 80 living cells. Sixty nanometer gold nanoparticles were self-assembled layer by layer on the inner wall of a 20 μm id fused-silica capillary. C 18 was then linked on the gold nanoparticles to make the liquid open tubular column show hydrophobic character. Enough loading capacities for analysis of 80 living cells, ∼100 fmol for pk-10 and ∼30 fmol for insulin, were obtained with the 2 m × 20 μm id five-layer GNPs@C 18 open tubular column. The open tubular column was used in an online pretreatment and direct nano-LC-MS/MS analysis system to analyze 80 living HepG2 cells. In total, 650 proteins were identified in triplicate runs. The subcellular localization of the identified proteins showed that our system had no bias toward different cellular compartments. Protein copy number per cell of the identified proteins showed that the detection limit could reach 50 zmol and the abundance of the identified proteins could cover a dynamic range of 6 orders. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Histone Deacetylase Inhibitor MS-275 Exhibits Poor Brain Penetration: Pharmacokinetic Studies of [11C]MS-275 using Positron Emission Tomography

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

Hooker, J.M.; Hooker, J.M.; Kim, S.W.

2009-10-01

MS-275 (entinostat) is a histone deacetylase (HDAC) inhibitor currently in clinical trials for the treatment of several types of cancer. Recent reports have noted that MS-275 can cross the blood-brain barrier (BBB) and cause region-specific changes in rodent brain histone acetylation. To characterize the pharmacokinetics and distribution of MS-275 in the brain using positron emission tomography (PET), we labeled the carbamate carbon of MS-275 with carbon-11. Using PET, we determined that [{sup 11}C]MS-275 has low uptake in brain tissue when administered intravenously to nonhuman primates. In rodent studies, we observed that pharmacokinetics and brain accumulation of [{sup 11}C]MS-275 were notmore » changed by the coadministration of large doses of unlabeled MS-275. These results, which both highlight the poor brain penetration of MS-275, clearly suggest its limitation as a therapeutic agent for the central nervous system (CNS). Moreover, our study demonstrates the effectiveness of PET at providing brain pharmacokinetic data for HDAC inhibitors. These data are important not only for the development of new compounds for peripheral cancer treatment (where CNS exclusion is often advantageous) but also for the treatment of neurological disorders (where CNS penetration is critical).« less

Application of HRAM screening and LC-MS/MS confirmation of active pharmaceutical ingredient in "natural" herbal supplements.

PubMed

Pascali, Jennifer P; Fais, Paolo; Vaiano, Fabio; Bertol, Elisabetta

2018-05-01

The growing market of herbal remedies worldwide could pose severe problems to consumers' health due to the possible presence of potentially harmful, undeclared synthetic substances or analogues of prescription drugs. The present work shows a simple but effective approach to unequivocally identify synthetic anorectic compounds in allegedly 'natural' herbal extracts, by exploiting liquid chromatography/time of flight (Q-TOF LC/MS) technology coupled to liquid chromatography/triple quadrupole (LC-MS/MS) confirmation and quantitation. The procedure was applied to five tea herbal extracts and pills sold as coadjutant for weigh loss. The method exploited liquid-liquid sample extraction (LLE) and separation in a C18 (2.1mm×150mm, 1.8μm) column. QTOF acquisitions were carried out both in scan mode and all ion MS/MS mode and results were obtained after search against ad hoc prepared library. Sibutramine, 4-hydroxyamphetamine, caffeine and theophylline were preliminary identified samples. Confirmation and quantitation of the preliminary identified compounds were obtained in LC-MS/MS after preparation of appropriated standards. Sibutramine, caffeine and theophylline were finally confirmed and quantitate. Copyright © 2018 Elsevier B.V. All rights reserved.

Fast targeted analysis of 132 acidic and neutral drugs and poisons in whole blood using LC-MS/MS.

PubMed

Di Rago, Matthew; Saar, Eva; Rodda, Luke N; Turfus, Sophie; Kotsos, Alex; Gerostamoulos, Dimitri; Drummer, Olaf H

2014-10-01

The aim of this study was to develop an LC-MS/MS based screening technique that covers a broad range of acidic and neutral drugs and poisons by combining a small sample volume and efficient extraction technique with simple automated data processing. After protein precipitation of 100μL of whole blood, 132 common acidic and neutral drugs and poisons including non-steroidal anti-inflammatory drugs, barbiturates, anticonvulsants, antidiabetics, muscle relaxants, diuretics and superwarfarin rodenticides (47 quantitated, 85 reported as detected) were separated using a Shimadzu Prominence HPLC system with a C18 separation column (Kinetex XB-C18, 4.6mm×150mm, 5μm), using gradient elution with a mobile phase of 25mM ammonium acetate buffer (pH 7.5)/acetonitrile. The drugs were detected using an ABSciex(®) API 2000 LC-MS/MS system (ESI+ and -, MRM mode, two transitions per analyte). The method was fully validated in accordance with international guidelines. Quantification data obtained using one-point calibration compared favorably to that using multiple calibrants. The presented LC-MS/MS assay has proven to be applicable for determination of the analytes in blood. The fast and reliable extraction method combined with automated processing gives the opportunity for high throughput and fast turnaround times for forensic and clinical toxicology. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Simultaneous determination of antidementia drugs in human plasma: procedure transfer from HPLC-MS to UPLC-MS/MS.

PubMed

Noetzli, Muriel; Ansermot, Nicolas; Dobrinas, Maria; Eap, Chin B

2012-05-01

A previously developed high performance liquid chromatography mass spectrometry (HPLC-MS) procedure for the simultaneous determination of antidementia drugs, including donepezil, galantamine, memantine, rivastigmine and its metabolite NAP 226-90, was transferred to an ultra performance liquid chromatography system coupled to a tandem mass spectrometer (UPLC-MS/MS). The drugs and their internal standards ([(2)H(7)]-donepezil, [(13)C,(2)H(3)]-galantamine, [(13)C(2),(2)H(6)]-memantine, [(2)H(6)]-rivastigmine) were extracted from 250 μL human plasma by protein precipitation with acetonitrile. Chromatographic separation was achieved on a reverse phase column (BEH C18 2.1 mm × 50 mm; 1.7 μm) with a gradient elution of an ammonium acetate buffer at pH 9.3 and acetonitrile at a flow rate of 0.4 mL/min and an overall run time of 4.5 min. The analytes were detected on a tandem quadrupole mass spectrometer operated in positive electrospray ionization mode, and quantification was performed using multiple reaction monitoring. The method was validated according to the recommendations of international guidelines over a calibration range of 1-300 ng/mL for donepezil, galantamine and memantine, and 0.2-50 ng/mL for rivastimgine and NAP 226-90. The trueness (86-108%), repeatability (0.8-8.3%), intermediate precision (2.3-10.9%) and selectivity of the method were found to be satisfactory. Matrix effects variability was inferior to 15% for the analytes and inferior to 5% after correction by internal standards. A method comparison was performed with patients' samples showing similar results between the HPLC-MS and UPLC-MS/MS procedures. Thus, this validated UPLC-MS/MS method allows to reduce the required amount of plasma, to use a simplified sample preparation, and to obtain a higher sensitivity and specificity with a much shortened run-time. Copyright © 2012 Elsevier B.V. All rights reserved.

Identification of clinical yeasts by Vitek MS system compared with API ID 32 C.

PubMed

Durán-Valle, M Teresa; Sanz-Rodríguez, Nuria; Muñoz-Paraíso, Carmen; Almagro-Moltó, María; Gómez-Garcés, José Luis

2014-05-01

We performed a clinical evaluation of the Vitek MS matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) system with the commercial database version 2.0 for rapid identification of medically important yeasts as compared with the conventional phenotypic method API ID 32 C. We tested 161 clinical isolates, nine isolates from culture collections and five reference strains. In case of discrepant results or no identification with one or both methods, molecular identification techniques were employed. Concordance between both methods was observed with 160/175 isolates (91.42%) and misidentifications by both systems occurred only when taxa were not included in the respective databases, i.e., one isolate of Candida etchellsii was identified as C. globosa by Vitek MS and two isolates of C. orthopsilosis were identified as C. parapsilosis by API ID 32 C. Vitek MS could not identify nine strains (5.14%) and API ID 32 C did not identify 13 (7.42%). Vitek MS was more reliable than API ID 32 C and reduced the time required for the identification of clinical isolates to only a few minutes.

Pre-rigor temperature control of Chinese yellow cattle carcasses to 12-18 °C during chilling improves beef tenderness.

PubMed

Liu, Yuqing; Mao, Yanwei; Zhang, Yimin; Liang, Rongrong; Wang, Renhuan; Zhu, Lixian; Meng, Xianyong; Luo, Xin

2015-02-01

This study evaluates the effects of pre-rigor temperature control on quality traits of Chinese yellow cattle M. longissimus lumborum (LL). One stepwise chilling (SC) treatment was used on one half-carcass, involved a fast chilling (-11 ± 1 °C;0.5 m/s) for 2h, then the refrigeration was stopped to hold a core temperature of 12-18 °C until 10h postmortem, followed by a 1 ± 1 °C chilling (0.5 m/s) to 48h postmortem. The other half-carcass was conventional chilled at 1 ± 1 °C (0.5 m/s) until 48h as control chilling (CC). Quality attributes were evaluated at 1, 7 and 14 days. The SC treatment resulted in decreased WBSF and increased myofibril fragmentation index compared with control. SC-treated LL at 7d postmortem had a lower WBSF than those of CC-treated at 14d. This pre-rigor temperature controlled chilling is a realistic alternative for the beef industry in China to ensure adequate tenderness and shorten aging time.

Determination of a selection of synthetic cannabinoids and metabolites in urine by UHPSFC-MS/MS and by UHPLC-MS/MS.

PubMed

Berg, Thomas; Kaur, Lakhwinder; Risnes, Anna; Havig, Stine Marie; Karinen, Ritva

2016-07-01

Two different analytical techniques, ultra-high performance supercritical fluid chromatography-tandem mass spectrometry (UHPSFC-MS/MS) and reversed phase ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), were used for the determination of two synthetic cannabinoids and eleven metabolites in urine; AM-2201 N-4-OH-pentyl, AM-2233, JWH-018 N-5-OH-pentyl, JWH-018 N-pentanoic acid, JWH-073 N-4-OH-butyl, JWH-073 N-butanoic acid, JWH-122 N-5-OH-pentyl, MAM-2201, MAM-2201 N-4-OH-pentyl, RCS-4 N-5-OH-pentyl, UR-144 degradant N-pentanoic acid, UR-144 N-4-OH-pentyl, and UR-144 N-pentanoic acid. Sample preparation included a liquid-liquid extraction after deconjugation with ß-glucuronidase. The UHPSFC-MS/MS method used an Acquity UPC(2 TM) BEH column with a mobile phase consisting of CO2 and 0.3% ammonia in methanol, while the UHPLC-MS/MS method used an Acquity UPLC® BEH C18 column with a mobile phase consisting of 5 mM ammonium formate (pH 10.2) and methanol. MS/MS detection was performed with positive electrospray ionization and two multiple reaction monitoring transitions. Deuterated internal standards were used for six of the compounds. Limits of quantification (LOQs) were between 0.04 and 0.4 µg/L. Between-day relative standard deviations at concentrations ≥ LOQ were ≤20%, with biases within ±19%. Recoveries ranged from 40 to 90%. Corrected matrix effects were within 100 ± 10%, except for MAM-2201 with UHPSFC-MS/MS, and for UR-144 N-pentanoic acid and MAM-2201 N-4-OH-pentyl with UHPLC-MS/MS. Elution order obtained by UHPSFC-MS/MS was almost opposite to that obtained by UHPLC-MS/MS, making this instrument setup an interesting combination for screening and confirmation analyses in forensic cases. The UHPLC-MS/MS method has, since August 2014, been successfully used for confirmation of synthetic cannabinoids in urine samples revealing a positive immunoassay screening result. Copyright © 2015

40 CFR 721.3025 - Fatty acids C12-18, C18 unsaturated, C12-18 alkyl esters (generic).

Code of Federal Regulations, 2010 CFR

2010-07-01

..., C12-18 alkyl esters (generic). 721.3025 Section 721.3025 Protection of Environment ENVIRONMENTAL... communication program. A significant new use of these substances is any manner or method of manufacture, import, or processing associated with any use of these substances without providing risk notification as...

Development and validation of an LC-MS/MS method for quantification of cyclic guanosine 3',5'-monophosphate (cGMP) in clinical applications: a comparison with a EIA method.

PubMed

Zhang, Yanhua; Dufield, Dawn; Klover, Jon; Li, Wenlin; Szekely-Klepser, Gabriella; Lepsy, Christopher; Sadagopan, Nalini

2009-02-15

An LC-MS/MS method was developed and validated to quantify endogenous cyclic guanosine 3',5'-monophosphate (cGMP) in human plasma. The LC-MS/MS and competitive enzyme immunoassay (EIA) assays were compared. cGMP concentrations of 20 human plasma samples were measured by both methods. For the MS-based assay, plasma samples were subjected to a simple protein precipitation procedure by acetonitrile prior to analysis by electrospray ionization LC-MS/MS. De-protonated analytes generated in negative ionization mode were monitored through multiple reaction monitoring (MRM). A stable isotope-labeled internal standard, (13)C(10),(15)N(5)-cGMP, which was biosynthesized in-house, was used in the LC-MS/MS method. The competitive EIA was validated using a commercially available cGMP fluorescence assay kit. The intra-assay accuracy and precision for MS-based assay for cGMP were 6-10.1% CV and -3.6% to 7.3% relative error (RE), respectively, while inter-assay precision and accuracy were 5.6-8.1% CV and -2.1% to 6.3% RE, respectively. The intra-assay accuracy and precision for EIA were 17.9-27.1% CV and -4.9% to 24.5% RE, respectively, while inter-assay precision and accuracy were 15.1-39.5% CV and -30.8% to 4.37% RE, respectively. Near the lower limits of detection, there was little correlation between the cGMP concentration values in human plasma generated by these two methods (R(2)=0.197, P=0.05). Overall, the MS-based assay offered better selectivity, recovery, precision and accuracy over a linear range of 0.5-20ng/mL. The LC-MS/MS method provides an effective tool for the quantitation of cGMP to support clinical mechanistic studies of curative pharmaceuticals.

Analysis of the constituents in jojoba wax used as a food additive by LC/MS/MS.

PubMed

Tada, Atsuko; Jin, Zhe-Long; Sugimoto, Naoki; Sato, Kyoko; Yamazaki, Takeshi; Tanamoto, Kenichi

2005-10-01

Jojoba wax is a natural gum base used as a food additive in Japan, and is obtained from jojoba oil with a characteristically high melting point. Although the constituents of jojoba oil have been reported, the quality of jojoba wax used as a food additive has not yet been clarified. In order to evaluate its quality as a food additive and to obtain basic information useful for setting official standards, we investigated the constituents and their concentrations in jojoba wax. LC/MS analysis of the jojoba wax showed six peaks with [M+H]+ ions in the range from m/z 533.6 to 673.7 at intervals of m/z 28. After isolation of the components of the four main peaks by preparative LC/MS, the fatty acid and long chain alcohol moieties of the wax esters were analyzed by methanolysis and hydrolysis, followed by GC/MS. The results indicated that the main constituents in jojoba wax were various kinds of wax esters, namely eicosenyl octadecenoate (C20:1-C18:1) (1), eicosenyl eicosenoate (C20:1-C20:1) (II), docosenyl eicosenoate (C22:1-C20:1) (III), eicosenyl docosenoate (C20:1-C22:1) (IV) and tetracosenyl eiosenoate (C24:1-C20:1) (V). To confirm and quantify the wax esters in jojoba wax directly, LC/MS/MS analysis was performed. The product ions corresponding to the fatty acid moieties of the wax esters were observed, and by using the product ions derived from the protonated molecular ions of wax esters the fatty acid moieties were identified by MRM analysis. The concentrations of the wax esters I, II and III, in jojoba wax were 5.5, 21.4 and 37.8%, respectively. In summary, we clarified the main constituents of jojoba wax and quantified the molecular species of the wax esters without hydrolysis by monitoring their product ions, using a LC/MS/MS system.

A new LC-MS/MS bioanalytical method for atenolol in human plasma and milk.

PubMed

Phyo Lwin, Ei Mon; Gerber, Cobus; Song, Yunmei; Leggett, Catherine; Ritchie, Usha; Turner, Sean; Garg, Sanjay

2017-04-01

A new sensitive LC-MS/MS method for the quantification of atenolol in human plasma and milk has been developed for clinical lactation studies. Atenolol and the internal standard, phenazone, were extracted from biological matrices by protein precipitation. A Phenomenex ® C-18 column and gradient chromatographic conditions were used for separation of the analyte, followed by detection with MS. Stability of samples was confirmed for atenolol in human plasma and milk for up to 3 months. Linearity range of 1-800 ng/ml (r 2 = 0.9995), the precision within 15% CV and the recovery of the analyte (80-100% range) were achieved. A new validated analytical method for atenolol in plasma and milk was developed.

Simultaneous determination of vinclozolin and detection of its degradation products in mouse plasma, serum and urine, and from rabbit bile, by high-performance liquid chromatography.

PubMed

Dhananjeyan, Mugunthu R; Erhardt, Paul W; Corbitt, Cynthia

2006-05-19

A specific high-performance liquid chromatography method has been developed for simultaneous detection of vinclozolin and its degradation products (M1, M2, and M3). The method has been validated according to ICH guidelines and can be extended to quantitation of vinclozolin. A base-line separation of vinclozolin and its degradation products was found with symmetrical peak shapes on an XTerra MS C18 column using 10 mM ammonium bicarbonate at pH 9.2 and acetonitrile as mobile phase. The retention times of vinclozolin, M1, M2, and M3 were 12.8, 8.1, 11.6, and 11.1 min, respectively. A linear calibration curve was obtained across a range from 5 to 200 microM for vinclozolin. The intra- and inter-day relative standard deviations (%RSD) were <1%. Greater than 90% recoveries of vinclozolin from bio-fluids including mouse plasma, serum and urine, and rabbit bile, were obtained in a single step with a single solvent.

Determination of a novel anticancer c-Met inhibitor LS-177 in rat plasma and tissues with a validated UPLC-MS/MS method: application to pharmacokinetics and tissue distribution study.

PubMed

Ju, Ping; Liu, Zhenzhen; Jiang, Yu; Zhao, Simin; Zhang, Lunhui; Zhang, Yuanyuan; Gu, Liqiang; Tang, Xing; Bi, Kaishun; Chen, Xiaohui

2015-07-01

LS-177 is a novel small-molecule kinase inhibitor employed to interrupt the c-Met signaling pathway. A rapid and sensitive ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for determination of LS-177 in rat plasma and tissues. The biosamples were extracted by liquid-liquid extraction with methyl tert-butyl ether and separated on a C18 column (50 × 4.6 mm, 2.6 µm) using a gradient elution mobile phase consisting of acetonitrile-0.1% formic acid water. Under the optimal conditions, the selectivity of the method was satisfactory with no endogenous interference. The intraday and interday precisions (relative standard deviation) were <10.5% and the accuracy (relative error) was from -12.5 to 12.5% at all quality control levels. Excellent recovery and negligible matrix effects were observed. Stability studies showed that LS-177 was stable during the preparation and analytical processes. The UPLC-MS/MS method was successfully applied to pharmacokinetic and tissue distribution studies. The results indicated that there was no significant drug accumulation after multiple-dose oral administration of LS-177. The tissue distribution study exhibited significant higher uptakes of LS-177 in stomach, intestine, lung and liver among all of the tissues. The results in pharmacokinetics and tissue distribution may provide a meaningful basis for clinical application. Copyright © 2014 John Wiley & Sons, Ltd.

Determination of 7alpha-OH cholesterol by LC-MS/MS: Application in assessing the activity of CYP7A1 in cholestatic minipigs

USDA-ARS?s Scientific Manuscript database

An LC-MS/MS method was developed and validated to determine 7alpha-OH cholesterol in liver microsome. This method was convenient and fast with high specificity and sensitivity. Briefly, a gradient elution was performed on a Synergi polar-C18 column (50 x 4.6mm i.d., 3microm). The mobile phase (cons...

LC-MS/MS and GC-MS methods in propofol detection: Evaluation of the two analytical procedures.

PubMed

Vaiano, Fabio; Serpelloni, Giovanni; Focardi, Martina; Fioravanti, Alessia; Mari, Francesco; Bertol, Elisabetta

2015-11-01

Propofol is a short-acting hypnotic agent that is commonly used to induce and maintain anesthesia. Propofol abuse and its involvement in suicide deaths have increased in recent years, especially among healthcare personnel. An example is the suicide of a 61-year-old nurse found with a propofol drip in his left arm. We describe the postmortem concentration of propofol in various tissues (femoral and cardiac blood, bile, urine, brain, and liver) and in the drip. The toxicological analyses were performed through two analytical methods, differing in derivatization reaction and in instrumentation: silylation for gas chromatograph-mass spectrometer (GC-MS), as routinely performed in our laboratory for this kind of analyses (lower limits of quantification-LLOQ-in urine and blood: 0.3 and 5ng/ml); for liquid chromatograph-tandem mass spectrometer (LC-MS/MS) an innovative azo-coupling derivatization (LLOQ: 0.0004 and 0.1ng/ml). This latter produces an azo-derivative (molecular composition: C18H22ON2; molecular weight: 282Da) highly ionizable in electro-spray ion source, both in negative and positive ionizations. These two methods were compared to evaluate the effectiveness of this new LC-MS/MS analysis. An acidic hydrolysis (HCl 6N, 100°C, and 1h) was performed for the biological samples (1ml or 1g) irrespective of the analytical method applied. The drip content was extracted adding phosphate buffer (pH 8) and a dichloromethane/ethylacetate 8:2 (v:v) mixture. Derivatization steps were: silylation with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA)+tetramethylammonium hydroxide (TMAH) for GC-MS; regarding LC-MS/MS, azo-coupling reaction with the aryl-diazonium salt (0-5°C, and 30min). The analyses were achieved in selected-ion monitoring for GC-MS (m/z, 235,250,73 propofol"; m/z, 252,267,27 propofol-d17) and in multiple reaction monitoring ([M-H](-): m/z 283→241,77, azo-propofol; m/z 299→251,77, azo-propofol-d17) for LC-MS/MS. Autopsy showed no significant findings

Development of a solvent-free analytical method for paracetamol quantitative determination in Blood Brain Barrier in vitro model.

PubMed

Langlois, Marie-Hélène; Vekris, Antonios; Bousses, Christine; Mordelet, Elodie; Buhannic, Nathalie; Séguard, Céline; Couraud, Pierre-Olivier; Weksler, Babette B; Petry, Klaus G; Gaudin, Karen

2015-04-15

A Reversed Phase-High Performance Liquid Chromatography/Diode Array Detection method was developed and validated for paracetamol quantification in cell culture fluid from an in vitro Blood Brain Barrier model. The chromatographic method and sample preparation were developed using only aqueous solvents. The column was a XTerra RP18 150 × 4.6mm, 3.5 μm with a guard column XTerra RP18 20 × 4.6 mm, 3.5 μm at 35 °C and the mobile phase was composed by 100% formate buffer 20 mM at pH 4 and flow rate was set at 1 mL/min. The detection was at 242 nm. The sample was injected at 10 μL. Validation was performed using the accuracy profile approach. The analytical procedure was validated with the acceptance limits at ± 10% over a range of concentration from 1 to 58 mg L(-1). The procedure was then used in routine to determine paracetamol concentration in a brain blood barrier in vitro model. Application of the Unither paracetamol formulation in Blood Brain Barrier model allowed the determination and comparison of the transcellular passage of paracetamol at 37 °C and 4 °C, that excludes paracellular or non specific leakage. Copyright © 2015 Elsevier B.V. All rights reserved.

Experimental Gonococcal Infection in Male Volunteers: Cumulative Experience with Neisseria Gonorrhoeae Strains FA1090 and MS11mkC

DTIC Science & Technology

2011-05-31

improved our understanding of the requirements for gonococcal LOS structures, pili, opacity proteins , IgA1 protease, and the ability of infecting...indicated by the horizontal dotted line) is 1.8× 103 cfu for MS11mkC and 1.0× 105 cfu for FA1090. contained predominantly piliated (P+), Opacity protein ...Gonococcal genetic island Absent Present Dillard and Seifert, (2001) Lactoferrin utilization (expression of lactoferrin-binding proteins B and A) Lf

Natural chlorate in the environment: Application of a new IC-ESI/MS/MS method with a Cl18O3- internal standard

USGS Publications Warehouse

Rao, Balaji; Hatzinger, Paul B.; Böhlke, John Karl; Sturchio, Neil C.; Andraski, Brian J.; Eckardt, Frank D.; Jackson, W. Andrew

2010-01-01

A new ion chromatography electrospray tandem mass spectrometry (IC-ESI/MS/MS) method has been developed for quantification and confirmation of chlorate (ClO3−) in environmental samples. The method involves the electro-chemical generation of isotopically labeled chlorate internal standard (Cl18O3−) using 18O water (H218O). The standard was added to all samples prior to analysis thereby minimizing the matrix effects that are associated with common ions without the need for expensive sample pretreatments. The method detection limit (MDL) for ClO3− was 2 ng L−1 for a 1 mL volume sample injection. The proposed method was successfully applied to analyze ClO3− in difficult environmental samples including soil and plant leachates. The IC-ESI/MS/MS method described here was also compared to established EPA method 317.0 for ClO3− analysis. Samples collected from a variety of environments previously shown to contain natural perchlorate (ClO4−) occurrence were analyzed using the proposed method and ClO3− was found to co-occur with ClO4− at concentrations ranging from <2 ng L−1 in precipitation from Texas and Puerto Rico to >500 mg kg−1 in caliche salt deposits from the Atacama Desert in Chile. Relatively low concentrations of ClO3− in some natural groundwater samples (<0.1 μg L−1) analyzed in this work may indicate lower stability when compared to ClO4− in the subsurface. The high concentrations of ClO3− in caliches and soils (3−6 orders of magnitude greater) as compared to precipitation samples indicate that ClO3−, like ClO4−, may be atmospherically produced and deposited, then concentrated in dry soils, and is possibly a minor component in the biogeochemical cycle of chlorine.

Profiling intact steroid sulfates and unconjugated steroids in biological fluids by liquid chromatography-tandem mass spectrometry (LC-MS-MS).

PubMed

Galuska, Christina E; Hartmann, Michaela F; Sánchez-Guijo, Alberto; Bakhaus, Katharina; Geyer, Joachim; Schuler, Gerhard; Zimmer, Klaus-Peter; Wudy, Stefan A

2013-07-07

Within the combined DFG research project "Sulfated Steroids in Reproduction" an analytical method was needed for determining sulfated and unconjugated steroids with highest specificity out of different biological matrices such as aqueous solution, cell lysate and serum. With regard to this analytical challenge, LC-MS-MS presents the technique of choice because it permits (1) analysis of the intact steroid conjugate, (2) allows for simultaneous determination of multiple analytes (profiling, targeted metabolomics approach) and (3) is independent of phenomena such as cross-reactivity. Sample work up consisted of incubation of sample with internal standards (deuterium labeled steroids) followed by solid phase extraction. Only serum samples required a protein precipitation step prior to solid phase extraction. The extract was divided in two parts: six steroid sulfates (E1S, E2S, AS, 16-OH-DHEAS, PREGS, DHEAS) were analyzed by C18aQ-ESI-MS-MS in negative ion mode and eleven unconjugated steroids (E3, 16-OH-DHEA, E1, E2, (4)A, DHEA, T, 17-OH-PREG, Prog, An, PREG) were analyzed by C18-APCI-MS-MS in positive ion mode. For steroid sulfates, we found high sensitivities with LoQ values ranging from 0.08 to 1 ng mL(-1). Unconjugated steroids showed LoQ values between 0.5 and 10 ng mL(-1). Calibration plots showed excellent linearity. Mean intra- and inter-assay CVs were 2.4% for steroid sulfates and 6.4% for unconjugated steroids. Accuracy - determined in a two-level spike experiment - showed mean relative errors of 5.9% for steroid sulfates and 6.1% for unconjugated steroids. In summary, we describe a novel LC-MS-MS procedure capable of profiling six steroid sulfates and eleven unconjugated steroids from various biological matrices.

Analysis of 13C-mixed triacylglycerol in stool by bulk (EA-IRMS) and compound specific (GC/MS) methods.

PubMed

Slater, C; Ling, S C; Preston, T; Weaver, L T

2002-06-01

This paper was presented in poster form at the 17th International Congress of Nutrition, August 27-31, Vienna, Austria (Annals of Nutrition & Metabolism 2001; 45(Suppl.1):349). Some of the data were also presented in poster form at the British Society of Gastroenterology Meeting, March 18-21, Glasgow, UK (Gut 2001; 48(Suppl.1):A91). The 13C-mixed triacylglycerol (MTG) breath test is used to measure intraluminal fat digestion. In normal digestion, 20-40% of the ingested 13C label is recovered in breath CO2. We aimed to identify the proportions of ingested label excreted in stool, as well as breath following ingestion of 13C-MTG by children with impaired exocrine pancreatic function and healthy controls. 13C enrichment of breath samples was measured by continuous flow isotope ratio mass spectrometry (IRMS) and cumulative percent dose recovered (cPDR) in 10 h was calculated. Total 13C of a faecal fat extract from each stool was measured by elemental analyser-IRMS, and 13C enrichment and concentration of the TBDMS derivative of octanoic acid was measured by GC/MS after hydrolysis of the fat extract. Stool 5-day cPDR was calculated. Mean breath cPDR was 35%. Mean cPDR in stool by combustion-IRMS and GC/ MS, respectively, was 0.8% and 1.0%. Therefore, the remaining 64% of the 13C label must remain in the body and variability in breath cPDR is due to postabsorptive rather than predigestive factors.

Simultaneous analysis of 17 diuretics in dietary supplements by HPLC and LC-MS/MS.

PubMed

Woo, H; Kim, J W; Han, K M; Lee, J H; Hwang, I S; Lee, J H; Kim, J; Kweon, S J; Cho, S; Chae, K R; Han, S Y; Kim, J

2013-01-01

In order to test health foods for illegally added diuretics for weight loss, we developed simple, rapid, selective, and sensitive methods using HPLC and LC-MS/MS for the simultaneous analysis of 17 diuretics in dietary supplements. HPLC conditions were set with a Capcell-pak C18, using a mobile phase consisting of gradient conditions, UV detection at 254 nm and validated for linearity (r(2)> 0.999), precision (CV ≤ 3%), recoveries (90.4-102.8%) and reproducibility. Identification and quantification of 17 diuretics were accomplished by ion-spray LC-MS/MS using multiple reaction monitoring (MRM). The chromatographic separation was carried out under the reversed-phase mechanism on an HSS-T3 column. The LC-MS/MS method was validated for linearity (r(2)> 0.99) and precision (CV < 13%). Sixteen dietary supplements were tested with the developed methods. Diuretics were not detected in all samples. Extraction recovery was also investigated and the extraction recoveries in different formulations were from 88% to 110% and from 81% to 116% using HPLC and LC-MS/MS, respectively. There was no significant difference in recoveries in the type of dietary supplements. Based on this result, the developed methods to monitor illegal drug adulterations in dietary supplements using HPLC and LC-MS/MS are simple, fast and reliable. Therefore, it is applicable to routine drug-adulteration screening.

Determination of 25-OCH3-PPD and the related substances by UPLC-MS/MS and their cytotoxic activity.

PubMed

Ding, Meng; Lu, Jingjing; Zhao, Chen; Zhang, Sainan; Zhao, Yuqing

2016-06-01

20(R)-25-methoxyl-dammarane-3β,12β,20-triol (25-OCH3-PPD) is a promising antitumor compound belonging to triterpenoid saponins isolated from radix notoginseng. A systematic research on the related impurities in raw material of 25-OCH3-PPD has not been conducted. In this study, three impurities obtained by HPLC-ELSD and characterized by (13)C NMR and MS were observed in the raw material of 25-OCH3-PPD. Cytotoxic activities of the related substances were also evaluated, of which impurity B with 25-OCH3-PPD showed synergistic inhibitory activity against BGC-823 with IC50 values of 8.33μM. Furthermore, a rapid and selective UPLC-MS/MS method was developed for simultaneous determination of the principal component and three related substances in the raw material of 25-OCH3-PPD. Multiple reaction monitoring scan mode was used for the quantification of 20(R)-25-OCH3-PPD and its three related substances. The four constituents were separated within 11min on a BEH C18 column (100 mm×2.1mm, 1.7μm) using a mobile phase comprising methanol and 0.03% formic acid water (82:18, v/v) at a flow rate of 0.2mL/min. The proposed UPLC-MS/MS method displayed acceptable levels of linearity, precision, repeatability, and accuracy. In addition, the proposed method was successfully applied for the establishment of a rational quality control standard for the raw material of 25-OCH3-PPD. Copyright © 2016 Elsevier B.V. All rights reserved.

MALDI-TOF MS for the identification of veterinary non-C. neoformans-C. gattii Cryptococcus spp. isolates from Italy.

PubMed

Danesi, Patrizia; Drigo, Ilenia; Iatta, Roberta; Firacative, Carolina; Capelli, Gioia; Cafarchia, Claudia; Meyer, Wieland

2014-08-01

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) offers an effective alternative to phenotypic and molecular methods for the rapid identification of microorganisms. Our aim in this study was to create an in-house library for a set of strains of nine uncommonly reported human and animal cryptococcal species, including Cryptococcus adeliensis, C. albidosimilis, C. albidus, C. aureus, C. carnescens, C. laurentii, C. magnus, C. victoriae and C. uniguttulatus, and to use this library to make timely and correct identifications using MALDI-TOF MS for use in routine laboratory diagnostics. Protein extracts obtained via the formic acid extraction method of 62 veterinary non-C. neoformans-C. gattii cryptococcal isolates were studied. The obtained mass spectra correctly grouped all 62 studied isolates according to species identification previously obtained by internal transcribe spacer sequence analysis. The in-house database was than exported and successfully uploaded to the Microflex LT (Maldi Biotyper; Bruker Daltonics) instrument at a different diagnostic laboratory in Italy. Scores >2.7 obtained from isolates reanalyzed in the latter laboratory supported the high reproducibility of the method. The possibility of creating and transferring an in-house library adds to the usefulness MALDI-TOF MS an important tool for the rapid and inexpensive identification of pathogenic and saprophytic fungi as required for differential diagnosis of human and animal mycoses. © The Author 2014. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

LC-MS/MS-based quantification of kynurenine metabolites, tryptophan, monoamines and neopterin in plasma, cerebrospinal fluid and brain.

PubMed

Fuertig, René; Ceci, Angelo; Camus, Sandrine M; Bezard, Erwan; Luippold, Andreas H; Hengerer, Bastian

2016-09-01

The kynurenine (KYN) pathway is implicated in diseases such as cancer, psychiatric, neurodegenerative and autoimmune disorders. Measurement of KYN metabolite levels will help elucidating the involvement of the KYN pathway in the disease pathology and inform drug development. Samples of plasma, cerebrospinal fluid or brain tissue were spiked with deuterated internal standards, processed and analyzed by LC-MS/MS; analytes were chromatographically separated by gradient elution on a C18 reversed phase analytical column without derivatization. We established an LC-MS/MS method to measure 11 molecules, namely tryptophan, KYN, 3-OH-KYN, 3-OH-anthranilic acid, quinolinic acid, picolinic acid, kynurenic acid, xanthurenic acid, serotonin, dopamine and neopterin within 5.5 min, with sufficient sensitivity to quantify these molecules in small sample volumes of plasma, cerebrospinal fluid and brain tissue.

Influence of 5,10-methylenetetrahydrofolate reductase polymorphism on whole-blood folate concentrations measured by LC-MS/MS, microbiologic assay, and bio-rad radioassay.

PubMed

Fazili, Zia; Pfeiffer, Christine M; Zhang, Mindy; Jain, Ram B; Koontz, Deborah

2008-01-01

The 5,10-methylenetetrahydrofolate reductase (NADPH) (MTHFR) C677T polymorphism may affect whole-blood folate pattern measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and total folate measured by LC-MS/MS, microbiologic assay, and Bio-Rad radioassay (BR). We analyzed 171 whole blood hemolysates from 2 blood banks for folate pattern and total folate concentrations using these 3 methods and determined MTHFR genotype. The median (range) total folate concentration by LC-MS/MS was higher in the US set [378 (228-820) nmol/L; n = 96] than in the European set [250 (122-582) nmol/L; n = 75]. The whole-blood folate pattern [median (range)] was similar for individuals with C/C (n = 73) and C/T (n = 66) genotype: 88% (71%-91%) and 86% (50%-91%), respectively, for 5-methyltetrahydrofolic acid (5CH(3)THF) vs 12% (9%-29%) and 14% (9%-51%) for forms other than 5-methyltetrahydrofolic acid (non-5CH(3)THF). Individuals with T/T (n = 32) genotype had 58% (22%-87%) 5CH(3)THF vs 42% (13%-78%) non-5CH(3)THF. Compared with microbiologic assay results, LC-MS/MS (r = 0.94) and BR (r = 0.87) results were significantly lower (-10% and -45%, respectively); however, these differences were concentration dependent and also genotype dependent for the BR assay (-48% for C/C+C/T and -31% for T/T). The microbiologic assay completely recovered [mean (SD)] folates added to a whole blood hemolysate, except for tetrahydrofolic acid (THF) [46.4% (8.1%)]. The BR assay under-recovered 5CH(3)THF [51% (4.1%)] and 5-formyltetrahydrofolic acid [18% (0.1%)], and over-recovered THF [152% (19%)]. MTHFR C677T polymorphism influences the folate pattern in whole blood. The agreement between total folate by LC-MS/MS and microbiologic assay, independent of the MTHFR genotype, allows the use of one regression equation. Because BR results are genotype dependent, different regression equations should be used.

LC-MS/MS analysis of uncommon paracetamol metabolites derived through in vitro polymerization and nitration reactions in liquid nitrogen.

PubMed

Trettin, Arne; Jordan, Jens; Tsikas, Dimitrios

2014-09-01

Paracetamol (acetaminophen, APAP) is a commonly used analgesic drug. Known paracetamol metabolites include the glucuronide, sulfate and mercapturate. N-Acetyl-benzoquinonimine (NAPQI) is considered the toxic intermediate metabolite of paracetamol. In vitro and in vivo studies indicate that paracetamol is also metabolized to additional poorly characterized metabolites. For example, metabolomic studies in urine samples of APAP-treated mice revealed metabolites such as APAP-sulfate-APAP and APAP-S-S-APAP in addition to the classical phase II metabolites. Here, we report on the development and application of LC-MS and LC-MS/MS approaches to study reactions of unlabelled and (2)H-labelled APAP with unlabelled and (15)N-labelled nitrite in aqueous phosphate buffers (pH 7.4) upon their immersion into liquid nitrogen (-196°C). In mechanistic studies, these reactions were also studied in aqueous buffer prepared in (18)O-labelled water. LC-MS and LC-MS/MS analyses were performed on a reverse-phase material (C18) using gradient elution (2mM ammonium acetate/acetonitrile), in positive and negative electrospray mode. We identified a series of APAP metabolites including di-, tri- and tetra-APAP, mono- and di-nitro-APAP and nitric ester of di-APAP. Our study indicates that nitrite induces oxidation, i.e., polymerization and nitration of APAP, when buffered APAP/nitrite solutions are immersed into liquid nitrogen. These reactions are specific for nitrite with respect to nitrate and do not proceed via intermediate formation of NAPQI. Potassium ions and physiological saline but not thiols inhibit nitrite- and shock-freeze-induced reactions of paracetamol. The underlying mechanism likely involves in situ formation of NO2 radicals from nitrite secondary to profound pH reduction (down to pH 1) and disproportionation. Polymeric paracetamol species can be analyzed as pentafluorobenzyl derivatives by LC-MS but not by GC-MS. Copyright © 2013 Elsevier B.V. All rights reserved.

Simultaneous quantification of five steroid saponins from Dioscorea zingiberensis C.H.Wright in rat plasma by HPLC-MS/MS and its application to the pharmacokinetic studies

PubMed Central

Zhang, Xinxin; Li, Jing; Ito, Yoichiro; Sun, Wenji

2014-01-01

A simple, reliable and sensitive high-performance liquid chromatography tandem mass spectrometry method (HPLC-MS/MS) was established for simultaneous analyses of the following 5 steroid saponins in rat plasma after the single dose administration of total steroid saponins extracted from the rhizome of Dioscorea zingiberensis C.H.Wright for the first time. Protodioscin, huangjiangsu A, zingiberensis new saponin, dioscin, and gracillin were quantified using ginsenoside Rb1 as the internal standard (IS). The plasma samples were pretreated by a single step acetonitrile-mediated protein precipitation. The chromatographic separation was performed on an Inersil ODS-3 C18 column (250 mm × 4.6 mm, 5 μm) with the mobile phase composed of acetonitrile and water containing 0.1% formic acid under a gradient elution mode at 0.2 mL min−1 using a microsplit after the eluent from the HPLC apparatus. The quantification was accomplished on a triple quadrupole tandem mass spectrometer using the multiple reaction monitoring (MRM) in the positive ionization mode. The above five analytes were stable under sample storage and preparation conditions applied in the present study. The linearity, precision, accuracy, and recoveries of the analysis confirmed the requirements for quality-control purposes. After validation, this proposed method was successfully adopted to investigate the pharmacokinetic parameters of these five analytes. PMID:25201262

Urinary amino acid analysis: a comparison of iTRAQ-LC-MS/MS, GC-MS, and amino acid analyzer.

PubMed

Kaspar, Hannelore; Dettmer, Katja; Chan, Queenie; Daniels, Scott; Nimkar, Subodh; Daviglus, Martha L; Stamler, Jeremiah; Elliott, Paul; Oefner, Peter J

2009-07-01

Urinary amino acid analysis is typically done by cation-exchange chromatography followed by post-column derivatization with ninhydrin and UV detection. This method lacks throughput and specificity. Two recently introduced stable isotope ratio mass spectrometric methods promise to overcome those shortcomings. Using two blinded sets of urine replicates and a certified amino acid standard, we compared the precision and accuracy of gas chromatography/mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) of propyl chloroformate and iTRAQ derivatized amino acids, respectively, to conventional amino acid analysis. The GC-MS method builds on the direct derivatization of amino acids in diluted urine with propyl chloroformate, GC separation and mass spectrometric quantification of derivatives using stable isotope labeled standards. The LC-MS/MS method requires prior urinary protein precipitation followed by labeling of urinary and standard amino acids with iTRAQ tags containing different cleavable reporter ions distinguishable by MS/MS fragmentation. Means and standard deviations of percent technical error (%TE) computed for 20 amino acids determined by amino acid analyzer, GC-MS, and iTRAQ-LC-MS/MS analyses of 33 duplicate and triplicate urine specimens were 7.27+/-5.22, 21.18+/-10.94, and 18.34+/-14.67, respectively. Corresponding values for 13 amino acids determined in a second batch of 144 urine specimens measured in duplicate or triplicate were 8.39+/-5.35, 6.23+/-3.84, and 35.37+/-29.42. Both GC-MS and iTRAQ-LC-MS/MS are suited for high-throughput amino acid analysis, with the former offering at present higher reproducibility and completely automated sample pretreatment, while the latter covers more amino acids and related amines.

Is it possible to detect PEth 16:0/18:1 and PEth 18:1/18:1 in red blood cells after 20 years of storage in liquid nitrogen?

PubMed

Boll, Robert; Johnson, Theron; Kaaks, Rudolf; Kühn, Tilman; Skopp, Gisela

2017-09-01

Phosphatidylethanol (PEth), as measured in freshly drawn blood samples, could be a promising new biomarker for habitual alcohol consumption, but it is still unknown whether PEth can also be determined from blood samples having been stored frozen for a longer period. PEth 16:0/18:1 and PEth 18:1/18:1 were determined by LC-MS/MS from red blood cells (RBC) derived from blood samples of (I) 20 healthy volunteers (after 1 month of storage at -80 °C) and (II) 232 participants of the population-based European Prospective Investigation into Cancer and Nutrition (EPIC)-Heidelberg study (after 20 years of storage at -196 °C). Analyses involved liquid-liquid extraction from 100 μl aliquots with phosphatidylpropanol (PProp 18:1/18:1) as the internal standard. Extracts were subjected to a 10-min LC gradient separation, using multiple reaction monitoring of deprotonated molecules for quantification. After 1 month of storage at -80 °C, PEth was detectable in all samples at mean concentrations of 393.6 ± 12.4 ng/ml (PEth 16:0/18:1) and 43.3 ± 1.1 ng/ml (PEth 18:1/18:1). In samples stored for 20 years at -196 °C, PEth was detectable in 23.7% of all samples at mean concentrations of 412.2 ± 655.5 ng/ml (PEth 16:0/18:1) and 38.0 ± 74.8 ng/ml (PEth 18:1/18:1). PEth can be determined reliably from samples of moderate habitual alcohol consumers after 1 month of storage at -80 °C. Our data suggest that PEth is generally also detectable in samples after 20 years of storage at -196 °C. Further studies are needed to assess the still unknown impact of storage duration and temperature on different PEth specimen concentrations.

Fingerprint of Hedyotis diffusa Willd. by HPLC-MS.

PubMed

Yang, Ting; Yang, Yi-Hua; Yang, Ju-Yun; Chen, Ben-Mei; Duan, Ju-Ping; Yu, Shu-Yi; Ouyang, Hong-Tao; Cheng, Jun-Ping; Chen, Yu-Xiang

2008-01-01

A HPLC-MS fingerprint method has been developed based on the consistent chromatographic features of the major chemical constituents among 10 batches of Hedyotis diffusa Willd. Chromatographic separation was conducted on a Hypersil-Keystone Hypurity C(18) column using methanol:water:acetic acid as the mobile phase. Major compounds, including oleanolic acid, ursolic acid and ferulic acid, were analysed by HPLC-MS. Their analysis was ascertained by comparison with data derived from the standard compounds. The HPLC-MS fingerprint was successfully applied to analyse and differentiate samples from different geographical origins, or processing methods. H. diffusa was well distinguished from Hedyotis chrysotricha by HPLC-MS. Therefore the establishment of fingerprint of H. diffusa is critical in assessing and controlling its overall quality.

Simultaneous determination of mequindox, quinocetone, and their major metabolites in chicken and pork by UPLC-MS/MS.

PubMed

Li, Yanshen; Liu, Kaili; Beier, Ross C; Cao, Xingyuan; Shen, Jianzhong; Zhang, Suxia

2014-10-01

This report presents a UPLC-MS/MS method for determination of mequindox (MEQ), quinocetone (QCT) and their 11 metabolites in chicken and pork samples. Following extraction process with acetonitrile-ethyl acetate, acidulation, and re-extraction with ethyl acetate in turn, target analytes were further purified using C18 solid phase extraction (SPE) cartridges for UPLC-MS/MS analysis. Validation was processed with mean recoveries from 69.1% to 113.3% with intra-day relative standard deviation (RSD) <14.7%, inter-day RSD <19.2%, and limit of detection between 0.05 and 1.0 μg/kg for each analytes. The verified method was successfully applied to the quantitative determination of commercial samples. This developed procedure will help to control food animal products with MEQ and QCT residues, and facilitate further pharmacokinetic and residue studies of similar quinoxaline-1,4-dioxide veterinary drugs. Copyright © 2014 Elsevier Ltd. All rights reserved.

Determination of Aflatoxin B1 in Smokeless Tobacco Products by use of UHPLC-MS/MS

PubMed Central

Zitomer, Nicholas; Rybak, Michael E.; Li, Zhong; Walters, Matthew J.; Holman, Matthew R.

2017-01-01

We have developed a UHPLC-MS/MS method for the detection and quantitation of aflatoxins in smokeless tobacco products and used it to determine aflatoxin B1 concentrations in 32 smokeless tobacco products commercially available in the US. Smokeless tobacco products were dried, milled and amended with 13C17-labelled internal standards, extracted in water/methanol solution in the presence of a surfactant, isolated through use of immunoaffinity column chromatography and reconstituted in mobile phase prior to UHPLC-MS/MS analysis. Our method was capable of baseline separation of aflatoxins B1, B2, G1 and G2 in a 2.5 min run by use of a fused core C18 column and a water/methanol gradient. MS/MS transition (m/z) 313.3>241.2 was used for aflatoxin B1 quantitation, with 313.3>285.1 used for confirmation. The limit of detection (LOD) for aflatoxin B1 was 0.007 parts per billion (ppb). Method imprecision for aflatoxin B1 (expressed as coefficient of variation) ranged from 5.5% to 9.4%. Spike recoveries were 105–111%. Aflatoxin B1 concentrations in the smokeless tobacco products analysed ranged from

Mastering analytical challenges for the characterization of pentacyclic triterpene mono- and diesters of Calendula officinalis flowers by non-aqueous C30 HPLC and hyphenation with APCI-QTOF-MS.

PubMed

Nicolaus, Christoph; Sievers-Engler, Adrian; Murillo, Renato; D'Ambrosio, Michele; Lämmerhofer, Michael; Merfort, Irmgard

2016-01-25

Pentacyclic triterpene mono- and diesters have been isolated from Calendula officinalis flowers. GC-MS, APCI-Exactive Orbitrap HR-MS and NMR allowed to identify the triterpene skeleton in various samples (different triterpene mixtures from Calendula n-hexane extract). NMR provided evidence that triterpene diesters are present in the samples as well. However, the corresponding quasi-molecular ions could not be detected by APCI-Exactive Orbitrap HR-MS. Instability of triterpene diesters and loss of a fatty acid residue, respectively, in the ion-source made their MS detection challenging. Thus, a set of new APCI-QTOF-MS methods (using the TripleTOF 5600+ mass spectrometer) were developed which made it eventually possible to solve this problem and confirm the diester structures by MS via quasi-molecular ion [M+H](+) detection. Direct infusion APCI-QTOF MS experiments in MS/MS high sensitivity scan mode with low collision energy and multi-channel averaging acquisition (MCA) allowed the detection of quasi-molecular ions of triterpene diesters for the first time and unequivocally confirmed the presence of faradiol 3,16-dimyristate and -dipalmitate, as well as the corresponding mixed diesters faradiol 3-myristate,16-palmitate and faradiol 3-palmitate,16-myristate. Preferential loss of the fatty acid in 16-position made it possible to distinguish the mixed diesters by MS/MS spectra. Their chromatographic separations turned out to be challenging due to their bulkiness and extended molecular dimensions. However, separation could be achieved by an uncommon non-aqueous RPLC mode with an in-house synthesized C30 phase. Finally, two (U)HPLC-APCI-QTOF-MS methods with C18- and C30-based non-aqueous RPLC provided suitable, sensitive assays to monitor the presence of monoesters and diesters of various triterpenes (faradiol, maniladiol, arnidiol, arnitriol A and lupane-3β,16β,20-triol esters) in the n-hexane extract of C. officinalis with high mass resolution and good mass accuracy

Urinary Amino Acid Analysis: A Comparison of iTRAQ®-LC-MS/MS, GC-MS, and Amino Acid Analyzer

PubMed Central

Kaspar, Hannelore; Dettmer, Katja; Chan, Queenie; Daniels, Scott; Nimkar, Subodh; Daviglus, Martha L.; Stamler, Jeremiah; Elliott, Paul; Oefner, Peter J.

2009-01-01

Urinary amino acid analysis is typically done by cation-exchange chromatography followed by post-column derivatization with ninhydrin and UV detection. This method lacks throughput and specificity. Two recently introduced stable isotope ratio mass spectrometric methods promise to overcome those shortcomings. Using two blinded sets of urine replicates and a certified amino acid standard, we compared the precision and accuracy of gas chromatography/mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) of propyl chloroformate and iTRAQ® derivatized amino acids, respectively, to conventional amino acid analysis. The GC-MS method builds on the direct derivatization of amino acids in diluted urine with propyl chloroformate, GC separation and mass spectrometric quantification of derivatives using stable isotope labeled standards. The LC-MS/MS method requires prior urinary protein precipitation followed by labeling of urinary and standard amino acids with iTRAQ® tags containing different cleavable reporter ions distinguishable by MS/MS fragmentation. Means and standard deviations of percent technical error (%TE) computed for 20 amino acids determined by amino acid analyzer, GC-MS, and iTRAQ®-LC-MS/MS analyses of 33 duplicate and triplicate urine specimens were 7.27±5.22, 21.18±10.94, and 18.34±14.67, respectively. Corresponding values for 13 amino acids determined in a second batch of 144 urine specimens measured in duplicate or triplicate were 8.39±5.35, 6.23±3.84, and 35.37±29.42. Both GC-MS and iTRAQ®-LC-MS/MS are suited for high-throughput amino acid analysis, with the former offering at present higher reproducibility and completely automated sample pretreatment, while the latter covers more amino acids and related amines. PMID:19481989

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

PubMed

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

2014-09-01

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

Determination of the glycation sites of Bacillus anthracis neoglycoconjugate vaccine by MALDI-TOF/TOF-CID-MS/MS and LC-ESI-QqTOF-tandem mass spectrometry

PubMed Central

Jahouh, Farid; Hou, Shu-jie; Kováč, Pavol; Banoub, Joseph H.

2012-01-01

We present herein an efficient mass spectrometric method for the localization of the glycation sites of a model neoglycoconjugate vaccine formed by a construct of the tetrasaccharide side chain of the Bacillus anthracis exosporium and the protein carrier bovine serum albumin. The glycoconjugate was digested with both trypsin and GluC V8 endoproteinases, and the digests were then analyzed by MALDI-TOF/TOF-CID-MS/MS and nano-LC-ESI-QqTOF-CID-MS/MS. The sequences of the unknown peptides analyzed by MALDI-TOF/TOF-CID-MS/MS, following digestion with the GluC V8 endoproteinase, allowed us to recognize three glycopeptides whose glycation occupancies were, respectively, on Lys 235, Lys 420, and Lys 498. Similarly, the same analysis was performed on the tryptic digests, which permitted us to recognize two glycation sites on Lys 100 and Lys 374. In addition, we have also used LC-ESI-QqTOF-CID-MS/MS analysis for the identification of the tryptic digests. However, this analysis identified a higher number of glycopeptides than would be expected from a glycoconjugate composed of a carbohydrate–protein ratio of 5.4:1, which would have resulted in glycation occupancies of 18 specific sites. This discrepancy was due to the large number of glycoforms formed during the synthetic carbohydrate–spacer–carrier protein conjugation. Likewise, the LC-ESI-QqTOF-MS/MS analysis of the GluC V8 digest also identified 17 different glycation sites on the synthetic glycoconjugate. PMID:22012665

RP-UHPLC-UV-ESI-MS/MS analysis of LPMO generated C4-oxidized gluco-oligosaccharides after non-reductive labeling with 2-aminobenzamide.

PubMed

Frommhagen, Matthias; van Erven, Gijs; Sanders, Mark; van Berkel, Willem J H; Kabel, Mirjam A; Gruppen, Harry

2017-08-07

Lytic polysaccharide monooxygenases (LPMOs) are able to cleave recalcitrant polysaccharides, such as cellulose, by oxidizing the C1 and/or C4 atoms. The analysis of the resulting products requires a variety of analytical techniques. Up to now, these techniques mainly focused on the identification of non-oxidized and C1-oxidized oligosaccharides. The analysis of C4-oxidized gluco-oligosaccharides is mostly performed by using high pressure anion exchange chromatography (HPAEC). However, the alkaline conditions used during HPAEC analysis lead to tautomerization of C4-oxidized gluco-oligosaccharides, which limits the use of this technique. Here, we describe the use of reverse phase-ultra high performance liquid chromatography (RP-UHPLC) in combination with non-reductive 2-aminobenzamide (2-AB) labeling. Non-reductive 2-AB labeling enabled separation of C4-oxidized gluco-oligosaccharides from their non-oxidized counterparts. Moreover, RP-UHPLC does not require buffered mobile phases, which reduce mass spectrometry (MS) sensitivity. The latter is seen as an advantage over other techniques such as hydrophilic interaction liquid chromatography and porous graphitized carbon coupled to MS. RP-UHPLC coupled to UV detection and mass spectrometry allowed the identification of both labeled non-oxidized and C4-oxidized oligosaccharides. Non-reductive labeling kept the ketone at the C4-position of LPMO oxidized oligosaccharides intact, while selective reducing agents such as sodium triacetoxyborohydride (STAB) reduced this ketone group. Our results show that RP-UHPLC-UV-ESI-MS in combination with non-reductively 2-AB labeling is a suitable technique for the separation and identification of LPMO-generated C4-oxidized gluco-oligosaccharides. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

[Separation and identification of red pigments in natural red yolk of duck's eggs by HPLC-MS-MS].

PubMed

Liu, Liangzhong; Zhang, Min; Peng, Guanghua; Wang, Haibin; Zhang, Shenghua

2004-05-01

The natural red yolk of duck's eggs is produced by the laying duck in the lake areas in southward of China. In the laying duck breeding areas such as Honghu, Jianli, Xiantao, Tianmen and Hanchuan citys in Hubei Province, the culturists are used to feeding fresh pondweeds to the laying ducks. The yolk of duck's eggs is natural red with the chrominance reaching up to and/or above RCF (Roche Yolk Color Fan) 15. The red pigment components of natural red yolk of duck's eggs were separated and identified by thin layer chromatography (TLC), high performance liquid chromatography-mass spectrometry-mass spectrometry (HPLC-MS-MS) and high resolution electron impact-mass spectrometry (EI-MS). Four isomers of red pigments were separated by HPLC on a RP-C18 column with methanol-water (99.5:0.5, v/v) as mobile phase. The lambda(max) of the four components were 482, 488, 496, 501 nm, respectively, and all of them were single peak on chromatogram. They had the same molecular mass (Mr = 562), and had the same fragment peaks of MS2 with rhodoxanthin. The molecular formula of red pigments was determined as C40H50O2 by high resolution EI-MS. The results indicate that the red pigment is rhodoxanthin, and they are all cis-isomers of rhodoxanthin.

Simultaneous determination of 18 abused opioids and metabolites in human hair using LC-MS/MS and illegal opioids abuse proven by hair analysis.

PubMed

Kim, Jihyun; Ji, Dajeong; Kang, Soyoung; Park, Meejung; Yang, Wonkyung; Kim, Eunmi; Choi, Hwakyung; Lee, Sooyeun

2014-02-01

Natural and synthetic opioids have efficient analgesic activity but can also be addictive. Thus, the determination of opioids and their metabolites in biological specimens is of interest in clinical and forensic toxicology laboratories. The analysis of drugs in hair provides valuable information on previous chronic drug use and has been successfully applied to the diagnosis of drug abuse, tolerance, compliance and gestational drug exposure. Despite the abuse of prescription opioids along with heroin and other illegal opiates, few studies have been conducted on the simultaneous determination of the broad range of opioids covering those drugs in hair. In the present study, an analytical method for the simultaneous detection in hair of 18 opioids and metabolites considered to have a high abuse risk based on the results of urine drug screening was established and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the purpose of clinical and forensic applications. The drugs and metabolites were extracted from hair using methanol and analyzed using LC-MS/MS. The validation results proved that the method was selective, accurate and precise with acceptable linearity within calibration ranges. No significant variation was observed by different sources of matrices. The limits of detection and the limits of quantification ranged from 0.05 to 0.25ng/10mg hair and from 0.05 to 0.5ng/10mg hair, respectively. The developed method was successfully applied to 15 hair samples from opioids users. This method will be very useful for monitoring the inappropriate use of opioid drugs. Copyright © 2013 Elsevier B.V. All rights reserved.

Steroids in porcine follicular fluid: analysis by HPLC, capillary CG and capillary CG/MS after purification on SEP-PAK C18 and ion exchange chromatography.

PubMed

Khalil, M W; Lawson, V

1983-04-01

Steroids in porcine follicular fluid have been concentrated by reverse phase chromatography in SEP-PAK C18 and purified further on the cation exchanger SP-Sephadex C-25. Fractionation into unconjugated neutral and phenolic steroids, glucuronides and sulfates was carried out on triethylaminohydroxypropyl Sephadex LH-20 (TEAP-LH-20). The unconjugated neutral fraction was analysed by high pressure liquid chromatography (HPLC) on a C18 radial cartridge 5 mm I.D.; 10 mu, or on a C18 5 mu RESOLVE column, and by capillary gas chromatography (GC) on a 12 M OV-1 cross linked fused silica column. Testosterone, progesterone and androstenedione were the major steroids detected by HPLC monitored at 254 nm, although 17- hydroxy-, 20 alpha-dihydro- and 20 beta-dihydroprogesterone were also present. Pregnenolone, pregnanediol, dehydroepiandrosterone, 17-hydroxypregnenolone and androsterone were detected by capillary CG as their 0-methyloxime trimethylsilyether derivatives. Further confirmation of structure was provided by complete mass spectral data or by selective ion monitoring (SIM).

Analytical determination of virginiamycin drug residues in edible porcine tissues by LC-MS with confirmation by LC-MS/MS.

PubMed

Boison, Joe; Lee, Stephen; Gedir, Ron

2009-01-01

A liquid chromatographic-mass spectrometric (LC-MS) method was developed and validated for the determination and confirmation of virginiamycin (VMY) M1 residues in porcine liver, kidney, and muscle tissues at concentrations > or =2 ng/g. Porcine liver, kidney, or muscle tissue is homogenized with methanol-acetonitrile. After centrifugation, the supernatant is diluted with phosphate buffer and cleaned up on a C18 solid-phase extraction cartridge. VMY in the eluate is partitioned into chloroform and the aqueous upper layer is removed by aspiration. After evaporating the chloroform in the residual mixture to dryness, the dried extract is reconstituted in mobile phase and VMY is quantified by LC-MS. Any samples eliciting quantifiable levels of VMY M1 (i.e., at concentrations > or =2 ng/g) are subjected to confirmatory analysis by LC-MSIMS. VMY S1, a minor component of the VMY complex, is monitored but not quantified or confirmed.

Kidney tissue targeted metabolic profiling of glucocorticoid-induced osteoporosis and the proposed therapeutic effects of Rhizoma Drynariae studied using UHPLC/MS/MS.

PubMed

Huang, Yue; Liu, Xinyu; Zhao, Longshan; Li, Famei; Xiong, Zhili

2014-06-01

Traditional Chinese medicine and modern science have indicated that there is a close relationship between bone and kidney. In light of this, this project was designed to study the metabolic profiling by UHPLC/MS/MS of glucocorticoid-induced osteoporosis in kidney tissue and the possible therapeutic effects of Rhizoma Drynariae (RD), a classic traditional Chinese medicine, in improving the kidney function and strengthening bone. Twenty-one Wistar rats were divided into three groups: control group (rats before prednisolone inducing), a model group (prednisolone-induced group) and a treatment group (prednisolone-induced rats that were then administered RD ethanol extracts). By using pattern recognition analysis, a significant change in the metabolic profile of kidney tissue samples was observed in the model group and restoration of the profile was observed after the administration of RD ethanol extracts. Some significantly changed biomarkers related to osteoporosis such as sphingolipids (C16 dihydrosphingosine, C18 dihydrosphingosine, C18 phytosphingosine, C20 phytosphingosine), lysophosphatidycholines (C16:0 LPC, C18:0 LPC) and phenylalanine were identified. As a complement to the metabolic profiling of RD in plasma, these biomarkers suggest that kidney damage, cell cytotoxicity and apoptosis exist in osteoporosis rats, which is helpful in further understanding the underlying process of glucocorticoid-induced osetoporosis and the suggested therapeutic effects of RD. The method shows that tissue target metabonomics might provide a powerful tool to further understand the process of disease and the mechanism of therapeutic effect of Chinese medicines. Copyright © 2014 John Wiley & Sons, Ltd.

Determination of phosphatidylethanolamine molecular species in various food matrices by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS2).

PubMed

Zhou, Li; Zhao, Minjie; Ennahar, Saïd; Bindler, Françoise; Marchioni, Eric

2012-04-01

A liquid chromatographic-electrospray ionization-tandem mass spectrometric (LC-ESI-MS(2)) method has been developed for determination of the molecular species of phosphatidylethanolamine (PE) in four food matrices (soy, egg yolk, ox liver, and krill oil). The extraction and purification method consisted of a pressurized liquid extraction procedure for total lipid (TL) extraction, purification of phospholipids (PLs) by adsorption on a silica gel column, and separation of PL classes by semi-preparative normal-phase HPLC. Separation and identification of PE molecular species were performed by reversed-phase HPLC coupled with electrospray ionization tandem mass spectrometry (ESI-MS(2)). Methanol containing 5 mmol L(-1) ammonium formate was used as the mobile phase. A variety of PE molecular species were detected in the four food matrices. (C16:0-C18:2)PE, (C18:2-C18:2)PE, and (C16:0-C18:1)PE were the major PE molecular species in soy. Egg yolk PE contained (C16:0-C18:1)PE, (C18:0-C18:1)PE, (C18:0-C18:2)PE, and (C16:0-C18:2)PE as the major molecular species. Ox liver PE was rich in the species (C18:0-C18:1)PE, (C18:0-C20:4)PE, and (C18:0-C18:2)PE. Finally, krill oil which was particularly rich in (C16:0(alkyl)-C22:6(acyl))plasmanylethanolamine (PakE), (C16:0-C22:6)PE, and (C16:0-C20:5)PE, seemed to be an interesting potential source for supplementation of food with eicosapentaenoic acid and docosahexaenoic acid.

Low Mass MS/MS Fragments of Protonated Amino Acids Used for Distinction of Their 13C- Isotopomers in Metabolic Studies

NASA Astrophysics Data System (ADS)

Ma, Xin; Dagan, Shai; Somogyi, Árpád; Wysocki, Vicki H.; Scaraffia, Patricia Y.

2013-04-01

Glu, Gln, Pro, and Ala are the main amino acids involved in ammonia detoxification in mosquitoes. In order to develop a tandem mass spectrometry method (MS2) to monitor each carbon of the above isotopically-labeled 13C-amino acids for metabolic studies, the compositions and origins of atoms in fragments of the protonated amino acid should be first elucidated. Thus, various electrospray (ESI)-based MS2 tools were employed to study the fragmentation of these unlabeled and isotopically-labeled amino acids and better understand their dissociation pathways. A broad range of fragments, including previously-undescribed low m/z fragments was revealed. The formulae of the fragments (from m/z 130 down to m/z 27) were confirmed by their accurate masses. The structures and conformations of the larger fragments of Glu were also explored by ion mobility mass spectrometry (IM-MS) and gas-phase hydrogen/deuterium exchange (HDX) experiments. It was found that some low m/z fragments ( m/z 27-30) are common to Glu, Gln, Pro, and Ala. The origins of carbons in these small fragments are discussed and additional collision induced dissociation (CID) MS2 fragmentation pathways are proposed for them. It was also found that small fragments (≤ m/z 84) of protonated, methylated Glu, and methylated Gln are the same as those of the underivatized Glu and Gln. Taken together, the new approach of utilizing low m/z fragments can be applied to distinguish, identify, and quantify 13C-amino acids labeled at various positions, either in the backbone or side chain.

Effect of muscle restraint on sheep meat tenderness with rigor mortis at 18°C.

PubMed

Devine, Carrick E; Payne, Steven R; Wells, Robyn W

2002-02-01

The effect on shear force of skeletal restraint and removing muscles from lamb m. longissimus thoracis et lumborum (LT) immediately after slaughter and electrical stimulation was undertaken at a rigor temperature of 18°C (n=15). The temperature of 18°C was achieved through chilling of electrically stimulated sheep carcasses in air at 12°C, air flow 1-1.5 ms(-2). In other groups, the muscle was removed at 2.5 h post-mortem and either wrapped or left non-wrapped before being placed back on the carcass to follow carcass cooling regimes. Following rigor mortis, the meat was aged for 0, 16, 40 and 65 h at 15°C and frozen. For the non-stimulated samples, the meat was aged for 0, 12, 36 and 60 h before being frozen. The frozen meat was cooked to 75°C in an 85°C water bath and shear force values obtained from a 1 × 1 cm cross-section. Commencement of ageing was considered to take place at rigor mortis and this was taken as zero aged meat. There were no significant differences in the rate of tenderisation and initial shear force for all treatments. The 23% cook loss was similar for all wrapped and non-wrapped situations and the values decreased slightly with longer ageing durations. Wrapping was shown to mimic meat left intact on the carcass, as it prevented significant prerigor shortening. Such techniques allows muscles to be removed and placed in a controlled temperature environment to enable precise studies of ageing processes.

Determination and pharmacokinetic study of Enasidenib in rat plasma by UPLC-MS/MS.

PubMed

Pang, Ni-Hong; Liu, Qian; Lu, Xiang-Ran; Yang, Su-Fen; Lin, Dong-Dong; Hu, Guo-Xin

2018-04-27

Enasidenib, an oral product for treating Acute Myeloid Leukemia, has been approved by FDA in Aug, 2017. In this study, we set up an ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS) method for measuring Enasidenib and imatinib (internal standard, IS), simultaneously. Enasidenib and imatinib were separated on an ACQUITY UPLC BEH C 18 Column (2.1 mm × 50 mm, 1.7 μm, 132 Å). Mass detection was carried out by electrospray ionization in the position mode, and the multiple reaction monitoring transitions were m/z 474.23 → 456.17 and m/z 494.30 → 394.20 for Enasidenib and imatinib, respectively. Linearity (2 - 500 ng·mL -1 , R 2  > 0.999), precision and accuracy (RE < ± 15%), extraction recovery (≥ 96.69%), matrix effect (≥ 96.47%) and stability (RE < ± 10%) were validated which demonstrated the robustness of our method. This rapid, efficient and reliable UPLC-MS/MS method shows specificity and repeatability of Enasidenib in rat plasma and can be used in further pharmacokinetic studies. Copyright © 2018 Elsevier B.V. All rights reserved.

Ultrafast quantification of β-lactam antibiotics in human plasma using UPLC-MS/MS.

PubMed

Carlier, Mieke; Stove, Veronique; De Waele, Jan J; Verstraete, Alain G

2015-01-26

There is an increasing interest in monitoring plasma concentrations of β-lactam antibiotics. The objective of this work was to develop and validate a fast ultra-performance liquid chromatographic method with tandem mass spectrometric detection (UPLC-MS/MS) for simultaneous quantification of amoxicillin, cefuroxime, ceftazidime, meropenem and piperacillin with minimal turn around time. Sample clean-up included protein precipitation with acetonitrile containing 5 deuterated internal standards, and subsequent dilution of the supernatant with water after centrifugation. Runtime was only 2.5 min. Chromatographic separation was performed on a Waters Acquity UPLC system using a BEH C18 column (1.7 μm, 100 mm × 2.1 mm) applying a binary gradient elution of water and methanol both containing 0.1% formic acid and 2 mmol/L ammonium acetate on a Water TQD instrument in MRM mode. All compounds were detected in electrospray positive ion mode and could be quantified between 1 and 100 mg/L for amoxicillin and cefuroxime, between 0.5 and 80 mg/L for meropenem and ceftazidime, and between 1 and 150 mg/L for piperacillin. The method was validated in terms of precision, accuracy, linearity, matrix effect and recovery and has been compared to a previously published UPLC-MS/MS method. Copyright © 2014 Elsevier B.V. All rights reserved.

An Improved LC-MS/MS Method for Simultaneous Determination of the Eleven Bioactive Constituents for Quality Control of Radix Angelicae Pubescentis and Its Related Preparations

PubMed Central

Li, Jin; Zhang, Qiu-Hong; He, Jun; Liu, Er-wei; Gao, Xiu-mei; Chang, Yan-xu

2015-01-01

An improved LC-MS/MS method was developed for simultaneous determination of eleven bioactive constituents of Radix Angelicae Pubescentis and its related preparations. It was the first report on the quantification of bioactive constituents in different preparations of Radix Angelicae Pubescentis by LC-MS/MS analytical method. These samples were separated with an Agilent Zorbax Extend reversed-phase C18 column (1.8 μm, 4.6 × 100 mm) by linear gradient elution using aqueous ammonium acetate and acetonitrile as mobile phase. The flow rate was 0.3 mL min−1. The eleven bioactive constituents showed good regression (R > 0.990) within test ranges and the recoveries were in the range of 87.1–110%. The limit of detections and quantifications for most of the major constituents were less than 0.5 and 1.0 ng mL−1, respectively. All results indicated that the developed method could be readily utilized as a suitable quality control method for Radix Angelicae Pubescentis and related preparations. PMID:26078992

LC-MS/MS quantification of 7α-hydroxy-4-cholesten-3-one (C4) in rat and monkey plasma.

PubMed

Kang, Lijuan; Connolly, Thomas M; Weng, Naidong; Jian, Wenying

2017-10-01

7α-hydroxy-4-cholesten-3-one (C4) is an oxidative enzymatic product of cholesterol metabolism via cholesterol 7α-hydroxylase, an enzyme also known as cholesterol 7-alpha-monooxygenase or cytochrome P450 7A1 (CYP7A1). C4 is a stable intermediate in the rate limiting pathway of bile acid biosynthesis. Previous studies showed that plasma C4 levels correlated with CYP7A1 enzymatic activity and could serve as a biomarker for bile acid synthesis. Here we developed and qualified a simple and robust high-throughput method using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) to quantify C4 in rat and monkey plasma. As C4 being an endogenous compound, this method used calibration standards in 50/50: acetonitrile/water (v/v). In order to mimic the incurred samples, quality control samples were prepared in the authentic plasma. Stable isotope labeled C4 (C4-d 7 ) was used as the internal standard. The sample volume for analysis was 20μL and the sample preparation method was protein precipitation with acetonitrile. The average endogenous C4 concentrations, from 10 different lots of rat and monkey plasma, were 53.0±16.5ng/mL and 6.8±5.6ng/mL, respectively. Based on these observed endogenous C4 levels, the calibration curve ranges were established at 1-200ng/mL and 0.5-100ng/mL for rat assay and monkey assay, respectively. The method was qualified with acceptable accuracy, precision, linearity, and specificity. Matrix effect, recovery, and plasma stability of bench-top, freeze-thaw, and long-term frozen storage were also evaluated. The method has been successfully applied to pre-clinical studies. Copyright © 2017 Elsevier B.V. All rights reserved.

Modeling Fungal Melanin Buildup: Biomimetic Polymerization of 1,8-Dihydroxynaphthalene Mapped by Mass Spectrometry.

PubMed

Cecchini, Martina Maya; Reale, Samantha; Manini, Paola; d'Ischia, Marco; De Angelis, Francesco

2017-06-12

Due to the emerging biomedical relevance and technological potential of fungal melanins, and prompted by the virtual lack of information about their structural arrangement, an optimized synthetic protocol has been devised for a potential structural model of Ascomyces allomelanin through enzyme-catalyzed oxidative polymerization of 1,8-dihydroxynaphthalene (1,8-DHN). Electrospray ionization mass spectrometry (ESI-MS) measurements of freshly synthesized DHN-polymer recorded in the negative ion mode allowed detection of oligomers up to m/z 4000, separated by 158 Da, corresponding to the in-chain DHN-unit. The dominant peaks were assigned to singly-charged distribution, up to 23 repeating units, whereas a doubly charged polymer distribution was also detectable. Chemical derivatization, ultra-performance liquid chromatography (UPLC)-ESI MS, and MS/MS data confirmed that oxidative polymerization of 1,8-DHN proceeds through C-C coupling of the naphthalene rings. The new insights reported here into synthetic 1,8-DHN oligomers/polymers as a mimic of fungal melanins may guide novel interesting advances and applications in the field of biomimetic functional materials. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

C18-coated stir bar sorptive extraction combined with high performance liquid chromatography-electrospray tandem mass spectrometry for the analysis of sulfonamides in milk and milk powder.

PubMed

Yu, Chunhe; Hu, Bin

2012-02-15

A simple, rapid, sensitive, inexpensive and less sample consuming method of C(18)-stir bar sorptive extraction (SBSE)-high performance liquid chromatography (HPLC)-tandem mass spectrometry (MS/MS) was proposed for the determination of six sulfonamides in milk and milk powder samples. C(18) silica particles coated stir bar was prepared by adhesion method, and two kinds of adhesive glue, polydimethylsiloxane (PDMS) sol and epoxy glue were tried. It was found that the C(18)-coated stir bar prepared by PDMS sol as adhesive glue is more robust than that prepared by epoxy glue when liquid desorption was employed, in terms of both lifetime and organic solvent tolerance. The preparation of C(18) stir bar was simple with good mechanic strength and the stir bar could be reused for more than 20 times. Granular coating has relatively high specific surface area and is propitious to sorptive extraction based process. Compared to conventional PDMS SBSE coating, C(18) coating shows good affinity to the target polar/weak polar sulfonamides. To achieve optimum SBSE extraction performance, several parameters including extraction and desorption time, ionic strength, sample pH and stirring speed were investigated. The detection limits of the proposed method for six sulfonamides were in the range of 0.9-10.5 μg/L for milk and 2.7-31.5 μg/kg for milk powder. Good linearities were obtained for sulfonamides with the correlation coefficients (R) above 0.9922. Finally, the proposed method was successfully applied to the determination of sulfonamides in milk and milk powder samples and satisfied recoveries of spiked target compounds in real samples were obtained. Copyright © 2012 Elsevier B.V. All rights reserved.

Simultaneous quantitation of sphingoid bases by UPLC-ESI-MS/MS with identical 13C-encoded internal standards.

PubMed

Mirzaian, M; Wisse, P; Ferraz, M J; Marques, A R A; Gaspar, P; Oussoren, S V; Kytidou, K; Codée, J D C; van der Marel, G; Overkleeft, H S; Aerts, J M

2017-03-01

Free sphingoid bases (lysosphingolipids) of primary storage sphingolipids are increased in tissues and plasma of several sphingolipidoses. As shown earlier by us, sphingoid bases can be accurately quantified using UPLC-ESI-MS/MS, particularly in combination with identical 13 C-encoded internal standards. The feasibility of simultaneous quantitation of sphingoid bases in plasma specimens spiked with a mixture of such standards is here described. The sensitivity and linearity of detection is excellent for all examined sphingoid bases (sphingosine, sphinganine, hexosyl-sphingosine (glucosylsphingosine), hexosyl 2 -sphingosine (lactosylsphingosine), hexosyl 3 -sphingosine (globotriaosylsphingosine), phosphorylcholine-sphingosine) in the relevant concentration range and the measurements show very acceptable intra- and inter-assay variation (<10% average). Plasma samples of a series of male and female Gaucher Disease and Fabry Disease patients were analyzed with the multiplex assay. The obtained data compare well to those earlier determined for plasma globotriaosylsphingosine and glucosylsphingosine in GD and FD patients. The same approach can be also applied to measure sphingolipids in the same sample. Following extraction of sphingolipids from the same sample these can be converted to sphingoid bases by microwave exposure and subsequently quantified using 13 C-encoded internal standards. Copyright © 2017 Elsevier B.V. All rights reserved.

Identification and characterization of stress degradants of lacosamide by LC-MS and ESI-Q-TOF-MS/MS: development and validation of a stability indicating RP-HPLC method.

PubMed

Ramisetti, Nageswara Rao; Kuntamukkala, Ramakrishna; Lakshetti, Sridhar; Sripadi, Prabhakar

2014-07-01

The current study dealt with the degradation behavior of lacosamide (LAC) under ICH prescribed stress conditions. LAC was found to be labile under acid and base hydrolytic stress conditions, while it was stable to neutral hydrolytic, oxidative, photolytic and thermal stress. In total, seven degradation products (DPs) were formed, which were separated on a C18 column using a stability-indicating method. LC-MS analyses indicated that one of the DPs had the same molecular mass as that of the drug. Structural characterization of DPs was carried out using ESI-Q-TOF-MS/MS technique. The degradation pathways and mechanisms of degradation of the drug were delineated by carrying out the degradation in different co-solvents viz. methanol, deuterated methanol, ethanol, 1-propanol and acetonitrile. The developed LC method was validated for the determination of related substances and assay of LAC as per ICH guidelines. This study demonstrates a comprehensive approach of LAC degradation studies during its development phase. Copyright © 2014. Published by Elsevier B.V.

40 CFR 721.10395 - Fatty acids, C14-18 and C16-18 unsatd., polymers with adipic acid and triethanolamine, di-Me...

Code of Federal Regulations, 2012 CFR

2012-07-01

...., polymers with adipic acid and triethanolamine, di-Me sulfate-quaternized. 721.10395 Section 721.10395... Fatty acids, C14-18 and C16-18 unsatd., polymers with adipic acid and triethanolamine, di-Me sulfate... sulfate-quaternized (PMN P-10-458; CAS No. 1211825-32-9) is subject to reporting under this section for...

40 CFR 721.10395 - Fatty acids, C14-18 and C16-18 unsatd., polymers with adipic acid and triethanolamine, di-Me...

Code of Federal Regulations, 2013 CFR

2013-07-01

...., polymers with adipic acid and triethanolamine, di-Me sulfate-quaternized. 721.10395 Section 721.10395... Fatty acids, C14-18 and C16-18 unsatd., polymers with adipic acid and triethanolamine, di-Me sulfate... sulfate-quaternized (PMN P-10-458; CAS No. 1211825-32-9) is subject to reporting under this section for...

40 CFR 721.10395 - Fatty acids, C14-18 and C16-18 unsatd., polymers with adipic acid and triethanolamine, di-Me...

Code of Federal Regulations, 2014 CFR

2014-07-01

...., polymers with adipic acid and triethanolamine, di-Me sulfate-quaternized. 721.10395 Section 721.10395... Fatty acids, C14-18 and C16-18 unsatd., polymers with adipic acid and triethanolamine, di-Me sulfate... sulfate-quaternized (PMN P-10-458; CAS No. 1211825-32-9) is subject to reporting under this section for...

[Determination of icaritin in rat plasma by HPLC-MS/MS].

PubMed

Liu, Hai-Pei; Meng, Fan-Hua; Guo, Ji-Fen; Si, Duan-Yun; Zhu, Xiao-Wei; Zhao, Yi-Min

2009-10-01

The paper is to report the development of a high-performance liquid chromatographic/tandem mass spectrometry (HPLC-MS/MS) method for the determination of icaritin (ICT) in rat plasma. After precipitated with acetonitrile from the plasma, ICT was isolated chromatographically on a Dikma C18 column. The mobile phase consisted of acetonitrile-water-acetic acid (72 : 28 : 1.5, v/v/v). Electrospray ionization (ESI) source was applied and operated in the positive ion mode. Multiple reaction monitoring (MRM) mode with the transitions of m/z 387 --> m/z 313 and m/z 331 --> m/z 315 were used to quantify ICT and the internal standard, respectively. The linear calibration curve was obtained in the concentration range of 2.5-1,000 ng x mL(-1). The lower limit of quantification was 2.5 ng x mL(-1). The inter- and intra-day precision (RSD) were less than 9.63%, and the accuracy (relative error) was within +/-7.42%. The method was proved to be suitable for the pharmacokinetics of ICT, which offers advantages of high sensitivity and selectivity.

18 CFR 3c.2 - Nonpublic information.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Nonpublic information. 3c.2 Section 3c.2 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION...)) of the Federal Power Act, and section 8(b) (15 U.S.C. 717g) of the Natural Gas Act prohibit any...

Quantification of phosphatidylethanol 16:0/18:1, 18:1/18:1, and 16:0/16:0 in venous blood and venous and capillary dried blood spots from patients in alcohol withdrawal and control volunteers.

PubMed

Kummer, Natalie; Ingels, Ann-Sofie; Wille, Sarah M R; Hanak, Catherine; Verbanck, Paul; Lambert, Willy E E; Samyn, Nele; Stove, Christophe P

2016-01-01

Phosphatidylethanol species (PEths) are promising biomarkers of alcohol consumption. Here, we report on the set-up, validation, and application of a novel UHPLC-ESI-MS/MS method for the quantification of PEth 16:0/18:1, PEth 18:1/18:1, and PEth 16:0/16:0 in whole blood (30 μL) and in venous (V, 30 μL) or capillary (C, 3 punches (3 mm)) dried blood spots (DBS). The methods were linear from 10 (LLOQ) to 2000 ng/mL for PEth 16:0/18:1, from 10 (LLOQ) to 1940 ng/mL for PEth 18:1/18:1, and from 19 (LLOQ) to 3872 ng/mL for PEth 16:0/16:0. Extraction efficiencies were higher than 55% (RSD < 18%) and matrix effects compensated for by IS were between 77 and 125% (RSD < 10%). Accuracy, repeatability, and intermediate precision fulfilled acceptance criteria (bias and RSD below 13%). Validity of the procedure for determination of PEth 16:0/18:1 in blood was demonstrated by the successful participation in a proficiency test. The quantification of PEths in C-DBS was not significantly influenced by the hematocrit, punch localization, or spot volume. The stability of PEths in V-DBS stored at room temperature was demonstrated up to 6 months. The method was applied to authentic samples (whole blood, V-DBS, and C-DBS) from 50 inpatients in alcohol withdrawal and 50 control volunteers. Applying a cut-off value to detect inpatients at 221 ng/mL for PEth 16:0/18:1 provided no false positive results and a good sensitivity (86%). Comparison of quantitative results (Bland-Altman plot, Passing-Bablok regression, and Wilcoxon signed rank test) revealed that V-DBS and C-DBS were valid alternatives to venous blood for the detection of alcohol consumption.

40 CFR 180.1284 - Ammonium salts of higher fatty acids (C8-C18 saturated; C8-C12 unsaturated); exemption from the...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Ammonium salts of higher fatty acids... Ammonium salts of higher fatty acids (C8-C18 saturated; C8-C12 unsaturated); exemption from the requirement of a tolerance. Ammonium salts of C8-C18 saturated and C8-C12 unsaturated higher fatty acids are...

40 CFR 180.1284 - Ammonium salts of higher fatty acids (C8-C18 saturated; C8-C12 unsaturated); exemption from the...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Ammonium salts of higher fatty acids... Ammonium salts of higher fatty acids (C8-C18 saturated; C8-C12 unsaturated); exemption from the requirement of a tolerance. Ammonium salts of C8-C18 saturated and C8-C12 unsaturated higher fatty acids are...

[LC-MS/MS analysis of determination of strychnine and brucine in formaldehyde fixed tissue].

PubMed

Zhan, Lan-fen; Liu, Ming-dong; Yan, You-yi; Ye, Yi; Wang, Wei; Wang, Zhi-hui; Zhao, Jun-hong; Liao, Lin-chuan

2012-10-01

To establish a method for determination of strychnine and brucine in formaldehyde fixed tissue by LC-MS/MS analysis. The samples were pretreated with solid phase extraction using SCX cartridges and separated on SB-C18 column with mobile phase 0.1% formic acid : 0.1% formic acid-acetonitrile (75:25). Electrospray ionization (ESI) source was utilized and operated in positive ion mode. Multiple reactions monitoring (MRM) mode was applied. External standard method was applied for quantitation. The chromatographic separation of strychnine and brucine in formaldehyde fixed nephritic and hepatic tissues resulted successfully. The standard curve was linear in the range of 0.002-2.0 microg/g for strychnine and brucine in formaldehyde fixed tissues, and the correlation coefficient was more than 0.996. The limits of detection (LOD) of strychnine and brucine in nephritic tissues were 0.06ng/g and 0.03 ng/g, respectively. The LOD of both chemicals were 0.3 ng/g in hepatic tissues. The extraction recovery rate was more than 74.5%. The precision of intra-day and inter-day were both less than 8.2%. Strychnine and brucine can be sensitive to be determined in formaldehyde fixed tissue by LC-MS/MS analysis. It can be applied in the forensic toxicological analysis.

The proteome pattern cGvHD_MS14 allows early and accurate prediction of chronic GvHD after allogeneic stem cell transplantation.

PubMed

Weissinger, E M; Human, C; Metzger, J; Hambach, L; Wolf, D; Greinix, H T; Dickinson, A M; Mullen, W; Jonigk, D; Kuzmina, Z; Kreipe, H; Schweier, P; Böhm, O; Türüchanow, I; Ihlenburg-Schwarz, D; Raad, J; Durban, A; Schiemann, M; Könecke, C; Diedrich, H; Holler, E; Beutel, G; Krauter, J; Ganser, A; Stadler, M

2017-03-01

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) may be curative, but is associated with significant morbidity and mortality. Chronic graft-versus-host disease (cGvHD), characterized by inflammation and fibrosis of multiple target organs, considerably contributes to the morbidity and mortality even years after allo-HSCT. Diagnosis of cGvHD is based on clinical features and histology of biopsies. Here, we report the generation of a urinary cGvHD-specific proteome-pattern (cGvHD_MS14) established by capillary electrophoresis-mass spectrometry to predict onset and severity of cGvHD as an unbiased laboratory test. cGvHD_MS14 was evaluated on samples from 412 patients collected prospectively in four transplant centers. Sensitivity and specificity was 84 and 76% by cGvHD_MS14 classification. Sensitivity further increased to 93% by combination of cGvHD_MS14 with relevant clinical variables to a logistic regression model. cGvHD was predicted up to 55 days prior to clinical diagnosis. Acute GvHD is not recognized by cGvHD_MS14. cGvHD_MS14 consists of 14 differentially excreted peptides, six of those have been sequenced to date and are fragments from thymosin β-4, eukaryotic translation initiation factor 4γ2, fibrinogen β-chain or collagens. In conclusion, the cGvHD_MS14-pattern allows early, highly sensitive and specific prediction of cGvHD as an independent diagnostic criterion of clinical diagnosis potentially allowing early therapeutic intervention.

Extension of the carotenoid test to superficially porous C18 bonded phases, aromatic ligand types and new classical C18 bonded phases.

PubMed

Lesellier, E

2012-11-30

The recent introduction of new stationary phases for liquid chromatography based on superficially porous particles, called core-shell or fused-core, dramatically improved the separation performances through very high efficiency, due mainly to reduced eddy diffusion. However, few studies have evaluated the retention and selectivity of C18 phases based on such particles, despite some retention order change reported in literature between some of these phases. The carotenoid test has been developed a few years ago in the goal to compare the chromatographic properties of C18 bonded phases. Based on the analysis of carotenoid pigments by using Supercritical Fluid Chromatography (SFC), it allows, with a single analysis, to measure three main properties of reversed phase chromatography stationary phases: hydrophobicity, polar surface activity and shape selectivity. Previous studies showed the effect of the endcapping treatment, the bonding density, the pore size, and the type of bonding (monomeric vs. polymeric) on these studied properties, and described the classification map used for a direct column comparison. It was applied to ten ODS superficially porous stationary phases, showing varied chromatographic behaviors amongst these phases. As expected, due to the lower specific surface area, these superficially porous phases are less hydrophobic than the fully porous one. In regards of the polar surface activity (residual silanols) and to the shape selectivity, some of these superficially porous phases display close chromatographic properties (Poroshell 120, Halo C18, Ascentis Express, Accucore C18, Nucleoshell C18 on one side and Aeris Wide pore, Aeris peptide and Kinetex XDB on the other side), whereas others, Kinetex C18 and Halo peptide ES C18 display more specific ones. Besides, they can be compared to classical fully porous phases, in the goal to improve method transfer from fully to superficially porous particles. By the way, the paper also report the extension of

Ice core profiles of saturated fatty acids (C12:0-C30:0) and oleic acid (C18:1) from southern Alaska since 1734 AD: A link to climate change in the Northern Hemisphere

NASA Astrophysics Data System (ADS)

Pokhrel, Ambarish; Kawamura, Kimitaka; Seki, Osamu; Matoba, Sumio; Shiraiwa, Takayuki

2015-01-01

An ice core drilled at Aurora Peak in southeast Alaska was analyzed for homologous series of straight chain fatty acids (C12:0-C30:0) including unsaturated fatty acid (oleic acid) using gas chromatography (GC/FID) and GC/mass spectrometry (GC/MS). Molecular distributions of fatty acids are characterized by even carbon number predominance with a peak at palmitic acid (C16:0, av. 20.3 ± SD. 29.8 ng/g-ice) followed by oleic acid (C18:1, 19.6 ± 38.6 ng/g-ice) and myristic acid (C14:0, 15.3 ± 21.9 ng/g-ice). The historical trends of short-chain fatty acids, together with correlation analysis with inorganic ions and organic tracers suggest that short-chain fatty acids (except for C12:0 and C15:0) were mainly derived from sea surface micro layers through bubble bursting mechanism and transported over the glacier through the atmosphere. This atmospheric transport process is suggested to be linked with Kamchatka ice core δD record from Northeast Asia and Greenland Temperature Anomaly (GTA). In contrast, long-chain fatty acids (C20:0-C30:0) are originated from terrestrial higher plants, soil organic matter and dusts, which are also linked with GTA. Hence, this study suggests that Alaskan fatty acids are strongly influenced by Pacific Decadal Oscillation/North Pacific Gyre Oscillation and/or extra tropical North Pacific surface climate and Arctic oscillation. We also found that decadal scale variability of C18:1/C18:0 ratios in the Aurora Peak ice core correlate with the Kamchatka ice core δD, which reflects climate oscillations in the North Pacific. This study suggests that photochemical aging of organic aerosols could be controlled by climate periodicity.

Development and application of UHPLC-MS/MS method for the determination of phenolic compounds in Chamomile flowers and Chamomile tea extracts.

PubMed

Nováková, Lucie; Vildová, Anna; Mateus, Joana Patricia; Gonçalves, Tiago; Solich, Petr

2010-09-15

UHPLC-MS/MS method using BEH C18 analytical column was developed for the separation and quantitation of 12 phenolic compounds of Chamomile (Matricaria recutita L.). The separation was accomplished using gradient elution with mobile phase consisting of methanol and formic acid 0.1%. ESI in both positive and negative ion mode was optimized with the aim to reach high sensitivity and selectivity for quantitation using SRM experiment. ESI in negative ion mode was found to be more convenient for quantitative analysis of all phenolics except of chlorogenic acid and kaempherol, which demonstrated better results of linearity, accuracy and precision in ESI positive ion mode. The results of method validation confirmed, that developed UHPLC-MS/MS method was convenient and reliable for the determination of phenolic compounds in Chamomile extracts with linearity >0.9982, accuracy within 76.7-126.7% and precision within 2.2-12.7% at three spiked concentration levels. Method sensitivity expressed as LOQ was typically 5-20 nmol/l. Extracts of Chamomile flowers and Chamomile tea were subjected to UHPLC-MS/MS analysis. The most abundant phenolic compounds in both Chamomile flowers and Chamomile tea extracts were chlorogenic acid, umbelliferone, apigenin and apigenin-7-glucoside. In Chamomile tea extracts there was greater abundance of flavonoid glycosides such as rutin or quercitrin, while the aglycone apigenin and its glycoside were present in lower amount. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Comparison of 4'-[methyl-(11)C]thiothymidine ((11)C-4DST) and 3'-deoxy-3'-[(18)F]fluorothymidine ((18)F-FLT) PET/CT in human brain glioma imaging.

PubMed

Toyota, Yasunori; Miyake, Keisuke; Kawai, Nobuyuki; Hatakeyama, Tetsuhiro; Yamamoto, Yuka; Toyohara, Jun; Nishiyama, Yoshihiro; Tamiya, Takashi

2015-01-01

3'-deoxy-3'-[(18)F]fluorothymidine ((18)F-FLT) has been used to evaluate tumor malignancy and cell proliferation in human brain gliomas. However, (18)F-FLT has several limitations in clinical use. Recently, (11)C-labeled thymidine analogue, 4'-[methyl-(11)C]thiothymidine ((11)C-4DST), became available as an in vivo cell proliferation positron emission tomography (PET) tracer. The present study was conducted to evaluate the usefulness of (11)C-4DST PET in the diagnosis of human brain gliomas by comparing with the images of (18)F-FLT PET. Twenty patients with primary and recurrent brain gliomas underwent (18)F-FLT and (11)C-4DST PET scans. The uptake values in the tumors were evaluated using the maximum standardized uptake value (SUVmax), the tumor-to-normal tissue uptake (T/N) ratio, and the tumor-to-blood uptake (T/B) ratio. These values were compared among different glioma grades. Correlation between the Ki-67 labeling index and the uptake values of (11)C-4DST and (18)F-FLT in the tumor was evaluated using linear regression analysis. The relationship between the individual (18)F-FLT and (11)C-4DST uptake values in the tumors was also examined. (11)C-4DST uptake was significantly higher than that of (18)F-FLT in the normal brain. The uptake values of (11)C-4DST in the tumor were similar to those of (18)F-FLT resulting in better visualization with (18)F-FLT. No significant differences in the uptake values of (18)F-FLT and (11)C-4DST were noted among different glioma grades. Linear regression analysis showed a significant correlation between the Ki-67 labeling index and the T/N ratio of (11)C-4DST (r = 0.50, P < 0.05) and (18)F-FLT (r = 0.50, P < 0.05). Significant correlations were also found between the Ki-67 labeling index and the T/B ratio of (11)C-4DST (r = 0.52, P < 0.05) and (18)F-FLT (r = 0.55, P < 0.05). A highly significant correlation was observed between the individual T/N ratio of (11)C-4DST and (18)F-FLT in the tumor (r�

Direct analysis of [6,6-(2)H2]glucose and [U-(13)C6]glucose dry blood spot enrichments by LC-MS/MS.

PubMed

Coelho, Margarida; Mendes, Vera M; Lima, Inês S; Martins, Fátima O; Fernandes, Ana B; Macedo, M Paula; Jones, John G; Manadas, Bruno

2016-06-01

A liquid chromatography tandem mass spectrometry (LC-MS/MS) using multiple reaction monitoring (MRM) in a triple-quadrupole scan mode was developed and comprehensively validated for the determination of [6,6-(2)H2]glucose and [U-(13)C6]glucose enrichments from dried blood spots (DBS) without prior derivatization. The method is demonstrated with dried blood spots obtained from rats administered with a primed-constant infusion of [U-(13)C6]glucose and an oral glucose load enriched with [6,6-(2)H2]glucose. The sensitivity is sufficient for analysis of the equivalent to <5μL of blood and the overall method was accurate and precise for the determination of DBS isotopic enrichments. Copyright © 2016 Elsevier B.V. All rights reserved.

40 CFR 721.10175 - 1-Propanaminium, N-(3-aminopropyl)-2-hydroxy-N,N-dimethyl-3-sulfo-, N-(C12-18 and C18-unsatd...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false 1-Propanaminium, N-(3-aminopropyl)-2... 1-Propanaminium, N-(3-aminopropyl)-2-hydroxy-N,N-dimethyl-3-sulfo-, N-(C12-18 and C18-unsatd. acyl... chemical substance identified as 1-Propanaminium, N-(3-aminopropyl)-2-hydroxy-N,N-dimethyl-3-sulfo-, N-(C12...

40 CFR 721.642 - Amines, N-(C14-18 and C16-16 unsaturated alkyl)] dipropylene-tri-, tripropylenetetra-, and...

Code of Federal Regulations, 2010 CFR

2010-07-01

... substances amines, N-(C14-18 and C16-18 unsaturated alkyl)] dipropylenetri-, (PMN P-94-1244... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Amines, N-(C14-18 and C16-16... Amines, N-(C14-18 and C16-16 unsaturated alkyl)] dipropylene-tri-, tripropylenetetra-, and...

Analysis of benzodiazepines and their metabolites using DBS cards and LC-MS/MS.

PubMed

Lee, Heesang; Park, Yujin; Jo, Jiyeong; In, Sangwhan; Park, Yonghoon; Kim, Eunmi; Pyo, Jaesung; Choe, Sanggil

2015-10-01

Dried Blood Spot (DBS) has been used a blood extraction method for inherited metabolic disorder screening since 1960s. With introduction of LC-MS/MS, not only DBS could be used to analysis drugs in small blood volume, but in various fields, such as toxicology, drug therapeutic monitoring, drug diagnostic screening, and illicit drugs. In toxicology field, many drugs (e.g. benzodiazepines, acetaminophen, small molecule drugs) have been tested with DBS. Compared with earlier blood extraction methods (SPE and LLE), DBS has lots of advantages; lower blood volume (less than 50μL), shorter analysis time caused by a more concise analysis procedure and lower cost. We optimized the DBS procedure and LC-MS/MS conditions for 18 benzodiazepines, seven benzodiazepine metabolites, and one z-drug (zolpidem) analysis in blood. 30μL of whole blood was spotted on FTA DMPK card C and dried for 2h in a desiccator. A 6-mm disk was punched and vortexed for 1min in a centrifuge tube with 300μL methanol/acetonitrile mixture (1:1, v/v). After evaporation, redissolved in 100μL mobile phase of LC-MS/MS and 5μL was injected. In the analysis for 26 target compounds in blood, all of the method validation parameters - LLOD, LLOQ, accuracy (intra- and inter-assay), and precision (intra- and inter-assay) - were satisfied with method validation criteria, within 15%. The results of matrix effect, recovery, and process efficiency were good. We developed a fast and reliable sample preparation method using DBS for 26 benzodiazepines, benzodiazepine metabolites, and z-drug (zolpidem). Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

A UHPLC-MS/MS method for profiling multifunctional steroids in human hair.

PubMed

Dong, Zhen; Wang, Caihong; Zhang, Jinlan; Wang, Zhe

2017-08-01

It is important to profile steroids in many physiological and pathological processes. Recently, hair has been used for the long-term measurement of endogenous steroid hormones. Analyzing hair has advantages of being noninvasive and time sequential compared with other bio-specimens. Liquid chromatography-mass spectrometry (LC-MS) techniques have been widely used over the past decades; however, it is challenging to profile estrogens in hair by LC-MS, and more comprehensive steroid profiling is required. In this paper, an ultra high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed to simultaneously profile 28 multifunctional steroids, including corticosteroids (n = 6), estrogens (n = 13), androgens (n = 5) and progestogens (n = 4), in human scalp hair in a single run. To optimize the sample preparation procedure, we evaluated extraction time, post-incubation purification and hair fragment length; 30 mg hair samples were washed with hexane, cut into 5 mm pieces and incubated in methanol for 18 h at 25 °C. Methanol extraction derivatized using Girard P and dansyl chloride reagent was analyzed within 25 min using an automated injection program combined with a diverter valve switch and step analysis (AIDSA). The method was well validated in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), precision, accuracy, matrix effect and recovery, and was successfully applied to a steroid profile from male and female hairs. Significant differences were observed between genders. In addition, steroids showed a declining trend from the proximal to more distal hair segments; thus, care should be taken when obtaining hair samples for analysis to account for this difference in steroid levels along the length of hair. Graphical Abstract The workflow of the estabished UHPLC-MS/MS method.

17 CFR 240.15c1-8 - Sales at the market.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 17 Commodity and Securities Exchanges 4 2014-04-01 2014-04-01 false Sales at the market. 240.15c1-8 Section 240.15c1-8 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION... Securities Exchange Act of 1934 Rules Relating to Over-The-Counter Markets § 240.15c1-8 Sales at the market...

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

PubMed

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

2017-08-01

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

Quantitation of melatonin and n-acetylserotonin in human plasma by nanoflow LC-MS/MS and electrospray LC-MS/MS.

PubMed

Carter, Melissa D; Calcutt, M Wade; Malow, Beth A; Rose, Kristie L; Hachey, David L

2012-03-01

Melatonin (MEL) and its chemical precursor N-acetylserotonin (NAS) are believed to be potential biomarkers for sleep-related disorders. Measurement of these compounds, however, has proven to be difficult due to their low circulating levels, especially that of NAS. Few methods offer the sensitivity, specificity and dynamic range needed to monitor MEL and its precursors and metabolites in small blood samples, such as those obtained from pediatric patients. In support of our ongoing study to determine the safety, tolerability and PK dosing strategies for MEL in treating insomnia in children with autism spectrum disorder, two highly sensitive LC-MS/MS assays were developed for the quantitation of MEL and precursor NAS at pg/mL levels in small volumes of human plasma. A validated electrospray ionization (ESI) method was used to quantitate high levels of MEL in PK studies, and a validated nanospray (nESI) method was developed for quantitation of MEL and NAS at endogenous levels. In both assays, plasma samples were processed by centrifugal membrane dialysis after addition of stable isotopic internal standards, and the components were separated by either conventional LC using a Waters SymmetryShield RP18 column (2.1 × 100  mm, 3.5 µm) or on a polyimide-coated, fused-silica capillary self-packed with 17 cm AquaC18 (3 µm, 125 Å). Quantitation was done using the SRM transitions m/z 233 → 174 and m/z 219 → 160 for MEL and NAS, respectively. The analytical response ratio versus concentration curves were linear for MEL (nanoflow LC: 11.7-1165  pg/mL, LC: 1165-116,500  pg/mL) and for NAS (nanoflow LC: 11.0-1095  pg/mL). Copyright © 2012 John Wiley & Sons, Ltd.

Quantitation of Melatonin and N-acetylserotonin in Human Plasma by Nanoflow LC-MS/MS and Electrospray LC-MS/MS

PubMed Central

Carter, Melissa D.; Calcutt, M. Wade; Malow, Beth A.; Rose, Kristie L.; Hachey, David L.

2012-01-01

Melatonin (MEL) and its chemical precursor N-acetylserotonin (NAS) are believed to be potential biomarkers for sleep-related disorders. Measurement of these compounds, however, has proven to be difficult due to their low circulating levels, especially that of NAS. Few methods offer the sensitivity, specificity and dynamic range needed to monitor MEL and its precursors and metabolites in small blood samples, such as those obtained from pediatric patients. In support of our ongoing study to determine the safety, tolerability, and PK dosing strategies for MEL in treating insomnia in children with autism spectrum disorder, two highly sensitive LC-MS/MS assays were developed for the quantitation of MEL and precursor NAS at pg/mL levels in small volumes of human plasma. A validated electrospray ionization (ESI) method was used to quantitate high levels of MEL in PK studies and a validated nanospray (nESI) method was developed for quantitation of MEL and NAS at endogenous levels. In both assays plasma samples were processed by centrifugal membrane dialysis after addition of stable isotopic internal standards, and the components were separated by either conventional LC using a Waters SymmetryShield RP18 column (2.1×100 mm, 3.5 μm) or on a polyimide-coated, fused-silica capillary self-packed with 17 cm AquaC18 (3 μm, 125 Å). Quantitation was done using the SRM transitions m/z 233→174 and m/z 219→160 for MEL and NAS, respectively. The analytical response ratio vs. concentration curves were linear for MEL (nanoflow LC: 11.7–1165 pg/mL, LC: 1165–116500 pg/mL) and for NAS (nanoflow LC: 11.0–1095 pg/mL). PMID:22431453

Global combined precursor isotopic labeling and isobaric tagging (cPILOT) approach with selective MS(3) acquisition.

PubMed

Evans, Adam R; Robinson, Renã A S

2013-11-01

Recently, we reported a novel proteomics quantitation scheme termed "combined precursor isotopic labeling and isobaric tagging (cPILOT)" that allows for the identification and quantitation of nitrated peptides in as many as 12-16 samples in a single experiment. cPILOT offers enhanced multiplexing and posttranslational modification specificity, however excludes global quantitation for all peptides present in a mixture and underestimates reporter ion ratios similar to other isobaric tagging methods due to precursor co-isolation. Here, we present a novel chemical workflow for cPILOT that can be used for global tagging of all peptides in a mixture. Specifically, through low pH precursor dimethylation of tryptic or LysC peptides followed by high pH tandem mass tags, the same reporter ion can be used twice in a single experiment. Also, to improve triple-stage mass spectrometry (MS(3) ) data acquisition, a selective MS(3) method that focuses on product selection of the y1 fragment of lysine-terminated peptides is incorporated into the workflow. This novel cPILOT workflow has potential for global peptide quantitation that could lead to enhanced sample multiplexing and increase the number of quantifiable spectra obtained from MS(3) acquisition methods. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simple and Fast Extraction-Coupled UPLC-MS/MS Method for the Determination of Mequindox and Its Major Metabolites in Food Animal Tissues.

PubMed

You, Yanli; Song, Liting; Li, Yanshen; Wu, Yongtao; Xin, Mao

2016-03-23

This research described a sensitive and rapid UPLC-MS/MS method for the determination of mequindox and its six major metabolites in chicken muscle, chicken liver, swine muscle, and swine liver. Among the metabolites, carbonyl reduction-1,4-bisdesoxy-mequindox is novel. Target analytes could be extracted by ethyl acetate without any acidolysis or enzymolysis steps. After purification by a Bond Elut C18 cartridge, analysis was carried out by UPLC-MS/MS using positive ion multiple reaction monitoring (MRM) mode. Validation was performed in spiked samples, and mean recoveries ranged from 64.3 to 114.4%, with intraday and interday variations of less than 14.7 and 19.2%, respectively. The limit of detection (LOD) was <1.0 μg kg(-1), whereas the limit of quantification (LOQ) was <4.0 μg kg(-1). This procedure will help monitor mequindox residues in animal-derived food, and it will also facilitate further pharmacokinetics of mequindox.

Quantification of the Triazole Antifungal Compounds Voriconazole and Posaconazole in Human Serum or Plasma Using Liquid Chromatography Electrospray Tandem Mass Spectrometry (HPLC-ESI-MS/MS).

PubMed

Molinelli, Alejandro R; Rose, Charles H

2016-01-01

Voriconazole and posaconazole are triazole antifungal compounds used in the treatment of fungal infections. Therapeutic drug monitoring of both compounds is recommended in order to guide drug dosing to achieve optimal blood concentrations. In this chapter we describe an HPLC-ESI-MS/MS method for the quantification of both compounds in human plasma or serum following a simple specimen preparation procedure. Specimen preparation consists of protein precipitation using methanol and acetonitrile followed by a cleanup step that involves filtration through a cellulose acetate membrane. The specimen is then injected into an HPLC-ESI-MS/MS equipped with a C18 column and separated over an acetonitrile gradient. Quantification of the drugs in the specimen is achieved by comparing the response of the unknown specimen to that of the calibrators in the standard curve using multiple reaction monitoring.

Improvement of Nicotinic Acid and Nicotinamide Analysis in Meats and Meat Products by HPLC and LC-MS/MS with Solid-Phase Extraction.

PubMed

Hiki, Asako; Yamajima, Yukiko; Uematsu, Yoko

2016-01-01

A method for nicotinic acid (NA) and nicotinamide (NAA) analysis in meats was developed. NA and NAA were extracted from meats or meat products with metaphosphate aqueous solution. The extract was cleaned up with an Oasis MCX cartridge. The cartridge was washed with 2% acetic acid (v/v) and acetic acid-methanol solution. NA and NAA were eluted with ammonia-methanol solution. NA and NAA in the eluate were chromatographed on a Scherzo SM-C18 (3.0×150 mm, 3.0 μm) column with 20 mmol/L ammonium acetate containing 0.1% acetic acid-acetonitrile (97 : 3) as a mobile phase and were monitored at 261 nm. Quantification was performed by LC and LC-MS/MS. Calibration curves showed high linearity (correlation coefficient>0.998) between 1-25 μg/mL for LC and LC-MS/MS. Recoveries were 84-108% (CV≦5.8%) by HPLC and 79-105% (CV≦9.0%) by LC-MS/MS. The limit of quantitation for NA was 0.005-0.01 g/kg and that for NAA was 0.01-0.02 g/kg.

[Determination of unknown impurities in cefotiam hexetil by HPLC-MS/MS].

PubMed

Tang, Qun-Xing; Liu, Ming-Dong; Yan, You-Yi; Ye, Yi; Wang, Zhi-Hui; Zhan, Lan-Fen; Liao, Lin-Chuan

2013-05-01

To detect unknown impurities in raw drug material of cefotiam hexetil. High performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was employed for the determination of impurities in cefotiam hexetil. Agilent SB-C18 column (150 mm x 2.1 mm i. d. , 3.5 microm particles) was used for chromatographic separations of cofotiam hexetil dissolved in deionized water, with mobile phase consisting of (A) 0.1% formic acid and (B) acetonitrile and timed gradient program T (min)/B (%): 0/3, 5/3, 15/20, 20/40, 30/60, 40/80. The flow rate was set at 0. 3 mL/min with DAD detector wavelength fixed at 254 nm. Electrospray ionization source was applied and operated in positive ion MRM mode. The source voltage was kept at 4 kV and cone voltage was 100 V with the mass range m/z 50-1000. Nitrogen was used as nebulizing gas and the nebulizer pressure was 40 psi. The drying gas temperature was 350 degrees C and the drying gas flow was 10 L/min. Results Unknown impurities of cefotiam hexetil were identified. Substance 1 was delta3-isomer of cefotiam hexetil. The structures of 3 other substances were also determined. The method is sensitive, rapid and credible for the analysis of cefotiam hexetil and its related impurities, which can be applied in quality control of cefotiam hexetil.

Annotation of Different Dehydrocatechin Oligomers by MS/MS and Their Occurrence in Black Tea.

PubMed

Verloop, Annewieke J W; Gruppen, Harry; Vincken, Jean-Paul

2016-08-03

Dehydrocatechins (DhC's), oligomeric oxidation products of (epi)catechins, were formed in model incubations of epicatechin with mushroom tyrosinase. DhC oligomers up to tetramers were detected by reversed-phase ultrahigh-performance liquid chromatography mass spectrometry (RP-UHPLC-MS) analysis. Measurements with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) showed formation of oligomers up to at least 15 catechin subunits. Isomeric DhC's were obtained, and a method based on MS(2) fragment ratios was set up to distinguish between the different interflavanic configurations of the isomers. In the model incubation, 8 dehydrodicatechins (DhC2's) and 22 dehydrotricatechins (DhC3's) were tentatively annotated by their MS(2) signature fragments. Three different interflavanic configuration types were determined for the DhC2's. DhC2's and DhC3's were shown to occur in a black tea extract for the first time. For the DhC2's, at least two isomeric types, i.e., DhC β and DhC ε, could be annotated in black tea.

Determination of dimethyltryptamine and β-carbolines (ayahuasca alkaloids) in plasma samples by LC-MS/MS.

PubMed

Oliveira, Carolina Dizioli Rodrigues; Okai, Guilherme Gonçalves; da Costa, José Luiz; de Almeida, Rafael Menck; Oliveira-Silva, Diogo; Yonamine, Mauricio

2012-07-01

Ayahuasca is a psychoactive plant beverage originally used by indigenous people throughout the Amazon Basin, long before its modern use by syncretic religious groups established in Brazil, the USA and European countries. The objective of this study was to develop a method for quantification of dimethyltryptamine and β-carbolines in human plasma samples. The analytes were extracted by means of C18 cartridges and injected into LC-MS/MS, operated in positive ion mode and multiple reaction monitoring. The LOQs obtained for all analytes were below 0.5 ng/ml. By using the weighted least squares linear regression, the accuracy of the analytical method was improved at the lower end of the calibration curve (from 0.5 to 100 ng/ml; r(2)> 0.98). The method proved to be simple, rapid and useful to estimate administered doses for further pharmacological and toxicological investigations of ayahuasca exposure.

Simultaneous UPLC-MS/MS assay for the detection of the traditional antipsychotics haloperidol, fluphenazine, perphenazine, and thiothixene in serum and plasma.

PubMed

Juenke, JoEtta M; Brown, Paul I; Urry, Francis M; Johnson-Davis, Kamisha L; McMillin, Gwendolyn A

2013-08-23

Most antipsychotic drugs that are commonly prescribed in the USA are monitored by liquid and gas chromatographic methods. Method performance has been improved using ultra high pressure liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). A rapid and simple procedure for monitoring haloperidol, thiothixene, fluphenazine, and perphenazine is described here. Antipsychotic drug concentrations in serum and plasma were determined by LCMS/MS (Waters Acquity UPLC TQD). The instrument is operated with an ESI interface, in multiple reaction monitoring (MRM), and positive ion mode. The resolution of both quadrupoles was maintained at unit mass with a peak width at half height of 0.7amu. Data analysis was performed using the Waters Quanlynx software. Serum or plasma samples were thawed at room temperature and a 100μL aliquot was placed in a tube. Then 300μL of precipitating reagent (acetonitrile-methanol [50:50, volume: volume]) containing the internal standard (0.12ng/μL Imipramine-D3) was added to each tube. The samples were vortexed and centrifuged. The supernatant was transferred to an autosampler vial and 8μL was injected into the UPLC-MS/MS. Utilizing a Waters Acquity UPLC HSS T3 1.8μm, 2.1×50mm column at 25ºC, the analytes were separated using a timed, linear gradient of acetonitrile and water, each having 0.1% formic acid added. The column is eluted into the LC-MS/MS to detect imipramine D3 at transition 284.25>89.10, haloperidol at 376.18>165.06, thiothixene at 444.27>139.24, fluphenazine at 438.27>171.11, and perphenazine at 404.19>143.07. Secondary transitions for each analyte are also monitored for imipramine D3 at 284.25>193.10, haloperidol at 376.18>122.97, thiothixene at 444.27>97.93, fluphenazine at 438.27>143.08, and perphenazine at 404.19>171.11. The run-time is 1.8min per injection with baseline resolved chromatographic separation. The analytical measurement range was 0.2 to 12.0ng/mL for fluphenazine and perphenazine, and was 1 to 60

Bioinspired Polyelectrolyte-Assembled Graphene-Oxide-Coated C18 Composite Solid-Phase Microextraction Fibers for In Vivo Monitoring of Acidic Pharmaceuticals in Fish.

PubMed

Qiu, Junlang; Chen, Guosheng; Liu, Shuqin; Zhang, Tianlang; Wu, Jiayi; Wang, Fuxin; Xu, Jianqiao; Liu, Yan; Zhu, Fang; Ouyang, Gangfeng

2016-06-07

A novel solid-phase microextraction (SPME) fiber was prepared by gluing poly(diallyldimethylammonium chloride) (PDDA) assembled graphene oxide (GO)-coated C18 composite particles (C18@GO@PDDA) onto a quartz fiber with polyaniline (PANI). The fiber surface coating was sequentially modified with bioinspired polynorepinephrine, which provided a smooth biointerface and makes the coating suitable for in vivo sampling. The novel custom-made coating was used to extract acidic pharmaceuticals, and high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) was employed for analysis. The custom-made coating exhibited a much higher extraction efficiency than the previously used commercial polydimethylsiloxane (PDMS) and polyacrylate (PA) coatings. The custom-made coating also possessed satisfactory stability (the relative standard deviations (RSDs) ranged from 1.60% to 10.3% for six sampling-desorption cycles), interfiber reproducibility (the RSDs ranged from 2.61% to 11.5%), and resistance to matrix effects. The custom-made fibers were used to monitor the presence of acid pharmaceuticals in dorsal-epaxial muscle of living fish, and satisfactory sensitivities (limits of detection ranged from 0.13 ng/g to 7.56 ng/g) were achieved. The accuracies were verified by the comparison with liquid extraction. Moreover, the novel fibers were successfully used to monitor the presence of acidic pharmaceuticals in living fish, which demonstrated that the custom-made fibers were feasible for possible long-term in vivo continuous pharmaceutical monitoring.

A new simple and rapid LC-ESI-MS/MS method for quantification of plasma oxysterols as dimethylaminobutyrate esters. Its successful use for the diagnosis of Niemann-Pick type C disease.

PubMed

Boenzi, Sara; Deodato, Federica; Taurisano, Roberta; Martinelli, Diego; Verrigni, Daniela; Carrozzo, Rosalba; Bertini, Enrico; Pastore, Anna; Dionisi-Vici, Carlo; Johnson, David W

2014-11-01

Two oxysterols, cholestan-3β,5α,6β-triol (C-triol) and 7-ketocholesterol (7-KC), have been recently proposed as diagnostic markers of Niemann-Pick type C (NP-C) disease, representing a potential alternative diagnostic tool to the more invasive and time consuming filipin test in cultured fibroblasts. Usually, the oxysterols are detected and quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) method using atmospheric pressure chemical ionization (APCI) or electro-spray-ionization (ESI) sources, after a variety of derivatization procedures to enhance sensitivity. We developed a sensitive LC-MS/MS method to quantify the oxysterols in plasma as dimethylaminobutyrate ester, suitable for ESI analysis. This method, with an easy liquid-phase extraction and a short derivatization procedure, has been validated to demonstrate specificity, linearity, recovery, lowest limit of quantification, accuracy and precision. The assay was linear over a concentration range of 0.5-200ng/mL for C-triol and 1.0-200ng/mL for 7-KC. Intra-day and inter-day coefficients of variation (CV%) were <15% for both metabolites. Receiver operating characteristic analysis estimates that the area under curve was 0.998 for C-triol, and 0.972 for 7-KC, implying a significant discriminatory power for the method in this patient population of both oxysterols. In summary, our method provides a simple, rapid and non-invasive diagnostic tool for the biochemical diagnosis of NP-C disease. Copyright © 2014 Elsevier B.V. All rights reserved.

40 CFR 180.1068 - C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false C12-C18 fatty acid potassium salts... RESIDUES IN FOOD Exemptions From Tolerances § 180.1068 C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance. C12-C18 fatty acids (saturated and unsaturated) potassium salts are...

40 CFR 180.1068 - C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 25 2013-07-01 2013-07-01 false C12-C18 fatty acid potassium salts... RESIDUES IN FOOD Exemptions From Tolerances § 180.1068 C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance. C12-C18 fatty acids (saturated and unsaturated) potassium salts are...

40 CFR 180.1068 - C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 25 2012-07-01 2012-07-01 false C12-C18 fatty acid potassium salts... RESIDUES IN FOOD Exemptions From Tolerances § 180.1068 C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance. C12-C18 fatty acids (saturated and unsaturated) potassium salts are...

40 CFR 180.1068 - C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 24 2011-07-01 2011-07-01 false C12-C18 fatty acid potassium salts... RESIDUES IN FOOD Exemptions From Tolerances § 180.1068 C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance. C12-C18 fatty acids (saturated and unsaturated) potassium salts are...

40 CFR 180.1068 - C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 24 2014-07-01 2014-07-01 false C12-C18 fatty acid potassium salts... RESIDUES IN FOOD Exemptions From Tolerances § 180.1068 C12-C18 fatty acid potassium salts; exemption from the requirement of a tolerance. C12-C18 fatty acids (saturated and unsaturated) potassium salts are...

UPLC/MS-MS assay development for estimation of mozavaptan in plasma and its pharmacokinetic study in rats.

PubMed

Ezzeldin, Essam; Mostafa, Gamal Ae; Iqbal, Muzaffar; Al-Rashood, Khalid A; Asiri, Yousef; El-Nahhas, Toqa

2018-05-10

Mozavaptan is a nonpeptide vasopressin receptor antagonist approved for the treatment of ectopic antidiuretic hormone secretion syndrome. A simple, rapid and fully validated UPLC/MS-MS method was developed for the quantitation of mozavaptan in rat plasma. The chromatographic separation was conducted on an Acquity UPLC BEH™ C 18 column with an optimum mobile phase of 10 mM ammonium acetate buffer and 0.1% formic acid in acetonitrile (30:70 v/v) at a flow rate of 0.3 ml/min. The multiple reaction monitoring transitions were performed at m/z 428.16→119.03 for mozavaptan and m/z 237.06→179.10 for carbamazepine (internal standard). The method was effectively applied for the determination of mozavaptan pharmacokinetic parameters after the oral administration of 3 mg/kg mozavaptan in rats.

Preparation of C18 composite solid-phase microextraction fiber and its application to the determination of organochlorine pesticides in water samples.

PubMed

Li, Siyan; Lu, Chengwei; Zhu, Fang; Jiang, Ruifen; Ouyang, Gangfeng

2015-05-11

In this work, a C18 composite solid-phase microextraction (SPME) fiber was prepared with a new method and applied to the analysis of organochlorine pesticides (OCPs) in water sample. A stainless steel wire (o.d. 127 μm) was used as the substrate, and a mixture of the C18 particle (3.5 μm) and the 184 silicone was used as the coating material. During the process of fiber preparation, a section of capillary column was used to fix the mixture onto the stainless steel wire and to ensure the constant of coating thickness. The prepared fiber showed excellent thermal stability and solvent resistance. By coupling with gas chromatography-mass spectrometry (GC-MS), the fiber exhibited wide linearity (2-500 ng L(-1)) and good sensitivity for the determination of six OCPs in water samples, the OCPs tested included hexachlorobezene, trans-chlordane, cis-chlordane, o,p-DDT, p,p-DDT and mirex. Not only the extraction performance of the newly prepared fiber was more than seven times higher than those of commercial fibers, the limits of detections (LODs) (0.059-0.151 ng L(-1)) for OCPs achieved under optimized conditions were also lower than those of reported SPME methods. The fiber was successfully applied to the determination of OCPs in real water samples by using developed SPME-GC-MS method. Copyright © 2015 Elsevier B.V. All rights reserved.

Determination of antibacterial agent tilmicosin in pig plasma by LC/MS/MS and its application to pharmacokinetics.

PubMed

Li, Bing; Gong, Shi-Yue; Zhou, Xu-Zheng; Yang, Ya-Jun; Li, Jian-Yong; Wei, Xiao-Juan; Cheng, Fu-Sheng; Niu, Jian-Rong; Liu, Xi-Wang; Zhang, Ji-Yu

2017-03-01

A rapid and sensitive high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to quantify tilmicosin in pig plasma. Plasma samples were prepared by liquid-liquid extraction. Chromatographic separation was achieved on a C 18 column (2.1 × 30 mm, 3.5 μm) using acetonitrile-water (90:10, v/v; water included 0.1% formic acid) as the mobile phase. Mass detection was carried out using positive electrospray ionization in multiple reaction monitoring mode. The calibration curve was linear from 0.5 to 2000 ng/mL (r 2  = 0.9998). The intra- and inter-day accuracy and precision were within the acceptable limits of ±10% for all tilmicosin concentrations. The recoveries ranged from 95 to 99% for the three tested concentrations. The LC-MS/MS method described herein was simple, fast and less laborious than other methods, achieved high sensitivity using a small sample volume, and was successfully applied to pharmacokinetic studies of tilmicosin enteric granules after oral delivery to pigs. In comparison with tilmicosin premix, tilmicosin enteric granules slowed the elimination rate of tilmicosin, prolonged its period of action and significantly improved its bioavailability. Copyright © 2016 John Wiley & Sons, Ltd.

Simultaneous determination of cucurbitacin B and cucurbitacin E in rat plasma by UHPLC-MS/MS: A pharmacokinetics study after oral administration of cucurbitacin tablets.

PubMed

Wang, Zhibin; Zhu, Wenbo; Gao, Mingjie; Wu, Chengcui; Yang, Chunjuan; Yang, Jing; Wu, Gaosong; Yang, Bingyou; Kuang, Haixue

2017-10-15

Cucurbitacin B (CuB) and cucurbitacin E (CuE) are tetracyclic triterpene compounds from Cucurbitaceae, and the main bioactive compounds of cucurbitacins tablets that used to treatment of chronic hepatitis. Pharmacological research has been very comprehensive, and there are few studies on pharmacokinetics, especially about CuE. An Ultra High Performance Liquid Chromatography-tandem Mass Spectrometry (UHPLC-MS/MS) method with high selectivity, simplicity and sensitivity has been used for quantitative analysis of Cucurbitacin B (CuB) and cucurbitacin E (CuE). Plasma samples were pretreatment by Liquid-liquid extraction (LLE) method with dichloromethane. The chromatographic separation was achieved on a C 18 column (Agilent Eclipse Plus, 1.8μm, 50×2.1mm) using gradient elution with water - methanol at a flow rate of 0.3mL/min and the column temperature was set at 30°C. The method was validated according to FDA guidelines. Lower limit of quantification (LLOQ) was 1.60ng/mL for CuB and 1.58ng/mL for CuE. Correlation coefficients of CuB and CuE were more than 0.99 in rat plasma. All values of intra-day and inter-day precision (RSD%) were not exceeded 15%, the accuracy (RE%) were within -5.57 to 5.20% for CuB and -3.33 to 7.37% for CuE. The mean extraction recoveries were more than 80%. Pharmacokinetic parameters were also evaluated by UHPLC-MS/MS method. The results suggestion that this method was successfully applied to pharmacokinetic study of CuB and CuE in rat plasma after oral administration cucurbitacin tablets. Published by Elsevier B.V.

Antithrombocytopenic activity of carpaine and alkaloidal extract of Carica papaya Linn. leaves in busulfan induced thrombocytopenic Wistar rats.

PubMed

Zunjar, Vishwanath; Dash, Ranjeet Prasad; Jivrajani, Mehul; Trivedi, Bhavna; Nivsarkar, Manish

2016-04-02

The decoction of Carica papaya Linn. leaves is used in folklore medicine in certain parts of Malaysia and Indonesia for the treatment of different types of thrombocytopenia associated with diseases and drugs. There are several scientific studies carried out on humans and animal models to confirm the efficacy of decoction of papaya leave for the treatment of disease induced and drug induced thrombocytopenia, however very little is known about the bio-active compounds responsible for the observed activity. The aim of present study was to identify the active phytochemical component of Carica papaya Linn. leaves decoction responsible for anti-thrombocytopenic activity in busulfan-induced thrombocytopenic rats. Antithrombocytopenic activity was assessed on busulfan induced thrombocytopenic Wistar rats. The antithrombocytopenic activity of different bio-guided fractions was evaluated by monitoring blood platelet count. Bioactive compound carpaine was isolated and purified by chromatographic methods and confirmed by spectroscopic methods (LC-MS and 1D/2D-1H/13C NMR) and the structure was confirmed by single crystal X-ray diffraction. Quantification of carpaine was carried out by LC-MS/MS equipped with XTerra(®) MS C18 column and ESI-MS detector using 90:10 CH3CN:CH3COONH4 (6mM) under isocratic conditions and detected with multiple reaction monitoring (MRM) in positive ion mode. Two different phytochemical groups were isolated from decoction of Carica papaya leaves: phenolics, and alkaloids. Out of these, only alkaloid fraction showed good biological activity. Carpaine was isolated from the alkaloid fraction and exhibited potent activity in sustaining platelet counts upto 555.50±85.17×10(9)/L with no acute toxicity. This study scientifically validates the popular usage of decoction of Carica papaya leaves and it also proves that alkaloids particularly carpaine present in the leaves to be responsible for the antithrombocytopenic activity. Copyright © 2016 Elsevier

75 FR 69870 - Delegation of Authority Under 18 U.S.C. 249

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-16

... Authority Under 18 U.S.C. 249 AGENCY: Department of Justice. ACTION: Final rule. SUMMARY: This rule amends 28 CFR part 0 to delegate the Attorney General's certification authority under 18 U.S.C. 249..., the Shepard-Byrd Act created a new federal hate crime statute to be codified at 18 U.S.C. 249. The...

A high-throughput UPC2-MS/MS method for the separation and quantification of C19 and C21 steroids and their C11-oxy steroid metabolites in the classical, alternative, backdoor and 11OHA4 steroid pathways.

PubMed

du Toit, Therina; Stander, Maria A; Swart, Amanda C

2018-03-30

In the present study an ultra-performance convergence chromatography tandem mass spectrometry (UPC 2 -MS/MS) analytical method was developed and validated for the determination of 17 C 19 and 14 C 21 steroids, including C11-oxy C 19 and C11-oxy C 21 steroids. The limit of detection and limit of quantification ranged from 0.01 to 10 ng/mL and from 0.01 to 20 ng/mL, respectively, and the method shows the recovery, matrix effect and process efficiency of steroids isolated from a serum matrix to be within acceptable limits. Good accuracy, repeatability and reproducibility were also shown and the method provided excellent sensitivity and selectivity as stereoisomers and regioisomers were also resolved and quantified accurately. Clinical conditions such as congenital adrenal hyperplasia, polycystic ovary syndrome in females and disorders of sex development in neonates and in children, amongst others, are characterized by abnormal steroid levels. Steroid profiling is essential to accurately diagnose steroid levels in the above settings as well as in androgen excess or deficiency in adrenal-linked endocrine diseases. Our method, separating C 19 and C 21 steroids in a single chromatographic step, offers a reduced sample turnover rate in the clinical setting, while providing comprehensive steroid profiles of in vivo steroids in the nmol/L range. This is, to our knowledge, the first method reported to simultaneously separate C 19 and C 21 steroids, together with their C11-hydroxy and C11-keto metabolites -one which may hold promise in the identification of new steroid markers in steroid-linked endocrine diseases, in addition to profiling steroid metabolism and abnormal enzyme activity in patients. Copyright © 2018 Elsevier B.V. All rights reserved.

Rugged LC-MS/MS survey analysis for acrylamide in foods.

PubMed

Roach, John A G; Andrzejewski, Denis; Gay, Martha L; Nortrup, David; Musser, Steven M

2003-12-17

The described liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the detection of acrylamide in food entails aqueous room temperature extraction, SPE cleanup, and analysis by LC-MS/MS. The method is applicable to a wide variety of foods. [(13)C(3)]acrylamide is the internal standard. The limit of quantitation is 10 ppb (microg/kg). Data were obtained in duplicate from >450 products representing >35 different food types. The variability in analyte levels in certain food types suggests that it may be possible to reduce acrylamide levels in those foods.

Correcting false positive medium-chain acyl-CoA dehydrogenase deficiency results from newborn screening; synthesis, purification, and standardization of branched-chain C8 acylcarnitines for use in their selective and accurate absolute quantitation by UHPLC-MS/MS.

PubMed

Minkler, Paul E; Stoll, Maria S K; Ingalls, Stephen T; Hoppel, Charles L

2017-04-01

While selectively quantifying acylcarnitines in thousands of patient samples using UHPLC-MS/MS, we have occasionally observed unidentified branched-chain C8 acylcarnitines. Such observations are not possible using tandem MS methods, which generate pseudo-quantitative acylcarnitine "profiles". Since these "profiles" select for mass alone, they cannot distinguish authentic signal from isobaric and isomeric interferences. For example, some of the samples containing branched-chain C8 acylcarnitines were, in fact, expanded newborn screening false positive "profiles" for medium-chain acyl-CoA dehydrogenase deficiency (MCADD). Using our fast, highly selective, and quantitatively accurate UHPLC-MS/MS acylcarnitine determination method, we corrected the false positive tandem MS results and reported the sample results as normal for octanoylcarnitine (the marker for MCADD). From instances such as these, we decided to further investigate the presence of branched-chain C8 acylcarnitines in patient samples. To accomplish this, we synthesized and chromatographically characterized several branched-chain C8 acylcarnitines (in addition to valproylcarnitine): 2-methylheptanoylcarnitine, 6-methylheptanoylcarnitine, 2,2-dimethylhexanoylcarnitine, 3,3-dimethylhexanoylcarnitine, 3,5-dimethylhexanoylcarnitine, 2-ethylhexanoylcarnitine, and 2,4,4-trimethylpentanoylcarnitine. We then compared their behavior with branched-chain C8 acylcarnitines observed in patient samples and demonstrated our ability to chromographically resolve, and thus distinguish, octanoylcarnitine from branched-chain C8 acylcarnitines, correcting false positive MCADD results from expanded newborn screening. Copyright © 2017 Elsevier Inc. All rights reserved.

A rapid UPLC-MS/MS assay for eicosanoids in human plasma: Application to evaluate niacin responsivity.

PubMed

Miller, Tricia M; Poloyac, Samuel M; Anderson, Kacey B; Waddell, Brooke L; Messamore, Erik; Yao, Jeffrey K

2017-01-18

A rapid and sensitive method using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed to simultaneously quantify hydroxyeicosatetraenoic (HETE), dihydroxyeicosatrienoic (DiHETrE), epoxyeicosatrienoic acid (EET), and prostaglandin metabolites of arachidonic acid in human plasma. Sample preparation consisted of solid phase extraction with Oasis HLB (30mg) cartridges for all metabolites. Separation of HETEs, EETs, and DiHETrEs was achieved on an Acquity UPLC BEH C18, 1.7µm (100×2.1mm) reversed-phase column (Waters Corp, Millford, MA) with negative electrospray ionization mass spectrometric detection. A second injection of the same extracted sample allowed for separation and assessment of prostaglandin metabolites under optimized UPLC-MS/MS conditions. Additionally, the endogenous levels of these metabolites in five different matrices were determined in order to select the optimal matrix for assay development. Human serum albumin was shown to have the least amount of endogenous metabolites, a recovery efficiency of 79-100% and a matrix effect of 71 - 100%. Linear calibration curves ranging from 0.416 to 66.67ng/ml were validated. Inter-assay and intra-assay variance was less than 15% at most concentrations. This method was successfully applied to quantify metabolite levels in plasma samples of healthy control subjects receiving niacin administration to evaluate the association between niacin administration and eicosanoid plasma level response. Published by Elsevier Ltd.

HPLC-DAD and HPLC-ESI-MS/MS methods for metabolite profiling of propolis extracts.

PubMed

Pellati, Federica; Orlandini, Giulia; Pinetti, Diego; Benvenuti, Stefania

2011-07-15

In this study, the composition of polyphenols (phenolic acids and flavonoids) in propolis extracts was investigated by HPLC-DAD and HPLC-ESI-MS/MS by comparing the performance of ion trap and triple quadrupole mass analyzers. The analyses were carried out on an Ascentis C(18) column (250mm×4.6mm I.D., 5μm), with a mobile phase composed by 0.1% formic acid in water and acetonitrile. Overall, the UV spectra, the MS and MS/MS data allowed the identification of 40 compounds. In the case of flavonoids, the triple quadrupole mass analyzer provided more collision energy if compared with the ion trap, originating product ions at best sensitivity. The HPLC method was validated in agreement with ICH guidelines: the correlation coefficients were >0.998; the limit of detection was in the range 1.6-4.6μg/ml; the recovery range was 96-105%; the intra- and inter-day %RSD values for retention times and peak areas were found to be <0.3 and 1.9%, respectively. The developed technique was applied to the analysis of hydroalcoholic extracts of propolis available on the Italian market. Although the chromatographic profile of the analyzed samples was similar, the quantitative analysis indicated that there is a great variability in the amount of the active compounds: the content of total phenolic acids ranged from 0.17 to 16.67mg/ml and the level of total flavonoids from 2.48 to 41.10mg/ml. The proposed method can be considered suitable for the phytochemical analysis of propolis extracts used in phytotherapy. Copyright © 2011 Elsevier B.V. All rights reserved.

Bioanalytical method for in vitro metabolism study of repaglinide using 96-blade thin-film solid-phase microextraction and LC-MS/MS.

PubMed

Simões, Rodrigo Almeida; Bonato, Pierina Sueli; Mirnaghi, Fatemeh S; Bojko, Barbara; Pawliszyn, Janusz

2015-01-01

A high-throughput bioanalytical method using 96-blade thin film microextraction (TFME) and LC-MS/MS for the analysis of repaglinide (RPG) and two of its main metabolites was developed and used for an in vitro metabolism study. The target analytes were extracted from human microsomal medium by a 96-blade-TFME system employing the low-cost prototype 'SPME multi-sampler' using C18 coating. Method validation showed recoveries around 90% for all analytes and was linear over the concentration range of 2-1000 ng ml(-1) for RPG and of 2-500 ng ml(-1) for each RPG metabolite. The method was applied to an in vitro metabolism study of RPG employing human liver microsomes and proved to be very useful for this purpose.

Misleading measures in Vitamin D analysis: a novel LC-MS/MS assay to account for epimers and isobars.

PubMed

Shah, Iltaf; James, Ricky; Barker, James; Petroczi, Andrea; Naughton, Declan P

2011-05-14

Recently, the accuracies of many commercially available immunoassays for Vitamin D have been questioned. Liquid chromatography tandem mass spectrometry (LC- MS/MS) has been shown to facilitate accurate separation and quantification of the major circulating metabolite 25-hydroxyvitamin-D3 (25OHD3) and 25-hydroxyvitamin-D2 (25OHD2) collectively termed as 25OHD. However, among other interferents, this method may be compromised by overlapping peaks and identical masses of epimers and isobars, resulting in inaccuracies in circulating 25OHD measurements. The aim of this study was to develop a novel LC-MS/MS method that can accurately identify and quantitate 25OHD3 and 25OHD2 through chromatographic separation of 25OHD from its epimers and isobars. A positive ion electrospray ionisation (ESI) LC-MS/MS method was used in the Multiple Reaction Monitoring (MRM) mode for quantification. It involved i) liquid-liquid extraction, ii) tandem columns (a high resolution ZORBAX C18 coupled to an ULTRON chiral, with guard column and inlet filter), iii) Stanozolol-D3 as internal standard, and iv) identification via ESI and monitoring of three fragmentation transitions. To demonstrate the practical usefulness of our method, blood samples were collected from 5 healthy male Caucasian volunteers; age range 22 to 37 years and 25OHD2, 25OHD3 along with co-eluting epimers and analogues were quantified. The new method allowed chromatographic separation and quantification of 25OHD2, 25OHD3, along with 25OHD3 epimer 3-epi-25OHD3 and isobars 1-α-hydroxyvitamin-D3 (1αOHD3), and 7-α-hydroxy-4-cholesten-3-one (7αC4). The new assay was capable of detecting 0.25 ng/mL of all analytes in serum. To our knowledge, this is the first specific, reliable, reproducible and robust LC-MS/MS method developed for the accurate detection of 25OHD (Vitamin D). The method is capable of detecting low levels of 25OHD3 and 25OHD2 together with chromatographic separation from the co-eluting epimers and isobars and

Mixed C18 and C1 modification on an optical fiber for chromatographic sensing.

PubMed

Zhou, Leiji; Wang, Kemin; Zuo, Xinbing; Choi, Martin M F; Chen, Yunqing; Huang, Shasheng

2003-09-01

An optical fiber-chromatographic sensor, aiming at simultaneous and selective response to multiple components following a chromatographic separation, is described. We report an improved approach for immobilization of octadecyl (C(18)) and methyl (C(1)) moieties as stationary phase on an optical fiber suitable as a sensing phase for organic solutes. By this approach, the stability and lifetime of the sensing layer as well as the detectability and retention behavior of the chromatographic sensor could be improved. Infrared spectroscopy was employed to confirm the presence of C(18) and C(1) moieties on the modified surface of the optical fiber. The chromatographic sensor was applied, with good sensitivity and chemical selectivity, to the simultaneous separation and detection of bromobenzene and toluene, using water as the mobile phase.

Metabolomics Characterization of Two Apocynaceae Plants, Catharanthus roseus and Vinca minor, Using GC-MS and LC-MS Methods in Combination.

PubMed

Chen, Qi; Lu, Xueyan; Guo, Xiaorui; Guo, Qingxi; Li, Dewen

2017-06-17

Catharanthus roseus ( C. roseus ) and Vinca minor ( V. minor ) are two common important medical plants belonging to the family Apocynaceae. In this study, we used non-targeted GC-MS and targeted LC-MS metabolomics to dissect the metabolic profile of two plants with comparable phenotypic and metabolic differences. A total of 58 significantly different metabolites were present in different quantities according to PCA and PLS-DA score plots of the GC-MS analysis. The 58 identified compounds comprised 16 sugars, eight amino acids, nine alcohols and 18 organic acids. We subjected these metabolites into KEGG pathway enrichment analysis and highlighted 27 metabolic pathways, concentrated on the TCA cycle, glycometabolism, oligosaccharides, and polyol and lipid transporter (RFOS). Among the primary metabolites, trehalose, raffinose, digalacturonic acid and gallic acid were revealed to be the most significant marker compounds between the two plants, presumably contributing to species-specific phenotypic and metabolic discrepancy. The profiling of nine typical alkaloids in both plants using LC-MS method highlighted higher levels of crucial terpenoid indole alkaloid (TIA) intermediates of loganin, serpentine, and tabersonine in V. minor than in C. roseus . The possible underlying process of the metabolic flux from primary metabolism pathways to TIA synthesis was discussed and proposed. Generally speaking, this work provides a full-scale comparison of primary and secondary metabolites between two medical plants and a metabolic explanation of their TIA accumulation and phenotype differences.

Identification and Characterization of Reaction Products of 5-Hydroxytryptamine with Methylglyoxal and Glyoxal by LC/MS/MS.

PubMed

Sai Sachin, L; Nagarjuna Chary, R; Pavankumar, P; Prabhakar, S

2018-06-06

The methylglyoxal (MGO) and glyoxal (GO) are known to be at high levels in the diabetic humans. They react with amine containing proteins and amino acids to form advanced glycation end products, however, the reactivity with the other amine containing metabolites, such as neurotransmitters are not explored. In this study, we aimed at studying the reactivity of 5-hydroxytryptamine (5-HT) with MGO or GO, which may alter the metabolic function of 5-HT. The stock solutions of 5-HT, MGO and GO were made in PBS buffer at pH 7.4 and incubated 5-HT with MGO or GO at difference concentrations. The reactions were also performed at physiological concentrations. The reaction mixtures collected at different incubation times were analyzed by direct ESI-HRMS, LC/MS and LC/MS/MS conditions to detect/characterize the products. Agilent 6545 Q-TOF and Agilent 6420 triple quadrupole mass spectrometer were used for the study, and LC separations were performed on a C18 column. The direct ESI-HRMS data of the reaction mixtures showed formation of three and four reaction products when 5-HT reacted with MGO and GO, respectively. All the products showed dominant [M+H] + ions. The products were characterized by HRMS, LC/MS/MS and the literature reports on similar compounds. The products can easily be identified by LC/MS based on the accurate mass values together with retention time information. The MS/MS of the reaction products showed structure indicative fragment ions. 5-HT reacts with one or two MGO/GO to form a set of reaction products. The reaction between 5-HT and MGO or GO was faster at higher concentrations of MGO/GO (<10 min), and the same products were found even at physiological concentrations (<48 hrs). The LC-MS/MS (SRM) method can be used to screen the reaction products when present at low level. This article is protected by copyright. All rights reserved.

40 CFR Appendix 8 to Subpart A of... - Reference C16-C18 Internal Olefin Drilling Fluid Formulation

Code of Federal Regulations, 2014 CFR

2014-07-01

... Drilling Fluid Formulation 8 Appendix 8 to Subpart A of Part 435 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) OIL AND GAS EXTRACTION POINT...—Reference C16-C18 Internal Olefin Drilling Fluid Formulation The reference C16-C18 internal olefin drilling...

40 CFR Appendix 8 to Subpart A of... - Reference C16-C18 Internal Olefin Drilling Fluid Formulation

Code of Federal Regulations, 2012 CFR

2012-07-01

... Drilling Fluid Formulation 8 Appendix 8 to Subpart A of Part 435 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) OIL AND GAS EXTRACTION POINT...—Reference C16-C18 Internal Olefin Drilling Fluid Formulation The reference C16-C18 internal olefin drilling...

40 CFR Appendix 8 to Subpart A of... - Reference C16-C18 Internal Olefin Drilling Fluid Formulation

Code of Federal Regulations, 2013 CFR

2013-07-01

... Drilling Fluid Formulation 8 Appendix 8 to Subpart A of Part 435 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) OIL AND GAS EXTRACTION POINT...—Reference C16-C18 Internal Olefin Drilling Fluid Formulation The reference C16-C18 internal olefin drilling...

A sensitive and specific LC-MS/MS method for rapid diagnosis of Niemann-Pick C1 disease from human plasma[S

PubMed Central

Jiang, Xuntian; Sidhu, Rohini; Porter, Forbes D.; Yanjanin, Nicole M.; Speak, Anneliese O.; te Vruchte, Danielle Taylor; Platt, Frances M.; Fujiwara, Hideji; Scherrer, David E.; Zhang, Jessie; Dietzen, Dennis J.; Schaffer, Jean E.; Ory, Daniel S.

2011-01-01

Niemann-Pick type C1 (NPC1) disease is a rare, progressively fatal neurodegenerative disease for which there are no FDA-approved therapies. A major barrier to developing new therapies for this disorder has been the lack of a sensitive and noninvasive diagnostic test. Recently, we demonstrated that two cholesterol oxidation products, specifically cholestane-3β,5α,6β-triol (3β,5α,6β-triol) and 7-ketocholesterol (7-KC), were markedly increased in the plasma of human NPC1 subjects, suggesting a role for these oxysterols in diagnosis of NPC1 disease and evaluation of therapeutics in clinical trials. In the present study, we describe the development of a sensitive and specific LC-MS/MS method for quantifying 3β,5α,6β-triol and 7-KC human plasma after derivatization with N,N-dimethylglycine. We show that dimethylglycine derivatization successfully enhanced the ionization and fragmentation of 3β,5α,6β-triol and 7-KC for mass spectrometric detection of the oxysterol species in human plasma. The oxysterol dimethylglycinates were resolved with high sensitivity and selectivity, and enabled accurate quantification of 3β,5α,6β-triol and 7-KC concentrations in human plasma. The LC-MS/MS assay was able to discriminate with high sensitivity and specificity between control and NPC1 subjects, and offers for the first time a noninvasive, rapid, and highly sensitive method for diagnosis of NPC1 disease. PMID:21518695

Characterisation of phenolic compounds by UPLC-QTOF-MS/MS of geopropolis from the stingless bee Melipona subnitida (jandaíra).

PubMed

de Souza, Silvana Alves; da Silva, Telma Maria Guedes; da Silva, Eva Monica Sarmento; Camara, Celso Amorim; Silva, Tania Maria Sarmento

2018-05-17

Melipona subnitida Ducke (jandaíra) is a stingless bee native to north-eastern Brazil, which produces geopropolis, a mixture of beeswax, plant resins, pollens and earth that is used for sealing beehives. To extend the knowledge on phenolic compounds in fractions obtained by C18-solid phase extraction (SPE) of nine geopropolis samples from Melipona subnitida collected at different times. Chromatographic profiles of nine samples of geopropolis from jandaíra were analysed by ultra-performance liquid chromatography coupled with a diode array detector and quadrupole time-of-flight mass spectrometry (UPLC-DAD-QTOF-MS/MS) and combined with the use of data-independent acquisition (MSE) for the profiling and structural characterisation of the phenolic compounds. The isolated compound was identified by nuclear magnetic resonance of hydrogen and carbon ( 1 H- and 13 C-NMR). The present study with geopropolis of jandaíra resulted in the characterisation of 51 phenolics by UPLC-DAD-QTOF-MS/MS: four galloyl glucosides, one ellagic acid, 11 acyl-hexosides, 23 acyl-galloyl-hexosides and 12 flavonoids. The structures of two compounds (1,6-di-O-(E)-coumaroyl-2-O-galloyl-β-d-glucopyranoside and 1-O-cinnamoyl-6-O-(E)-coumaroyl-2-O-galloyl-β-d-glucopyranoside) were established by 1 H and the attached proton test (APT) experiments as well as high-resolution electrospray ionisation mass spectroscopy (HR-ESI-MS) analysis. The geopropolis of jandaíra showed phenolic compounds galloyl hexosides, ellagic acid, acyl-(cinnamoyl/coumaroyl)-hexosides, acyl-(cinnamoyl/coumaroyl)-galloyl-hexosides and flavonoids (aglycones and acylated-O-glycosides). Copyright © 2018 John Wiley & Sons, Ltd.

Multifamily determination of pesticide residues in soya-based nutraceutical products by GC/MS-MS.

PubMed

Páleníková, Agneša; Martínez-Domínguez, Gerardo; Arrebola, Francisco Javier; Romero-González, Roberto; Hrouzková, Svetlana; Frenich, Antonia Garrido

2015-04-15

An analytical method based on a modified QuEChERS extraction coupled with gas chromatography-tandem mass spectrometry (GC-MS/MS) was evaluated for the determination of 177 pesticides in soya-based nutraceutical products. The QuEChERS method was optimised and different extraction solvents and clean-up approaches were tested, obtaining the most efficient conditions with a mixture of sorbents (PSA, C18, GBC and Zr-Sep(+)). Recoveries were evaluated at 10, 50 and 100 μg/kg and ranged between 70% and 120%. Precision was expressed as relative standard deviation (RSD), and it was evaluated for more than 160 pesticides as intra and inter-day precision, with values always below 20% and 25%, respectively. Limits of detection (LODs) ranged from 0.1 to 10 μg/kg, whereas limits of quantification (LOQs) from 0.5 to 20 μg/kg. The applicability of the method was proved by analysing soya-based nutraceuticals. Two pesticides were found in these samples, malathion and pyriproxyfen, at 11.1 and 1.5 μg/kg respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

Characterization of biodegradation intermediates of nonionic surfactants by MALDI-MS. 2. Oxidative biodegradation profiles of uniform octylphenol polyethoxylate in 18O-labeled water.

PubMed

Sato, Hiroaki; Shibata, Atsushi; Wang, Yang; Yoshikawa, Hiromichi; Tamura, Hiroto

2003-01-01

This paper reports the characterization of the biodegradation intermediates of octylphenol octaethoxylate (OP(8)EO) by means of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The biodegradation test study was carried out in a pure culture (Pseudomonas putida S-5) under aerobic conditions using OP(8)EO as the sole carbon source and (18)O-labeled water as an incubation medium. In the MALDI-MS spectra of biodegraded samples, a series of OP(n)EO molecules with n = 2-8 EO units and their corresponding carboxylic acid products (OP(n)EC) were observed. The use of purified OP(8)EO enabled one to distinguish the shortened OPEO molecules as biodegradation intermediates. Furthermore, the formation of OP(8)EC (the oxidized product of OP(8)EO) supported the notion that terminal oxidation is a step in the biodegradation process. When biodegradation study was carried out in (18)O-labeled water, incorporation of (18)O atoms into the carboxyl group was observed for OPEC, while no incorporation was observed for the shortened OPEO products. These results could provide some rationale to the biodegradation mechanism of alkylphenol polyethoxylates.

HPLC-ESI-MS/MS analysis of hemoglobin peptides in tryptic digests of dried-blood spot extracts detects HbS, HbC, HbD, HbE, HbO-Arab, and HbG-Philadelphia mutations.

PubMed

Haynes, Christopher A; Guerra, Stephanie L; Fontana, Jessalyn C; DeJesús, Víctor R

2013-09-23

Hemoglobinopathies are mutations resulting in abnormal globin chain structure; some have clinically significant outcomes such as anemia or reduced lifespan. Five β-globin mutations are (c.20A>T, p.E6V), (c.19G>A, p. E6K), (c.79G>A, p.E26K), (c.364G>C, p.E121Q), and (c.364G>A, p.E121K), resulting in HbS (sickle-cell hemoglobin), HbC, HbE, HbD-Los Angeles, and HbO-Arab, respectively. One α-globin mutation is (c.[207C>G or 207C>A], p.N68K), resulting in HbG-Philadelphia. HPLC-ESI-MS/MS analysis of dried-blood spot (DBS) punches from newborns extracted with a trypsin-containing solution provides greater than 90% coverage of α-, β-, and γ-globin amino acid sequences. Because the (c.20A>T, p.E6V), (c.19G>A, p. E6K), (c.79G>A, p.E26K), (c.364G>C, p.E121Q), (c.364G>A, p.E121K), and (c.[207C>G or 207C>A], p.N68K) mutations generate globin peptides with novel amino acid sequences, detecting one of these peptides in DBS extracts is indicative of the presence of a hemoglobinopathy in the newborn. The method described here can distinguish normal β-globin peptides from the mutant HbS, HbC, HbE, HbD-Los Angeles and HbO-Arab peptides, as well as normal α-globin peptide from the mutant HbG-Philadelphia peptide, allowing the identification of unaffected heterozygotes such as HbAS, and of compound heterozygotes such as HbASG-Philadelphia. This HPLC-ESI-MS/MS analytical approach provides information that is not available from traditional hemoglobin analyses such as isoelectric focusing and HPLC-UV. It is also capable of determining the amino acid sequence of hemoglobin peptides, potentially allowing the detection of numerous hemoglobinopathies resulting from point mutations. Published by Elsevier B.V.

Multiresidue determination of ten nonsteroidal anti-inflammatory drugs in bovine, porcine, and chicken liver tissues by HPLC-MS/MS.

PubMed

Kang, JeongWoo; Park, Su-Jeong; Park, Hae-Chul; Gedi, Vinayakumar; So, ByungJae; Lee, Kwang-Jick

2014-09-01

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the group of drugs having the therapeutic efficacy of analgesic and antipyretic. To detect health-threatening residues of NSAIDs, a fast and easy multiresidue method based on liquid chromatography tandem mass spectrometry (LC-MS/MS) was described. Ten NSAIDs were extracted from the tissues using 2 mL of acetonitrile and 0.1 mL of 2 mM ammonium formate in distilled water. After clean-up using C18 sorbent, it was evaporated under nitrogen, reconstituted with 1 mL distilled water and analyzed by LC-MS/MS. The method was validated based on guideline for residue testing laboratory. Furthermore, the method has also been applied successfully to detect ten NSAIDs from bovine, porcine, and chicken liver tissues. In a total of 315 liver samples tested, acetylic salicylic acid was detected from 28 porcine and 2 chicken liver tissues at levels of 13 ∼ 576 and 50 ∼ 53 ng/g, respectively. Subsequently, paracetamol was detected in 15 porcine liver tissues with a detection levels of 28 ∼ 381 ng/g. Phenylbutazone and its metabolite, oxyphenylbutazone, were detected at 247 and 15 ng/g range in one of the bovine liver tissue, respectively.

HPLC-MS/MS methods for the determination of 52 perfluoroalkyl and polyfluoroalkyl substances in aqueous samples.

PubMed

Gremmel, Christoph; Frömel, Tobias; Knepper, Thomas P

2017-02-01

Two quantitative methods using high-performance liquid chromatography (HPLC) combined with triple quadrupole tandem mass spectrometry (MS/MS) were developed to determine perfluoroalkyl and polyfluoroalkyl substances (PFASs) in aqueous samples. The first HPLC-MS/MS method was applied to 47 PFASs of 12 different substance classes with acidic characteristics such as perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkane sulfonic acids (PFSAs), as well as precursor substances and biotransformation intermediates (e.g., unsaturated fluorotelomer carboxylic acids). In addition, 25 13 C-, 18 O-, and 2 H-labeled PFASs were used as internal standards in this method. The second HPLC-MS/MS method was applied to fluorotelomer alcohols (FTOHs) and perfluorooctane sulfonamidoethanols as these compounds have physicochemical properties different from those of the previous ones. Accuracy between 82% and 110% and a standard deviation in the range from 2% to 22% depending on the substances were determined during the evaluation of repeatability and precision. The method quantification limit after solid-phase extraction ranged from 0.3 to 199 ng/L depending on the analyte and matrix. The HPLC-MS/MS methods developed were suitable for the determination of PFASs in aqueous samples (e.g., wastewater treatment plant effluents or influents after solid-phase extraction). These methods will be helpful in monitoring campaigns to evaluate the relevance of precursor substances as indirect sources of perfluorinated substances in the environment. In one exemplary application in an industrial wastewater treatment plant, FTOHs were found to be the major substance class in the influent; in particular, 6:2-FTOH was the predominant compound in the industrial samples and accounted for 74% of the total PFAS concentration. The increase in the concentration of the transformation products of FTOHs in the corresponding effluent, such as fluorotelomer carboxylic acids, unsaturated fluorotelomer

A validated UPLC-MS/MS method for flibanserin in plasma and its pharmacokinetic interaction with bosentan in rats.

PubMed

Iqbal, Muzaffar; Ezzeldin, Essam; Rezk, Naser L; Bajrai, Amal A; Al-Rashood, Khalid A

2018-04-25

The purpose of this study was development, validation and application of ultra-performance liquid chromatography (UPLC)-ESI-MS/MS method for quantitation of flibanserin in plasma samples. After extraction of analyte from plasma by diethyl ether, separation was performed on UPLC C 18 column using mobile phase composition of 10 mM ammonium formate-acetonitrile (30:70, v/v) by isocratic elution of 0.3 ml/min. The multiple reaction monitoring transitions of m/z 391.13→ 161.04 and 384.20→ 253.06 were used for detection of analyte and internal standard (quetiapine), respectively. The calibration curves were linear (r ≥0.995) between 0.22 and 555 ng/ml concentration and all validation results were within the acceptable range as per US FDA guidelines. The assay procedure was fully validated and successfully applied in pharmacokinetic interaction study of flibanserin with bosentan in rats.

28 CFR 572.40 - Compassionate release under 18 U.S.C. 4205(g).

Code of Federal Regulations, 2011 CFR

2011-07-01

.... 4205(g)) § 572.40 Compassionate release under 18 U.S.C. 4205(g). 18 U.S.C. 4205(g) was repealed... 28 Judicial Administration 2 2011-07-01 2011-07-01 false Compassionate release under 18 U.S.C. 4205(g). 572.40 Section 572.40 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE...

28 CFR 572.40 - Compassionate release under 18 U.S.C. 4205(g).

Code of Federal Regulations, 2010 CFR

2010-07-01

.... 4205(g)) § 572.40 Compassionate release under 18 U.S.C. 4205(g). 18 U.S.C. 4205(g) was repealed... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Compassionate release under 18 U.S.C. 4205(g). 572.40 Section 572.40 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE...

28 CFR 572.40 - Compassionate release under 18 U.S.C. 4205(g).

Code of Federal Regulations, 2014 CFR

2014-07-01

.... 4205(g)) § 572.40 Compassionate release under 18 U.S.C. 4205(g). 18 U.S.C. 4205(g) was repealed... 28 Judicial Administration 2 2014-07-01 2014-07-01 false Compassionate release under 18 U.S.C. 4205(g). 572.40 Section 572.40 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE...

28 CFR 572.40 - Compassionate release under 18 U.S.C. 4205(g).

Code of Federal Regulations, 2013 CFR

2013-07-01

.... 4205(g)) § 572.40 Compassionate release under 18 U.S.C. 4205(g). 18 U.S.C. 4205(g) was repealed... 28 Judicial Administration 2 2013-07-01 2013-07-01 false Compassionate release under 18 U.S.C. 4205(g). 572.40 Section 572.40 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE...

28 CFR 572.40 - Compassionate release under 18 U.S.C. 4205(g).

Code of Federal Regulations, 2012 CFR

2012-07-01

.... 4205(g)) § 572.40 Compassionate release under 18 U.S.C. 4205(g). 18 U.S.C. 4205(g) was repealed... 28 Judicial Administration 2 2012-07-01 2012-07-01 false Compassionate release under 18 U.S.C. 4205(g). 572.40 Section 572.40 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE...

Interleukin-18 and testosterone levels in men with metabolic syndrome.

PubMed

Angelova, Petya; Kamenov, Zdravko; Tsakova, Adelina; El-Darawish, Yosif; Okamura, Haruki

2018-06-01

Interleukin 18 (IL-18) is an adipokine associated with obesity. Data about the relationship of IL-18 to the metabolic syndrome (MS) are still scarce. Low testosterone (T) levels are common in men with MS, but we did not find data about the levels of IL-18 in men with low T. The aim of this study was to determine the levels of IL-18 in men with MS with or without low T. A total of 251 men were included in the study. Of them 218 had MS (IDF 2005) and they were divided according to their morning total testosterone (TT) level (cutoff 10.4 nmol/l) into two groups: MS-low T (N = 84) and MS-normal T (N = 134). The control group consisted of 33 men without MS and low T. IL-18 was determined in serum using enzyme-linked immunosorbent assay. A small group of eight men with MS and low T levels received testosterone therapy for three months and physical and laboratory parameters were monitored at the end of that period. MS men were at mean age (±SD) = 53.77 ± 9.59 years; body mass index (BMI) = 34.0 ± 6.3 kg/m 2 ; and TT = 12.59 ± 5.66 nmol/l. The control group was at age = 52.12 ± 5.2 years (NS); BMI = 25.6 ± 2.4 kg/m 2 (p < .001); and TT = 17.8 ± 5.68 nmol/l (p < .001), respectively. The levels of IL-18 were higher in the MS group - 345 pg/ml compared to the control one - 264 pg/ml (p < .01). There was no significant difference between MS-low T (330.6 pg/ml) and MS-normal T (350.2 pg/ml) subgroups. The MS-normal T differed more significantly from the control group (p < .001). Significant correlation of testosterone with IL-18 levels was not found. IL-18 correlated with parameters of obesity, lipids, fasting blood sugar (p < .05) and the number of criteria for MS (p < .001). Three months on T treatment showed improvement in obesity parameters and only in one patient IL-18 had clear reduction while the rest showed no change. In this study, higher IL-18 levels were found in

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

PubMed

Bae, Jung-Woo; Choi, Chang-Ik; Jang, Choon-Gon; Lee, Seok-Yong

2011-11-01

A simple and sensitive liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) technique was developed and validated for the determination of sibutramine and its N-desmethyl metabolites (M1 and M2) in human plasma. After extraction with methyl t-butyl ether, chromatographic separation of analytes in human plasma was performed using a reverse-phase Luna C18 column with a mobile phase of acetonitrile-10 mm ammonium formate buffer (50:50, v/v) and quantified by ESI-MS/MS detection in positive ion mode. The flow rate of the mobile phase was 200 μL/min and the retention times of sibutramine, M1, M2 and internal standard (chlorpheniramine) were 1.5, 1.4, 1.3 and 0.9 min, respectively. The calibration curves were linear over the range 0.05-20 ng/mL, for sibutramine, M1 and M2. The lower limit of quantification was 0.05 ng/mL using 500 μL of human plasma. The mean accuracy and the precision in the intra- and inter-day validation for sibutramine, M1 and M2 were acceptable. This LC-MS/MS method showed improved sensitivity and a short run time for the quantification of sibutramine and its two active metabolites in plasma. The validated method was successfully applied to a pharmacokinetic study in human. Copyright © 2011 John Wiley & Sons, Ltd.

A Validated UPLC-MS-MS Assay for the Rapid Determination of Lorcaserin in Plasma and Brain Tissue Samples.

PubMed

Bajrai, Amal A; Ezzeldin, Essam; Al-Rashood, Khalid A; Raish, Mohammad; Iqbal, Muzaffar

2016-03-01

Lorcaserin is a novel, potent and highly efficacious 5-HT2C receptor agonist, recently approved by US Food and Drug Administration for the treatment of obesity. It has some abuse potential also and is listed as a Schedule IV drug in the Controlled Substances Act. Herein, a sensitive, selective and reliable UPLC-MS-MS assay was developed and validated for the quantitative analysis of lorcaserin in rat plasma and brain tissue using carbamazepine as an internal standard (IS). After the extraction of samples by protein precipitation, both lorcaserin and IS were separated on an Acquity BEH™ C18 (50 × 2.1 mm, 1.7 µm) column using a mobile phase consisting of acetonitrile-10 mM ammonium acetate-formic acid (85:15:0.1, v/v/v) at a flow rate of 0.25 mL/min. Detection and quantification were performed on a positive electrospray ionization interface in the multiple-reaction monitoring (MRM) mode. The MS-MS ion transitions were monitored at m/z 195.99 > 143.91 for lorcaserin and m/z 237.00 > 178.97 for IS, respectively. The calibration curves were linear over a concentration range of 1.08-500 ng/mL in plasma and 3.07-500 ng/mL in brain tissue homogenates, respectively. All the validation parameters results were within the acceptable range described in guidelines for bioanalytical method validation. The assay was successfully applied in a pharmacokinetic study of lorcaserin after oral administration in rats. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A 10 bit 200 MS/s pipeline ADC using loading-balanced architecture in 0.18 μm CMOS

NASA Astrophysics Data System (ADS)

Wang, Linfeng; Meng, Qiao; Zhi, Hao; Li, Fei

2017-07-01

A new loading-balanced architecture for high speed and low power consumption pipeline analog-to-digital converter (ADC) is presented in this paper. The proposed ADC uses SHA-less, op-amp and capacitor-sharing technique, capacitor-scaling scheme to reduce the die area and power consumption. A new capacitor-sharing scheme was proposed to cancel the extra reset phase of the feedback capacitors. The non-standard inter-stage gain increases the feedback factor of the first stage and makes it equal to the second stage, by which, the load capacitor of op-amp shared by the first and second stages is balanced. As for the fourth stage, the capacitor and op-amp no longer scale down. From the system’s point of view, all load capacitors of the shared OTAs are balanced by employing a loading-balanced architecture. The die area and power consumption are optimized maximally. The ADC is implemented in a 0.18 μm 1P6M CMOS technology, and occupies a die area of 1.2 × 1.2 mm{}2. The measurement results show a 55.58 dB signal-to-noise-and-distortion ratio (SNDR) and 62.97 dB spurious-free dynamic range (SFDR) with a 25 MHz input operating at a 200 MS/s sampling rate. The proposed ADC consumes 115 mW at 200 MS/s from a 1.8 V supply.

Immunoassay or LC-MS/MS for the measurement of salivary cortisol in children?

PubMed

Bae, Yoon Ju; Gaudl, Alexander; Jaeger, Sonia; Stadelmann, Stephanie; Hiemisch, Andreas; Kiess, Wieland; Willenberg, Anja; Schaab, Michael; von Klitzing, Kai; Thiery, Joachim; Ceglarek, Uta; Döhnert, Mirko; Kratzsch, Juergen

2016-05-01

Dysregulation of the adrenal cortex has been assessed with measurement of salivary cortisol. So far salivary cortisol is routinely measured with immunoassay (IA). However, liquid chromatography-tandem mass spectrometry (MS) is known to offer better specificity. We compared the concentrations of salivary cortisol measured by MS and IA at basal and stress induced conditions and evaluated reasons for the difference in method-dependent cortisol results. Saliva samples (n=2703) were collected from 169 children (age range: 8-14 years; 81 healthy children; 55 with internalizing and 33 with externalizing disorders) under circadian conditions and during the Trier Social Stress Test for Children (TSST-C). Biochemical analyses were performed with MS for cortisol and cortisone, IA (IBL, RE62011) for cortisol, and enzyme kinetic assay for α-amylase. MS and IA showed mostly comparable results for circadian activity and TSST-C response with similar statistical power. However, IA measured cortisol concentrations about 2.39-fold higher than MS. We found that this difference in measured values between MS and IA was mainly due to different standardization of IA compared to MS. In addition, at cortisol IA concentration below 5 nmol/L, cross-reactivity with cortisone was found to contribute to the lower concordance between MS and IA. Immunoassay and LC-MS/MS were largely comparable in the interpretation of salivary cortisol dynamics in stress research. But the IA method revealed a restricted accuracy in the measuring range below 5 nmol/L.

26 CFR 1.501(c)(18)-1 - Certain funded pension trusts.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 26 Internal Revenue 7 2010-04-01 2010-04-01 true Certain funded pension trusts. 1.501(c)(18)-1... pension trusts. (a) In general. Organizations described in section 501(c)(18) are trusts created before... contributions of employees. In order to be exempt, such trusts must also meet the requirements set forth in...

Development and validation of a serum total testosterone liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay calibrated to NIST SRM 971.

PubMed

French, Deborah

2013-01-16

At our institution, serum testosterone in adult males is measured by immunoassay while female and pediatric specimens are sent to a reference laboratory for liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis due to low concentrations. As this is of significant cost, a testosterone LC-MS/MS assay was developed in-house. A 5500 QTRAP® using electrospray ionization and a Shimadzu Prominence with a C18 column were used. Gradient elution with formic acid, water and methanol:acetonitrile at 0.5 ml/min had a 7-min run-time. A liquid-liquid extraction with hexane:ethyl acetate was carried out on 200 μl of serum. Multiple reaction monitoring was employed. Sample preparation took ~80 min for 21 samples. Six calibrators were used (0-1263 ng/dl; concentration assigned by NIST SRM 971) with 3 quality controls (9, 168 and 532 ng/dl). The limits of detection and quantitation were 1 and 2 ng/dl respectively. Extraction recovery was ~90% and ion suppression ~5%. Within-run and total precision studies yielded <15% CV at the limit of quantitation and <7% CV through the rest of the linear range. Isobaric interferences were baseline separated from testosterone. Method comparisons between this assay, an immunoassay, and another LC-MS/MS assay were completed. An accurate and sensitive LC-MS/MS assay for total testosterone was developed. Bringing this assay in-house reduces turnaround time for clinicians and patients and saves our institution funds. Copyright © 2012 Elsevier B.V. All rights reserved.

LC-ESI-MS/MS and cytotoxic activity of three Pistacia species.

PubMed

Kirollos, F N; Elhawary, S S; Salama, O M; Elkhawas, Y A

2018-01-28

LC-ESI-MS/MS was used for a comprehensive characterisation of ethanol extract from the leaves of three Pistacia species. After optimisation of the method and the use of the negative ionisation mode, a total of 42 different compounds were identified, of which 22 were tentatively characterised in P. chinensis Bunge, 33 in P. khinjuk stocks and 25 in P. lentiscus L. leaves. Flavonoids, phenolic acids, and their derivatives were the most abundant identified compounds. LC-ESI-MS/MS revealed identification of 15, 18 and 6 not previously detected compounds in P. chinensis Bunge, P. khinjuk Stocks and P. lentiscus L., respectively. The three extracts were also tested for their cytotoxic activities against human PC3 prostate cancer, A549 lung cancer, MCF7 breast cancer and HepG2 liver cancer. Generally, all the extracts have a moderate cytotoxic activity against lung, breast and prostate cancer, with different IC 50 . However, only P. lentiscus L. showed moderate activity against liver cancer.

Serum IL-18 level, clinical symptoms and IL-18-607A/C polymorphism among chronic patients with schizophrenia in a Chinese Han population.

PubMed

Zhang, Xiang Yang; Tan, Yun-Long; Chen, Da-Chun; Tan, Shu-Ping; Malouta, Michelle Z; Bernard, Jared D; Combs, Jessica L; Bhatti, Sarai; Davis, Michael C; Kosten, Thomas R; Soares, Jair C

2016-06-01

Literature suggests that alterations in the inflammatory and immune systems are involved in the pathogenesis of schizophrenia. Specifically, patients diagnosed with schizophrenia exhibit increased IL-18, a pleiotropic proinflammatory cytokine in type 1 T-helper (Th1) responses. The functional 607A/C promoter polymorphism of the IL-18 gene is also associated with the psychopathology of this disorder. However, no current study has explored its role in the clinical symptoms of schizophrenia as mediated through IL-18 levels. We recruited 772 inpatients with schizophrenia and 775 healthy controls in a Han Chinese population and genotyped the IL-18-607A/C polymorphism. Patient psychopathology was assessed using the Positive and Negative Syndrome Scale (PANSS). Serum IL-18 levels were measured in 80 patients and 93 healthy controls. Our results showed that there were no significant differences in the distribution of the allele and genotype frequencies between the patients and controls. Both increased IL-18 serum level and the IL-18-607A/C polymorphism were positively associated with the PANSS general psychopathology subscore and the PANSS total score. Moreover, interaction of increased IL-18 serum level and the IL-18-607A/C polymorphism influenced the clinical psychopathological symptoms, indicating that association of IL-18 level with the PANSS general psychopathology subscale or the total scores was present only among patients carrying the C allele. We demonstrate an association between the IL-18-607A/C variant and clinical psychopathological symptoms in schizophrenia. Findings suggest that the association between higher IL-18 levels and clinical symptoms in schizophrenia is dependent on the IL-18-607A/C polymorphism. Copyright © 2016 Elsevier Ltd. All rights reserved.

NanoESI-MS-based lipidomics to discriminate between cultivars, cultivation ages, and parts of Panax ginseng.

PubMed

Kim, So-Hyun; Shin, Yoo-Soo; Choi, Hyung-Kyoon

2016-03-01

Korean ginseng (Panax ginseng C.A. Meyer) is one of the most popular medicinal herbs used in Asia, including Korea and China. In the present study lipid profiling of two officially registered cultivars (P. ginseng 'Chunpoong' and P. ginseng 'Yunpoong') was performed at different cultivation ages (5 and 6 years) and on different parts (tap roots, lateral roots, and rhizomes) using nano-electrospray ionization-mass spectrometry (nanoESI-MS). In total, 30 compounds including galactolipids, phospholipids, triacylglycerols, and ginsenosides were identified. Among them, triacylglycerol 54:6 (18:2/18:2/18:2), phosphatidylglycerol 34:3 (16:0/18:3), monogalactosyldiacylglycerol 36:4 (18:2/18:2), phosphatidic acid species 36:4 (18:2/18:2), and 34:1 (16:0/18:1) were selected as biomarkers to discriminate cultivars, cultivation ages, and parts. In addition, an unknown P. ginseng sample was successfully predicted by applying validated partial least squares projection to latent structures regression models. This is the first study regarding the identification of intact lipid species from P. ginseng and to predict cultivars, cultivation ages, and parts of P. ginseng using nanoESI-MS-based lipidomic profiling with a multivariate statistical analysis.

18. Historic American Buildings Survey L. C. Durette, Photographer Oct. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

18. Historic American Buildings Survey L. C. Durette, Photographer Oct. 18, 1936 DETAIL OF PORCH - Colonel Paul Wentworth House, Dover Street (Salmon Falls, NH) (moved to Dover, MA, and then to 47 Water Street, Rollinsford, NH), Rollinsford, Strafford County, NH

Improved simultaneous quantitation of candesartan and hydrochlorthiazide in human plasma by UPLC-MS/MS and its application in bioequivalence studies.

PubMed

Singh, Bhupinder; Lokhandae, Rama S; Dwivedi, Ashish; Sharma, Sandeep; Dubey, Naveen

2014-04-01

A validated ultra-performance liquid chromatography mass spectrometric method (UPLC-MS/MS) was used for the simultaneous quantitation of candesartan (CN) and hydrochlorothiazide (HCT) in human plasma. The analysis was performed on UPLC-MS/MS system using turbo ion spray interface. Negative ions were measured in multiple reaction monitoring (MRM) mode. The analytes were extracted using a liquid-liquid extraction (LLE) method by using 0.1 mL of plasma volume. The lower limit of quantitation for CN and HCT was 1.00 ng/mL whereas the upper limit of quantitation was 499.15 ng/mL and 601.61 ng/mL for CN and HCT respectively. CN d 4 and HCT- 13 Cd 2 were used as the internal standards for CN and HCT respectively. The chromatography was achieved within 2.0 min run time using a C18 Phenomenex, Gemini NX (100 mm×4.6 mm, 5 µm) column with organic mixture:buffer solution (80:20, v/v) at a flow rate of 0.800 mL/min. The method has been successfully applied to establish the bioequivalence of candesartan cilexetil (CNC) and HCT immediate release tablets with reference product in human subjects.

Misleading measures in Vitamin D analysis: A novel LC-MS/MS assay to account for epimers and isobars

PubMed Central

2011-01-01

Background Recently, the accuracies of many commercially available immunoassays for Vitamin D have been questioned. Liquid chromatography tandem mass spectrometry (LC- MS/MS) has been shown to facilitate accurate separation and quantification of the major circulating metabolite 25-hydroxyvitamin-D3 (25OHD3) and 25-hydroxyvitamin-D2 (25OHD2) collectively termed as 25OHD. However, among other interferents, this method may be compromised by overlapping peaks and identical masses of epimers and isobars, resulting in inaccuracies in circulating 25OHD measurements. The aim of this study was to develop a novel LC-MS/MS method that can accurately identify and quantitate 25OHD3 and 25OHD2 through chromatographic separation of 25OHD from its epimers and isobars. Methods A positive ion electrospray ionisation (ESI) LC-MS/MS method was used in the Multiple Reaction Monitoring (MRM) mode for quantification. It involved i) liquid-liquid extraction, ii) tandem columns (a high resolution ZORBAX C18 coupled to an ULTRON chiral, with guard column and inlet filter), iii) Stanozolol-D3 as internal standard, and iv) identification via ESI and monitoring of three fragmentation transitions. To demonstrate the practical usefulness of our method, blood samples were collected from 5 healthy male Caucasian volunteers; age range 22 to 37 years and 25OHD2, 25OHD3 along with co-eluting epimers and analogues were quantified. Results The new method allowed chromatographic separation and quantification of 25OHD2, 25OHD3, along with 25OHD3 epimer 3-epi-25OHD3 and isobars 1-α-hydroxyvitamin-D3 (1αOHD3), and 7-α-hydroxy-4-cholesten-3-one (7αC4). The new assay was capable of detecting 0.25 ng/mL of all analytes in serum. Conclusions To our knowledge, this is the first specific, reliable, reproducible and robust LC-MS/MS method developed for the accurate detection of 25OHD (Vitamin D). The method is capable of detecting low levels of 25OHD3 and 25OHD2 together with chromatographic separation from

Investigation on the IL-18 -607A/C and -137C/G on the susceptibility of ischemic stroke.

PubMed

Shi, Jin-He; Niu, Li-Dan; Chen, Xi-Yan; Hou, Jing-Yu; Yang, Ping; Li, Guang-Peng

2015-01-01

We conducted a case-control study with 322 cases and 322 controls to assess the role of the two common SNPs in the promoter of IL-18 gene. Polymerase chain reaction restriction fragment length of polymorphism (PCR-RFLP) was taken to genotype -607A/C and -137C/G in the promoter of the IL-18 gene. By comparing cases and control subjects, we found that IS cases were more likely to have higher BMI, higher proportion of hypertension, and have higher proportion of smokers and drinkers. We found that IL-18 -607CC genotype (OR=1.70, 95% CI=1.03-2.81) and C allele (OR=1.26, 95% CI=1.01-1.58) were significantly more frequent in IS patients when compared with AA genotype. We did not find significant association between IL-18 -607A/C gene polymorphism and BMI, hypertension, smoking and drinking on the risk of IS. Our study suggests that polymorphisms in IL-18 -607A/C can influence the development of IS, and this gene polymorphism is associated with risk of IS in a Chinese population.

Development of a LC-MS/MS method for the simultaneous screening of seven water-soluble vitamins in processing semi-coarse wheat flour products.

PubMed

Nurit, Eric; Lyan, Bernard; Piquet, Agnès; Branlard, Gérard; Pujos-Guillot, Estelle

2015-05-01

Wheat is the second largest crop cultivated around the world and constitutes a major part of the daily diet in Europe. It is therefore important to determine the content of micronutrient in wheat and wheat-based food products to define the contribution of wheat-based foods to the nutrition of the consumers. The aim of the present work was to develop a simple and rapid method based on liquid chromatography tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of seven water-soluble vitamins in various wheat-based food materials. The vitamins present in the test material were separated in less than 15 min by using a reverse-phase C18 column, and analyzed by positive ion electrospray selected reaction monitoring MS/MS. The MS response for all the vitamins was linear over the working range (0.05 to 9 μg/mL) with correlation coefficients ranging between 0.991 and 1. Limits of quantification in the different food materials ranged from 0.09 to 3.5 μg/g. Intra-day and inter-day precision were found satisfactory. The developed method was applied for the simultaneous analysis of the water-soluble vitamin natural content of different semi-coarse wheat flours and in their corresponding baking products.

pyOpenMS: a Python-based interface to the OpenMS mass-spectrometry algorithm library.

PubMed

Röst, Hannes L; Schmitt, Uwe; Aebersold, Ruedi; Malmström, Lars

2014-01-01

pyOpenMS is an open-source, Python-based interface to the C++ OpenMS library, providing facile access to a feature-rich, open-source algorithm library for MS-based proteomics analysis. It contains Python bindings that allow raw access to the data structures and algorithms implemented in OpenMS, specifically those for file access (mzXML, mzML, TraML, mzIdentML among others), basic signal processing (smoothing, filtering, de-isotoping, and peak-picking) and complex data analysis (including label-free, SILAC, iTRAQ, and SWATH analysis tools). pyOpenMS thus allows fast prototyping and efficient workflow development in a fully interactive manner (using the interactive Python interpreter) and is also ideally suited for researchers not proficient in C++. In addition, our code to wrap a complex C++ library is completely open-source, allowing other projects to create similar bindings with ease. The pyOpenMS framework is freely available at https://pypi.python.org/pypi/pyopenms while the autowrap tool to create Cython code automatically is available at https://pypi.python.org/pypi/autowrap (both released under the 3-clause BSD licence). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The proteins cleaved by endogenous tryptic proteases in normal EDTA plasma by C18 collection of peptides for liquid chromatography micro electrospray ionization and tandem mass spectrometry.

PubMed

Dufresne, Jaimie; Florentinus-Mefailoski, Angelique; Ajambo, Juliet; Ferwa, Ammara; Bowden, Peter; Marshall, John

2017-01-01

The tryptic peptides from ice cold versus room temperature plasma were identified by C18 liquid chromatography and micro electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Samples collected on ice showed low levels of endogenous tryptic peptides compared to the same samples incubated at room temperature. Plasma on ice contained peptides from albumin, complement, and apolipoproteins and others that were observed by the X!TANDEM and SEQUEST algorithms. In contrast to ice cold samples, after incubation at room temperature, greater numbers of tryptic peptides from well characterized plasma proteins, and from cellular proteins were observed. A total of 583,927 precursor ions and MS/MS spectra were correlated to 94,669 best fit peptides that reduced to 22,287 correlations to the best accession within a gene symbol and to 7174 correlations to at least 510 gene symbols with ≥ 5 independent MS/MS correlations (peptide counts) that showed FDR q-values ranging from E-9 (i.e. FDR = 0.000000001) to E-227. A set of 528 gene symbols identified by X!TANDEM and SEQUEST including C4B showed ≥ fivefold variation between ice cold versus room temperature incubation. STRING analysis of the protein gene symbols observed from endogenous peptides in normal plasma revealed an extensive protein-interaction network of cellular factors associated with cell signalling and regulation, the formation of membrane bound organelles, cellular exosomes and exocytosis network proteins. Taken together the results indicated that a pool of cellular proteins, or protein complexes, in plasma are apparently not stable and degrade soon after incubation at room temperature.

Application of internal quality control to the analysis of quaternary ammonium compounds in surface and groundwater from Andalusia (Spain) by liquid chromatography with mass spectrometry.

PubMed

Vidal, J L Martínez; Vega, A Belmonte; López, F J Sánchez; Frenich, A Garrido

2004-10-01

A method has been developed for the simultaneous determination of paraquat (PQ), deiquat (DQ), chlormequat (CQ) and mepiquat (MQ) in water samples by liquid chromatography (LC) coupled with electrospray ionization mass spectrometry (MS). The LC separations of the target compounds, as well as their MS parameters, were optimized in order to improve selectivity and sensitivity. Separation was carried out in a Xterra C8 column, using as mobile phase methanol-heptafluorobutyric acid (HFBA) in isocratic mode. The molecular ion was selected for the quantitation in selected ion monitoring (SIM) mode. Off-line solid-phase extraction (SPE) was applied with silica cartridges in order to preconcentrate the compounds from waters. Detection limits were in the range 0.02-0.40 microg l(-1). Recovery range varied between 89 and 99.5% with precision values lower than 6%. The method has been applied successfully to the analysis of both surface and groundwater samples from agricultural areas of Andalusia (Spain), using well defined internal quality control (IQC) criteria. The results revealed the presence of deiquat and paraquat in some samples.

The computer-based Symbol Digit Modalities Test: establishing age-expected performance in healthy controls and evaluation of pediatric MS patients.

PubMed

Bigi, Sandra; Marrie, R A; Till, C; Yeh, E A; Akbar, N; Feinstein, A; Banwell, B L

2017-04-01

Decreased information processing speed (IPS) is frequently reported in pediatric multiple sclerosis (MS) patients. The computerized version of the Symbol Digit Modalities Test (c-SDMT) measures IPS over eight consecutive trials per session and additionally captures changes in performance within the session. Here, we establish normative c-SDMT performance and test-retest reliability in healthy children (HC) and explore differences in the overall c-SDMT-performance between HC and MS patients. This cross-sectional study included 478 HC (237 female, 49.5%) divided into five age groups (2 years each), and 27 MS patients (22 female, 81.5%) aged 8-18 years. The average time to complete the c-SDMT increased with age (|r| 0.70, 95% CI -0.74, -0.64). Test-retest reliability was high (ICC = 0.91) in HC. The total time to complete the c-SDMT did not differ between children with MS and sex- and age- matched HC (p = 0.23). However, MS patients were less likely to show faster performance across all the successive eight trials compared to HC (p = 0.0001). Healthy children demonstrate faster IPS with increasing age, as well as during successive trials of the c-SDMT. The inability of pediatric MS patients to maintain the increase in processing speed over successive trials suggests a reduced capacity for procedural learning, possibly resulting from cognitive fatigue.

Simultaneous determination of eight chemicals in Fufang Xueshuantong capsules by LC-MS-MS with periodic polarity switching.

PubMed

Zhou, Chunhua; Su, Linfei; Shang, Weiding; Rong, Zhihuan; Sun, Mengmeng; Zhang, Kai; Shi, Xiaowei; Wang, Qiao

2015-01-01

A rapid, sensitive, selective and periodic polarity-switching liquid chromatography-tandem mass spectrometry(LC-MS-MS) method was developed for the simultaneous determination of eight components in an important traditional Chinese medicinal capsule, Fufang Xueshuantong. LC analysis was carried out on a Kinetex 2.6 µm XB-C18 column by gradient elution. The detection was performed by multiple reaction monitoring (MRM) with a periodic polarity-switching electrospray ionization (ESI) source across five periods of switching between positive and negative mode. Periodic polarity-switching was used to acquire maximal responses and to simultaneously detect eight constituents in one analysis run lasting 8 min. All of the analytes showed good linearity (r > 0.9947) in the tested ranges. The average recoveries were in the range of 95.4-103.9% with relative standard deviations ≤6.3%, and the intra- and inter-day variations were ≤3.7%. The developed method was successfully employed to analyze three batches of Fufang Xueshuantong capsule samples. The results showed that the levels of notoginsenoside R1, ginsenoside Rb1 and salvianolic acid B were clearly different in different batches of Fufang Xueshuantong capsules. Furthermore, the new established periodic polarity-switching LC-MS-MS method was proven to be highly sensitive and effective in evaluating the quality of Fufang Xueshuantong capsules. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Simultaneous determination of creatinine and creatine in human serum by double-spike isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-mass spectrometry (GC-MS).

PubMed

Fernández-Fernández, Mario; Rodríguez-González, Pablo; Añón Álvarez, M Elena; Rodríguez, Felix; Menéndez, Francisco V Álvarez; García Alonso, J Ignacio

2015-04-07

This work describes the first multiple spiking isotope dilution procedure for organic compounds using (13)C labeling. A double-spiking isotope dilution method capable of correcting and quantifying the creatine-creatinine interconversion occurring during the analytical determination of both compounds in human serum is presented. The determination of serum creatinine may be affected by the interconversion between creatine and creatinine during sample preparation or by inefficient chemical separation of those compounds by solid phase extraction (SPE). The methodology is based on the use differently labeled (13)C analogues ((13)C1-creatinine and (13)C2-creatine), the measurement of the isotopic distribution of creatine and creatinine by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and the application of multiple linear regression. Five different lyophilized serum-based controls and two certified human serum reference materials (ERM-DA252a and ERM-DA253a) were analyzed to evaluate the accuracy and precision of the proposed double-spike LC-MS/MS method. The methodology was applied to study the creatine-creatinine interconversion during LC-MS/MS and gas chromatography-mass spectrometry (GC-MS) analyses and the separation efficiency of the SPE step required in the traditional gas chromatography-isotope dilution mass spectrometry (GC-IDMS) reference methods employed for the determination of serum creatinine. The analysis of real serum samples by GC-MS showed that creatine-creatinine separation by SPE can be a nonquantitative step that may induce creatinine overestimations up to 28% in samples containing high amounts of creatine. Also, a detectable conversion of creatine into creatinine was observed during sample preparation for LC-MS/MS. The developed double-spike LC-MS/MS improves the current state of the art for the determination of creatinine in human serum by isotope dilution mass spectrometry (IDMS), because corrections are made for all the possible errors

Carotenoid composition of jackfruit (Artocarpus heterophyllus), determined by HPLC-PDA-MS/MS.

PubMed

de Faria, A F; de Rosso, V V; Mercadante, A Z

2009-06-01

Carotenoids are pigments responsible for the yellow-reddish color of many foods and are related to important functions and physiological actions, preventing several chronic-degenerative diseases. The objective of this study was to confirm the carotenoid composition of jackfruit by high-performance liquid chromatography connected to photodiode array and mass spectrometry detectors (HPLC-PDA-MS/MS). The main carotenoids were all-trans-lutein (24-44%), all-trans-beta-carotene (24-30%), all-trans-neoxanthin (4-19%), 9-cis-neoxanthin (4-9%) and 9-cis-violaxanthin (4-10%). Either qualitative or quantitative differences, mainly related to the lutein proportion, were found among three batches of jackfruit. Since the fruits from batch A showed significantly lower contents for almost all carotenoids, it also had the lowest total carotenoid content (34.1 microg/100 g) and provitamin A value, whereas the total carotenoid ranged from 129.0 to 150.3 microg/100 g in the other batches. The provitamin A values from batches B and C were 3.3 and 4.3 microg RAE/100 g, respectively. The carotenoid composition of jackfruit was successfully determined, where 14 of the 18 identified carotenoids were reported for first time. Differences among batches may be due to genetic and/or agricultural factors.

ESI-MS2 and Anti-inflammatory Studies of Cyclopropanic Triterpenes. UPLC-ESI-MS and MS2 Search of Related Metabolites from Donella ubanguiensis.

PubMed

Sandjo, Louis P; Nascimento, Marcus V P Dos Santos; da Silva, Layzon A L; Munhoz, Antonio C M; Pollo, Luiz A E; Biavatti, Maique W; Ngadjui, Bonaventure T; Opatz, Till; Fröde, Tania S

2017-01-01

Triterpenes are one of the largest secondary metabolites groups spread in the plant kingdom with various skeletons. These metabolites have showed various bioactivities including anti-inflammatory activity. The study aims to explore the mass spectrometry fragmentation of donellanic acids A-C (DA A-C), three compounds identified from Donella ubanguiensis; in addition, the fragmentation behaviour of these metabolites will serve as a fingerprint to search and characterise triterpenes congeners in fruits, bark and wood crude extracts of D. ubanguiensis. This work was prompted by the anti-inflammatory activity on leukocyte migration, exudate concentrations and myeloperoxidase activity obtained for DA A-B. The bioactivity was performed on mouse model of pleurisy induced by carrageenan and the parameters were analysed by veterinarian automated cell counter and colorimetric assays. While the tandem mass analyses of DA A-C were carried out by a direct infusion ESI-QTOF-MS/MS, the extracts were studied by UPLC-ESI-QTOF-MS and UPLC-ESI-QTOF-MS/MS. DA A displayed interesting anti-inflammatory activity by inhibiting leukocyte migration, exudate concentrations and myeloperoxidase activity (p < 0.05) while DA B was weakly active (p > 0.05). Moreover, the diagnostic of the MS 2 behaviour of DA A-C in conjunction with the chromatograms and the obtained MS 2 data of the crude extract led to the characterisation of three cyclopropane triterpenes (T1-T3) and six saponins (T4-T9) from the fruits, the bark, and the wood extracts. Donella species deserve more investigation since metabolites related to the anti-inflammatory compound (DA A) could be identified. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Determination of Asymmetric and Symmetric Dimethylarginine in Serum from Patients with Chronic Kidney Disease: UPLC-MS/MS versus ELISA.

PubMed

Boelaert, Jente; Schepers, Eva; Glorieux, Griet; Eloot, Sunny; Vanholder, Raymond; Lynen, Frédéric

2016-05-13

Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide (NO) synthesis, and its structural isomer symmetric dimethylarginine (SDMA) are uremic toxins accumulating in chronic kidney disease (CKD) patients. The objective of this study was to develop and validate a robust UPLC-MS/MS method for the simultaneous determination of ADMA and SDMA in human serum. Chromatographic separation after butyl ester derivatization was achieved on an Acquity UPLC BEH C18 column, followed by tandem mass spectrometric detection. After validation, the applicability of the method was evaluated by the analysis of serum samples from 10 healthy controls and 77 CKD patients on hemodialysis (CKD5HD). Both ADMA (0.84 ± 0.19 µM vs. 0.52 ± 0.07 µM) and SDMA concentrations (2.06 ± 0.82 µM vs. 0.59 ± 0.13 µM) were significantly (p < 0.001) elevated in CKD5HD patients compared to healthy controls. In general, low degrees of protein binding were found for both ADMA and SDMA. In addition, an established commercially available ELISA kit was utilized on the same samples (n = 87) to compare values obtained both with ELISA and UPLC-MS/MS. Regression analysis between these two methods was significant (p < 0.0001) but moderate for both ADMA (R = 0.78) and SDMA (R = 0.72).

Quantitative estimation of gymnemagenin in Gymnema sylvestre extract and its marketed formulations using the HPLC-ESI-MS/MS method.

PubMed

Kamble, Bhagyashree; Gupta, Ankur; Patil, Dada; Janrao, Shirish; Khatal, Laxman; Duraiswamy, B

2013-02-01

Gymnema sylvestre, with gymnemic acids as active pharmacological constituents, is a popular ayurvedic herb and has been used to treat diabetes, as a remedy for cough and as a diuretic. However, very few analytical methods are available for quality control of this herb and its marketed formulations. To develop and validate a new, rapid, sensitive and selective HPLC-ESI (electrospray ionisation)-MS/MS method for quantitative estimation of gymnemagenin in G. sylvestre and its marketed formulations. HPLC-ESI-MS/MS method using a multiple reactions monitoring mode was used for quantitation of gymnemagenin. Separation was carried out on a Luna C-18 column using gradient elution of water and methanol (with 0.1% formic acid and 0.3% ammonia). The developed method was validated as per International Conference on Harmonisation Guideline ICH-Q2B and found to be accurate, precise and linear over a relatively wide range of concentrations (5.280-305.920 ng/mL). Gymnemagenin contents were found from 0.056 ± 0.002 to 4.77 ± 0.59% w/w in G. sylvestre and its marketed formulations. The method established is simple, rapid, with high sample throughput, and can be used as a tool for quality control of G. sylvestre and its formulations. Copyright © 2012 John Wiley & Sons, Ltd.

LC-MS/MS profiling-based secondary metabolite screening of Myxococcus xanthus.

PubMed

Kim, Jiyoung; Choi, Jung Nam; Kim, Pil; Sok, Dai-Eun; Nam, Soo-Wan; Lee, Choong Hwan

2009-01-01

Myxobacteria, Gram-negative soil bacteria, are a well-known producer of bioactive secondary metabolites. Therefore, this study presents a methodological approach for the high-throughput screening of secondary metabolites from 4 wild-type Myxococcus xanthus strains. First, electrospray ionization mass spectrometry (ESI-MS) was performed using extracellular crude extracts. As a result, 22 metabolite peaks were detected, and the metabolite profiling was then conducted using the m/z value, retention time, and MS/MS fragmentation pattern analyses. Among the peaks, one unknown compound peak was identified as analogous to the myxalamid A, B, and C series. An analysis of the tandem mass spectrometric fragmentation patterns and HR-MS identified myxalamid K as a new compound derived from M. xanthus. In conclusion, LC-MS/MS-based chemical screening of diverse secondary metabolites would appear to be an effective approach for discovering unknown microbial secondary metabolites.

STM study of C60F18 high dipole moment molecules on Au(111)

NASA Astrophysics Data System (ADS)

Bairagi, K.; Bellec, A.; Chumakov, R. G.; Menshikov, K. A.; Lagoute, J.; Chacon, C.; Girard, Y.; Rousset, S.; Repain, V.; Lebedev, A. M.; Sukhanov, L. P.; Svechnikov, N. Yu.; Stankevich, V. G.

2015-11-01

Scanning tunneling microscopy and spectroscopy studies of C60F18 molecules deposited on Au(111) are reported and compared to C60 molecules both at liquid helium temperature and room temperature (RT). Whereas adsorption and electronic properties of C60F18 single molecules were studied at low temperature (LT), self-assemblies were investigated at RT. In both cases, the fluorine atoms of the C60F18 molecules are pointed towards the surface. Individual C60F18 molecules on Au(111) have a HOMO-LUMO gap of 2.9 eV. The self-assembled islands exhibit a close-packed hexagonal lattice with amorphous borders. The comparison with C60 molecules clearly demonstrates the influence of the C60F18 electric dipole moment (EDM) on the electronic properties of single molecules and on the thermodynamics of self-assembled islands. Besides, the apparent height value of a separate molecule increases in a self-assembly environment as a result of a depolarization phenomenon.

Quantifying MMA by SLE LC-MS/MS: Unexpected challenges in assay development.

PubMed

Lo, Sheng-Ying; Gordon, Cindy; Sadilkova, Katerina; Jack, Rhona M; Dickerson, Jane A

2016-09-01

Analysis of serum/plasma methylmalonic acid (MMA) is important for the diagnosis and management of methylmalonic acidemia in pediatric populations. This work focuses on developing and validating a liquid chromatography tandem mass spectrometry (LC-MS/MS) method to monitor methylmalonic acidemia using a simple method preparation. MMA and stable isotope labeled d3-MMA was extracted using supported liquid extraction (SLE). Assay imprecision, bias, linearity, recovery and carryover were determined. The relationship between MMA and propionyl acylcarnitine (C3-acylcarnitine) was also evaluated using historical paired results from 51 unique individuals. Baseline separation between MMA and succinic acid was completed in 7min. The assay was linear from 0.1 to 500μM. The intra-day and inter-day imprecision CV ranged from 4.1 to 13.2% (0.3 to 526μM) and 5.0 to 15.7% (0.3 to 233μM), respectively. Recovery ranged from 93 to 125%. The correlation with a national reference laboratory LC-MS/MS assay showed a Deming regression of 1.026 and intercept of -1.335. Carryover was determined to be <0.04%. Patient-specific correlation was observed between MMA and C3-acylcarnitine. This report describes the first LC-MS/MS method using SLE for MMA extraction. In addition, we illustrate the challenges encountered during this method development that should be assessed and resolved by any laboratory implementing a SLE LC-MS/MS assay designed to quantify analytes across several orders of magnitude. Copyright © 2016 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

[Study on UPLC specific chromatogram of Lily and its specific peaks compositions analysis by QTOF-MS].

PubMed

Nie, Hui; Yan, Hui; Qian, Da-Wei; Duan, Jin-Ao; Ou, Yang-Zhen; Qian, Ye-Fei; Guan, Han-Liang

2013-07-01

To establish the UPLC specific chromatogram of Lily and analyze the specific peaks compositions by ESI-QTOF-MS. The samples were conducted by ACQUITY UPLC BEH C18 Column (2.1 mm x 100 mm, 1.7 microm) and eluted with acetonitrile and 0.1% formic acid at the flow rate of 0.4 mL/min. The detection wavelength was set at 320 nm and column temperature was 35 degrees C. Negative ion mode was chosen for qualitative analysis. The capillary voltage was set at 3.0 kV. The nebulization gas was set to 600 L/h at 350 degrees C, and the source temperature was 120 degrees C. The specific chromatogram of Lily was obtained. There were 19 common peaks. Twelve phenylpropenoid glycerides compositions were identified. Among them, 6 compositions were identified by comparison with the reference substances and others were identified by MS and MS2 data. UPLC specific chromatogram can be used for the quality evaluation of Lily, giving support to quality control comprehensively.

Bioanalytical LC-MS/MS method validation for plasma determination of topiramate in healthy Indian volunteers.

PubMed

Goswami, Dipanjan; Kumar, Ajay; Khuroo, Arshad H; Monif, Tausif; Rab, Shamsur

2009-11-01

A LC-MS/MS method for plasma topiramate analysis is delineated involving least number of healthy volunteers. Topiramate and amlodipine internal standard (IS) were extracted by simple centrifuge-coupled solid-phase extraction and reverse-phase chromatographic separation was performed on an Ascentis C(18) column. Turbo-spray negative-ion mode multiple-reaction monitoring was selected for mass pair detection at m/z 338.3 --> 78.0 and m/z 407.3 --> 295.5 for analyte and IS respectively. The method showed a dynamic linearity range from 10.4 to 2045.0 ng/mL, lower limit of quantitation achieved at 10.4 ng/mL and finally a mass spectrometric total run time of within 2.5 min for human sample analysis. Bioequivalence was assessed successfully using this fully validated method on 16 fasted Indian male subjects with 25 mg topiramate tablet administration. An appropriate study design describes plasma samples collection up to 216 h post dose in two periods, separated by a 28 day washout period. The challenge of half-life matching for test and reference drug was achieved with 73.43 +/- 9.68 and 73.06 +/- 14.03 h, respectively, and intra-subject coefficient of variation achieved within 11% for AUCs and C(max) evaluated by non-compartmental pharmacokinetic analysis. The results of LCMS topiramate complete method validation supported by pharmacokinetic study have not been published before, and are presented and discussed for the first time in this article. Copyright (c) 2009 John Wiley & Sons, Ltd.

Study of vortex-assisted MSPD and LC-MS/MS using alternative solid supports for pharmaceutical extraction from marketed fish.

PubMed

Hertzog, Gabriel I; Soares, Karina L; Caldas, Sergiane S; Primel, Ednei G

2015-06-01

A procedure based on vortex-assisted matrix solid-phase dispersion (MSPD) for the extraction of 15 pharmaceuticals from fish samples with determination by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was validated. Florisil, C18, diatomaceous earth, chitin, and chitosan were evaluated as solid supports. Best results were obtained with 0.5 g of diatomaceous earth, 0.5 g of sodium sulfate, and 5 mL of methanol. Analytical recoveries ranged from 58 to 128 % with relative standard deviation (RSD) lower than 15 %. Limit of quantification (LOQ) values for the 15 compounds ranged from 5 to 1000 ng g(-1). The method under investigation has shown to be a simple and fast extraction tool with minimum instrumentation and low amount of reagent, resulting in method low cost. Besides, alternative materials, such as chitin and chitosan, which were applied to the dispersion step for the first time, were found to be interesting alternatives.

Simultaneous determination of mangiferin and neomangiferin in rat plasma by UPLC-MS/MS and its application for pharmacokinetic study.

PubMed

Qiu, Xiangjun; Zhao, Jian-Long; Hao, Cong; Yuan, Canli; Tian, Nuan; Xu, Zhi-Sheng; Zou, Ruan-Min

2016-05-30

In this study, a sensitive and rapid ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed to determine mangiferin and neomangiferin in rat plasma simultaneously. Chromatographic separation was carried out on an Acquity UPLC BEH C18 column and mass spectrometric analysis was performed using a Xevo TQD triple quadruple mass spectrometer coupled with an electrospray ionization (ESI) source. The MRM transitions of m/z 423.2 → 303.1 and m/z 585.0 → 273.1 were used to quantify for mangiferin and neomangiferin, respectively. The linearity of this method was found to be within the concentration range of 5-2000 ng/mL for mangiferin, and 2-1000 ng/mL for neomangiferin in rat plasma, respectively. Only 3.0 min was needed for an analytical run. This assay was used to support a preclinical study to investigate the pharmacokinetics of mangiferin and neomangiferin in rats. Copyright © 2016 Elsevier B.V. All rights reserved.

[Simultaneous determination of formononetin, calycosin and isorhamnetin from Astragalus mongholicus in rat plasma by LC-MS/MS and application to pharmacokinetic study].

PubMed

Lin, Qing; Li, Yuan; Tan, Xiao-Mei; Yao, Xiang-Chao

2013-04-01

To establish a method to determine the concentration of formononetin, calycosin and isorhamnetin from Astragalus mongholicus in rats' plasma using LC-MS/MS and calculate their pharmacokinetic parameters. The contents of formononetin, calycosin and isorhamnetin in plasma were detected before and 24 h after 10 rats were treated with 10 g/kg Astragalus mongholicus. Rutin was used as internal standard. Agilent 1 200 HPLC system with Alltima C18 (150 mm x 2.1 mm, 5 microm) was used. Mobile phase was methanol-water solution with gradient elute at a flow rate of 0.3 mL/min. The column temperature was 40 degrees C. The LC-MS/ MS system was operated using an electrospray ionization probe in negative ion mode; Scan mode: multiple reaction ion monitoring (MRM) mode. The ion of monitor: m/z 267.0 --> 251.9 for formononetin, m/z 283.1 --> 268.2 for calycosin, m/z 315.4 --> 300.1 for isorhamnetin and m/z 609.4 --> 300.1 for rutin (internal standard), respectively. The linear range of formononetin, calycosin and isorhamnetin was 5 - 1 000 (r = 0.9996), 3.91 - 500 (r = 0.9989) and 0.5 - 100 ng/mL (r = 0.9992), respectively. The lowest limit of quantification (LLOQ) of formononetin, calycosin and isorhamnetin was 0.625, 0.5 and 0.1 ng/mL, respectively. The pharmacokinetic parameter, t(1/2beta), of formononetin, calycosin and isorhamnetin was (10.43 +/- 2.94), (6.91 +/- 1.33) and (5.07 +/- 1.21) h, respectively. The C(max) of formononetin, calycosin and isorhamnetin was (398.5 +/- 103.7), (138.7 +/- 32.8) and (58.3 +/- 14.5) ng/mL, respectively. The AUC(0 -> 12h), of formononetin, calycosin and isorhamnetin was (1238.8 +/- 311.3), (669.5 +/- 159.7) and (274.1 +/- 83.9)ng x h/mL, respectively. A sensitive, accuracy and suitable LC-MS/MS method for determination of formononetin, calycosin and isorhamnetin is developed and successfully applied to the pharmacokinetic study of 10 g/kg Astragalus mongholicus after oral administration in rats.

Simultaneous Determination of Decursin, Decursinol Angelate, Nodakenin, and Decursinol of Angelica gigas Nakai in Human Plasma by UHPLC-MS/MS: Application to Pharmacokinetic Study.

PubMed

Kim, Sook-Jin; Ko, Se-Mi; Choi, Eun-Jeong; Ham, Seong-Ho; Kwon, Young-Dal; Lee, Yong-Bok; Cho, Hea-Young

2018-04-26

Coumarins in Cham-dang-gwi, the dried root of Angelica gigas Nakai (AGN), possess pharmacological effects on anemia, pain, infection, and articular rheumatism. The AGN root containes decursin (D), decursinol angelate (DA), nodakenin, and decursinol (DOH), a major metabolite of D and DA. The aim of this study was to develop a simultaneous determination method for these four coumarins in human plasma using ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Chromatographic separation was performed on dual columns (Kinetex ® C 18 column and Capcell core C 18 column) with mobile phase consisting of water and acetonitrile at a flow rate of 0.3 mL/min using gradient elution. Multiple reaction monitoring was operated in positive ion mode with precursors to product ion transition values of m / z 328.9→228.8, 328.9→228.9, 409.4→248.8, and 246.8→212.9 to measure D, DA, nodakenin, and DOH, respectively. Linear calibration curves were fitted over concentration range of 0.05⁻50 ng/mL for these four components, with correlation coefficient greater than 0.995. Inter- and intra-day accuracies were between 90.60% and 108.24%. These precisions were within 11.19% for all components. The established method was then applied to a pharmacokinetic study for the four coumarins after usual dosing in Korean subjects.

Clinical Relevance of Ceramide Metabolism in the Pathogenesis of Human Head and Neck Squamous Cell Carcinoma (HNSCC): Attenuation of C18-ceramide in HNSCC Tumors Correlates with Lymphovascular Invasion and Nodal Metastasis

PubMed Central

Karahatay, Serdar; Thomas, Kesha; Koybasi, Serap; Senkal, Can E.; ElOjeimy, Saeed; Liu, Xiang; Bielawski, Jacek; Day, Terry A.; Boyd Gillespie, M; Sinha, Debajyoti; Norris, James S.; Hannun, Yusuf A.; Ogretmen, Besim

2007-01-01

It has been documented previously that defects in the generation of C18-ceramide, a product of ceramide synthase 1 (CerS1), also known as longevity assurance gene 1 (hLASS1), play important roles in the pathogenesis and/or progression of HNSCC. However, whether altered levels of ceramide generation in HNSCC tumors have any clinical relevance remains unknown. In this study, the levels of endogenous ceramides were measured in tumor tissues of 45 HNSCC patients as compared to their normal tissues using high-pressure liquid chromatography/mass spectrometry (LC/MS), and then possible link between ceramide levels and the clinical parameters of HNSCC were examined. The data showed that the levels of C16-, C24-, C24:1-ceramide were significantly elevated in the majority of tumor tissues compared to their normal tissues, while the levels of only C18-ceramide were significantly decreased in HNSCC tumors, especially in tumor tissues of male patients. Importantly, it was also shown here that decreased C18-ceramide levels in HNSCC tumor tissues were significantly associated with the higher incidences of lymphovascular invasion, and pathologic nodal metastasis. Importantly, attenuation of C18-ceramide was also positively linked to the higher overall stages of the primary HNSCC tumors. Therefore, these data suggest, for the first time, that the defects in the generation/accumulation of C18-ceramide might have important clinical roles in HNSCC, especially in lymphovascular invasion and nodal disease. PMID:17619081

Inventory of File SN.2012091412.grib6th.f18.grib2

Science.gov Websites

ground UGRD 18 hour fcst U-Component of Wind [m/s] 003.2 35 m above ground VGRD 18 hour fcst V-Component of Wind [m/s] 004 surface TMP 18 hour fcst Temperature [K] 005 0.5 m underground TMP 18 hour fcst ] 008.1 10 mb UGRD 18 hour fcst U-Component of Wind [m/s] 008.2 10 mb VGRD 18 hour fcst V-Component of

Adhesive blood microsampling systems for steroid measurement via LC-MS/MS in the rat.

PubMed

Heussner, Kirsten; Rauh, Manfred; Cordasic, Nada; Menendez-Castro, Carlos; Huebner, Hanna; Ruebner, Matthias; Schmidt, Marius; Hartner, Andrea; Rascher, Wolfgang; Fahlbusch, Fabian B

2017-04-01

Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) allows for the direct analysis of multiple hormones in a single probe with minimal sample volume. Rodent-based animal studies strongly rely on microsampling, such as the dry blood spot (DBS) method. However, DBS suffers the drawback of hematocrit-dependence (non-volumetric). Hence, novel volumetric microsampling techniques were introduced recently, allowing sampling of fixed accurate volumes. We compared these methods for steroid analysis in the rat to improve inter-system comparability. We analyzed steroid levels in blood using the absorptive microsampling devices Whatman® 903 Protein Saver Cards, Noviplex™ Plasma Prep Cards and the Mitra™ Microsampling device and compared the obtained results to the respective EDTA plasma levels. Quantitative steroid analysis was performed via LC-MS/MS. For the determination of the plasma volume factor for each steroid, their levels in pooled blood samples from each human adults and rats (18weeks) were compared and the transferability of these factors was evaluated in a new set of juvenile (21days) and adult (18weeks) rats. Hematocrit was determined concomitantly. Using these approaches, we were unable to apply one single volume factor for each steroid. Instead, plasma volume factors had to be adjusted for the recovery rate of each steroid and device individually. The tested microsampling systems did not allow the use of one single volume factor for adult and juvenile rats based on an unexpectedly strong hematocrit-dependency and other steroid specific (pre-analytic) factors. Our study provides correction factors for LC-MS/MS steroid analysis of volumetric and non-volumetric microsampling systems in comparison to plasma. It argues for thorough analysis of chromatographic effects before the use of novel volumetric systems for steroid analysis. Copyright © 2017 Elsevier Inc. All rights reserved.

An UPLC-MS/MS method for the quantitation of alectinib in rat plasma.

PubMed

Huang, Xiang-Xin; Li, Yun-Xuan; Li, Xiang-Yu; Hu, Xiao-Xia; Tang, Peng-Fei; Hu, Guo-Xin

2017-01-05

Currently, crizotinib is the first generation drug, which has been used in the treatment of ALK-rearranged non-small cell lung cancer (NSCLC). However, more and more patients are found in crizotinib-resistance. In the last year, alectinib has been approved for treatment of patients with crizotinib-resistance. In this study, we aim to develop and validate a simple, rapid and sensitive tandem mass spectrometry (UHPLC-MS/MS) method for determination of alectinib in rat plasma. Diazepam was chosen as an internal standard (IS). Protein precipitation by acetonitrile was utilized to prepare plasma samples. Chromatographic separation was achieved on a RRHD Eclipse Plus C18 (2.1×50mm, 1.8μ) column with a gradient mobile phase consisting of acetonitrile and water (containing 0.1% formic acid). The analytes were detected by an electrospray ionization (ESI) source in positive mode. A dynamic multiple reaction monitoring (MRM) method was developed to detect specific precursor and product ions. The target fragment ions were m/z 483.2→396.1 for alectinib and m/z 285.0→192.9 for diazepam (IS). Linear calibration plots were achieved in the range of 1-500ng/ml for alectinib (R 2 =0.997) in rat plasma. Mean recoveries of alectinib in rat plasma ranged from 84.2% to 92.2%. The intra- and inter-day precision was below 9.3% and accuracy was from -1.4% to 12.1%. No obvious matrix effect was found. This method shows a good performance: accuracy, precision and stability. It has been fully validated and successfully applied to pharmacokinetic study of alectinib. Copyright © 2016 Elsevier B.V. All rights reserved.

Quantification of amlodipine and atorvastatin in human plasma by UPLC-MS/MS method and its application to a bioequivalence study.

PubMed

Rezk, Mamdouh R; Badr, Kamal A

2018-07-01

A robust, rapid and sensitive UPLC-MS/MS method has been developed, optimized and validated for the determination of amlodipine (AML) and atorvastatin (ATO) in human plasma using eplerenone as an internal standard (IS). Multiple-reaction monitoring in positive electrospray ionization mode was utilized in Xevo TQD LC-MS/MS. Double extraction was used in sample preparation using diethyl ether and ethyl acetate. The prepared samples were analyzed using an Acquity UPLC BEH C 18 (50 × 2.1 mm, 1.7 μm) column. Ammonium formate and acetonitrile, pumped isocraticaly at a flow rate of 0.25 mL/min, were used as a mobile phase. Method validation was done as per the US Food and Drug Administration guidelines. Linearity was achieved in the range of 0.1-10 ng/mL for AML and 0.05-50 ng/mL for ATO. Intra-day and inter-day accuracy and precision were calculated and found to be within the acceptable range. A short run time, of <1.5 min, permits analysis of a large number of plasma samples per batch. The developed and validated method was applied to estimate AML and ATO in a bioequivalence study in healthy human volunteers. Copyright © 2018 John Wiley & Sons, Ltd.

Decomposed Fragment Identification in C_8F_18 RF Plasma for a-C:F Film Production

NASA Astrophysics Data System (ADS)

Sakai, Yosuke; Tazawa, Shota; Bratescu, Maria; Suda, Yoshiyuki; Sugawara, Hirotake

2004-09-01

Amorphous fluorocarbon polymer (a-C:F) film shows excellent insulation properties such as low dielectric constant (<2.5), high dielectric strength (>2 MV/cm), low surface energy, and chemical inertness. Therefore, we have studied this film for a purpose of an additional insulator to enhance the breakdown voltage in an alternative to a SF6 gas insulation system. The films are prepared using a C_8F_18 vapor RF plasma. When per-fluorocarbon, such as C_8F_18 as source gases, then the deposition rate becomes roughly two orders of magnitude higher than that obtained from conventional low molecular-weight source monomers (CF_4, C_2F_6, C_3F_6, and C_4F_8) [1]. The breakdown voltage (V_s) of N_2, Ar and He gases between the a-C:F film coated Al sphere-sphere electrodes for a gas pressure (p) times gap length (d), pd=0.1-100 Torr¥cm, was studied as well. Then, Vs between the a-C:F film coated electrodes was a several times higher than that between the Al electrodes in the present pd range[2]. In this work, the decomposed species of C_8F_18 in the plasma were identified using emission spectra from the plasma and Quadra-pole mass spectrograph, and the reason why the high deposition rate was obtained was discussed. The physical and chemical properties of a-C:F film was analyzed. [1] C.P.Lungu, et.al., Jpn. J. Appl. Phys. 38 (12B) L1544 - L1546 (1999) [2] C.Biloiu, et.al., Jpn. J. Appl. Phys. 42 (2B) L 201- L203 (2003) Work supported by Grant-in-Aid for Scientific Research (B), JSPS.

Characterization of epoxy carotenoids by fast atom bombardment collision-induced dissociation MS/MS.

PubMed

Maoka, Takashi; Fujiwara, Yasuhiro; Hashimoto, Keiji; Akimoto, Naoshige

2004-02-01

The characterization and structure of epoxy carotenoids possessing 5,6-epoxy, 5,8-epoxy and 3,6-epoxy end groups conjugated to the polyene chain were investigated using high-energy fast atom bombardment collision-induced dissociation MS/MS methods. In addition to [M - 80](+*), a characteristic fragment ion of an epoxy carotenoid, product ions resulting from the cleavage of C-C bonds in the polyene chain from the epoxy end group, such as m/z 181 (b ion) and 121 (c ion), were detected. On the other hand, diagnostic ions of m/z 286 (e-H ion) and 312 (f-H ion) were observed, not in the 5,6-epoxy or 5,8-epoxy carotenoid but in the 3,6-epoxy carotenoid. These fragmentation patterns can be used to distinguish 3,6-epoxy carotenoids from 5,6-epoxy or 5,8-epoxy carotenoids. The structure of an epoxy carotenoid, 3,6-epoxy-5,6-dihydro-7',8'-didehydro-beta,beta-carotene-5,3'-diol (8), isolated from oyster, was characterized using FAB CID-MS/MS by comparing fragmentation patterns with those of related known compounds.

IsoMS: automated processing of LC-MS data generated by a chemical isotope labeling metabolomics platform.

PubMed

Zhou, Ruokun; Tseng, Chiao-Li; Huan, Tao; Li, Liang

2014-05-20

A chemical isotope labeling or isotope coded derivatization (ICD) metabolomics platform uses a chemical derivatization method to introduce a mass tag to all of the metabolites having a common functional group (e.g., amine), followed by LC-MS analysis of the labeled metabolites. To apply this platform to metabolomics studies involving quantitative analysis of different groups of samples, automated data processing is required. Herein, we report a data processing method based on the use of a mass spectral feature unique to the chemical labeling approach, i.e., any differential-isotope-labeled metabolites are detected as peak pairs with a fixed mass difference in a mass spectrum. A software tool, IsoMS, has been developed to process the raw data generated from one or multiple LC-MS runs by peak picking, peak pairing, peak-pair filtering, and peak-pair intensity ratio calculation. The same peak pairs detected from multiple samples are then aligned to produce a CSV file that contains the metabolite information and peak ratios relative to a control (e.g., a pooled sample). This file can be readily exported for further data and statistical analysis, which is illustrated in an example of comparing the metabolomes of human urine samples collected before and after drinking coffee. To demonstrate that this method is reliable for data processing, five (13)C2-/(12)C2-dansyl labeled metabolite standards were analyzed by LC-MS. IsoMS was able to detect these metabolites correctly. In addition, in the analysis of a (13)C2-/(12)C2-dansyl labeled human urine, IsoMS detected 2044 peak pairs, and manual inspection of these peak pairs found 90 false peak pairs, representing a false positive rate of 4.4%. IsoMS for Windows running R is freely available for noncommercial use from www.mycompoundid.org/IsoMS.

A simple, fast and sensitive screening LC-ESI-MS/MS method for antibiotics in fish.

PubMed

Guidi, Letícia Rocha; Santos, Flávio Alves; Ribeiro, Ana Cláudia S R; Fernandes, Christian; Silva, Luiza H M; Gloria, Maria Beatriz A

2017-01-15

The objective of this study was to develop and validate a fast, sensitive and simple liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method for the screening of six classes of antibiotics (aminoglycosides, beta-lactams, macrolides, quinolones, sulfonamides and tetracyclines) in fish. Samples were extracted with trichloroacetic acid. LC separation was achieved on a Zorbax Eclipse XDB C18 column and gradient elution using 0.1% heptafluorobutyric acid in water and acetonitrile as mobile phase. Analysis was carried out in multiple reaction monitoring mode via electrospray interface operated in the positive ionization mode, with sulfaphenazole as internal standard. The method was suitable for routine screening purposes of 40 antibiotics, according to EC Guidelines for the Validation of Screening Methods for Residues of Veterinary Medicines, taking into consideration threshold value, cut-off factor, detection capability, limit of detection, sensitivity and specificity. Real fish samples (n=193) from aquaculture were analyzed and 15% were positive for enrofloxacin (quinolone), one of them at a higher concentration than the level of interest (50µgkg -1 ), suggesting possible contamination or illegal use of that antibiotic. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparison of the docetaxel concentration in human plasma measured with liquid chromatography-tandem mass spectrometry (LC-MS/MS) and a nanoparticle immunoassay and clinical applications of that assay.

PubMed

Geng, Chunmei; Li, Pingli; Chen, Xuwang; Yuan, Guiyan; Guo, Nan; Liu, Huanjun; Zhang, Rui; Guo, Ruichen

2017-05-23

To determine the feasibility of using a nanoparticle immunoassay for clinical therapeutic drug monitoring (TDM) of docetaxel concentrations, a sensitive and simple method of liquid chromatography-tandem mass spectrometry (LC-MS/MS) was established to measure the docetaxel concentration in human plasma and the results of LC-MS/MS and the immunoassay were compared. Docetaxel and paclitaxel (the internal standard, or IS) in human plasma were extracted through protein precipitation, separated on a Diamonsil C18 column (150 mm × 4.6 mm, 5 μm), ionized with positive ions, and detected with LC-MS/MS in multi-reaction monitoring (MRM) mode. Plasma samples from 248 cancer patients were assayed with LC-MS/MS and a nanoparticle immunoassay. Data from the samples were analyzed with the statistical software SPSS and the software MedCalc. Results indicated that the calibration curve of the validated method of LC-MS/MS was linear over the range of 10-2,000 ng/mL, with an lowest limit of quantitation (LLOQ) of 10 ng/mL, and the intra- and inter- day precision and accuracy were both < ± 15%. Comparison of the two methods indicated that results of the LC-MS/MS were closely related to those of the nanoparticle immunoassay, with a correlation coefficient (R) of 0.965 and acceptable 95% confidence intervals (CI) of ‒ 231.7-331.1 ng/mL. Overall, the established method of LC-MC/MS and the nanoparticle immunoassay were both suitable for measurement of the docetaxel concentration in human plasma, and the immunoassay was far more cost-effective and better at clinical TDM of docetaxel in clinical practice.

LC-MS n Analysis of Isomeric Chondroitin Sulfate Oligosaccharides Using a Chemical Derivatization Strategy

NASA Astrophysics Data System (ADS)

Huang, Rongrong; Pomin, Vitor H.; Sharp, Joshua S.

2011-09-01

Improved methods for structural analyses of glycosaminoglycans (GAGs) are required to understand their functional roles in various biological processes. Major challenges in structural characterization of complex GAG oligosaccharides using liquid chromatography-mass spectrometry (LC-MS) include the accurate determination of the patterns of sulfation due to gas-phase losses of the sulfate groups upon collisional activation and inefficient on-line separation of positional sulfation isomers prior to MS/MS analyses. Here, a sequential chemical derivatization procedure including permethylation, desulfation, and acetylation was demonstrated to enable both on-line LC separation of isomeric mixtures of chondroitin sulfate (CS) oligosaccharides and accurate determination of sites of sulfation by MS n . The derivatized oligosaccharides have sulfate groups replaced with acetyl groups, which are sufficiently stable to survive MS n fragmentation and reflect the original sulfation patterns. A standard reversed-phase LC-MS system with a capillary C18 column was used for separation, and MS n experiments using collision-induced dissociation (CID) were performed. Our results indicate that the combination of this derivatization strategy and MS n methodology enables accurate identification of the sulfation isomers of CS hexasaccharides with either saturated or unsaturated nonreducing ends. Moreover, derivatized CS hexasaccharide isomer mixtures become separable by LC-MS method due to different positions of acetyl modifications.

Tandem solid-phase extraction followed by HPLC-ESI/QTOF/MS/MS for rapid screening and structural identification of trace diterpenoids in flowers of Rhododendron molle.

PubMed

Zou, Hong-Yan; Luo, Jun; Xu, De-Ran; Kong, Ling-Yi

2014-01-01

'Naoyanghua', composed of the flowers of Rhododendron molle G. Don, is a traditional Chinese medicine that is widely known for its toxicity. Grayanane-type diterpenoids are the main active ingredients in R. molle, as well as possibly their toxicity: they are, however, difficult to isolate and analyse using common chromatographic methods, due to their small amounts and absence of conjugated groups, such as phenyl and α, β-unsaturated ketone. To establish a highly sensitive, selective and reliable method for the qualitative evaluation of trace diterpenoids in the flowers of R. molle by using tandem solid-phase extraction followed by high-performance liquid chromatography with electrospray ionisation quadrupole-time-of-flight mass spectrometry (HPLC-ESI/QTOF/MS/MS). Tandem solid phase extraction (SPE) was undertaken using a polyamide cartridge and a C18E cartridge in succession to enrich the trace diterpenoids. HPLC-ESI/QTOF/MS/MS was used to determine the fragmentation patterns of diterpenoids and to tentatively characterise their fragmentation pathways. HPLC-ESI/QTOF/MS/MS detected a total of 14 diterpenoids, eight of which were identified by comparison with literature sources and six based on fragmentation analysis. Among the latter six, rhodojaponin VI-3-glucoside was tentatively identified as a new diterpenoid glycoside and rhodojaponin VII, rhodojaponin IV and rhodojaponin I were reported from R. molle for the first time. By qualitative research of diterpenoids in this plant by HPLC-ESI/QTOF/MS/MS, a reliable methodology for the analysis of these active constituents of R. molle was established for the first time. Copyright © 2014 John Wiley & Sons, Ltd.

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

PubMed

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

2015-09-01

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

A novel UPLC-MS/MS method for sensitive quantitation of boldine in plasma, a potential anti-inflammatory agent: application to a pharmacokinetic study in rats.

PubMed

Zeng, Rong-Jie; Li, Yu; Chen, Jian-Zhong; Chou, Gui-Xin; Gao, Yu; Shao, Jing-Wei; Jia, Lee; Wu, Sheng-Dong; Wu, Shui-Sheng

2015-03-01

Boldine is a potential anti-inflammatory agent found in several different plants. Published bioanalytical methods using HPLC with ultraviolet and fluorescent detection lacked enough sensitivity and required tedious sample preparation procedures. Herein, we describe the development of a novel ultra-high performance LC with MS/MS for determination of boldine in plasma. Boldine in plasma was recovered by liquid-liquid extraction using 1 mL of methyl tert-butyl ether. Chromatographic separation was performed on a C18 column at 45°C, with a gradient elution consisting of acetonitrile and water containing 0.1% (v/v) formic acid at a flow rate of 0.3 mL/min. The detection was performed on an electrospray triple-quadrupole MS/MS by positive ion multiple reaction monitoring mode. Good linearity (r(2) > 0.9926) was achieved in a concentration range of 2.555-2555 ng/mL with a lower limit of quantification of 2.555 ng/mL for boldine. The intra- and inter-day precisions of the assay were 1.2-6.0 and 1.8-7.4% relative standard deviation with an accuracy of -6.0-8.0% relative error. This newly developed method was successfully applied to a single low-dose pharmacokinetic study in rats and was demonstrated to be simpler and more sensitive than the published methods, allowing boldine quantification in reduced plasma volume. Copyright © 2014 John Wiley & Sons, Ltd.

Systematic assessment of survey scan and MS2-based abundance strategies for label-free quantitative proteomics using high-resolution MS data.

PubMed

Tu, Chengjian; Li, Jun; Sheng, Quanhu; Zhang, Ming; Qu, Jun

2014-04-04

Survey-scan-based label-free method have shown no compelling benefit over fragment ion (MS2)-based approaches when low-resolution mass spectrometry (MS) was used, the growing prevalence of high-resolution analyzers may have changed the game. This necessitates an updated, comparative investigation of these approaches for data acquired by high-resolution MS. Here, we compared survey scan-based (ion current, IC) and MS2-based abundance features including spectral-count (SpC) and MS2 total-ion-current (MS2-TIC), for quantitative analysis using various high-resolution LC/MS data sets. Key discoveries include: (i) study with seven different biological data sets revealed only IC achieved high reproducibility for lower-abundance proteins; (ii) evaluation with 5-replicate analyses of a yeast sample showed IC provided much higher quantitative precision and lower missing data; (iii) IC, SpC, and MS2-TIC all showed good quantitative linearity (R(2) > 0.99) over a >1000-fold concentration range; (iv) both MS2-TIC and IC showed good linear response to various protein loading amounts but not SpC; (v) quantification using a well-characterized CPTAC data set showed that IC exhibited markedly higher quantitative accuracy, higher sensitivity, and lower false-positives/false-negatives than both SpC and MS2-TIC. Therefore, IC achieved an overall superior performance than the MS2-based strategies in terms of reproducibility, missing data, quantitative dynamic range, quantitative accuracy, and biomarker discovery.

Systematic Assessment of Survey Scan and MS2-Based Abundance Strategies for Label-Free Quantitative Proteomics Using High-Resolution MS Data

PubMed Central

2015-01-01

Survey-scan-based label-free method have shown no compelling benefit over fragment ion (MS2)-based approaches when low-resolution mass spectrometry (MS) was used, the growing prevalence of high-resolution analyzers may have changed the game. This necessitates an updated, comparative investigation of these approaches for data acquired by high-resolution MS. Here, we compared survey scan-based (ion current, IC) and MS2-based abundance features including spectral-count (SpC) and MS2 total-ion-current (MS2-TIC), for quantitative analysis using various high-resolution LC/MS data sets. Key discoveries include: (i) study with seven different biological data sets revealed only IC achieved high reproducibility for lower-abundance proteins; (ii) evaluation with 5-replicate analyses of a yeast sample showed IC provided much higher quantitative precision and lower missing data; (iii) IC, SpC, and MS2-TIC all showed good quantitative linearity (R2 > 0.99) over a >1000-fold concentration range; (iv) both MS2-TIC and IC showed good linear response to various protein loading amounts but not SpC; (v) quantification using a well-characterized CPTAC data set showed that IC exhibited markedly higher quantitative accuracy, higher sensitivity, and lower false-positives/false-negatives than both SpC and MS2-TIC. Therefore, IC achieved an overall superior performance than the MS2-based strategies in terms of reproducibility, missing data, quantitative dynamic range, quantitative accuracy, and biomarker discovery. PMID:24635752

Simultaneous detection of 15 antibiotic growth promoters in bovine muscle, blood and urine by UPLC-MS/MS.

PubMed

Wang, Zhi; Shi, Zongwei; Xi, Cunxian; Wang, Guomin; Cao, Shurui; Zhang, Lei; Tang, Bobin; Mu, Zhaode

2017-12-01

An analytical method was established for the rapid detection of antibiotic growth promoters (AGPs) in bovine muscle, and bovine blood and bovine urine, using ultra high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). After the addition of an aqueous solution of EDTA-Na 2 , the pH of bovine urine samples was directly adjusted to 5.2 by acetic acid-ammonium acetate and purified by HLB solid-phase extraction cartridge; bovine muscle and bovine blood samples processing were extracted with acetonitrile (ACN) and ACNwater (90:10; v/v) without any purification step. The samples were then centrifuged, concentrated and analysed by UPLC-MS/MS on an ACQUITY UPLC® BEH C18 column using gradient elution. The developed method was validated and mean recovery percentages at three spiked levels were 74-119%, 76-115% and 76-119%, respectively, in bovine muscle, bovine blood, and bovine urine. The relative standard deviation (RSD) ranged from 1.0% to 14.7% in spiked bovine muscle, bovine blood and bovine urine. The limits of detection (LOD) of all analytes were in the ranges 0.11-3.82 µg kg -1 , 0.10-2.49 µg kg -1 and 0.06-4.53 µg kg -1 in bovine muscle, bovine blood, and bovine urine, respectively. The method was sensitive, accurate and was applied to monitor real samples. To the best of our knowledge, this is first method available for simultaneous determination of several classes of APGs in bovine muscle, and bovine blood and bovine urine.

Simultaneous quantitation of hydroxychloroquine and its metabolites in mouse blood and tissues using LC-ESI-MS/MS: An application for pharmacokinetic studies.

PubMed

Chhonker, Yashpal S; Sleightholm, Richard L; Li, Jing; Oupický, David; Murry, Daryl J

2018-01-01

Hydroxychloroquine (HCQ) has been shown to disrupt autophagy and sensitize cancer cells to radiation and chemotherapeutic agents. However, the optimal delivery method, dose, and tumor concentrations required for these effects are not known. This is in part due to a lack of sensitive and reproducible analytical methods for HCQ quantitation in small animals. As such, we developed and validated a selective and sensitive liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method for simultaneous quantitation of hydroxychloroquine and its metabolites in mouse blood and tissues. The chromatographic separation and detection of analytes were achieved on a reversed phase Thermo Aquasil C 18 (50×4.6mm, 3μ) column, with gradient elution using 0.2% formic acid and 0.1% formic acid in methanol as mobile phase at a flow rate of 0.5mL/min. Simple protein precipitation was utilized for extraction of analytes from the desired matrix. Analytes were separated and quantitated using MS/MS with an electrospray ionization source in positive multiple reaction monitoring (MRM) mode. The MS/MS response was linear over the concentration range from 1 to 2000ng/mL for all analytes with a correlation coefficient (R 2 ) of 0.998 or better. The within- and between-day precision (relative standard deviation, % RSD) and accuracy were within the acceptable limits per FDA guidelines. The validated method was successfully applied to a preclinical pharmacokinetic mouse study involving low volume blood and tissue samples for hydroxychloroquine and metabolites. Copyright © 2017 Elsevier B.V. All rights reserved.

Quantification of isoflavones in coffee by using solid phase extraction (SPE) and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS).

PubMed

Caprioli, Giovanni; Navarini, Luciano; Cortese, Manuela; Ricciutelli, Massimo; Torregiani, Elisabetta; Vittori, Sauro; Sagratini, Gianni

2016-09-01

A new method for extracting isoflavones from espresso coffee (EC) was coupled with high-performance liquid chromatography-tandem mass spectrometry (MS/MS) for the first time to analyse five isoflavones, which included both a glycosilated form, genistin and the aglycons daidzein, genistein, formononetin and biochanin A. Isoflavones were extracted from coffee samples using methanol, stored in a freezer overnight to precipitate proteic or lipidic residues and purified on SPE C18 cartridges before high-performance liquid chromatography-MS/MS analysis. The recovery percentages obtained by spiking the matrix at concentrations of 10 and 100 µg l(-1) with a standard mixture of isoflavones were in the range of 70 to 104%. The limits of detection and limits of quantification were in the range of 0.015-0.3 µg l(-1) and 0.05-1 µg l(-1) , respectively. Once validated, the method was used to analyze the concentrations of isoflavones in six ECs and ten ground coffee samples. Only formononetin and biochanin A were found, and their respective concentrations ranged from 0.36 to 0.41 µg l(-1) and from 0.58 to 3.26 µg l(-1) in ECs and from 0.36 to 4.27 µg kg(-1) and from 0.71 to 3.95 µg kg(-1) in ground coffees. This method confirms the high specificity and selectivity of MS/MS systems for detecting bioactives in complex matrices such as coffee.Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Validation Study on a Rapid Method for Simultaneous Determination of Pesticide Residues in Vegetables and Fruits by LC-MS/MS.

PubMed

Sato, Tamaki; Miyamoto, Iori; Uemura, Masako; Nakatani, Tadashi; Kakutani, Naoya; Yamano, Tetsuo

2016-01-01

A validation study was carried out on a rapid method for the simultaneous determination of pesticide residues in vegetables and fruits by LC-MS/MS. Preparation of the test solution was performed by a solid-phase extraction technique with QuEChERS (STQ method). Pesticide residues were extracted with acetonitrile using a homogenizer, followed by salting-out and dehydration at the same time. The acetonitrile layer was purified with C18 and PSA mini-columns. The method was assessed for 130 pesticide residues in 14 kinds of vegetables and fruits at the concentration level of 0.01 μg/g according to the method validation guideline of the Ministry of Health, Labour and Welfare of Japan. As a result 75 to 120 pesticide residues were determined satisfactorily in the tested samples. Thus, this method could be useful for a rapid and simultaneous determination of multi-class pesticide residues in various vegetables and fruits.

Development of an LC-MS based enzyme activity assay for MurC: application to evaluation of inhibitors and kinetic analysis.

PubMed

Deng, Gejing; Gu, Rong-Fang; Marmor, Stephen; Fisher, Stewart L; Jahic, Haris; Sanyal, Gautam

2004-06-29

An enzyme activity assay, based on mass spectrometric (MS) detection of specific reaction product following HPLC separation, has been developed to evaluate pharmaceutical hits identified from primary high throughput screening (HTS) against target enzyme Escherichia coli UDP-N-acetyl-muramyl-L-alanine ligase (MurC), an essential enzyme in the bacterial peptidoglycan biosynthetic pathway, and to study the kinetics of the enzyme. A comparative analysis of this new liquid chromatographic-MS (LC-MS) based assay with a conventional spectrophotometric Malachite Green (MG) assay, which detects phosphate produced in the reaction, was performed. The results demonstrated that the LC-MS assay, which determines specific ligase activity of MurC, offers several advantages including a lower background (0.2% versus 26%), higher sensitivity (> or = 10 fold), lower limit of quantitation (LOQ) (0.02 microM versus 1 microM) and wider linear dynamic range (> or = 4 fold) than the MG assay. Good precision for the LC-MS assay was demonstrated by the low intraday and interday coefficient of variation (CV) values (3 and 6%, respectively). The LC-MS assay, free of the artifacts often seen in the Malachite Green assay, offers a valuable secondary assay for hit evaluation in which the false positives from the primary high throughput screening can be eliminated. In addition, the applicability of this assay to the study of enzyme kinetics has also been demonstrated. Copyright 2004 Elsevier B.V.

Simultaneous quantification of the organophosphorus pesticides dimethoate and omethoate in porcine plasma and urine by LC-ESI-MS/MS and flow-injection-ESI-MS/MS.

PubMed

John, Harald; Eddleston, Michael; Clutton, R Eddie; Worek, Franz; Thiermann, Horst

2010-05-15

Dimethoate is an organophosphorus toxicant used in agri- and horticulture as a systemic broad-spectrum insecticide. It also exhibits toxic activity towards mammalian organism provoked by catalytic desulfuration in the liver producing its oxon-derivative omethoate thus inhibiting acetylcholinesterase, initiating cholinergic crisis and ultimately leading to death by respiratory paralysis and cardiovascular collapse. Pharmaco- and toxicokinetic studies in animal models help to broaden basic understanding of medical intervention by antidotes and supportive care. Therefore, we developed and validated a LC-ESI-MS/MS method suitable for the simultaneous, selective, precise (RSD(intra-day) 1-8%; RSD(inter-day) 5-14%), accurate (intra-day: 95-107%; inter-day: 90-115%), and robust quantification of both pesticides from porcine urine and plasma after deproteinization by precipitation and extensive dilution (1:11,250 for plasma and 1:40,000 for urine). Accordingly, lower limits of quantification (0.24-0.49 microg/ml plasma and 0.78-1.56 microg/ml urine) and lower limits of detection (0.12-0.24 microg/ml plasma and 0.39-0.78 microg/ml urine) were equivalent to quite low absolute on-column amounts (1.1-2.1 pg for plasma and 2.0-3.9 pg for urine). The calibration range (0.24-250 microg/ml plasma and 0.78-200 microg/ml urine) was subdivided into two linear ranges (r(2)>or=0.998) each covering nearly two orders of magnitude. The lack of any interfering peak in 6 individual blank specimens from plasma and urine demonstrated the high selectivity of the method. Furthermore, extensive sample dilution causing lowest concentration of potentially interfering matrix ingredients prompted us to develop and validate an additional flow-injection method (FI-ESI-MS/MS). Validation characteristics were as good as for the chromatographic method but sample throughput was enhanced by a factor of 6. Effects on ionization provoked by plasma and urine matrix from 6 individuals as well as in the

Profiling LC-DAD-ESI-TOF MS method for the determination of phenolic metabolites from avocado (Persea americana).

PubMed

Hurtado-Fernández, Elena; Carrasco-Pancorbo, Alegría; Fernández-Gutiérrez, Alberto

2011-03-23

A powerful HPLC-DAD-ESI-TOF MS method was established for the efficient identification of the chemical constituents in the methanolic extracts of avocado (Persea americana). Separation and detection conditions were optimized by using a standard mix containing 39 compounds belonging to phenolic acids and different categories of flavonoids, analytes that could be potentially present in the avocado extracts. Optimum LC separation was achieved on a Zorbax Eclipse Plus C18 analytical column (4.6×150 mm, 1.8 μm particle size) by gradient elution with water+acetic acid (0.5%) and acetonitrile as mobile phases, at a flow rate of 1.6 mL/min. The detection was carried out by ultraviolet-visible absorption and ESI-TOF MS. The developed method was applied to the study of 3 different varieties of avocado, and 17 compounds were unequivocally identified with standards. Moreover, around 25 analytes were tentatively identified by taking into account the accuracy and isotopic information provided by TOF MS.

Pharmacokinetic study of indocyanine Green after intravenous administration by UPLC-MS/MS.

PubMed

Chen, Yu; Chen, Dongxin; Hu, Wenhao; Lin, Guanyang; Huang, Shiyong

2015-01-01

Indocyanine Green is widely used in medical diagnosis and to evaluate liver function and other regional blood flows in clinical application or animal experiments. In this work, a sensitive and selective ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for determination of Indocyanine Green in rat plasma was developed and validated. After addition of rutin as an internal standard (IS), protein precipitation by acetonitrile-methanol (9:1, v/v) was used to prepare samples. Chromatographic separation was achieved on a UPLC BEH C18 column (2.1 mm × 100 mm, 1.7 μm) with 0.1% formic acid and acetonitrile as the mobile phase with gradient elution. An electrospray ionization source was applied and operated in positive ion mode; multiple reactions monitoring (MRM) mode was used for quantification using target fragment ions m/z 753.4→330.2 for Indocyanine Green, and m/z 611.1→303.1 for IS. Calibration plots were linear throughout the range 20-5000 ng/mL for Indocyanine Green in rat plasma. Mean recoveries of Indocyanine Green in rat plasma ranged from 79.5% to 85.4%. RSD of intra-day and inter-day precision were both < 12%. The accuracy of the method was between 95.9% and 113.9%. The method was successfully applied to pharmacokinetic study of Indocyanine Green after intravenous administration.

Pharmacokinetic study of indocyanine Green after intravenous administration by UPLC-MS/MS

PubMed Central

Chen, Yu; Chen, Dongxin; Hu, Wenhao; Lin, Guanyang; Huang, Shiyong

2015-01-01

Indocyanine Green is widely used in medical diagnosis and to evaluate liver function and other regional blood flows in clinical application or animal experiments. In this work, a sensitive and selective ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for determination of Indocyanine Green in rat plasma was developed and validated. After addition of rutin as an internal standard (IS), protein precipitation by acetonitrile-methanol (9:1, v/v) was used to prepare samples. Chromatographic separation was achieved on a UPLC BEH C18 column (2.1 mm × 100 mm, 1.7 μm) with 0.1% formic acid and acetonitrile as the mobile phase with gradient elution. An electrospray ionization source was applied and operated in positive ion mode; multiple reactions monitoring (MRM) mode was used for quantification using target fragment ions m/z 753.4→330.2 for Indocyanine Green, and m/z 611.1→303.1 for IS. Calibration plots were linear throughout the range 20-5000 ng/mL for Indocyanine Green in rat plasma. Mean recoveries of Indocyanine Green in rat plasma ranged from 79.5% to 85.4%. RSD of intra-day and inter-day precision were both < 12%. The accuracy of the method was between 95.9% and 113.9%. The method was successfully applied to pharmacokinetic study of Indocyanine Green after intravenous administration. PMID:26629038

Analysis of poly-beta-hydroxybutyrate in environmental samples by GC-MS/MS.

PubMed

Elhottová, D; Tríska, J; Petersen, S O; Santrůcková, H

2000-05-01

Application of gas chromatography-mass spectrometry (GC-MS) can significantly improve trace analyses of compounds in complex matrices from natural environments compared to gas chromatography only. A GC-MS/MS technique for determination of poly-beta-hydroxybutyrate (PHB), a bacterial storage compound, has been developed and used for analysis of two soils stored for up to 319 d, fresh samples of sewage sludge, as well as a pure culture of Bacillus megaterium. Specific derivatization of beta-hydroxybutyrate (3-OH C4:0) PHB monomer units by N-tert-butyl-dimethylsilyl-N-methyltrifluoracetamide (MTBSTFA) improved chromatographic and mass spectrometric properties of the analyte. The diagnostic fragmentation scheme of the derivates tert-butyldimethylsilyl ester and ether of beta-hydroxybutyric acid (MTBSTFA-HB) essential for the PHB identification was shown. The ion trap MS was used, therefore the scan gave the best sensitivity and with MS/MS the noise decreased, so the S/N was better and also with second fragmentation the amount of ions increased compared to SIM. The detection limit for MTBSTFA-HB by GC-MS/MS was about 10(-13) g microL(-1) of injected volume, while by GC (FID) and GC-MS (scan) it was around 10(-10) g microL(-1) of injected volume. Sensitivity of GC-MS/MS measurements of PHB in arable soil and activated sludge samples was down to 10 pg of PHB g(-1) dry matter. Comparison of MTBSTFA-HB detection in natural soil sample by GC (FID), GC-MS (scan) and by GC-MS/MS demonstrated potentials and limitations of the individual measurement techniques.

Rapid determination of underivatized pyroglutamic acid, glutamic acid, glutamine and other relevant amino acids in fermentation media by LC-MS-MS.

PubMed

Qu, Jun; Chen, Wei; Luo, Guoan; Wang, Yiming; Xiao, Shengyuan; Ling, Zhihua; Chen, Guoqiang

2002-01-01

Determination of amino acids in a complex matrix without derivatization is advantageous, however, difficulties are found in both the detection and the separation of those compounds. In this study, a rapid and reliable LC-MS-MS method for the quantitation of underivatized amino acids in exocellular media was established. Injections were made directly after centrifugation of the samples, without further preparation. The separation of seven underivatized amino acids was achieved on a reversed-phase C18 column with pentadecafluorooctanoic acid as a volatile ion-pair reagent, and the specific detection of most amino acids was achieved by MS-MS of the specific transitions [M + H]+-->[M + H - 46]+. The calibration curves of all analytes were linear over the range of 1.0-1000 microg ml(-1) and the detection limits ranged from 0.1 to 5 ng ml(-1), with an injection volume of 20 microl. The inter-day and intra-day precisions ranged from 2.6 to 5.7% and 4.8 to 8.2%, respectively; the mean recoveries of the seven analytes were 81-104%, 91-107% and 93-101% respectively at the spiked level of 10, 40 and 200 microg ml(-1). A large number of fermentation samples were analysed using this method. The technique is simple, rapid, selective and sensitive, and shows potential for the high-throughput quantitation of amino acids from other biological matrices.

Development of high-throughput multi-residue method for non-steroidal anti-inflammatory drugs monitoring in swine muscle by LC-MS/MS.

PubMed

Castilhos, Tamara S; Barreto, Fabiano; Meneghini, Leonardo; Bergold, Ana Maria

2016-07-01

A reliable and simple method for the detection and quantification of residues of 14 non-steroidal anti-inflammatory drugs and a metamizole metabolite in swine muscle was developed using liquid chromatography-electrospray ionisation-tandem mass spectrometry (LC-ESI-MS/MS). The samples were extracted with acetonitrile (ACN) in solid-liquid extraction followed by a low-temperature partitioning (LLE-LTP) process at -20 ± 2°C. After evaporation to dryness, the residue was reconstituted with hexane and a mixture of water:acetonitrile (1:1). LC separation was achieved on a reversed-phase (RP18) column with gradient elution using water (phase A) and ACN (phase B) both containing 1 mmol l(-)(1) ammonium acetate (NH4COO) with 0.025% acetic acid. Analysis was carried out on a triple-quadrupole tandem mass spectrometer (LC-MS/MS) in multiple reaction monitoring mode using an electrospray interface in negative and positive mode in a single run. Method validation was performed according to the criteria of Commission Decision No. 2002/657/EC. The matrix effect and linearity were evaluated. Decision limit (CCα), detection capability (CCβ), accuracy and repeatability of the method are also reported. The proposed method proved to be simple, easy and adequate for high-throughput analysis and was applied to routine analysis by the Brazilian Ministry of Agriculture, Livestock and Food Supply.

LC-MS/MS method for simultaneous determination of thalidomide, lenalidomide, cyclophosphamide, bortezomib, dexamethasone and adriamycin in serum of multiple myeloma patients.

PubMed

Shu, Chang; Zeng, Tianmei; Gao, Shouhong; Xia, Tianyi; Huang, Lifeng; Zhang, Feng; Chen, Wansheng

2016-08-15

Multiple myeloma (MM), a malignant neoplastic serum-cell disorder, has been a serious threat to human health. The determination of 6 commonly used drug concentrations, including thalidomide, lenalidomide, cyclophosphamide, bortezomib, dexamethasone and adriamycin, in MM patients was of great clinical interest. Herein, we reported a method for the rapid and simultaneous measurement of the above therapeutics by liquid chromatography-tandem mass spectroscopy (LC-MS/MS) method with solid phase extraction. Analysis was performed on a Waters XBridge(®) BEH C18 column (2.5μm, 2.1 mm×50mm), with formic acid aqueous solution and acetonitrile as the mobile phase at flow rate 0.3mL/min. All analytes showed good correlation coefficients (r>0.996), and LLOQ of thalidomide, lenalidomide, cyclophosphamide, bortezomib, dexamethasone and adriamycin were 4, 2, 2, 2, 2 and 2ng/mL, respectively. The inter- and intra-day precisions and stability were expressed as variation coefficients within 15% and relative error less than 15%. Dilution effect, carryover and incurred sample reanalysis were investigated according to the 2015 edition Chinese Pharmacopoeia guidelines, as US FDA (2013, revision 1) required. The LC-MS/MS based assay described in this article may improve future clinical studies evaluating common therapeutics for MM treatment. Copyright © 2016 Elsevier B.V. All rights reserved.

Simultaneous Detection of Human C-Terminal p53 Isoforms by Single Template Molecularly Imprinted Polymers (MIPs) Coupled with Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)-Based Targeted Proteomics.

PubMed

Jiang, Wenting; Liu, Liang; Chen, Yun

2018-03-06

Abnormal expression of C-terminal p53 isoforms α, β, and γ can cause the development of cancers including breast cancer. To date, much evidence has demonstrated that these isoforms can differentially regulate target genes and modulate their expression. Thus, quantification of individual isoforms may help to link clinical outcome to p53 status and to improve cancer patient treatment. However, there are few studies on accurate determination of p53 isoforms, probably due to sequence homology of these isoforms and also their low abundance. In this study, a targeted proteomics assay combining molecularly imprinted polymers (MIPs) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for simultaneous quantification of C-terminal p53 isoforms. Isoform-specific surrogate peptides (i.e., KPLDGEYFTLQIR (peptide-α) for isoform α, KPLDGEYFTLQDQTSFQK (peptide-β) for isoform β, and KPLDGEYFTLQMLLDLR (peptide-γ) for isoform γ) were first selected and used in both MIPs enrichment and mass spectrometric detection. The common sequence KPLDGEYFTLQ of these three surrogate peptides was used as single template in MIPs. In addition to optimization of imprinting conditions and characterization of the prepared MIPs, binding affinity and cross-reactivity of the MIPs for each surrogate peptide were also evaluated. As a result, a LOQ of 5 nM was achieved, which was >15-fold more sensitive than that without MIPs. Finally, the assay was validated and applied to simultaneous quantitative analysis of C-terminal p53 isoforms α, β, and γ in several human breast cell lines (i.e., MCF-10A normal cells, MCF-7 and MDA-MB-231 cancer cells, and drug-resistant MCF-7/ADR cancer cells). This study is among the first to employ single template MIPs and cross-reactivity phenomenon to select isoform-specific surrogate peptides and enable simultaneous quantification of protein isoforms in LC-MS/MS-based targeted proteomics.

Advancing a High Throughput Glycotope-centric Glycomics Workflow Based on nanoLC-MS2-product Dependent-MS3 Analysis of Permethylated Glycans.

PubMed

Hsiao, Cheng-Te; Wang, Po-Wei; Chang, Hua-Chien; Chen, Yen-Ying; Wang, Shui-Hua; Chern, Yijuang; Khoo, Kay-Hooi

2017-12-01

The intrinsic nature of glycosylation, namely nontemplate encoded, stepwise elongation and termination with a diverse range of isomeric glyco-epitopes (glycotopes), translates into ambiguity in most cases of mass spectrometry (MS)-based glycomic mapping. It is arguable that whether one needs to delineate every single glycomic entity, which may be counterproductive. Instead, one should focus on identifying as many structural features as possible that would collectively define the glycomic characteristics of a cell or tissue, and how these may change in response to self-programmed development, immuno-activation, and malignant transformation. We have been pursuing this line of analytical strategy that homes in on identifying the terminal sulfo-, sialyl, and/or fucosylated glycotopes by comprehensive nanoLC-MS 2 -product dependent MS 3 analysis of permethylated glycans, in conjunction with development of a data mining computational tool, GlyPick, to enable an automated, high throughput, semi-quantitative glycotope-centric glycomic mapping amenable to even nonexperts. We demonstrate in this work that diagnostic MS 2 ions can be relied on to inform the presence of specific glycotopes, whereas their possible isomeric identities can be resolved at MS 3 level. Both MS 2 and associated MS 3 data can be acquired exhaustively and processed automatically by GlyPick. The high acquisition speed, resolution, and mass accuracy afforded by top-notch Orbitrap Fusion MS system now allow a sensible spectral count and/or summed ion intensity-based glycome-wide glycotope quantification. We report here the technical aspects, reproducibility and optimization of such an analytical approach that uses the same acidic reverse phase C18 nanoLC conditions fully compatible with proteomic analysis to allow rapid hassle-free switching. We further show how this workflow is particularly effective when applied to larger, multiply sialylated and fucosylated N-glycans derived from mouse brain. The

PCI-GC-MS-MS approach for identification of non-amino organic acid and amino acid profiles.

PubMed

Luan, Hemi; Yang, Lin; Ji, Fenfen; Cai, Zongwei

2017-03-15

Alkyl chloroformate have been wildly used for the fast derivatization of metabolites with amino and/or carboxyl groups, coupling of powerful separation and detection systems, such as GC-MS, which allows the comprehensive analysis of non-amino organic acids and amino acids. The reagents involving n-alkyl chloroformate and n-alcohol are generally employed for providing symmetric labeling terminal alkyl chain with the same length. Here, we developed an asymmetric labeling strategy and positive chemical ionization gas chromatography-tandem mass spectrometry (PCI-GC-MS-MS) approach for determination of non-amino organic acids and amino acids, as well as the short chain fatty acids. Carboxylic and amino groups could be selectively labelled by propyl and ethyl groups, respectively. The specific neutral loss of C 3 H 8 O (60Da), C 3 H 5 O 2 (74Da) and C 4 H 8 O 2 (88Da) were useful in the selective identification for qualitative analysis of organic acids and amino acid derivatives. PCI-GC-MS-MS using multiple reaction monitoring (MRM) was applied for semi-quantification of typical non-amino organic acids and amino acids. This method exhibited a wide range of linear range, good regression coefficient (R 2 ) and repeatability. The relative standard deviation (RSD) of targeted metabolites showed excellent intra- and inter-day precision (<5%). Our method provided a qualitative and semi-quantitative PCI-GC-MS-MS, coupled with alkyl chloroformate derivatization. Copyright © 2016 Elsevier B.V. All rights reserved.

[Simultaneous determination of 4 diterpenoids in Rabdosia japonica var.glaucocalyx by HPLC-ESI-MS/MS and cluster analysis].

PubMed

Tian, Ting-Ting; Ma, Ying-Hua; Xie, Wei-Wei; Jin, Yi-Ran; Xu, Hui-Jun; Zhang, Lan-Tong; Du, Ying-Feng

2016-01-01

A quick HPLC-ESI-MS/MS method was established for simultaneous determination of four major diterpenoids in Rabdosia japonica var.glaucocalyx, including glaucocalyxin A, oridonin, hebeirubesensin and enmenol. Analysis was performed on an Agilent ZORBAX SB-C18(4.6 mm×250 mm, 5 μm ) column eluted in a gradient program with methanol and water. The flow rate was 0.8 mL•min⁻¹. Multiple reaction monitoring (MRM) scanning mode was performed in negative ion switching mode to apply for the quantitative determination. The calibration curves for the above four compounds were linear in corresponding injection amount. The average recoveries of the compounds ranged from 92.40% to 105.9%, with RSDs of 1.7%-6.5%. The method is simple, rapid, accurate with good repeatability, which can provide a reference for overcalling evaluation the quality of R. japonica var.glaucocalyx. The result of cluster analysis- showed that the quality of R. japonica glaucocalyx var. greatly varied between areas and parts. Copyright© by the Chinese Pharmaceutical Association.

Imaging of adrenal incidentalomas with PET using (11)C-metomidate and (18)F-FDG.

PubMed

Minn, Heikki; Salonen, Anna; Friberg, Johan; Roivainen, Anne; Viljanen, Tapio; Långsjö, Jaakko; Salmi, Jorma; Välimäki, Matti; Någren, Kjell; Nuutila, Pirjo

2004-06-01

Our aim was to evaluate the use of PET with (11)C-metomidate and (18)F-FDG for the diagnosis of adrenal incidentalomas. Twenty-one patients underwent hormonal screening before dynamic imaging of the upper abdomen with (11)C-metomidate, and for 19 of these 21 patients, static (18)F-FDG imaging followed. Uptake of (11)C-metomidate and (18)F-FDG in incidentalomas was quantified and correlated with the hormonal work-up and the mass size on CT (median, 2.5 cm; range, 2-10 cm). The final diagnoses were hormonally active adenoma (n = 7), nonsecretory adenoma (n = 5), adrenocortical carcinoma (n = 1), pheochromocytoma (n = 2), benign noncortical tumor (n = 2), normal adrenal (n = 1), and malignant noncortical tumor (n = 3). Diagnosis was established at surgery (n = 9), percutaneous biopsy (n = 4), or follow-up (n = 8). The highest uptake of (11)C-metomidate, expressed as standardized uptake value (SUV), was found in adrenocortical carcinoma (SUV = 28.0), followed by active adenomas (median SUV = 12.7), nonsecretory adenomas (median SUV = 12.2), and noncortical tumors (median SUV = 5.7). Patients with adenomas had significantly higher tumor-to-normal-adrenal (11)C-metomidate SUV ratios than did patients with noncortical tumors. (18)F-FDG detected 2 of 3 noncortical malignancies but failed to detect adrenal metastases from renal cell carcinoma. All inactive and most active adenomas were difficult to detect with (18)F-FDG against background activity, whereas both pheochromocytomas and adrenocortical carcinoma showed slightly increased uptake of (18)F-FDG. There was no correlation between uptake of (11)C-metomidate or (18)F-FDG and mass size. (11)C-Metomidate is a promising PET tracer to identify incidentalomas of adrenocortical origin. (18)F-FDG should be reserved for patients with a moderate to high likelihood of neoplastic disease.

Determination of astaxanthin and astaxanthin esters in the microalgae Haematococcus pluvialis by LC-(APCI)MS and characterization of predominant carotenoid isomers by NMR spectroscopy.

PubMed

Holtin, Karsten; Kuehnle, Maximilian; Rehbein, Jens; Schuler, Paul; Nicholson, Graeme; Albert, Klaus

2009-11-01

The oily product ZANTHIN consists of natural astaxanthin, which is manufactured from the microalgae Haematococcus pluvialis by supercritical CO(2) extraction. An HPLC method was developed to separate all of the components of the complex astaxanthin extract using a C(30) column. The separation resulted in different isomers of astaxanthin accompanied by two other carotenoids. The main component consisted of astaxanthin singly esterified with several different fatty acids. C18:3, C18:2, C18:1 and C16:0 were identified as the most commonly occurring fatty acids. Doubly esterified astaxanthin was also found, although in lower concentrations compared to singly esterified astaxanthin. After performing a detailed fatty acid analysis by GC-MS, the peaks from the extract were assigned via HPLC-MS. A trans to cis transmutation of the all-trans compound was performed by thermal treatment in order to obtain an enrichment of cis isomers as the basis for unambiguous identification via NMR experiments. The all-trans as well as the 9- and 13-cis isomers of astaxanthin were characterized in detail by UV/Vis, (1)H, and (1)H,(1)H COSY NMR spectroscopy.

Theoretical estimates of equilibrium 13C-18O clumping in carbonates and organic acids

NASA Astrophysics Data System (ADS)

Schauble, E. A.; Eiler, J. M.

2004-12-01

The development of techniques for measuring small gas-phase molecules containing more than one rare stable isotope (e.g., 13C18O16O) at natural, ppm-level abundances1,2 has made it possible to track sources and sinks of atmospheric gases from a new perspective. Similar measurements of 13C-18O clumping in ancient samples could improve our understanding of ancient climates, if the abundances of `clumped' rare stable isotopes in materials that retain isotopic signatures over geologic time can be measured with sufficient precision. This theoretical study estimates the abundances of such 13C-18O `clumps' in carbonates and organic acids and discusses their potential applications. Accompanying abstracts by Eiler et al. and Ghosh et al. will present the analytical methods and some initial data for carbonate minerals to examine the applicability of our theoretical models. Equilibrium isotopic speciations in carbonate minerals and organic acids are calculated from the reduced partition function ratios of isotopically substituted crystals and molecules. Vibrational frequencies used as input for these calculations come from ab initio force fields, determined using density functional theory. Our calculations indicate that carbonate minerals, including calcite, dolomite, and aragonite, when equilibrated at earth-surface temperatures, will have a slight overabundance of CO32- groups containing both 13C and 18O (i.e., 13C18O16O22-) relative to what would be expected if carbon and oxygen isotopes were distributed randomly in the crystal lattice. Calcite and dolomite crystals are predicted to have 0.4‰ excesses of 13C18O16O22- at 298 K; in aragonite the excess will be about 0.05‰ larger. The excesses are smaller for crystals formed or equilibrated at higher temperatures, decreasing by 0.003\\permil/oC at room temperature and essentially disappearing at temperatures of 1000 K or higher. Similarly, there is an excess of both 13C18O16OH and 13C16O18OH groups in organic acids like

Sequencing the oligosaccharide pool in the low molecular weight heparin dalteparin with offline HPLC and ESI-MS/MS.

PubMed

Wang, Zhangjie; Zhang, Tianji; Xie, Shaoshuai; Liu, Xinyue; Li, Hongmei; Linhardt, Robert J; Chi, Lianli

2018-03-01

Low molecular weight heparins (LMWHs) are widely used anticoagulant drugs. The composition and sequence of LMWH oligosaccharides determine their safety and efficacy. The short oligosaccharide pool in LMWHs undergoes more depolymerization reactions than the longer chains and is the most sensitive indicator of the manufacturing process. Electrospray ionization tandem mass spectrometry (ESI-MS/MS) has been demonstrated as a powerful tool to sequence synthetic heparin oligosaccharide but never been applied to analyze complicated mixture like LMWHs. We established an offline strong anion exchange (SAX)-high performance liquid chromatography (HPLC) and ESI-MS/MS approach to sequence the short oligosaccharides of dalteparin sodium. With the help of in-house developed MS/MS interpretation software, the sequences of 18 representative species ranging from tetrasaccharide to octasaccharide were obtained. Interestingly, we found a novel 2,3-disulfated hexauronic acid structure and reconfirmed it by complementary heparinase digestion and LC-MS/MS analysis. This approach provides straightforward and in-depth insight to the structure of LMWHs and the reaction mechanism of heparin depolymerization. Copyright © 2017 Elsevier Ltd. All rights reserved.

Stable-isotope GC-MS/MS determination of aminoethylcysteine ketimine decarboxylated dimer in biological samples

PubMed Central

Tsikas, Dimitrios; Evans, Christopher E.; Denton, Travis T.; Mitschke, Anja; Gutzki, Frank-Mathias; Pinto, John T.; Khomenko, Tetyana; Szabo, Sandor; Cooper, Arthur J.L.

2012-01-01

Aminoethylcysteine ketimine decarboxylated dimer [AECK-DD; systematic name: 1,2–3,4–5,6–7,8-octahydro-1,8a-diaza-4,6-dithiafluoren-9(8aH)-one] is a previously described metabolite of cysteamine that has been reported to be present in mammalian brain, urine, plasma, cells in culture and vegetables, and to possess potent anti-oxidative properties. Here, we describe a stable-isotope GC-MS/MS method for specific and sensitive determination of AECK-DD in biological samples. 13C2-AECK-DD was synthesized and used as the internal standard. Derivatization was carried out by N-pentafluorobenzylation with pentafluorobenzyl bromide in acetonitrile. Quantification was performed by selected-reaction monitoring of the mass transitions m/z 328 to m/z 268 for AECK-DD and m/z 330 to m/z 270 for 13C2-AECK-DD in the electron-capture negative-ion chemical ionization mode. The procedure was systematically validated for human plasma and urine samples. AECK-DD was not detectable in human plasma above ~ 4 nM, but was present in urine samples of healthy humans at a maximal concentration of 46 nM. AECK-DD was detectable in rat brain at very low levels of about 8 pmol/g wet weight. Higher levels of AECK-DD were detected in mouse brain (~1 nmol/g wet weight). Among nine dietary vegetables evaluated, only shallots were found to contain trace amounts of AECK-DD (~ 6.8 pmol/g fresh tissue). PMID:22858756

Removal of sudan dyes from water with C18-functional ultrafine magnetic silica nanoparticles.

PubMed

Jiang, Chunzhu; Sun, Ying; Yu, Xi; Zhang, Lei; Sun, Xiumin; Gao, Yan; Zhang, Hanqi; Song, Daqian

2012-01-30

In this study, the new C(18)-functionalized ultrafine magnetic silica nanoparticles (C(18)-UMS NPs) were successfully synthesized and applied for extraction of sudan dyes in water samples based on the magnetic solid-phase extraction (MSPE). The extraction and concentration were carried out in one step by blending C(18)-UMS NPs and water samples. The sudan dyes adsorbed C(18)-UMS NPs were isolated from the matrix easily with an external magnetic field. After desorption the quantitation of sudan dyes was done by ultra fast liquid chromatography (UFLC). Satisfactory extraction recovery can be obtained with only 50 mg C(18)-UMS NPs. The effects of experimental parameters, including the amount of the nanoparticles, extraction time, pH value, desorption solvent, volume of desorption solvent and desorption time were investigated. The limits of detection for sudan I, II, III and IV were 0.066, 0.070, 0.12 and 0.12 ng mL(-1), respectively. Recoveries obtained by analyzing the six spiked water samples were between 68% and 103%. Copyright © 2011 Elsevier B.V. All rights reserved.

Multiple C-terminal tail Ca2+/CaMs regulate CaV1.2 function but do not mediate channel dimerization

PubMed Central

Kim, Eun Young; Rumpf, Christine H; Van Petegem, Filip; Arant, Ryan J; Findeisen, Felix; Cooley, Elizabeth S; Isacoff, Ehud Y; Minor, Daniel L

2010-01-01

Interactions between voltage-gated calcium channels (CaVs) and calmodulin (CaM) modulate CaV function. In this study, we report the structure of a Ca2+/CaM CaV1.2 C-terminal tail complex that contains two PreIQ helices bridged by two Ca2+/CaMs and two Ca2+/CaM–IQ domain complexes. Sedimentation equilibrium experiments establish that the complex has a 2:1 Ca2+/CaM:C-terminal tail stoichiometry and does not form higher order assemblies. Moreover, subunit-counting experiments demonstrate that in live cell membranes CaV1.2s are monomers. Thus, contrary to previous proposals, the crystallographic dimer lacks physiological relevance. Isothermal titration calorimetry and biochemical experiments show that the two Ca2+/CaMs in the complex have different properties. Ca2+/CaM bound to the PreIQ C-region is labile, whereas Ca2+/CaM bound to the IQ domain is not. Furthermore, neither of lobes of apo-CaM interacts strongly with the PreIQ domain. Electrophysiological studies indicate that the PreIQ C-region has a role in calcium-dependent facilitation. Together, the data show that two Ca2+/CaMs can bind the CaV1.2 tail simultaneously and indicate a functional role for Ca2+/CaM at the C-region site. PMID:20953164

Multiple C-terminal tail Ca(2+)/CaMs regulate Ca(V)1.2 function but do not mediate channel dimerization.

PubMed

Kim, Eun Young; Rumpf, Christine H; Van Petegem, Filip; Arant, Ryan J; Findeisen, Felix; Cooley, Elizabeth S; Isacoff, Ehud Y; Minor, Daniel L

2010-12-01

Interactions between voltage-gated calcium channels (Ca(V)s) and calmodulin (CaM) modulate Ca(V) function. In this study, we report the structure of a Ca(2+)/CaM Ca(V)1.2 C-terminal tail complex that contains two PreIQ helices bridged by two Ca(2+)/CaMs and two Ca(2+)/CaM-IQ domain complexes. Sedimentation equilibrium experiments establish that the complex has a 2:1 Ca(2+)/CaM:C-terminal tail stoichiometry and does not form higher order assemblies. Moreover, subunit-counting experiments demonstrate that in live cell membranes Ca(V)1.2s are monomers. Thus, contrary to previous proposals, the crystallographic dimer lacks physiological relevance. Isothermal titration calorimetry and biochemical experiments show that the two Ca(2+)/CaMs in the complex have different properties. Ca(2+)/CaM bound to the PreIQ C-region is labile, whereas Ca(2+)/CaM bound to the IQ domain is not. Furthermore, neither of lobes of apo-CaM interacts strongly with the PreIQ domain. Electrophysiological studies indicate that the PreIQ C-region has a role in calcium-dependent facilitation. Together, the data show that two Ca(2+)/CaMs can bind the Ca(V)1.2 tail simultaneously and indicate a functional role for Ca(2+)/CaM at the C-region site.

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

PubMed

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

2009-10-01

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

CE-microreactor-CE-MS/MS for protein analysis

PubMed Central

Schoenherr, Regine M.; Ye, Mingliang; Vannatta, Michael

2008-01-01

We present a proof-of-principle for a fully automated bottom-up approach to protein characterization. Proteins are first separated by capillary electrophoresis. A pepsin microreactor is incorporated into the distal end of this capillary. Peptides formed in the reactor are transferred to a second capillary, where they are separated by capillary electrophoresis and characterized by mass spectrometry. While peptides generated from one digestion are being separated in the second capillary, the next protein fraction undergoes digestion in the microreactor. The migration time in the first dimension capillary is characteristic of the protein while migration time in the second dimension is characteristic of the peptide. Spot capacity for the two-dimensional separation is 590. A MS/MS analysis of a mixture of cytochrome C and myoglobin generated Mascot MOWSE scores of 107 for cytochrome C and 58 for myoglobin. The sequence coverages were 48% and 22%, respectively. PMID:17295444

A Simple and Sensitive LC-MS/MS Method for the Determination of Free 8-Hydroxy-2'-Deoxyguanosine in Human Urine

NASA Technical Reports Server (NTRS)

Wang, Zuwei; Smith, Scott M.

2016-01-01

Urinary free 8-hydroxy-2'-deoxyguanosine (8OHdG), an oxidized product of DNA, and is frequently chosen as a biomarker of oxidative stress in humans, including studies of oxidative DNA damage during space flight. It is challenging to accurately and efficiently quantify urinary free 8OHdG in large scale human studies. LC-MS/MS is emerging as a preferable analytical technique owing its high sensitivity, selectivity and efficiency, compared to some traditional methods such as ELISA and HPLC. A simple and sensitive LC-MS/MS method has been developed for the determination of free 8OHdG in human urine. Sample preparation was done by solid phase extraction with a Waters Oasis HLB 96 well plate. A Waters Alliance 2795 HT Separation Module combined with a Quattro Micro tandem mass spectrometer was used as the LC-MS/MS system. The runtime of one injection can be less than 5 minutes using a reversed phase C18 column and an isocratic flow of methanol/water. ESI positive ions were quantified in the multiple reaction modes (MRM) using m/z 284 yields 168 for 8OHdG and m/z 289 yields173 for stable isotope labeled internal standard [(15)N5] 8OHdG. With this method for 8OHdG, a lower limit of quantitation of 1.0 nM (0.28 ng/mL) has been achieved using 100 microliter urine sample. The analytical range is between 1.0 and 100 nM with a correlation coefficient greater than or equal to 0.99. Good reproducibility can be obtained with intra-assay and inter-assay CVs less than or equal to 10% for 8OHdG spiked urine QC samples. This method can be used in high-throughput routine analysis of free 8OHdG in human urine.

Metabolites profiling of Pulsatilla saponin D in rat by ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS/MS).

PubMed

Ouyang, Hui; Zhou, Maofu; Guo, Yicheng; He, Mingzhen; Huang, Hesong; Ye, Xide; Feng, Yulin; Zhou, Xin; Yang, Shilin

2014-07-01

Pulsatilla saponin D, an antitumor substance isolated from traditional Chinese herbal medicine Pulsatilla chinensis (Bge.) Regel, is a promising candidate for new drug development. The purpose of the present study is to establish a simple and practical strategy for the metabolite profiling of Pulsatilla saponin D in vivo. A total of 18 metabolites were identified in rat plasma, urine and feces samples based on MS and MS/MS data by using ESI-Q-TOF-MS/MS, and eight of them (M11-M18) were reported for the first time. The results indicated that deglycosylation, dehydrogenation, hydroxylation and sulfation were the major metabolic transformations of Pulsatilla saponin D in vivo. This study has improved our understanding of the metabolic fate of Pulsatilla saponin D in vivo, and the information gained from the current study is relevant to the pharmacological activity of Pulsatilla saponin D. Copyright © 2014 Elsevier B.V. All rights reserved.

Structure Annotation and Quantification of Wheat Seed Oxidized Lipids by High-Resolution LC-MS/MS.

PubMed

Riewe, David; Wiebach, Janine; Altmann, Thomas

2017-10-01

Lipid oxidation is a process ubiquitous in life, but the direct and comprehensive analysis of oxidized lipids has been limited by available analytical methods. We applied high-resolution liquid chromatography-mass spectrometry (LC-MS) and tandem mass spectrometry (MS/MS) to quantify oxidized lipids (glycerides, fatty acids, phospholipids, lysophospholipids, and galactolipids) and implemented a platform-independent high-throughput-amenable analysis pipeline for the high-confidence annotation and acyl composition analysis of oxidized lipids. Lipid contents of 90 different naturally aged wheat ( Triticum aestivum ) seed stocks were quantified in an untargeted high-resolution LC-MS experiment, resulting in 18,556 quantitative mass-to-charge ratio features. In a posthoc liquid chromatography-tandem mass spectrometry experiment, high-resolution MS/MS spectra (5 mD accuracy) were recorded for 8,957 out of 12,080 putatively monoisotopic features of the LC-MS data set. A total of 353 nonoxidized and 559 oxidized lipids with up to four additional oxygen atoms were annotated based on the accurate mass recordings (1.5 ppm tolerance) of the LC-MS data set and filtering procedures. MS/MS spectra available for 828 of these annotations were analyzed by translating experimentally known fragmentation rules of lipids into the fragmentation of oxidized lipids. This led to the identification of 259 nonoxidized and 365 oxidized lipids by both accurate mass and MS/MS spectra and to the determination of acyl compositions for 221 nonoxidized and 295 oxidized lipids. Analysis of 15-year aged wheat seeds revealed increased lipid oxidation and hydrolysis in seeds stored in ambient versus cold conditions. © 2017 The author(s). All Rights Reserved.

Methods for the analysis of organophosphorus flame retardants-Comparison of GC-EI-MS, GC-NCI-MS, LC-ESI-MS/MS, and LC-APCI-MS/MS.

PubMed

Tokumura, Masahiro; Miyake, Yuichi; Wang, Qi; Nakayama, Hayato; Amagai, Takashi; Ogo, Sayaka; Kume, Kazunari; Kobayashi, Takeshi; Takasu, Shinji; Ogawa, Kumiko

2018-04-16

Organophosphorus flame retardants (PFRs) are extensively used as alternatives to banned polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD). In this study, we analyzed 14 PFRs by means of four mass-spectrometry-based methods: gas chromatography combined with electron-impact mass spectrometry (GC-EI-MS) or negative-chemical-ionization mass spectrometry (GC-NCI-MS) and liquid chromatography combined with tandem mass spectrometry using electrospray ionization (LC-ESI-MS/MS) or atmospheric pressure chemical ionization (LC-APCI-MS/MS). The limits of quantification (LOQs) for LC-ESI-MS/MS and LC-APCI-MS/MS (0.81-970 pg) were 1-2 orders of magnitude lower than the LOQs for GC-EI-MS and GC-NCI-MS (2.3-3900 pg). LC-APCI-MS/MS showed the lowest LOQs (mean = 41 pg; median = 3.4 pg) for all but two of the PFRs targeted in this study. For LC-APCI-MS/MS, the lowest LOQ was observed for tributyl phosphate (TBP) (0.81 pg), and the highest was observed for tris(butoxyethyl) phosphate (TBOEP) (36 pg). The results of this study indicate that LC-APCI-MS/MS is the optimum analytical method for the target PFRs, at least in terms of LOQ.

IsoCor: correcting MS data in isotope labeling experiments.

PubMed

Millard, Pierre; Letisse, Fabien; Sokol, Serguei; Portais, Jean-Charles

2012-05-01

Mass spectrometry (MS) is widely used for isotopic labeling studies of metabolism and other biological processes. Quantitative applications-e.g. metabolic flux analysis-require tools to correct the raw MS data for the contribution of all naturally abundant isotopes. IsoCor is a software that allows such correction to be applied to any chemical species. Hence it can be used to exploit any isotopic tracer, from well-known ((13)C, (15)N, (18)O, etc) to unusual ((57)Fe, (77)Se, etc) isotopes. It also provides new features-e.g. correction for the isotopic purity of the tracer-to improve the accuracy of quantitative isotopic studies, and implements an efficient algorithm to process large datasets. Its user-friendly interface makes isotope labeling experiments more accessible to a wider biological community. IsoCor is distributed under OpenSource license at http://metasys.insa-toulouse.fr/software/isocor/

Validation of a sensitive LC/MS/MS method for the determination of telaprevir and its R-isomer in human plasma.

PubMed

Chen, Xinhui; Bushman, Lane R; McAllister, Kevin J; Anderson, Peter L; Kiser, Jennifer J

2014-12-01

The purpose of this study was to validate a reversed-phase high-performance liquid chromatographic (HPLC), tandem mass spectrometry (MS/MS) assay for the determination of telaprevir and its R-diastereomer (VRT-127394) in acidified and nonacidified human plasma. The chromatographic baseline separation of telaprevir and telaprevir-R was performed on a Waters XBridge(TM) BEH Shield C18 , 2.1 × 75 mm column with a 2.5 µm particle size, under isocratic conditions consisting of a mobile phase of 50:45:5 water-acetonitrile-isopropanol with 1% ammonia at 0.2 mL/min. This method utilized a stable isotope internal standard with 11 deuterium atoms on the structure of the telaprevir molecule (telaprevir-d11). An internal standard for the telaprevir-R (telaprevir-R-d11) was also prepared by incubating telaprevir-d11 in basic solution, which facilitated isomer inter-conversion. The detection and quantitation of telaprevir, telaprevir-R, telaprevir-IS and telaprevir-R-IS was achieved by positive ion electrospray (ESI+) MS/MS detection. The assay quantifiable limit was 5.0 ng/mL when 0.100 mL of acidified human plasma was extracted. Accuracy and precision were validated over the calibration range of 5.0-5000 ng/mL. It was demonstrated using patient samples that, contrary to previous recommendations, quantitation of telaprevir does not require acidified plasma. Copyright © 2014 John Wiley & Sons, Ltd.

UPLC-MS/MS Profile of Alkaloids with Cytotoxic Properties of Selected Medicinal Plants of the Berberidaceae and Papaveraceae Families

PubMed Central

Och, Anna; Pecio, Łukasz

2017-01-01

Cancer is one of the most occurring diseases in developed and developing countries. Plant-based compounds are still researched for their anticancer activity and for their quantity in plants. Therefore, the modern chromatographic methods are applied to quantify them in plants, for example, UPLC-MS/MS (ultraperformance liquid chromatography tandem mass spectrometry). Therefore, the aim of the present study was to evaluate the content of sanguinarine, berberine, protopine, and chelidonine in Dicentra spectabilis (L.) Lem., Fumaria officinalis L., Glaucium flavum Crantz, Corydalis cava L., Berberis thunbergii DC., Meconopsis cambrica (L.) Vig., Mahonia aquifolium (Pursh) Nutt., Macleaya cordata Willd., and Chelidonium majus L. For the first time, N,N-dimethyl-hernovine was identified in M. cambrica, B. thunbergii, M. aquifolium, C. cava, G. flavum, and C. majus; methyl-hernovine was identified in G. flavum; columbamine was identified in B. thunbergii; and methyl-corypalmine, chelidonine, and sanguinarine were identified in F. officinalis L. The richest source of protopine among all the examined species was M. cordata (5463.64 ± 26.3 μg/g). The highest amounts of chelidonine and sanguinarine were found in C. majus (51,040.0 ± 1.8 μg/g and 7925.8 ± 3.3 μg/g, resp.), while B. thunbergi contained the highest amount of berberine (6358.4 ± 4.2 μg/g). PMID:28951771

UPLC-MS/MS Profile of Alkaloids with Cytotoxic Properties of Selected Medicinal Plants of the Berberidaceae and Papaveraceae Families.

PubMed

Och, Anna; Szewczyk, Katarzyna; Pecio, Łukasz; Stochmal, Anna; Załuski, Daniel; Bogucka-Kocka, Anna

2017-01-01

Cancer is one of the most occurring diseases in developed and developing countries. Plant-based compounds are still researched for their anticancer activity and for their quantity in plants. Therefore, the modern chromatographic methods are applied to quantify them in plants, for example, UPLC-MS/MS (ultraperformance liquid chromatography tandem mass spectrometry). Therefore, the aim of the present study was to evaluate the content of sanguinarine, berberine, protopine, and chelidonine in Dicentra spectabilis (L.) Lem., Fumaria officinalis L., Glaucium flavum Crantz, Corydalis cava L., Berberis thunbergii DC., Meconopsis cambrica (L.) Vig., Mahonia aquifolium (Pursh) Nutt., Macleaya cordata Willd., and Chelidonium majus L. For the first time, N,N-dimethyl-hernovine was identified in M. cambrica , B. thunbergii , M. aquifolium , C. cava , G. flavum , and C. majus ; methyl-hernovine was identified in G. flavum ; columbamine was identified in B. thunbergii ; and methyl-corypalmine, chelidonine, and sanguinarine were identified in F. officinalis L. The richest source of protopine among all the examined species was M. cordata (5463.64 ± 26.3  μ g/g). The highest amounts of chelidonine and sanguinarine were found in C. majus (51,040.0 ± 1.8  μ g/g and 7925.8 ± 3.3  μ g/g, resp.), while B. thunbergi contained the highest amount of berberine (6358.4 ± 4.2  μ g/g).

Overexpression of ceramide synthase 1 increases C18-ceramide and leads to lethal autophagy in human glioma

PubMed Central

Wang, Zheng; Wen, Lijun; Zhu, Fei; Wang, Yanping; Xie, Qing; Chen, Zijun; Li, Yunsen

2017-01-01

Ceramide synthase 1 (CERS1) is the most highly expressed CERS in the central nervous system, and ceramide with an 18-carbon–containing fatty acid chain (C18-ceramide) in the brain plays important roles in signaling and sphingolipid development. However, the roles of CERS1 and C18-ceramide in glioma are largely unknown. In the present study, measured by electrospray ionization linear ion trap mass spectrometry, C18-ceramide was significantly lower in glioma tumor tissues compared with controls (P < 0.001), indicating that C18-ceramide might have a role in glioma. These roles were examined by reconstitution of C18-ceramide in U251 and A172 glioma cells via addition of exogenous C18-ceramide or overexpression of CERS1, which has been shown to specifically induce the generation of C18-ceramide. Overexpression of CERS1 or adding exogenous C18-ceramide inhibited cell viability and induced cell death by activating endoplasmic reticulum stress, which induced lethal autophagy and inhibited PI3K/AKT signal pathway in U251 and A172 glioma cells. Moreover, overexpression of CERS1 or adding exogenous C18-ceramide increased the sensitivity of U251 and A172 glioma cells to teniposide (VM-26). Thus, the combined therapy of CERS1/C18-ceramide and VM-26 may be a novel therapeutic strategy for the treatment of human glioma. PMID:29262618

Determination of vandetanib in human plasma and cerebrospinal fluid by liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS).

PubMed

Bai, Feng; Johnson, Jennifer; Wang, Fan; Yang, Lei; Broniscer, Alberto; Stewart, Clinton F

2011-09-01

A sensitive and precise LC-ESI-MS/MS method for the determination of vandetanib (ZD6474) in human plasma and cerebrospinal fluid (CSF) using [(13)C,d(3)]-ZD6474 as an internal standard (ISTD) was developed and validated. Sample preparation consisted of a simple liquid-liquid extraction with tert-butyl methyl ether containing 0.1% or 0.5% ammonium hydroxide. ZD6474 and ISTD were separated on a Kinetex C18 column (2.6 μm, 50 mm × 2.1 mm) at ambient temperature with an isocratic mobile phase (acetonitrile/10mM ammonium formate=50/50, v/v, at pH 5.0) delivered at 0.11 mL/min. The retention time of both compounds was at 1.60 min in a runtime of three min. Detection was achieved by an API-3200 LC-MS/MS system, monitoring m/z 475.1/112.1 and m/z 479.1/116.2 for vandetanib and ISTD, respectively. The method was linear in the range of 0.25-50 ng/mL (R(2) ≥ 0.990) for the CSF curve and from 1.0 to 3000 ng/mL (R(2) ≥ 0.992) for the plasma curve. The mean recovery for vandetanib was 80%. Within-day and between-day precisions were ≤ 8.8% and ≤ 5.9% for CSF and plasma, respectively. Within-day and between-day accuracies ranged from 95.0 to 98.5% for CSF, and from 104.0 to 108.5% for plasma. Analysis of plasma from six different sources showed no matrix effect for vandetanib (MF=0.98, %CV ≤ 4.97, n=6). This method was successfully applied to the analysis of pharmacokinetic samples from children with brain tumors treated with oral vandetanib. Copyright © 2011 Elsevier B.V. All rights reserved.

18 CFR 1c.1 - Prohibition of natural gas market manipulation.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false Prohibition of natural gas market manipulation. 1c.1 Section 1c.1 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY GENERAL RULES PROHIBITION OF ENERGY MARKET MANIPULATION § 1c.1...

18 CFR 1c.1 - Prohibition of natural gas market manipulation.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Prohibition of natural gas market manipulation. 1c.1 Section 1c.1 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY GENERAL RULES PROHIBITION OF ENERGY MARKET MANIPULATION § 1c.1...

18 CFR 1c.1 - Prohibition of natural gas market manipulation.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Prohibition of natural gas market manipulation. 1c.1 Section 1c.1 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY GENERAL RULES PROHIBITION OF ENERGY MARKET MANIPULATION § 1c.1...

18 CFR 1c.2 - Prohibition of electric energy market manipulation.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false Prohibition of electric energy market manipulation. 1c.2 Section 1c.2 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY GENERAL RULES PROHIBITION OF ENERGY MARKET MANIPULATION § 1c.2...

18 CFR 1c.2 - Prohibition of electric energy market manipulation.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Prohibition of electric energy market manipulation. 1c.2 Section 1c.2 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY GENERAL RULES PROHIBITION OF ENERGY MARKET MANIPULATION § 1c.2...

18 CFR 1c.1 - Prohibition of natural gas market manipulation.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Prohibition of natural gas market manipulation. 1c.1 Section 1c.1 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY GENERAL RULES PROHIBITION OF ENERGY MARKET MANIPULATION § 1c.1...

18 CFR 1c.2 - Prohibition of electric energy market manipulation.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Prohibition of electric energy market manipulation. 1c.2 Section 1c.2 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY GENERAL RULES PROHIBITION OF ENERGY MARKET MANIPULATION § 1c.2...

18 CFR 1c.2 - Prohibition of electric energy market manipulation.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Prohibition of electric energy market manipulation. 1c.2 Section 1c.2 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY GENERAL RULES PROHIBITION OF ENERGY MARKET MANIPULATION § 1c.2...

Evaluation of tamoxifen and metabolites by LC-MS/MS and HPLC methods.

PubMed

Heath, D D; Flat, S W; Wu, A H B; Pruitt, M A; Rock, C L

2014-01-01

Epidemiological and laboratory evidence suggests that quantification of serum or plasma levels of tamoxifen and its metabolites, 4-hydroxy-N-desmethyl-tamoxifen (endoxifen), Z-4-hydroxytamoxifen (4HT), N-desmethyl-tamoxifen (ND-tam), is a clinically useful tool in the assessment and monitoring of breast cancer status in patients taking adjuvant tamoxifen. A liquid chromatographic mass spectrometric method (LC-MS/MS) was used to measure the blood levels of tamoxifen and its metabolites. This fully automated analytical method is specific, accurate and sensitive. The LC-MS/MS automated technique has now become a widely accepted reference method. This study analysed a randomly selected batch of blood samples from participants enrolled in a breast cancer study to compare results from this reference method in 40 samples with those obtained from a recently developed high-performance liquid chromatography (HPLC) method with fluorescence detection. The mean (SD) concentrations for the LC-MS/MS method (endoxifen 12.6 [7.5] ng/mL, tamoxifen 105 [44] ng/mL, 4-HT 1.9 [1.0] ng/mL, ND-tam 181 [69] ng/mL) and the HPLC method (endoxifen 13.1 [7.8] ng/mL, tamoxifen 108 [55] ng/mL, 4-HT 1.8 [0.8] ng/mL, ND-tam 184 [81] ng/mL) did not show any significant differences. The results confirm that the HPLC method offers an accurate and comparable alternative for the quantification of tamoxifen and tamoxifen metabolites.

Simultaneous analysis method for GHB, ketamine, norketamine, phenobarbital, thiopental, zolpidem, zopiclone and phenytoin in urine, using C18 poroshell column.

PubMed

Anilanmert, Beril; Çavuş, Fatma; Narin, Ibrahim; Cengiz, Salih; Sertler, Şefika; Özdemir, Ali Acar; Açikkol, Münevver

2016-06-01

Date-rape drugs have the potential to be used in drug-facilitated sexual assault, organ theft and property theft. Since they are colorless, tasteless and odorless, victims can drink without noticing, when added to the beverages. These drugs must be detected in time, before they are cleared up from the biofluids. A simultaneous extraction and determination method in urine for GHB, ketamine, norketamine, phenobarbital, thiopental, zolpidem, zopiclone and phenytoin (an anticonvulsant and antiepileptic drug) with LC-MS/MS was developed for the first time with analytically acceptable recoveries and validated. A 4 steps liquid-liquid extraction was applied, using only 1.000mL urine. A new age commercial C18 poroshell column with high column efficiency was used for LC-MS/MS analysis with a fast isocratic elution as 5.5min. A new MS transition were introduced for barbital. 222.7>179.8 with the effect of acetonitrile. Recoveries (%) were between 80.98-99.27 for all analytes, except for GHB which was 71.46. LOD and LOQ values were found in the ranges of 0.59-49.50 and 9.20-80.80ngmL(-1) for all the analytes (except for GHB:3.44 and 6.00μgmL(-1)). HorRat values calculated (between 0.25-1.21), revealed that the inter-day and interanalist precisions (RSD%≤14.54%) acceptable. The simultaneous extraction and determination of these 8 analytes in urine is challenging because of the difficulty arising from the different chemical properties of some. Since the procedure can extract drugs from a wide range of polarity and pKa, it increases the window of detection. Group representatives from barbiturates, z-drugs, ketamine, phenytoin and polar acidic drugs (GHB) have been successfully analyzed in this study with low detection limits. The method is important from the point of determining the combined or single use of these drugs in crimes and finding out the reasons of deaths related to these drugs. Copyright © 2016 Elsevier B.V. All rights reserved.

Identification of C-geranylated flavonoids from Paulownia catalpifolia Gong Tong fruits by HPLC-DAD-ESI-MS/MS and their anti-aging effects on 2BS cells induced by H2O2.

PubMed

Tang, Wen-Zhao; Wang, Ying-Ai; Gao, Tian-Yang; Wang, Xiao-Jing; Zhao, Yun-Xue

2017-05-01

The fruits of Paulownia catalpifolia Gong Tong are used as a Chinese folk herbal medicine for the treatment of enteritis, tonsillitis, bronchitis, and dysentery, etc. Our previous study has identified new C-geranylated flavanones with obvious anti-proliferative effects in lung cancer A549 cells. In the present study, a new C-geranylated flavone, paucatalinone C (1) and five known C-geranylated flavanones (2-6) were isolated. In addition, a total of 34 C-geranylated flavonoids were detected by HPLC-DAD-ESI-MS/MS coupling techniques from the CH 2 Cl 2 extract of P. catalpifolia. Futhermore, anti-aging effects of isolated compounds were evaluated in vitro with premature senescent 2BS cells induced by H 2 O 2 . Phytochemical results indicated that P. catalpifolia was a natural resource of abundant C-geranylated flavonoids. Diplacone (3) and paucatalinone A (5) were the potent anti-aging agents in the premature senescent 2BS cells induced by H 2 O 2 and the C-geranyl substituent may be an important factor because of its lipophilic character. Copyright © 2017 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

High-throughput method for the determination of residues of β-lactam antibiotics in bovine milk by LC-MS/MS.

PubMed

Jank, Louise; Martins, Magda Targa; Arsand, Juliana Bazzan; Hoff, Rodrigo Barcellos; Barreto, Fabiano; Pizzolato, Tânia Mara

2015-01-01

This study describes the development and validation procedures for scope extension of a method for the determination of β-lactam antibiotic residues (ampicillin, amoxicillin, penicillin G, penicillin V, oxacillin, cloxacillin, dicloxacillin, nafcillin, ceftiofur, cefquinome, cefoperazone, cephapirine, cefalexin and cephalonium) in bovine milk. Sample preparation was performed by liquid-liquid extraction (LLE) followed by two clean-up steps, including low temperature purification (LTP) and a solid phase dispersion clean-up. Extracts were analysed using a liquid chromatography-electrospray-tandem mass spectrometry system (LC-ESI-MS/MS). Chromatographic separation was performed in a C18 column, using methanol and water (both with 0.1% of formic acid) as mobile phase. Method validation was performed according to the criteria of Commission Decision 2002/657/EC. Main validation parameters such as linearity, limit of detection, decision limit (CCα), detection capability (CCβ), accuracy, and repeatability were determined and were shown to be adequate. The method was applied to real samples (more than 250) and two milk samples had levels above maximum residues limits (MRLs) for cloxacillin - CLX and cefapirin - CFAP.

Determination and pharmacokinetic study of pirfenidone in rat plasma by UPLC-MS/MS.

PubMed

Sun, Wei; Jiang, Zhe-li; Zhou, Lei; Chen, Rui-min; Wang, Zhe; Li, Wan-shu; Jiang, Shuo-min; Hu, Guo-xin; Chen, Rui-jie

2015-02-15

A rapid, sensitive and selective ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was developed and validated for the determination and pharmacokinetic investigation of pirfenidone in rat plasma. Sample preparation was accomplished through a simple one-step deproteinization procedure with 0.2 mL of acetonitrile to a 0.1 mL plasma sample. Plasma samples were separated by UPLC on an Acquity UPLC BEH C18 column using a mobile phase consisting of acetonitrile-0.1% formic acid in water with gradient elution. The total run time was 3.0 min and the elution of pirfenidone was at 1.39 min. The detection was performed on a triple quadrupole tandem mass spectrometer in the multiple reaction-monitoring (MRM) mode using the respective transitions m/z 186.2→92.1 for pirfenidone and m/z 237.1→194.2 for carbamazepine (IS), respectively. The calibration curve was linear over the range of 5-2000 ng/mL with a lower limit of quantitation (LLOQ) of 5 ng/mL. Mean recovery of pirfenidone in plasma was in the range of 80.4-84.3%. Intra-day and inter-day precision were both <12.1%. This method was successfully applied in pharmacokinetic study after oral administration of 10.0mg/kg pirfenidone in rats. Copyright © 2015 Elsevier B.V. All rights reserved.

Dementia in MS complicated by coexistent Alzheimer disease

PubMed Central

Flanagan, Eoin P.; Knopman, David S.

2014-01-01

Summary Distinguishing dementia due to multiple sclerosis (MS) from that of an accompanying neurodegenerative dementia coexisting with MS has been difficult. The recent introduction of Alzheimer disease (AD) biomarkers of amyloid-β and neuronal degeneration has improved diagnosis of AD premortem. We describe 3 patients with MS with coexisting AD, 1 diagnosed at autopsy before AD biomarkers were available and 2 diagnosed premortem by decreased CSF amyloid-β1-42/tau index, MRI, and 18F-flourodeoxyglucose-PET patterns. AD biomarkers may be of diagnostic value in selected patients with severe dementia and MS. PMID:25110620

Development and validation of LC-MS/MS method for the determination of Ochratoxin A and its metabolite Ochratoxin α in poultry tissues and eggs.

PubMed

Paoloni, Angela; Solfrizzo, Michele; Bibi, Rita; Pecorelli, Ivan

2018-05-04

The objective of this study was to develop a liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the determination of Ochratoxin A (OTA) and Ochratoxin α (OTα) in poultry tissues and eggs. The two toxins were extracted by a mixture of acetonitrile/water, purified with a reversed phase C18 solid phase extraction column (SPE) and determined by LC-MS/MS. The LC-MS/MS method performances were evaluated in terms of linearity in solvent and in matrix (ranged from 0.5 to 15.10 µg L -1 for OTA and from 0.60 to 17.85 µg L -1 for OTα), limit of detection (LOD), limit of quantitation (LOQ), specificity, accuracy and precision in repeatability conditions. Recovery experiments were performed by spiking poultry liver, kidney, muscle and eggs around 1 µg kg -1 and 10 µg kg -1 . LODs were 0.27 and 0.26 µg kg -1 while LOQs were fixed at 1.0 and 1.2 µg kg -1 for OTA and OTα, respectively. Main recoveries for OTA ranged from 82 to 109% and for OTα ranged from 55 to 89%. The values of within-laboratory relative standard deviation (RSD r ) were equal to or below 20%. Considering the results obtained and that all analytical performance criteria were fulfilled, the new extraction and purification method developed for OTA and OTα determination in animal tissues and eggs was found appropriate for control laboratories and research activities designed to ensure food safety.

LC-MS-Guided Isolation of Penicilfuranone A: A New Antifibrotic Furancarboxylic Acid from the Plant Endophytic Fungus Penicillium sp. sh18.

PubMed

Wang, Wei-Guang; Li, Ao; Yan, Bing-Chao; Niu, Shu-Bin; Tang, Jian-Wei; Li, Xiao-Nian; Du, Xue; Challis, Gregory L; Che, Yongsheng; Sun, Han-Dong; Pu, Jian-Xin

2016-01-22

Penicilfuranone A (1), a novel furancarboxylic acid, and its proposed biosynthetic precursor, gregatin A (2), were isolated from the cultures of the fungus Penicillium sp. sh18 endophytic to the stems of Isodon eriocalyx var. laxiflora guided by HPLC-MS. X-ray crystallography was applied to the structure determination of furancarboxylic acid for the first time, allowing unambiguous assignment of 1. Penicilfuranone A displays a significant antifibrotic effect in activated hepatic stellate cells via negative regulation of transforming growth factor-β (TGF-β)/Smad signaling.

76 FR 68243 - Social Security Rulings, SSR 91-1c and SSR 66-18c; Rescission of Social Security Rulings (SSR) 66...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-03

..., Social Security Online, at http://www.socialsecurity.gov . SUPPLEMENTARY INFORMATION: SSRs make available... SOCIAL SECURITY ADMINISTRATION [Docket No. SSA-2011-0068] Social Security Rulings, SSR 91-1c and SSR 66-18c; Rescission of Social Security Rulings (SSR) 66-18c and SSR 91-1c AGENCY: Social Security...

Biomarker Candidates of Chlamydophila pneumoniae Proteins and Protein Fragments Identified by Affinity-Proteomics Using FTICR-MS and LC-MS/MS

NASA Astrophysics Data System (ADS)

Susnea, Iuliana; Bunk, Sebastian; Wendel, Albrecht; Hermann, Corinna; Przybylski, Michael

2011-04-01

We report here an affinity-proteomics approach that combines 2D-gel electrophoresis and immunoblotting with high performance mass spectrometry to the identification of both full length protein antigens and antigenic fragments of Chlamydophila pneumoniae (C. pneumoniae). The present affinity-mass spectrometry approach effectively utilized high resolution FTICR mass spectrometry and LC-tandem-MS for protein identification, and enabled the identification of several new highly antigenic C. pneumoniae proteins that were not hitherto reported or previously detected only in other Chlamydia species, such as Chlamydia trachomatis. Moreover, high resolution affinity-MS provided the identification of several neo-antigenic protein fragments containing N- and C-terminal, and central domains such as fragments of the membrane protein Pmp21 and the secreted chlamydial proteasome-like factor (Cpaf), representing specific biomarker candidates.

Interleukin-18 -607C/A gene polymorphism in Egyptian asthmatic children.

PubMed

Shaaban, Hala Hamdi; Mohy, Abeer Mohamed; Abdel-Razek, Abdel-Rahman Ahmed; Wahab, Amira Abdel

2014-08-01

Asthma is a multifactorial respiratory disease determined by interactions of multiple disease susceptibility genes and environmental factors. Interleukin (IL)-18 is an important cytokine for initiating and perpetuating the catabolic and inflammatory response in allergic asthma. A number of single nucleotide polymorphisms that influence IL-18 production are found in the gene promoter region. The aim of this study was to investigate the association of IL-18 -607C/A promoter polymorphism with asthma and whether this polymorphism influenced the severity of asthma in affected children. The influence of this promoter gene polymorphism on total serum IgE level in studied subjects was also investigated. This study was carried out at the Allergy Clinic of Abu El Reesh Children's Hospital at Cairo University, Egypt. This study included 40 asthmatic children, subdivided into four groups according to different degrees of asthma severity, and 20 apparently healthy subjects as the control group. All cases were subjected to history taking, clinical examination, and the following laboratory investigations: complete blood count, total serum IgE level assay by ELISA and genomic DNA extraction, and analysis for IL-18 -607C/A promoter gene polymorphism using the PCR-RFLP (restriction fragment length polymorphism) technique. In the present study the IL-18 -607AA genotype frequency was higher in cases (22.5 %) than in the control group (15 %); however, the difference was not statistically significant (p = 0.773). No statistically significant difference between the degree of asthma severity and IL-18 -607C/A polymorphism was found (p = 0.489). No significant association could be detected upon comparing the frequencies of C and A alleles among the two studied groups (p = 0.366). Also, no significant differences were demonstrated for the allele frequencies when the intermittent with mild [odds ratio (OR) = 2.72, 95 % CI 1.03-2.33, p = 0.067], intermittent with moderate, and severe (OR = 2

Validation of NHB 8060.1C, Test 18 Arc Tracking, September 30, 1991

NASA Technical Reports Server (NTRS)

Linley, Larry

2005-01-01

A test project was conducted to validate Test 18 of NASA Handbook (NHB) 8060.1C and, if necessary, identify and recommend improvements in the procedures or criteria of the test. The NHB 8060.1C, Test 18 test system was modified to produce better discrimination of test results. Changes, and their effects on test results, in the graphite immersion-depth, test timing sequence, and atmospheric conditions were investigated for the wire-insulation constructions tested. Based on the test results, the graphite immersion-depths (between 0.8 mm and 1.6 mm), the timing sequence, and the change in the test conditions from ambient to three environments common in manned spaceflight did not significantly affect test results. The criteria used in Test 18 of NHB 8060.1C was found to be appropriate for qualifying arc-tracking and arc-propagation characteristics of wire-insulation materials, Using the Test 18 criteria, Kapton and ETFE were considered inappropriate for use, while PTFE was considered appropriate. Recommendations from this test project for Test 18 of NHB 8060.1C include changing the experimental setup and configurational tests and performing qualification testing in air rather than in the three environments common in manned spaceflight.

LC-MS-MS simultaneous determination of atorvastatin and ezetimibe in human plasma.

PubMed

El-Bagary, Ramzia I; Elkady, Ehab F; El-Sherif, Zeinab Abdelaziz; Kadry, Ahmed M

2014-09-01

Atorvastatin and ezetimibe are lipid-lowering drugs prescribed for the treatment of hypercholesterolemia. An LC-MS-MS method has been developed and validated for the simultaneous estimation of atorvastatin and ezetimibe in human plasma using pitavastatin as an internal standard. Liquid-liquid extraction was used for the purification and preconcentration of analytes from human plasma matrix. The chromatographic separation was achieved within 3.0 min by an isocratic mobile phase consisting of 0.2% formic acid in water-acetonitrile (30:70, v/v), flowing through Agilent Eclipse-plus C18, 100 × 4.6 mm, 3.5 µm analytical column, at a flow rate of 0.6 mL min(-1). Multiple reaction monitoring transitions were measured in the positive ion mode for atorvastatin and internal standard, while ezetimibe was measured in negative ion mode. A detailed validation of the method was performed as per US-FDA guidelines and the standard curves were found to be linear in the range of 0.2-30.0 ng mL(-1) with a mean correlation coefficient >0.999 for both drugs. In human plasma, atorvastatin and ezetimibe were stable for at least 36 days at -70 ± 5 °C and 6 h at ambient temperature. After extraction from plasma, the reconstituted samples of atorvastatin and ezetimibe were stable in an autosampler at ambient temperature for 6 h. Also, the cited drugs were stable in plasma samples upon subjecting to three freeze thaw cycles. The method is simple, specific, sensitive, precise, accurate and suitable for bioequivalence and pharmacokinetic studies of this combination. © The Author [2013]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Development and validation of an HPLC–MS/MS method to determine clopidogrel in human plasma

PubMed Central

Liu, Gangyi; Dong, Chunxia; Shen, Weiwei; Lu, Xiaopei; Zhang, Mengqi; Gui, Yuzhou; Zhou, Qinyi; Yu, Chen

2015-01-01

A quantitative method for clopidogrel using online-SPE tandem LC–MS/MS was developed and fully validated according to the well-established FDA guidelines. The method achieves adequate sensitivity for pharmacokinetic studies, with lower limit of quantifications (LLOQs) as low as 10 pg/mL. Chromatographic separations were performed on reversed phase columns Kromasil Eternity-2.5-C18-UHPLC for both methods. Positive electrospray ionization in multiple reaction monitoring (MRM) mode was employed for signal detection and a deuterated analogue (clopidogrel-d4) was used as internal standard (IS). Adjustments in sample preparation, including introduction of an online-SPE system proved to be the most effective method to solve the analyte back-conversion in clinical samples. Pooled clinical samples (two levels) were prepared and successfully used as real-sample quality control (QC) in the validation of back-conversion testing under different conditions. The result showed that the real samples were stable in room temperature for 24 h. Linearity, precision, extraction recovery, matrix effect on spiked QC samples and stability tests on both spiked QCs and real sample QCs stored in different conditions met the acceptance criteria. This online-SPE method was successfully applied to a bioequivalence study of 75 mg single dose clopidogrel tablets in 48 healthy male subjects. PMID:26904399

Online extraction LC-MS/MS method for the simultaneous quantitative confirmation of urine drugs of abuse and metabolites: amphetamines, opiates, cocaine, cannabis, benzodiazepines and methadone.

PubMed

de Jager, Andrew D; Bailey, Neville L

2011-09-01

A rapid LC-MS/MS method for confirmatory testing of five major categories of drugs of abuse (amphetamine-type substances, opiates, cocaine, cannabis metabolites and benzodiazepines) in urine has been developed. All drugs of abuse mandated by the Australian/New Zealand Standard AS/NZS 4308:2008 are quantified in a single chromatographic run. Urine samples are diluted with a mixture of isotope labelled internal standards. An on-line trap-and-flush approach, followed by LC-ESI-MS/MS has been successfully used to process samples in a functioning drugs of abuse laboratory. Following injection of diluted urine samples, compounds retained on the trap cartridge are flushed onto a reverse-phase C18 HPLC column (5-μm particle size) with embedded hydrophylic functionality. A total chromatographic run-time of 15 min is required for adequate resolution. Automated quantitation software algorithms have been developed in-house using XML scripting to partially automate the identification of positive samples, taking into account ion ratio (IR) and retention times (Rt). The sensitivity of the assay was found to be adequate for the quantitation of drugs in urine at and below the confirmation cut-off concentrations prescribed by AS/NZS 4308:2008. Copyright © 2011 Elsevier B.V. All rights reserved.

HPLC-MS/MS method for the simultaneous determination of MB07133 and its metabolites, cytarabine and arabinofuranosyluracil, in rat plasma.

PubMed

Wang, Dan; Xiao, Qingqing; Yang, Wanqiu; Qian, Wei; Yang, Jin

2016-02-20

MB07133 is an intravenously administered cytarabine mononucleotide (araCMP) prodrug, for the treatment of hepatocellular carcinoma (HCC). A simple, selective and sensitive HPLC-MS/MS method using high pressure liquid chromatography (HPLC) coupled to triple-quadrupole mass spectrometer, was developed and validated for the detection of prodrug MB07133 and its metabolites, cytarabine (araC) and arabinofuranosyluracil (araU) in rat plasma. Protein precipitation using 3% trichloroacetic acid (TCA) was employed to extract analytes from 100μL rat plasma. Adequate separation of araC and araU from their endogenous compounds was achieved on the Synergi(®) fusion-RP column (150mm×4.6mm, 4μm) by a gradient-elution with a mobile phase consisting of ammonium formate (1mM) and methanol at a flow rate of 1mL/min. Multiple reaction monitoring mode (MRM) was applied in the detection of MB07133, araC, araU and Ganciclovir (internal standard) with ion pairs 441.2/330.2, 244.2/112.2, 245.2/113.2 and 256.1/152.2, respectively. The assays were validated with respect to specificity, linearity (100-50000ng/mL for MB07133, 2-1000ng/mL for araC and araU), accuracy and precision, extraction recovery, matrix effect and stability. The validated method has been successfully applied to an intravenous bolus pharmacokinetic study of MB07133 in male Sprague-Dawley rats (18mg/kg i.v.). Copyright © 2015 Elsevier B.V. All rights reserved.

Quantitative determination of dopamine in human plasma by a highly sensitive LC-MS/MS assay: Application in preterm neonates.

PubMed

Zhang, Daping; Wu, Lei; Chow, Diana S-L; Tam, Vincent H; Rios, Danielle R

2016-01-05

The determination of dopamine facilitates better understanding of the complex brain disorders in the central nervous system and the regulation of endocrine system, cardiovascular functions and renal functions in the periphery. The purpose of this study was to develop a highly sensitive and reliable assay for the quantification of dopamine in human neonate plasma. Dopamine was extracted from human plasma by strong cation exchange (SCX) solid phase extraction (SPE), and subsequently derivatized with propionic anhydride. The derivatized analyte was separated by a Waters Acquity UPLC BEH C18 column using gradient elution at 0.4 ml/min with mobile phases A (0.2% formic acid in water [v/v]) and B (MeOH-ACN [v/v, 30:70]). Analysis was performed under positive electrospray ionization tandem mass spectrometer (ESI-MS/MS) in the multiple reaction monitoring (MRM) mode. The stable and relatively non-polar nature of the derivatized analyte enables reliable quantification of dopamine in the range of 10-1000 pg/ml using 200 μl of plasma sample. The method was validated with intra-day and inter-day precision less than 7%, and the intra-day and inter-day accuracy of 91.9-101.9% and 92.3-102.6%, respectively. The validated assay was applied to quantify dopamine levels in two preterm neonate plasma samples. In conclusion, a sensitive and selective LC-MS/MS method has been developed and validated, and successfully used for the determination of plasma dopamine levels in preterm neonates. Copyright © 2015 Elsevier B.V. All rights reserved.

Sensitive quantification of apomorphine in human plasma using a LC-ESI-MS-MS method.

PubMed

Abe, Emuri; Alvarez, Jean-Claude

2006-06-01

An analytical method based on liquid chromatography coupled with ion trap mass spectrometry (MS) detection with electrospray ionization interface has been developed for the identification and quantification of apomorphine in human plasma. Apomorphine was isolated from 0.5 mL of plasma using a liquid-liquid extraction with diethyl ether and boldine as internal standard, with satisfactory extraction recoveries. Analytes were separated on a 5-microm C18 Highpurity (Thermohypersil) column (150 mm x 2.1 mm I.D.) maintained at 30 degrees C, coupled to a precolumn (C18, 5-microm, 10 mm x 2.0 mm I.D., Thermo). The elution was achieved isocratically with a mobile phase of 2 mM NH4COOH buffer pH 3.8/acetonitrile (50/50, vol/vol) at a flow rate of 200 microL per minute. Data were collected either in full-scan MS mode at m/z 150 to 500 or in full-scan tandem mass spectrometry mode, selecting the [M+H]ion at m/z 268.0 for apomorphine and m/z 328.0 for boldine. The most intense daughter ion of apomorphine (m/z 237.1) and boldine (m/z 297.0) were used for quantification. Retention times were 2.03 and 2.11 minutes for boldine and apomorphine, respectively. Calibration curves were linear in the 0.025 to 20 ng/mL range. The limits of detection and quantification were 0.010 ng/mL and 0.025 ng/mL, respectively. Accuracy and precision of the assay were measured by analyzing 54 quality control samples for 3 days. At concentrations of 0.075, 1.5, and 15 ng/mL, intraday precisions were less than 10.1%, 5.3%, and 3.8%, and interday precisions were less than 4.8%, 6.6%, and 6.5%, respectively. Accuracies were in the 99.5 to 104.2% range. An example of a patient who was given 6 mg of apomorphine subcutaneously is shown, with concentrations of 14.1 ng/mL after 30 minutes and 0.20 ng/mL after 6 hours. The method described enables the unambiguous identification and quantification of apomorphine with very good sensitivity using only 0.5 mL of sample, and is very convenient for therapeutic drug

The Rotational Spectrum of Ketene Isotopomers with 18O and 13C Revisited

NASA Astrophysics Data System (ADS)

Guarnieri, A.; Huckaufa, A.

2003-06-01

The pure rotational spectra of [18O]ketene, H2C=C18O, [1-13C]ketene, H2C=13CO, and [2-13C]ketene, H213C=CO, have been revisited in the frequency region 200 - 350 GHz in the ground vibrational state. From more than 100 R-branch transitions for each isotopomer a set of rotational and centrifugal distortion constants could be derived using the Watson S-reduction formalism. The values obtained for the rotational constants B and C agree very well with results of former investigations. The agreement is worse with respect to the A constants, but our newly determined A values agree well with the corresponding values of the main species and the 17O isotopomer.

Development and validation of an UPLC-ESI-MS/MS method for determination of dehydroevodiamine, limonin, evodiamine, and rutaecarpine in Evodiae Fructus

PubMed Central

Zhao, Yang; Zhao, Yunling; Zhou, Xin; Gong, Xiaojian

2014-01-01

Objective: Evodiae Fructus (EF), one of the most widely used traditional Chinese medicines, mainly consists of alkaloids, is widely used for the treatments of headache and gastrointestinal disorders. In this study, a sensitive and reliable UPLC-ESI-MS/MS method was developed for qualitative determination of dehydroevodiamine, limonin, evodiamine, and rutaecarpine. Materials and Methods: Chromatographic separations were accomplished on a Phenomenex Kinetex XB-C18 column (2.1 × 150 mm, 1.7 μm) by using a gradient elution profile with a mobile phase consisting of 0.5% formic acid in water (A) and acetonitrile (B). Detection was performed using multiple reactions monitoring mode under ESI in the positive ion mode. Results: The results showed good linearity over the investigated concentration ranges (R2>0.9900) for the analytes. The limit of quantitations (LOQs) were 6.88 ng/mL for dehydroevodiamine, 18.6 ng/mL for limonin, 6.24 ng/mL for evodiamine, and 2.56 ng/mL for rutaecarpine, respectively. Intraday and interday precisions (relative standard deviations, %) were <5% and accuracies ranged from 92% to 106%. Conclusion: The validated method was successfully applied to assay the contents of the four compounds in EF samples from different regions, with which just 10 min was needed to analyze each sample. PMID:25210328

Determination of blood cyanide by HPLC-MS.

PubMed

Tracqui, A; Raul, J S; Géraut, A; Berthelon, L; Ludes, B

2002-04-01

An original high-performance liquid chromatographic-mass spectrometric (HPLC-MS) procedure was developed for the determination of cyanide (CN) in whole blood. After the addition of K13C15N as internal standard, blood was placed in a microdiffusion device, the inner well of which was filled with a mixture of taurine (50mM in water)/naphthalene-2,3-dicarboxaldehyde (NDA, 10mM in methanol)/methanol/ concentrated (approximately 20%) ammonia solution (25:25:45:5, v/v). Concentrated H2SO4 was added to the blood sample, and the microdiffusion chamber was sealed. After 30 min of gentle agitation, 2 microL of the contents of the inner vial were pipetted and directly injected onto a NovaPak C18 HPLC column. Separation was performed by a gradient of acetonitrile in 2mM NH4COOH, pH 3.0 buffer (35-80% in 10 min). Detection was done with a Perkin-Elmer Sciex API-100 mass analyzer with an ionspray interface, operated in the negative ionization mode. MS data were collected as either TIC or SIM at m/z (299 + 191) and (301 + 193) for the derivatives formed with CN and 13C15N, respectively. Inspired by previous works dealing with the complexation of CN by NDA + taurine to form a 1-cyano [f] benzoisoindole derivative analyzed by HPLC-fluorimetry, this method appears simple, rapid, and extremely specific. Limits of detection and quantitation for blood CN are 5 and 15 ng/mL, respectively. The use of 13C15N as internal standard allows the quantitation of CN with elegance and accuracy in comparison with previously reported methods.

Evaluation of Tamoxifen and metabolites by LC-MS/MS and HPLC Methods

PubMed Central

Heath, D.D.; Flatt, S.W.; Wu, A.H.B.; Pruitt, M.A.; Rock, C.L.

2015-01-01

Epidemiological and laboratory evidence suggests that quantification of serum or plasma levels of tamoxifen and the metabolites of tamoxifen, 4-hydroxy-N-desmethyl-tamoxifen (endoxifen), Z-4-hydroxy-tamoxifen (4HT), N-desmethyl-tamoxifen (ND-tam) is a clinically useful tool in the assessment and monitoring of breast cancer status in patients taking adjuvant tamoxifen. A liquid chromatographic mass spectrometric method (LC-MS/MS) was used to measure the blood levels of tamoxifen and the metabolites of tamoxifen. This fully automated analytical method is specific, accurate and sensitive. The LC-MS/MS automated technique has now become a widely accepted reference method. We analyzed a randomly selected batch of blood samples from participants enrolled in a breast cancer study to compare results from this reference method in 40 samples with those obtained from a recently developed high performance liquid chromatography (HPLC) method with fluorescence detection. The mean (SD) concentration for the LC-MS/MS (endoxifen 12.6 [7.5] ng/mL, tamoxifen 105 [44] ng/mL, 4-HT 1.9 [1.0] ng/mL, ND-tam 181 [69] ng/mL) and the HPLC (endoxifen 13.1 [7.8] ng/mL, tamoxifen 108[55]ng/mL, 4-HT 1.8 [0.8] ng/mL, ND-tam 184 [81] ng/mL), the methods did not show any significant differences. Our results confirm that the HPLC method offers an accurate and comparable alternative for the quantification of tamoxifen and tamoxifen metabolites. PMID:24693573

mzDB: A File Format Using Multiple Indexing Strategies for the Efficient Analysis of Large LC-MS/MS and SWATH-MS Data Sets*

PubMed Central

Bouyssié, David; Dubois, Marc; Nasso, Sara; Gonzalez de Peredo, Anne; Burlet-Schiltz, Odile; Aebersold, Ruedi; Monsarrat, Bernard

2015-01-01

The analysis and management of MS data, especially those generated by data independent MS acquisition, exemplified by SWATH-MS, pose significant challenges for proteomics bioinformatics. The large size and vast amount of information inherent to these data sets need to be properly structured to enable an efficient and straightforward extraction of the signals used to identify specific target peptides. Standard XML based formats are not well suited to large MS data files, for example, those generated by SWATH-MS, and compromise high-throughput data processing and storing. We developed mzDB, an efficient file format for large MS data sets. It relies on the SQLite software library and consists of a standardized and portable server-less single-file database. An optimized 3D indexing approach is adopted, where the LC-MS coordinates (retention time and m/z), along with the precursor m/z for SWATH-MS data, are used to query the database for data extraction. In comparison with XML formats, mzDB saves ∼25% of storage space and improves access times by a factor of twofold up to even 2000-fold, depending on the particular data access. Similarly, mzDB shows also slightly to significantly lower access times in comparison with other formats like mz5. Both C++ and Java implementations, converting raw or XML formats to mzDB and providing access methods, will be released under permissive license. mzDB can be easily accessed by the SQLite C library and its drivers for all major languages, and browsed with existing dedicated GUIs. The mzDB described here can boost existing mass spectrometry data analysis pipelines, offering unprecedented performance in terms of efficiency, portability, compactness, and flexibility. PMID:25505153

Pre-Column Derivatization HPLC Procedure for the Quantitation of Aluminium Chlorohydrate in Antiperspirant Creams Using Quercetin as Chromogenic Reagent.

PubMed

Kalogria, Eleni; Varvaresou, Athanasia; Papageorgiou, Spyridon; Protopapa, Evaggelia; Tsaknis, Ioannis; Matikas, Alexios; Panderi, Irene

2014-01-01

This article describes the development and validation of a selective high-performance liquid chromatography method that allows, after liquid-liquid extraction and pre-column derivatization reaction with quercetin, the quantification of aluminium chlorohydrate in antiperspirant creams. Chromatographic separation was achieved on an XTerra MS C18 analytical column (150 × 3.0 mm i.d., particle size 5 μm) using a mobile phase of acetonitrile:water (15:85, v/v) containing 0.08 % trifluoroacetic acid at a flow rate of 0.30 mL min -1 . Ultraviolet spectrophotometric detection at 415 nm was used. The assay was linear over a concentration range of 3.7-30.6 μg mL -1 for aluminium with a limit of quantitation of 3.74 μg mL -1 . Quality control samples (4.4, 17.1 and 30.6 μg mL -1 ) in five replicates from five different runs of analysis demonstrated intra-assay precision (% coefficient of variation <3.8 %), inter-assay precision (% coefficient of variation <5.4 %) and an overall accuracy (% recovery) between 96 and 101 %. The method was used to quantify aluminium in antiperspirant creams containing 11.0, 13.0 and 16.0 % (w/w) aluminium chlorohydrate, respectively.

LC–MS/MS determination of carbamathione in microdialysis samples from rat brain and plasma

PubMed Central

Kaul, Swetha; Williams, Todd D.; Lunte, Craig E.; Faiman, Morris D.

2009-01-01

A selective liquid chromatography–tandem mass spectrometric (LC–MS/MS) method was developed for the determination of S-(N, N-diethylcarbamoyl) glutathione (carbamathione) in microdialysis samples from rat brain and plasma. S-(N, N-Diethylcarbamoyl) glutathione (carbamathione) is a metabolite of disulfiram. This metabolite may be responsible for disulfiram’s effectiveness in the treatment of cocaine dependence. An analytical method using liquid chromatography–tandem mass spectrometric (LC–MS/MS) was developed to determine carbamathione in vivo using microdialysis sampling from rat brain and plasma. Chromatographic separations were carried out on an Alltech Altima C-18 (50 mm long × 2.1 mm i.d., 3 μm particles) analytical column at a flow rate of 0.3 ml/min. Solvent A consisted of 10 mM ammonium formate, methanol, and formic acid (99:1:0.06, v/v/v). Solvent B consisted of methanol, 10 mM ammonium formate and formic acid (99:1:0.06, v/v/v). A 20 min linear gradient from 95% aqueous to 95% organic was used. Tandem mass spectra were acquired on a Micromass Quattro Ultima “triple” quadrupole mass spectrometer equipped with an ESI interface. Quantitative mass spectrometric analysis was conducted in positive ion mode selected reaction monitoring (SRM) mode looking at the transition of m/z 407–100 and 175 for carbamathione and m/z 392–263 for the internal standard S-hexyl glutathione. The simultaneous collection of microdialysate from blood and brain was used to monitor carbamathione concentrations centrally and peripherally. Good linearity was obtained over a concentration range of 0.25–10,000 nM. The lowest limit of quantification (LLOQ) was determined to be 1 nM and the lowest limit of detection (LLOD) was calculated to be 0.25 nM. Intra- and inter-day accuracy and precision were determined and for all the samples evaluated, the variability was less that 10% (R.S.D.). PMID:19709836

Simultaneous determination of vitamins A and D3 in dairy products by liquid chromatography-tandem mass spectrometry (LC-MS/MS)

NASA Astrophysics Data System (ADS)

Barakat, I. S. A.; Hammouri, M. K.; Habib, I.

2015-10-01

A potential method for simultaneous determination of vitamin A and vitamin D3 (25- hydroxyvitamin D3) in fresh milk samples is addressed. The method is based on combination of high performance liquid chromatography and mass spectrometry during the course of analysis. The method applied for determination of vitamins A and D3 on eighteen (18) different fresh milk samples using liquid chromatography along with tandem -mass spectrometry. The work describes the suitability of the proposed method for the simultaneous determination of both vitamins using LC-MS/MS as a specific and quantitative technique. The vitamins of milk were separated by C18 Thermo gold column(100mm × 4.6mm × 5 μm) with a flow rate of 1ml/min (using an isocratic mobile phase). The method was validated using duplicate analyses, relative recovery experiment, and comparative analysis with control samples. Liquid- liquid extraction was employed as a pre-concentration step with n-hexane - dichloromethane mixture (90%:10%) as an extraction solvent. The molecular ions (m/z) appeared near 286 and 385nm and for the base peaks were appeared near 255 and 355nm for vitamins A and D3. Good correlation coefficients were obtained, 0.9999 for vitamin D3 and 0.9994 for vitamin A. The limit of detection and the limit of quantification were found to be 0.09ng/ml and 0.54ng/ml for vitamin D3 and 0.32ng/ml and 1.8ng/ml and for vitamin A. The proposed method showed excellent recoveries, about 98% for both vitamins A and D3.

Ellagitannin composition of blackberry as determined by HPLC-ESI-MS and MALDI-TOF-MS.

PubMed

Hager, Tiffany J; Howard, Luke R; Liyanage, Rohana; Lay, Jackson O; Prior, Ronald L

2008-02-13

Blackberries ( Rubus sp.) were evaluated by high-performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF-MS) to identify the ellagitannins present in flesh, torus (receptacle tissue), and seeds. Most ellagitannins were present (or detectable) only in seed tissues. Ellagitannins identified by HPLC-ESI-MS in the seeds included pedunculagin, casuarictin/potentillin, castalagin/vescalagin, lambertianin A/sanguiin H-6, lambertianin C, and lambertianin D. For several of the ellagitannins, isomeric separation was also obtained. The MALDI-TOF-MS analysis was primarily utilized to evaluate and identify high molecular mass (>1000 Da) ellagitannins. The MALDI analysis verified the presence of the ellagitannins identified by HPLC-ESI-MS including lambertianin A/sanguiin H-6, lambertianin C, and lambertianin D, but the analysis also indicated the presence of several other compounds that were most likely ellagitannins based on the patterns observed in the masses (i.e., loss or addition of a gallic acid moiety to a known ellagitannin). This study determined the presence of several possible isomeric forms of ellagitannins previously unidentified in fruit and presents a possible analytical HPLC method for the analysis of the major ellagitannins present in the fruit.

Separation of [(99m)Tc]pertechnetate and molybdate using polyethylene glycol coated C18 and C30 resins.

PubMed

Andersson, J D; Wilson, J S; Romaniuk, J A; McEwan, A J B; Abrams, D N; McQuarrie, S A; Gagnon, K

2016-04-01

Hydrophobic adsorbents such as C18 and C30 were coated with PEG and subsequently used for the separation of Mo/Tc. The most effective resin for adsorbing PEG was the C18-U resin, which demonstrated a coating capacity of 97.6±2.8mg PEG per g of resin. The ability to adsorb pertechnetate was proportional to the amount of PEG coated on the hydrophobic resin. The [(99m)Tc]pertechnetate recovery during the separation of cyclotron produced (99m)Tc from (100)Mo was 91.8±0.3% (n=2). The resultant product met relevant USP monograph specifications. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development and validation of a simple and sensitive method for quantification of levodopa and carbidopa in rat and monkey plasma using derivatization and UPLC-MS/MS.

PubMed

Junnotula, Venkatraman; Licea-Perez, Hermes

2013-05-01

A simple, selective, and sensitive quantitative method has been developed for the simultaneous determination of levodopa and carbidopa in rat and monkey plasma by protein precipitation using acetonitrile containing the derivatizing reagent, flourescamine. Derivatized products of levodopa and carbidopa were separated on a BEH C18 column (2.1 mm × 50 mm; 1.7 μm particle size) using ultra high performance liquid chromatography (UHPLC) without any further purification. Tandem mass spectrometry (MS/MS) was used for detection. The method was validated over the concentration range of 5-5000 ng/mL and 3-3000 ng/mL for levodopa and carbidopa, respectively in rat and monkey plasma. Due to the poor stability of the investigated analytes in biological matrices, a mixture of sodium metabisulfite and hydrazine dihydrochloride was used as a stabilizer. This method was successfully utilized to support pharmacokinetic studies in both species. The results from assay validations and incurred samples re-analysis show that the method is selective, sensitive and robust. To our knowledge, this is the first UHPLC-MS/MS based method that utilizes derivatization with fluorescamine and provides adequate sensitivity for both levodopa and carbidopa with 50 μL of sample and a run time of 3.5 min. Copyright © 2013 Elsevier B.V. All rights reserved.

Lipstick dermatitis due to C18 aliphatic compounds.

PubMed

Hayakawa, R; Matsunaga, K; Suzuki, M; Arima, Y; Ohkido, Y

1987-04-01

An 18-year-old girl developed cheilitis. She had a past history of lip cream dermatitis, but the cause was not found. Patch tests with 2 lipsticks were strongly positive. Tests with the ingredients were positive to 2 aliphatic compounds, glyceryl diisostearate and diisostearyl malate. Impurities in the materials were suspected as the cause. Analysis by gas chromatography detected 3 chemicals in glyceryl diisostearate and 1 in diisostearyl malate as impurities. Patch testing with the impurities and glyceryl monoisostearate 0.01% pet in glyceryl diisostearate and isostearyl alcohol 0.25% pet in diisostearyl malate were strongly positive. The characteristics common to the 2 chemicals were liquidity at room temperature, branched C18 aliphatic compound and primary alcohol. Chemicals lacking any of the above 3 features did not react.

[Metabolites and metabolic pathways of mesaconitine in rat liver microsomal investigated by using UPLC-MS/MS method in vitro].

PubMed

Bi, Yun-Feng; Liu, Shu; Zhang, Rui-Xing; Song, Feng-Rui; Liu, Zhi-Qiang

2013-12-01

Mesaconitine was incubated with rat liver microsomes in vitro. The metabolites of mesaconitine in rat liver microsomes were identified by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method with high resolution power. A typical reaction mixture of 100 mol L-1 Tris-HCI buffer (pH 7.4) containing 0.5 gL-1 microsomal protein and 50 micro molL-1 mesaconitine was prepared. The above reaction mixture was divided into six groups, and the volume of each group was 200 micro L. The incubation mixture was pre-incubated at 37 degrees C for 2 min and the reactions were initiated by adding NADPH generating system. After 90 min incubation at 37 degrees C, 200 micro L of acetonitrile was added to each group to stop the reaction. The metabolites of mesaconitine were investigated by UPLC-MS/MS method. Mesaconitine and 6 metabolites M1-M6 were found in the incubation system. The structures were characterized according to the data from MS/MS spectra and literatures. The metabolic reactions of mesaconitine in rat liver microsomes included the demethylation, deacetylation, dehydrogenation and hydroxylation. The major metabolic pathways of mesaconitine in rat liver microsomes were determined by UPLC-MS/MS on multiple reaction monitoring (MRM) mode combined with specific inhibitors of cytochrome P450 (CYP) isoforms, including alpha-naphthoflavone (CYP1A2), quinine (CYP2D), diethyldithiocarbamate (CYP2E1), ketoconazole (CYP3A) and sulfaphenazole (CYP2C), separately. Mesaconitine was mainly metabolized by CYP3A. CYP2C and CYP2D were also more important CYP isoforms for the metabolism reactions of mesaconitine, but CYP1A2 and CYP2E1 haven't any contribution to MA metabolism in rat liver microsomes.

Plasma Pharmacokinetic Determination of Canagliflozin and Its Metabolites in a Type 2 Diabetic Rat Model by UPLC-MS/MS.

PubMed

Dong, Song-Tao; Niu, Hui-Min; Wu, Yin; Jiang, Jia-Lei; Li, Ying; Jiang, Kun-Yu; Wang, Xin; Zhang, Mao-Fan; Han, Ming-Feng; Meng, Sheng-Nan

2018-05-20

Canagliflozin is a novel, orally selective inhibitor of sodium-dependent glucose co-transporter-2 (SGLT2) for the treatment of patients with type 2 diabetes mellitus. In this study, a sensitive and efficient UPLC-MS/MS method for the quantification of canagliflozin and its metabolites in rat plasma was established and applied to pharmacokinetics in a type 2 diabetic rat model. We firstly investigated the pharmacokinetic changes of canagliflozin and its metabolites in type 2 diabetic rats in order to use canagliflozin more safely, reasonably and effectively. We identified three types of O-glucuronide metabolites (M5, M7 and M17), two kinds of oxidation metabolites (M8 and M9) and one oxidation and glucuronide metabolite (M16) using API 5600 triple-TOF-MS/MS. Following liquid⁻liquid extraction by tert-butyl methyl ether, chromatographic separation of canagliflozin and its metabolites were performed on a Waters XBridge BEH C18 column (100 × 2.1 mm, 2.5 μm) using 0.1% acetonitrile⁻formic acid (75:15, v / v ) as the mobile phase at a flow rate of 0.7 mL/min. Selected ion monitoring transitions of m / z 462.00→191.10, 451.20→153.10, 638.10→191.10 and 478.00→267.00 were chosen to quantify canagliflozin, empagliflozin (IS), O-glucuronide metabolites (M5, M7 and M17), and oxidation metabolites (M9) using an API 5500-triple-MS/MS in the positive electrospray ionization mode. The validation of the method was found to be of sufficient specificity, accuracy and precision. The pathological condition of diabetes could result in altered pharmacokinetic behaviors of canagliflozin and its metabolites. The pharmacokinetic parameters (AUC 0⁻t , AUC 0⁻∞ , CL z /F, and V z /F) of canagliflozin were significantly different between the CTRL and DM group rats ( p < 0.05 or p < 0.01), which may subsequently cause different therapeutic effects.

High-Precision C17O, C18O, and C16O Measurements in Young Stellar Objects: Analogues for Co Self-shielding in the Early Solar System

NASA Astrophysics Data System (ADS)

Smith, Rachel L.; Pontoppidan, Klaus M.; Young, Edward D.; Morris, Mark R.; van Dishoeck, Ewine F.

2009-08-01

Using very high resolution (λ/Δλ ≈ 95 000) 4.7 μm fundamental and 2.3 μm overtone rovibrational CO absorption spectra obtained with the Cryogenic Infrared Echelle Spectrograph infrared spectrometer on the Very Large Telescope (VLT), we report detections of four CO isotopologues—C16O, 13CO, C18O, and the rare species, C17O—in the circumstellar environment of two young protostars: VV CrA, a binary T Tauri star in the Corona Australis molecular cloud, and Reipurth 50, an intermediate-mass FU Ori star in the Orion Molecular Cloud. We argue that the observed CO absorption lines probe a protoplanetary disk in VV CrA, and a protostellar envelope in Reipurth 50. All CO line profiles are spectrally resolved, with intrinsic line widths of ≈3-4 km s-1 (FWHM), permitting direct calculation of CO oxygen isotopologue ratios with 5%-10% accuracy. The rovibrational level populations for all species can be reproduced by assuming that CO absorption arises in two temperature regimes. In the higher temperature regime, in which the column densities are best determined, the derived oxygen isotope ratios in VV CrA are: [C16O]/[C18O] =690 ± 30; [C16O]/[C17O] =2800 ± 300, and [C18O]/[C17O]=4.1 ± 0.4. For Reipurth 50, we find [C16O]/[C18O] =490 ± 30; [C16O]/[C17O] =2200 ± 150, [C18O]/[C17O] = 4.4 ± 0.2. For both objects, 12C/13C are on the order of 100, nearly twice the expected interstellar medium (ISM) ratio. The derived oxygen abundance ratios for the VV CrA disk show a significant mass-independent deficit of C17O and C18O relative to C16O compared to ISM baseline abundances. The Reipurth 50 envelope shows no clear differences in oxygen CO isotopologue ratios compared with the local ISM. A mass-independent fractionation can be interpreted as being due to selective photodissociation of CO in the disk surface due to self-shielding. The deficits in C17 O and C18 O in the VV CrA protoplanetary disk are consistent with an analogous origin of the 16O variability in the solar

Twoplex 12/13 C6 aniline stable isotope and linkage-specific sialic acid labeling 2D-LC-MS workflow for quantitative N-glycomics.

PubMed

Albrecht, Simone; Mittermayr, Stefan; Smith, Josh; Martín, Silvia Millán; Doherty, Margaret; Bones, Jonathan

2017-01-01

Quantitative glycomics represents an actively expanding research field ranging from the discovery of disease-associated glycan alterations to the quantitative characterization of N-glycans on therapeutic proteins. Commonly used analytical platforms for comparative relative quantitation of complex glycan samples include MALDI-TOF-MS or chromatographic glycan profiling with subsequent data alignment and statistical evaluation. Limitations of such approaches include run-to-run technical variation and the potential introduction of subjectivity during data processing. Here, we introduce an offline 2D LC-MS E workflow for the fractionation and relative quantitation of twoplex isotopically labeled N-linked oligosaccharides using neutral 12 C 6 and 13 C 6 aniline (Δmass = 6 Da). Additional linkage-specific derivatization of sialic acids using 4-(4,6-dimethoxy-1,3,5-trizain-2-yl)-4-methylmorpholinium chloride offered simultaneous and advanced in-depth structural characterization. The potential of the method was demonstrated for the differential analysis of structurally defined N-glycans released from serum proteins of patients diagnosed with various stages of colorectal cancer. The described twoplex 12 C 6 / 13 C 6 aniline 2D LC-MS platform is ideally suited for differential glycomic analysis of structurally complex N-glycan pools due to combination and analysis of samples in a single LC-MS injection and the associated minimization in technical variation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Metabolomics driven analysis of six Nigella species seeds via UPLC-qTOF-MS and GC-MS coupled to chemometrics.

PubMed

Farag, Mohamed A; Gad, Haidy A; Heiss, Andreas G; Wessjohann, Ludger A

2014-05-15

Nigella sativa, commonly known as black cumin seed, is a popular herbal supplement that contains numerous phytochemicals including terpenoids, saponins, flavonoids, alkaloids. Only a few of the ca. 15 species in the genus Nigella have been characterized in terms of phytochemical or pharmacological properties. Here, large scale metabolic profiling including UPLC-PDA-MS and GC-MS with further multivariate analysis was utilized to classify 6 Nigella species. Under optimized conditions, we were able to annotate 52 metabolites including 8 saponins, 10 flavonoids, 6 phenolics, 10 alkaloids, and 18 fatty acids. Major peaks in UPLC-MS spectra contributing to the discrimination among species were assigned as kaempferol glycosidic conjugates, with kaempferol-3-O-[glucopyranosyl-(1→2)-galactopyranosyl-(1→2)-glucopyranoside, identified as potential taxonomic marker for N. sativa. Compared with GC-MS, UPLC-MS was found much more efficient in Nigella sample classification based on genetic and geographical origin. Nevertheless, both GC-MS and UPLC-MS support the remote position of Nigella nigellastrum in relation to the other taxa. Copyright © 2013 Elsevier Ltd. All rights reserved.

OSSE Observations of Centaurus A Over 18 Months

DTIC Science & Technology

1994-01-01

OSSE OBSERVATIONS OF CENTAURUS A OVER 18 MONTHS R.L. Kinzer, W.N. Johnson, J.D. Kurfess, M.S. Strickman, J.E. Grove, R.A. Kroeger E. O. Hulburt...D.C. 20375-5320 ABSTRACT OSSE observed Centaurus A at energies between 0.05 and 10 MeV in 1991, 1992, and in 1993. During each observation, this...radio galaxy Centaurus A (NGC 5128) on three occasions in 1991, 1992, and 1993. This source is among the brightest extragalactic objects above 100 keV

Development and validation of sensitive LC/MS/MS method for quantitative bioanalysis of levonorgestrel in rat plasma and application to pharmacokinetics study.

PubMed

Ananthula, Suryatheja; Janagam, Dileep R; Jamalapuram, Seshulatha; Johnson, James R; Mandrell, Timothy D; Lowe, Tao L

2015-10-15

Rapid, sensitive, selective and accurate LC/MS/MS method was developed for quantitative determination of levonorgestrel (LNG) in rat plasma and further validated for specificity, linearity, accuracy, precision, sensitivity, matrix effect, recovery efficiency and stability. Liquid-liquid extraction procedure using hexane:ethyl acetate mixture at 80:20 v:v ratio was employed to efficiently extract LNG from rat plasma. Reversed phase Luna column C18(2) (50×2.0mm i.d., 3μM) installed on a AB SCIEX Triple Quad™ 4500 LC/MS/MS system was used to perform chromatographic separation. LNG was identified within 2min with high specificity. Linear calibration curve was drawn within 0.5-50ng·mL(-1) concentration range. The developed method was validated for intra-day and inter-day accuracy and precision whose values fell in the acceptable limits. Matrix effect was found to be minimal. Recovery efficiency at three quality control (QC) concentrations 0.5 (low), 5 (medium) and 50 (high) ng·mL(-1) was found to be >90%. Stability of LNG at various stages of experiment including storage, extraction and analysis was evaluated using QC samples, and the results showed that LNG was stable at all the conditions. This validated method was successfully used to study the pharmacokinetics of LNG in rats after SubQ injection, providing its applicability in relevant preclinical studies. Copyright © 2015 Elsevier B.V. All rights reserved.

Development and validation of LC-MS/MS method for quantitative determination of (-)-securinine in mouse plasma.

PubMed

Wabuyele, Simuli L; Wald, David; Xu, Yan

2014-06-01

(-)-Securinine (SE) is a major alkaloid found in plant Securinega suffruticosa, which has a wide range of pharmacological activities including anticancer, anti-parasitic and central nervous system stimulating effects, etc. To aid the pharmacological study of SE, we developed an LC-MS/MS method for quantitative determination of SE in mouse plasma. In this method, plasma samples were first prepared with salting-out assisted liquid-liquid extraction using cold acetonitrile (-20°C) and 2.00 M ammonium acetate. Separation of SE and the internal standard (IS) from sample matrix was achieved on a Gemini Nx C18 column using 40% acetonitrile and 60% 10.0mM ammonium acetate at a flow rate of 0.200 mL min(-1). Quantification of SE was accomplished with positive electrospray ionization tandem mass spectrometry using mass transitions m/z 218.1→84.1 for SE, and m/z 204.1→70.2 for the IS. This method has a lower limit of quantitation (LLOQ) of 0.600 ng mL(-1) and a linear calibration range up to 600 ng mL(-1) in mouse plasma. The intra- and inter-run accuracy (%RE) and precision (%CV) were ≤ ± 6% and 6%, respectively. The IS normalized matrix factors from six lots of plasma matrices ranged 0.92-1.07, and the recoveries of plasma SE were 99-109%. The validated method has been applied to the measurement of SE in plasma samples of a mouse study. Copyright © 2014 Elsevier B.V. All rights reserved.

A new LC-MS/MS bioanalytical method for perindopril and perindoprilat in human plasma and milk.

PubMed

Lwin, Ei Mon Phyo; Gerber, Cobus; Song, Yunmei; Leggett, Catherine; Ritchie, Usha; Turner, Sean; Garg, Sanjay

2017-10-01

A first of its kind, simple, rapid, and sensitive liquid chromatography mass spectrometry (LC-MS/MS) method was developed and validated for quantification of perindopril and perindoprilat in both human plasma and breast milk. The analytes and internal standards (phenazone and acetyl salicylic acid) were extracted from biological matrices by protein precipitation. A Phenomenex® C-18 column was used to provide an appropriate chromatographic separation of the analytes, followed by detection with tandem mass spectrometry. Gradient chromatographic and mass spectrometric detection conditions with mobile phases (A: 5% methanol + 0.1% formic acid in water v/v, and B: 95% methanol + 0.1% formic acid in water v/v) were developed to achieve a LOQ of 0.5 ng/mL in both human plasma and milk. The method was suitable of evaluating clinical samples. The mass transition was followed as m/z 369.10/172.00 for perindopril, m/z 339.00/168.10 for perindoprilat, m/z 188.90/55.95 for phenazone, and m/z 179.04/137.02 for acetyl salicylic acid. The developed method was optimized and validated with a linear range of 0.1-200 ng/mL (r 2  = better than 0.99 for both perindopril and perindoprilat). The precision and accuracy values were within 15% CV. The overall recovery of the analytes was 80-110%. The method has good specificity and repeatability. Stability studies were conducted in both human plasma and bovine milk for up to 3 months, at the storage conditions of 25, 4, and -80 °C.

A high-throughput urinalysis of abused drugs based on a SPE-LC-MS/MS method coupled with an in-house developed post-analysis data treatment system.

PubMed

Cheng, Wing-Chi; Yau, Tsan-Sang; Wong, Ming-Kei; Chan, Lai-Ping; Mok, Vincent King-Kuen

2006-10-16

A rapid urinalysis system based on SPE-LC-MS/MS with an in-house post-analysis data management system has been developed for the simultaneous identification and semi-quantitation of opiates (morphine, codeine), methadone, amphetamines (amphetamine, methylamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA) and 3,4-methylenedioxymethamphetamine (MDMA)), 11-benzodiazepines or their metabolites and ketamine. The urine samples are subjected to automated solid phase extraction prior to analysis by LC-MS (Finnigan Surveyor LC connected to a Finnigan LCQ Advantage) fitted with an Alltech Rocket Platinum EPS C-18 column. With a single point calibration at the cut-off concentration for each analyte, simultaneous identification and semi-quantitation for the above mentioned drugs can be achieved in a 10 min run per urine sample. A computer macro-program package was developed to automatically retrieve appropriate data from the analytical data files, compare results with preset values (such as cut-off concentrations, MS matching scores) of each drug being analyzed and generate user-defined Excel reports to indicate all positive and negative results in batch-wise manner for ease of checking. The final analytical results are automatically copied into an Access database for report generation purposes. Through the use of automation in sample preparation, simultaneous identification and semi-quantitation by LC-MS/MS and a tailored made post-analysis data management system, this new urinalysis system significantly improves the quality of results, reduces the post-data treatment time, error due to data transfer and is suitable for high-throughput laboratory in batch-wise operation.

MALDI MS analysis of oligonucleotides: desalting by functional magnetite beads using microwave-assisted extraction.

PubMed

Chen, Wei-Yu; Chen, Yu-Chie

2007-11-01

The presence of alkali cation adductions of oligonucleotides commonly deteriorates matrix-assisted laser desorption/ionization (MALDI) mass spectra. Thus, desalting is required for oligonucleotide samples prior to MALDI MS analysis in order to prevent the mass spectra from developing poor quality. In this paper, we demonstrate a new approach to extract traces of oligonucleotides from aqueous solutions containing high concentrations of salts using microwave-assisted extraction. The C18-presenting magnetite beads, capable of absorbing microwave irradiation, are used as affinity probes for oligonucleotides with the addition of triethylammonium acetate as the counterions. This new microwave-assisted extraction approach using magnetite beads as the trapping agents and as microwave-absorbers has been demonstrated to be very effective in the selective binding of oligonucleotides from aqueous solutions. The extraction of oligonucleotides from solutions onto the C18-presenting magnetite beads takes only 30 s to enrich oligonucleotides in sufficient quantities for MALDI MS analysis. After using this desalting approach, alkali cation adductions of oligonucleotides are dramatically reduced in the MALDI mass spectra. The presence of saturated NaCl (approximately 6 M) in the oligonucleotide sample is tolerated without degrading the mass spectra. The detection limit for d(A)6 is approximately 2.8 fmol.

Storage stability study of porcine hepatic and intestinal cytochrome P450 isoenzymes by use of a newly developed and fully validated highly sensitive HPLC-MS/MS method.

PubMed

Schelstraete, Wim; Devreese, Mathias; Croubels, Siska

2018-02-01

Microsomes are an ideal medium to investigate cytochrome P450 (CYP450) enzyme-mediated drug metabolism. However, before microsomes are prepared, tissues can be stored for a long time. Studies about the stability of these enzymes in porcine hepatic and intestinal tissues upon storage are lacking. To be able to investigate CYP450 stability in microsomes prepared from these tissues, a highly sensitive and rapid HPLC-MS/MS method for the simultaneous determination of six CYP450 metabolites in incubation medium was developed and validated. The metabolites, paracetamol (CYP1A), 7-hydroxy-coumarin (CYP2A), 1-hydroxy-midazolam (CYP3A), 4-hydroxy-tolbutamide (CYP2C), dextrorphan (CYP2D), and 6-hydroxy-chlorzoxazone (CYP2E) were extracted with ethyl acetate at pH 1.0, followed by evaporation and separation on an Agilent Zorbax Eclipse Plus C18 column. The method was fully validated in a GLP-compliant laboratory according to European guidelines and was highly sensitive (LOQ = 0.25-2.5 ng/mL), selective, had good precision (RSD-within, 1.0-9.1%; RSD-between, 1.0-18.4%) and accuracy (within-run, 83.3-102%; between-run, 78.5-102%), and showed no relative signal suppression and enhancement. Consequently, this method was applied to study the stability of porcine hepatic and intestinal CYP450 isoenzymes when tissues were stored at - 80 °C. The results indicate that porcine CYP450 isoenzymes are stable in tissues at least up to 4 months when snap frozen and stored at - 80 °C. Moreover, the results indicate differences in porcine CYP450 stability compared to rat, rabbit, and fish CYP450, as observed by other research groups, hence stressing the importance to investigate the CYP450 stability of a specific species.

Quantification of seven β-lactam antibiotics and two β-lactamase inhibitors in human plasma using a validated UPLC-MS/MS method.

PubMed

Carlier, Mieke; Stove, Veronique; Roberts, Jason A; Van de Velde, Eric; De Waele, Jan J; Verstraete, Alain G

2012-11-01

There is an increasing interest in monitoring plasma concentrations of β-lactam antibiotics. The objective of this work was to develop and validate a rapid ultra-performance liquid chromatographic method with tandem mass spectrometric detection (UPLC-MS/MS) for simultaneous quantification of amoxicillin, ampicillin, cefuroxime, cefazolin, ceftazidime, meropenem, piperacillin, clavulanic acid and tazobactam. Sample clean-up included protein precipitation with acetonitrile and back-extraction of acetonitrile with dichloromethane. Six deuterated β-lactam antibiotics were used as internal standards. Chromatographic separation was performed on a Waters ACQUITY UPLC system using a BEH C(18) column (1.7 μm, 100 mm×2.1 mm) applying a binary gradient elution of water and acetonitrile both containing 0.1% formic acid. The total run time was 5.5 min. The developed method was validated in terms of precision, accuracy, linearity, matrix effect and recovery. The assay has now been successfully used to determine concentrations of amoxicillin/clavulanic acid, cefuroxime and meropenem in plasma samples from intensive care patients. Copyright © 2012 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Complementary b/y fragment ion pairs from post-source decay of metastable YahO for calibration of MALDI-TOF-TOF-MS/MS

USDA-ARS?s Scientific Manuscript database

Complementary b/y fragment ion pairs from post-source decay (PSD) of metastable YahO protein ion were evaluated for use in the calibration of MALDI-TOF-TOF for tandem mass spectrometry (MS/MS). The yahO gene from pathogenic Escherichia coli O157:H7 strain EDL933 was cloned into a pBAD18 plasmid vect...

Comparison of (11)C-4'-thiothymidine, (11)C-methionine, and (18)F-FDG PET/CT for the detection of active lesions of multiple myeloma.

PubMed

Okasaki, Momoko; Kubota, Kazuo; Minamimoto, Ryogo; Miyata, Yoko; Morooka, Miyako; Ito, Kimiteru; Ishiwata, Kiichi; Toyohara, Jun; Inoue, Tomio; Hirai, Risen; Hagiwara, Shotaro; Miwa, Akiyoshi

2015-04-01

The aims of this study were to evaluate the possibility of using (11)C-methionine ((11)C-MET) and (11)C-4'-thiothymidine ((11)C-4DST) whole-body PET/CT for the imaging of amino acid metabolism and DNA synthesis, respectively, when searching for bone marrow involvement in patients with multiple myeloma (MM) and to compare these findings with those for (18)F-FDG PET/CT and aspiration cytology. A total of 64 patients with MM, solitary plasmacytoma, monoclonal gammopathy of undetermined significance, or an unspecified diagnosis were prospectively enrolled. All the patients underwent three whole-body PET/CT examinations within a period of 1 week. First, the tracer accumulation was visually evaluated as positive, equivocal, or negative for 55 focal lytic lesions visualized using CT in 24 patients. Second, the percentages of marrow plasma cells as calculated using a bone marrow aspiration smear and tracer accumulation were evaluated in the posterior iliac crests of 36 patients. Among the 55 lytic lesions, the (11)C-MET and (11)C-4DST findings tended to reveal more positive findings than the (18)F-FDG findings. Based on the standard criteria for the diagnosis of active myeloma using the percentage of marrow plasma cells, significant differences were found between the (18)F-FDG and (11)C-MET findings and between the (18)F-FDG and (11)C-4DST findings, but no significant difference was observed between the (11)C-MET and (11)C-4DST findings. The addition of (11)C-MET and (11)C-4DST to (18)F-FDG when performing PET/CT enabled clearer evaluations of equivocal lesions. Based on cytological diagnostic criteria, (11)C-MET and (11)C-4DST were more sensitive than (18)F-FDG for the detection of active lesions. (11)C-MET and (11)C-4DST were more useful than (18)F-FDG for the detection of active lesions, especially during the early stage of disease.

Assessing phosphatidylethanol (PEth) levels reflecting different drinking habits in comparison to the alcohol use disorders identification test - C (AUDIT-C).

PubMed

Schröck, Alexandra; Wurst, Friedrich M; Thon, Natasha; Weinmann, Wolfgang

2017-09-01

In addition to monitoring problematic or harmful alcohol consumption, drinking experiments indicated the potential of phosphatidylethanols (PEth) in abstinence monitoring. To date, no profound evaluation of thresholds for the differentiation of abstinence from moderate drinking and for detection of excessive consumption based on PEth homologues exists. Investigations with a large group of healthy volunteers (n=300) were performed to establish PEth reference values reflecting different drinking habits. Blood samples were analyzed for PEth 16:0/18:1 and 16:0/18:2 by online-SPE-LC-MS/MS method. Results were compared to AUDIT-C questionnaires, to the amounts of alcohol consumed during the two-weeks prior to blood sampling, and were statistically evaluated. PEth concentrations were significantly correlated with self-reported alcohol consumption (r>0.69) and with AUDIT-C scores (r>0.65). 4.0% of 300 volunteers reported abstinence (AUDIT-C score: 0), no PEth was detectable in their blood. PEth 16:0/18:1 concentrations below the limit of detection of 10.0ng/mL match with abstinence and light drinking habits (≤10g pure alcohol/day). However, some volunteers classified as "excessive alcohol consumers" had negative PEth results. In the group of volunteers classified as "moderate drinkers" (AUDIT-C score: 1-3 (women) and 1-4 (men)), 95% of the test persons had PEth 16:0/18:1 ranging from not detected to 112ng/mL, and PEth 16:0/18:2 ranging from not detected to 67.0ng/mL. Combination of self-reported alcohol consumption and AUDIT-C score showed that negative PEth results match with abstinence or light drinking. Moderate alcohol consumption resulted in PEth 16:0/18:1 from 0 to 112ng/mL and for PEth 16:0/18:2 ranged from 0 to 67.0ng/mL. Higher PEth concentrations indicated excessive alcohol consumption. Copyright © 2017 Elsevier B.V. All rights reserved.

In vivo TSPO imaging in patients with multiple sclerosis: a brain PET study with [18F]FEDAA1106.

PubMed

Takano, Akihiro; Piehl, Fredrik; Hillert, Jan; Varrone, Andrea; Nag, Sangram; Gulyás, Balázs; Stenkrona, Per; Villemagne, Victor L; Rowe, Christopher C; Macdonell, Richard; Tawil, Nabil Al; Kucinski, Thomas; Zimmermann, Torsten; Schultze-Mosgau, Marcus; Thiele, Andrea; Hoffmann, Anja; Halldin, Christer

2013-04-24

The activation of microglia, in general, and the upregulation of the translocator protein (18 kDa) (TSPO) system, in particular, are key features of neuroinflammation, of which the in vivo visualization and quantitative assessment are still challenging due to the lack of appropriate molecular imaging biomarkers. Recent positron emission tomography (PET) studies using TSPO radioligands such as [11C]PK11195 and [11C]PBR28 have indicated the usefulness of these PET biomarkers in patients with neuroinflammatory diseases, including multiple sclerosis (MS). [18F]FEDAA1106 is a recently developed PET radioligand for the in vivo quantification of TSPO. In the present study, we aimed at investigating the diagnostic usefulness of [18F]FEDAA1106 in patients with MS. Nine patients (three on the interferon beta therapy and six without immunomodulatory therapy; seven females/two males; age 34.2 ± 9.1 years old) with relapsing-remitting MS in acute relapse and with gadolinium (Gd)-enhancing lesion(s) in the magnetic resonance imaging (MRI) scans and five healthy controls (four females/one male, age 38.0 ± 9.7 years old) were investigated in this study. Genetic information about the TSPO binding could not be obtained because knowledge about the importance of genetic background for TSPO binding was not available at the time the study was performed. Dynamic PET measurements were performed using an ECAT EXACT HR system (CTI/Siemens, Knoxville, TN, USA) for a total of 150 min, with a 30-min break after the injection of 153.4 ± 10.2 MBq of [18F]FEDAA1106. Metabolite-corrected arterial plasma samples were used to calculate the input function. PET data were analyzed in the following ways: (1) region-of-interest analysis for cortical and subcortical regions was performed using a two-tissue compartment kinetic model in order to estimate binding potentials (BPND) and distribution volume (VT), (2) the feasibility of the estimation of BPND and VT was investigated for MS lesions, and (3) VT

Rapid method for the measurement of circulating thyroid hormones in low volumes of teleost fish plasma by LC-ESI/MS/MS

PubMed Central

Noyes, Pamela D.; Lema, Sean C.; Roberts, Simon C.; Cooper, Ellen M.

2014-01-01

Thyroid hormones are critical regulators of normal development and physiological functioning in all vertebrates. Radioimmunoassay (RIA) approaches have been the method of choice for measuring circulating levels of thyroid hormones in vertebrates. While sensitive, RIA-based approaches only allow for a single analyte measurement per assay, can lack concordance across platforms and laboratories, and can be prone to analytical interferences especially when used with fish plasma. Ongoing advances in liquid chromatography tandem mass spectrometry (LC/MS/MS) have led to substantial decreases in detection limits for thyroid hormones and other biomolecules in complex matrices, including human plasma. Despite these advances, current analytical approaches do not allow for the measurement of native thyroid hormone in teleost fish plasma by mass spectrometry and continue to rely on immunoassay. In this study, we developed a new method that allows for the rapid extraction and simultaneous measurement of total T4 (TT4) and total T3 (TT3) in low volumes (50 μL) of fish plasma by LC/MS/MS. Methods were optimized initially in plasma from rainbow trout (Oncorhynchus mykiss) and applied to plasma from other teleost fishes, including fathead minnows (Pimephales promelas), mummichogs (Fundulus heteroclitus), sockeye salmon (Oncorhynchus nerka), and coho salmon (Oncorhynchus kisutch). Validation of method performance with T4- and T3-spiked rainbow trout plasma at 2 and 4 ng/mL produced mean recoveries ranging from 82 to 95 % and 97 to 105 %, respectively. Recovery of 13C12-T4 internal standard in plasma extractions was: 99±1.8 % in rainbow trout, 85±11 % in fathead minnow, 73±5.0 % in mummichog, 73±1.7 % in sockeye salmon, and 80±8.4 % in coho salmon. While absolute levels of thyroid hormones measured in identical plasma samples by LC/MS/MS and RIA varied depending on the assay used, T4/T3 ratios were generally consistent across both techniques. Less variability was measured among

Al-Mn CVD-FBR coating on P92 steel as protection against steam oxidation at 650 °C: TGA-MS study

NASA Astrophysics Data System (ADS)

Castañeda, S. I.; Pérez, F. J.

2018-02-01

The initial stages oxidation of the P92 ferritic/martensitic steel with and without Al-Mn coating at 650 °C in Ar+40%H2O for 240 h were investigated by mass spectrometry (MS) and thermogravimetric analysis (TGA). TGA-MS measurements were conducted in a closed steam loop. An Al-Mn coating was deposited on P92 steel at 580 °C for 2 h by chemical vapour deposition in a fluidized bed reactor (CVD-FBR). The coating as-deposited was treated in the same reactor at 700 °C in Ar for 2h, in order to produce aluminide phases that form the protective alumina layer (Al2O3) during oxidation. MS measurements at 650 °C of the Al-Mn/P92 sample for 200 h indicated the presence of (Al-Mn-Cr-Fe-O) volatile species of small intensity. Uncoated P92 steel oxidized under the same steam oxidation conditions emitted greater intensities of volatile species of Cr, Fe and Mo in comparison with intensities from coated steel. TGA measurements verified that the mass gained by the coated sample was up to 300 times lower than for uncoated P92 steel. The morphology, composition and structure of samples by Scanning Electron Microscopy SEM, Backscattered Electron (BSE) detection, X-ray Energy Dispersive Spectrometry (EDAX) and X-ray Diffraction (XRD) are described.

Analysis of 25 C NBOMe in Seized Blotters by HPTLC and GC–MS

PubMed Central

Duffau, Boris; Camargo, Cristian; Kogan, Marcelo; Fuentes, Edwar; Cassels, Bruce Kennedy

2016-01-01

Use of unauthorized synthetic drugs is a serious, forensic, regulatory and public health issue. In this scenario, consumption of drug-impregnated blotters is very frequent. For decades, blotters have been generally impregnated with the potent hallucinogen known as lysergic acid diethylamide (LSD); however, since 2013 blotter stamps with N-2 methoxybenzyl-substituted phenylethylamine hallucinogen designated as “NBOMes” have been seized in Chile. To address this issue with readily accessible laboratory equipment, we have developed and validated a new HPTLC method for the identification and quantitation of 25-C-NBOMe in seized blotters and its confirmation by GC–MS. The proposed method was validated according to SWGTOX recommendations and is suitable for routine analysis of seized blotters containing 25-C-NBOMe. With the validated method, we analyzed 15 real samples, in all cases finding 25-C-NBOMe in a wide dosage range (701.0–1943.5 µg per blotter). In this situation, we can assume that NBOMes are replacing LSD as the main hallucinogenic drug consumed in blotters in Chile. PMID:27406128

Development and validation of an HPLC/UV/MS method for simultaneous determination of 18 preservatives in grapefruit seed extract.

PubMed

Ganzera, Markus; Aberham, Anita; Stuppner, Hermann

2006-05-31

Grapefruit seed extracts are used in cosmetics, food supplements, and pesticides because of their antimicrobial properties, but suspicions about the true nature of the active compounds arose when synthetic disinfectants such as benzethonium or benzalkonium chloride were found in commercial products. The HPLC method presented herein allows the quality assessment (qualitative and quantitative) of these products for the first time. On the basis of a standard mixture of 18 preservatives most relevant for food and grapefruit products, a method was developed allowing the baseline separation of all compounds within 40 min. Optimum results were obtained with a C-8 stationary phase and a solvent system comprising aqueous trifluoroacetic acid, acetonitrile, and 2-propanol. The assay was fully validated and shown to be sensitive (LOD < or= 12.1 ng on-column), accurate (recovery rates > or = 96.1%), repeatable (sigma(rel) < or = 3.5%), precise (intra-day variation < or = 4.5%, interday variation < or = 4.1%), and rugged. Without any modifications the method could be adopted for LC-MS experiments, where the compounds of interest were directly assignable in positive ESI mode. The quantitative results of several products for ecofarming confirmed previous studies, as seven out of nine specimens were adulterated with preservatives in varying composition. The samples either contained benzethonium chloride (2.5-176.9 mg/mL) or benzalkonium chloride (138.2-236.3 mg/mL), together with smaller amounts of 4-hydroxybenzoic acid esters, benzoic acid, and salicylic acid.

STS-33 MS Carter and MS Thornton display 'Maggot on Board' sign and candy

NASA Technical Reports Server (NTRS)

1989-01-01

STS-33 Mission Specialist (MS) Manley L. Carter, Jr (left) and MS Kathryn C. Thornton display 'Maggot on Board' sign and 'SMARTIES' candy stored in plastic bag on the aft flight deck of Discovery, Orbiter Vehicle (OV) 103. The mission specialists are wearing their mission polo shirts and communications kit assembly headsets. An overhead window appears above their heads. A gold necklace chain floats around Carter's neck.

[Simultaneous determination of sivelestat and its metabolite XW-IMP-A in human plasma using HPLC-MS/MS].

PubMed

Wang, Jing; Dai, Xiao-jian; Zhang, Yi-fan; Zhong, Da-fang; Wu, Yu-lin; Chen, Xiao-yan

2015-10-01

A simple and rapid method was developed based on high performance liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) to determine sivelestat and its metabolite XW-IMP-A in human plasma. After a simple protein precipitation, the samples and internal standards were analyzed on a C18 column by a gradient elution program. The mobile phase consisted of 30% acetonitrile in methanol and 5 mmol · L(-1) ammonium acetate at a flow rate of 0.7 mL · min(-1). The mass spectrometric data was collected in multiple reaction monitoring mode (MRM) in the negative electrospray ionization. The standard curves were linear in the range of 10.0-15,000 ng · mL(-1) for sivelestat, and 2.50-1000 ng · mL(-1) for XW-IMP-A. The low limits of quantitation were identified at 10.0 and 2.50 ng · mL for sivelestat and XW-IMP-A, respectively. The intra- and inter-day precision were within 11.3% and 13.1% for sivelestat and XW-IMP-A, and accuracy was 0.3% and 0.6% for sivelestat and XW-IMP-A, within the acceptable limits across all concentrations. The method was successfully validated in the pharmacokinetic study of sivelestat in healthy Chinese volunteers.

Validated UPLC/MS/MS assay for quantitative bioanalysis of elbasvir in rat plasma and application to pharmacokinetic study.

PubMed

Liu, Haiyan; Xu, Hongjiang; Song, Wei; Zhang, Yinsheng; Yu, Sen; Huang, Xin

2016-03-15

Rapid, sensitive, selective and accurate ultra performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the quantification of elbasvir (ELB) in rat plasma with deuterated elbasvir (ELB-D6) as internal standard (IS).Sample preparation was done by protein precipitation using acetonitrile containing 50 ng/mL IS. Chromatographic separation was achieved by an UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 μm) column with a gradient mobile phase consisting of acetonitrile-water (containing 5.0mM ammonium acetate with 0.01% acetic acid, pH 4.5) as mobile phase at a flow rate of 0.3 mL/min for 3 min. ELB was monitored using positive electrospray triple quadrupole mass spectrometer (Waters Xevo TQ-S) via multiple reaction monitoring (MRM) mode. The monitored transitions were set at m/z 882.51→656.42 and m/z 888.49→662.43 for ELB and ELB-D6, respectively. The achieved lower limit of quantification was 1.0 ng/mL. The validated method had an excellent linearity in the range of 1.0-2000 ng/mL (r(2)>0.996). Recovery efficiency at three levels QC concentrations of 2.0 (low), 160 (medium) and 1600 (high) ng/mLwas in the range of 98.29-106.40% for ELB. Matrix effect was found to be minimal. The intra- and inter-day precisions were less than 7.01%. The intra- and inter-day accuracies were determined to be within ±6.23% for all accuracy measurements. The validated simple and rapid UPLC-MS/MS method was successfully used to the pharmacokinetics study of ELB in rats, providing its applicability in relevant preclinical studies. Copyright © 2016 Elsevier B.V. All rights reserved.

Determination of crenolanib in human serum and cerebrospinal fluid by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS).

PubMed

Roberts, Michael S; Turner, David C; Owens, Thandranese S; Ramachandran, Abhijit; Wetmore, Cynthia; Throm, Stacy L; Stewart, Clinton F

2013-06-15

A LC-ESI-MS/MS method for the determination of crenolanib (CP-868,596) in human serum was developed and validated employing d4-CP-868,596 as an internal standard (ISTD). In addition to human serum, the method was also partially validated for crenolanib determination in human cerebrospinal fluid (CSF) samples. Sample aliquots (50μl of serum or CSF) were prepared for analysis using liquid-liquid extraction (LLE) with tert-butyl methyl ether. Chromatography was performed using a phenomenex Gemini C18 column (3μm, 100mm×4.6mm I.D.) in a column heater set at 50°C and an isocratic mobile phase (methanol/water/formic acid at a volume ratio of 25/25/0.15, v/v/v). The flow rate was 0.45mL/min, and the retention time for both analyte and ISTD was less than 3.5min. Samples were analyzed with an API-5500 LC-MS/MS system (ESI) in positive ionization mode coupled to a Shimadzu HPLC system. The ion transitions monitored were m/z 444.4→373.1 and m/z 448.2→374.2 for crenolanib and ISTD, respectively. The method was linear over the range of 5-1000ng/mL for serum and 0.5-1000ng/mL for CSF. For human serum, both intra-day and inter-day precision were <4%, while intra-day and inter-day accuracy were within 8% of nominal values. Recovery was greater than 50% for both the analyte and ISTD. For CSF samples, both intra-day and inter-day precision were <9% except at the lower limit of quantification (LLOQ) which was <17%. The intra-day and inter-day accuracy were within 11% of the nominal CSF concentrations. After validation, this method was successfully applied to the analysis of serial pharmacokinetic samples obtained from a child treated with oral crenolanib. Copyright © 2013 Elsevier B.V. All rights reserved.

Metabolism of the new psychoactive substances N,N-diallyltryptamine (DALT) and 5-methoxy-DALT and their detectability in urine by GC-MS, LC-MSn, and LC-HR-MS-MS.

PubMed

Michely, Julian A; Helfer, Andreas G; Brandt, Simon D; Meyer, Markus R; Maurer, Hans H

2015-10-01

N,N-Diallyltryptamine (DALT) and 5-methoxy-DALT (5-MeO-DALT) are synthetic tryptamine derivatives commonly referred to as so-called new psychoactive substances (NPS). They have psychoactive effects that may be similar to those of other tryptamine derivatives. The objectives of this work were to study the metabolic fate and detectability, in urine, of DALT and 5-MeO-DALT. For metabolism studies, rat urine obtained after high-dose administration was prepared by precipitation and analyzed by liquid chromatography-high-resolution mass spectrometry (LC-HR-MS-MS). On the basis of the metabolites identified, several aromatic and aliphatic hydroxylations, N-dealkylation, N-oxidation, and combinations thereof are proposed as the main metabolic pathways for both compounds. O-Demethylation of 5-MeO-DALT was also observed, in addition to extensive glucuronidation or sulfation of both compounds after phase I transformation. The cytochrome P450 (CYP) isoenzymes predominantly involved in DALT metabolism were CYP2C19, CYP2D6, and CYP3A4; those mainly involved in 5-MeO-DALT metabolism were CYP1A2, CYP2C19, CYP2D6, and CYP3A4. For detectability studies, rat urine was screened by GC-MS, LC-MS(n), and LC-HR-MS-MS after administration of low doses. LC-MS(n) and LC-HR-MS-MS were deemed suitable for monitoring consumption of both compounds. The most abundant targets were a ring hydroxy metabolite of DALT, the N,O-bis-dealkyl metabolite of 5-MeO-DALT, and their glucuronides. GC-MS enabled screening of DALT by use of its main metabolites only.

Enhanced detection of type C botulinum neurotoxin by the Endopep-MS assay through optimization of peptide substrates

PubMed Central

Wang, Dongxia; Krilich, Joan; Baudys, Jakub; Barr, John R.; Kalb, Suzanne R.

2015-01-01

It is essential to have a simple, quick and sensitive method for the detection and quantification of botulinum neurotoxins, the most toxic substances and the causative agents of botulism. Type C botulinum neurotoxin (BoNT/C) represents one of the seven members of distinctive BoNT serotypes (A to G) that cause botulism in animals and avians. Here we report the development of optimized peptide substrates for improving the detection of BoNT/C and /CD mosaic toxins using an Endopep-MS assay, a mass spectrometry-based method that is able to rapidly and sensitively detect and differentiate all types of BoNTs by extracting the toxin with specific antibodies and detecting the unique cleavage products of peptide substrates. Based on the sequence of a short SNAP-25 peptide, we conducted optimization through a comprehensive process including length determination, terminal modification, single and multiple amino acid residue substitution, and incorporation of unnatural amino acid residues. Our data demonstrate that an optimal peptide provides a more than 200-fold improvement over the substrate currently used in the Endopep-MS assay for the detection of BoNT/C1 and /CD mosaic. Using the new substrate in a four-hour cleavage reaction, the limit of detection for the BoNT/C1 complex spiked in buffer, serum and milk samples was determined to be 0.5, 0.5 and 1 mouseLD50/mL, respectively, representing a similar or higher sensitivity than that obtained by traditional mouse bioassay. PMID:25913863

LC-MS/MS suggests that hole hopping in cytochrome c peroxidase protects its heme from oxidative modification by excess H2O2 † †Electronic supplementary information (ESI) available. See DOI: 10.1039/c6sc03125k Click here for additional data file.

PubMed Central

Kathiresan, Meena

2017-01-01

We recently reported that cytochrome c peroxidase (Ccp1) functions as a H2O2 sensor protein when H2O2 levels rise in respiring yeast. The availability of its reducing substrate, ferrocytochrome c (CycII), determines whether Ccp1 acts as a H2O2 sensor or peroxidase. For H2O2 to serve as a signal it must modify its receptor so we employed high-performance LC-MS/MS to investigate in detail the oxidation of Ccp1 by 1, 5 and 10 M eq. of H2O2 in the absence of CycII to prevent peroxidase activity. We observe strictly heme-mediated oxidation, implicating sequential cycles of binding and reduction of H2O2 at Ccp1's heme. This results in the incorporation of ∼20 oxygen atoms predominantly at methionine and tryptophan residues. Extensive intramolecular dityrosine crosslinking involving neighboring residues was uncovered by LC-MS/MS sequencing of the crosslinked peptides. The proximal heme ligand, H175, is converted to oxo-histidine, which labilizes the heme but irreversible heme oxidation is avoided by hole hopping to the polypeptide until oxidation of the catalytic distal H52 in Ccp1 treated with 10 M eq. of H2O2 shuts down heterolytic cleavage of H2O2 at the heme. Mapping of the 24 oxidized residues in Ccp1 reveals that hole hopping from the heme is directed to three polypeptide zones rich in redox-active residues. This unprecedented analysis unveils the remarkable capacity of a polypeptide to direct hole hopping away from its active site, consistent with heme labilization being a key outcome of Ccp1-mediated H2O2 signaling. LC-MS/MS identification of the oxidized residues also exposes the bias of electron paramagnetic resonance (EPR) detection toward transient radicals with low O2 reactivity. PMID:28451256

UPLC-MS/MS Analysis of Methotrexate in Human Plasma and Comparison with the Fluorescence Polarization Immunoassay.

PubMed

Mei, Shenghui; Zhu, Leting; Li, Xingang; Wang, Jiaqing; Jiang, Xueyun; Chen, Haiyan; Huo, Jiping; Yang, Li; Lin, Song; Zhao, Zhigang

2017-01-01

Methotrexate (MTX) plasma concentration is routinely monitored to guide the dosage regimen of rescue drugs. This study aims to develop and validate an ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for plasma MTX analysis, and to establish its agreement with the fluorescence polarization immunoassay (FPIA) in patients with high-dose MTX therapy. Separation was achieved by gradient elution with methanol and water (0.05% formic acid) at 40°C with a run time of 3 min. The intra- and inter-day inaccuracy and imprecision of the UPLC-MS/MS method were -4.25 to 3.1 and less than 7.63%, respectively. The IS-normalized recovery and matrix effect were 87.05 to 92.81 and 124.43 to 134.57%. The correlation coefficients between UPLC-MS/MS and FPIA were greater than 0.98. The UPLC-MS/MS method was in agreement with the FPIA at high levels of MTX (1.0 - 100 μmol/L), but not at low levels (0.01 - 1.0 μmol/L). Further studies are warranted to confirm these results.

18 CFR 2.55 - Definition of terms used in section 7(c).

Code of Federal Regulations, 2014 CFR

2014-04-01

... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false Definition of terms used in section 7(c). 2.55 Section 2.55 Conservation of Power and Water Resources FEDERAL ENERGY... Commission's regulations (18 CFR 1b.21(g)) and the Dispute Resolution Division Helpline number. (2) “Affected...

The structure investigations of dehydroacetic acid and 1,8-diaminonaphthalene condensation product by NMR, MS, and X-ray measurements

NASA Astrophysics Data System (ADS)

Kołodziej, B.; Morawiak, M.; Kamieński, B.; Schilf, W.

2016-05-01

A new unexpected product of condensation reaction of 1,8-diaminonaphthalene (DAN) and carbonyl compound (here: dehydroacetic acid (dha)) was synthesized. Discussion about the molecular structure of possible products of this reaction was done on the base of NMR studies. The structure of the titled product in both DMSO solution and in the solid state was resolved by analysis of its spectral data (X-ray structure analysis, multinuclear NMR in solution and solid state spectra) and MS measurements. The presented studies provided clear evidence that the titled product exists in diluted DMSO solution as the mixture of two kinetic free ionic species whereas in concentrated DMSO solution as well as in the solid state this system forms associated ionic pairs bonded together by hydrogen bonds.

Development of an LC-MS/MS method for the determination of endogenous cortisol in hair using (13)C3-labeled cortisol as surrogate analyte.

PubMed

Binz, Tina M; Braun, Ueli; Baumgartner, Markus R; Kraemer, Thomas

2016-10-15

Hair cortisol levels are increasingly applied as a measure for stress in humans and mammals. Cortisol is an endogenous compound and is always present within the hair matrix. Therefore, "cortisol-free hair matrix" is a critical point for any analytical method to accurately quantify especially low cortisol levels. The aim of this project was to modify current methods used for hair cortisol analysis to more accurately determine low endogenous cortisol concentrations in hair. For that purpose, (13)C3-labeled cortisol, which is not naturally present in hair (above 13C natural abundance levels), was used for calibration and comparative validation applying cortisol versus (13)C3-labeled cortisol. Cortisol was extracted from 20mg hair (standard sample amount) applying an optimized single step extraction protocol. An LC-MS/MS method was developed for the quantitative analysis of cortisol using either cortisol or (13)C3-cortisol as calibrators and D7-cortisone as internal standard (IS). The two methods (cortisol/(13)C3-labeled cortisol) were validated in a concentration range up to 500pg/mg and showed good linearity for both analytes (cortisol: R(2)=0.9995; (13)C3-cortisol R(2)=0.9992). Slight differences were observed for limit of detection (LOD) (0.2pg/mg/0.1pg/mg) and limit of quantification (LOQ) (1pg/mg/0.5pg/mg). Precision was good with a maximum deviation of 8.8% and 10% for cortisol and (13)C3-cortisol respectively. Accuracy and matrix effects were good for both analytes except for the quality control (QC) low cortisol. QC low (2.5pg/mg) showed matrix effects (126.5%, RSD 35.5%) and accuracy showed a deviation of 26% when using cortisol to spike. These effects are likely to be caused by the unknown amount of endogenous cortisol in the different hair samples used to determine validation parameters like matrix effect, LOQ and accuracy. No matrix effects were observed for the high QC (400pg/mg) samples. Recovery was good with 92.7%/87.3% (RSD 9.9%/6.2%) for QC low and

Determination of polyadipates migrating from lid gaskets of glass jars. Hydrolysis to adipic acid and measurement by LC-MS/MS.

PubMed

Driffield, M; Bradley, E L; Harmer, N; Castle, L; Klump, S; Mottier, P

2010-10-01

Polyadipate plasticizers can be present in the polyvinylchloride (PVC) gaskets used to seal the lids of glass jars. As the gaskets can come into direct contact with the foodstuffs inside the jar, the potential exists for polyadipate migration into the food. The procedure and performance characteristics of a test method for the analysis of polyadipates in food simulants (3% aqueous acetic acid and 10% aqueous ethanol) and the volatile test media used in substitute fat tests (isooctane and 95% aqueous ethanol) are described. The PVC gaskets were exposed to the food simulants or their substitutes under standard test conditions. Studies were initially carried out using direct measurement of the polyadipate oligomers by liquid chromatography with time-of-flight mass spectrometric detection (LC-TOF-MS) but this was not practical due to the number of peaks detected. Instead, the migrating polyadipates were hydrolysed to adipic acid and measured by liquid chromatography with tandem mass spectrometric detection (LC-MS/MS). The amount of polyadipate that this measurement of adipic acid represents was then calculated. Method performance was assessed by analysis of gaskets from two types of jar lids by single-laboratory validation. Linearity, sensitivity, repeatability, intermediate reproducibility and recovery were determined to be suitable for checking compliance with the 30 mg/kg specific migration limits for polyesters of 1,2-propane diol and/or 1,3- and/or 1,4-butanediol and/or polypropylene-glycol with adipic acid, which may be end-capped with acetic acid or fatty acids C(12)-C(18) or n-octanol and/or n-decanol. The method was found to be much quicker than previous methods involving extraction, clean-up, hydrolysis, esterification, derivatisation and GC measurement, consequently saving time and money.

LC-MS/MS method for the simultaneous determination of Lys-MCC-DM1, MCC-DM1 and DM1 as potential intracellular catabolites of the antibody-drug conjugate trastuzumab emtansine (T-DM1).

PubMed

Liu, Yazhong; Zhou, Fang; Sang, Hua; Ye, Hui; Chen, Qianying; Yao, Lan; Ni, Ping; Wang, Guangji; Zhang, Jingwei

2017-04-15

Lysine-MCC-DM1, MCC-DM1 and DM1 are potential catabolites of trastuzumab emtansine (T-DM1). A convenient liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to detect these catabolites simultaneously in in vitro investigations for the first time. Protein precipitation was utilized to prepare the samples. Chromatographic separation was achieved on a Phenomenex Kinetex C18 column (100×2.1mm, 2.6μm) with mobile-phase gradient elution. The calibration curves of each analyte ranging from 1 to 100nM showed good linearity (r 2 >0.995). The method was validated successfully and applied to the intracellular catabolism and regulation of T-DM1. Copyright © 2017 Elsevier B.V. All rights reserved.

17 CFR 240.15c1-8 - Sales at the market.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Sales at the market. 240.15c1... Securities Exchange Act of 1934 Rules Relating to Over-The-Counter Markets § 240.15c1-8 Sales at the market... securities exchange that such security is being offered to such customer “at the market” or at a price...

18 CFR 2.55 - Definition of terms used in section 7(c).

Code of Federal Regulations, 2013 CFR

2013-04-01

... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Definition of terms used in section 7(c). 2.55 Section 2.55 Conservation of Power and Water Resources FEDERAL ENERGY..., 25 FR 2363, Mar. 19, 1960; Order 241, 27 FR 510, Jan. 18, 1962; Order 148-A, 38 FR 11450, May 8, 1973...

Kinetic Modelling of Infection Tracers [18F]FDG, [68Ga]Ga-Citrate, [11C]Methionine, and [11C]Donepezil in a Porcine Osteomyelitis Model.

PubMed

Jødal, Lars; Jensen, Svend B; Nielsen, Ole L; Afzelius, Pia; Borghammer, Per; Alstrup, Aage K O; Hansen, Søren B

2017-01-01

Positron emission tomography (PET) is increasingly applied for infection imaging using [ 18 F]FDG as tracer, but uptake is unspecific. The present study compares the kinetics of [ 18 F]FDG and three other PET tracers with relevance for infection imaging. A juvenile porcine osteomyelitis model was used. Eleven pigs underwent PET/CT with 60-minute dynamic PET imaging of [ 18 F]FDG, [ 68 Ga]Ga-citrate, [ 11 C]methionine, and/or [ 11 C]donepezil, along with blood sampling. For infectious lesions, kinetic modelling with one- and two-tissue-compartment models was conducted for each tracer. Irreversible uptake was found for [ 18 F]FDG and [ 68 Ga]Ga-citrate; reversible uptake was found for [ 11 C]methionine (two-tissue model) and [ 11 C]donepezil (one-tissue model). The uptake rate for [ 68 Ga]Ga-citrate was slow and diffusion-limited. For the other tracers, the uptake rate was primarily determined by perfusion (flow-limited uptake). Net uptake rate for [ 18 F]FDG and distribution volume for [ 11 C]methionine were significantly higher for infectious lesions than for correspondingly noninfected tissue. For [ 11 C]donepezil in pigs, labelled metabolite products appeared to be important for the analysis. The kinetics of the four studied tracers in infection was characterized. For clinical applications, [ 18 F]FDG remains the first-choice PET tracer. [ 11 C]methionine may have a potential for detecting soft tissue infections. [ 68 Ga]Ga-citrate and [ 11 C]donepezil were not found useful for imaging of osteomyelitis.

Lack of association of -607 C/A and -137 G/C polymorphisms in interleukin 18 gene with susceptibility to gout disease in Chinese Han male population.

PubMed

Li, Changgui; Yuan, Ying; Wang, Xinfeng; Han, Lin; Chu, Nan; Wang, Hui; Liu, Shiguo

2012-06-01

To identify association of IL18-607 C/A and -137 G/C polymorphism with susceptibility to gout in Chinese Han male population, We evaluate the genetic contribution of the IL18-607 C/A and -137 G/C polymorphism in 202 gout male patients and 493 gout-free control of Chinese Han population by allele-specific polymerase chain reaction assay. Our results reveal no significant association between the polymorphisms -607C/A and -137G/C in IL18 with gout. Our study might suggest that -607 C/A and -137 G/C polymorphisms in the promoter of IL18 are not associated with susceptibility to gout and thus do not play a major role in the development of gout in the Chinese Han male population.

Evaluation of Prostate Cancer with 11C- and 18F-Choline PET/CT: Diagnosis and Initial Staging.

PubMed

Nitsch, Sascha; Hakenberg, Oliver W; Heuschkel, Martin; Dräger, Desiree; Hildebrandt, Guido; Krause, Bernd J; Schwarzenböck, Sarah M

2016-10-01

Early diagnosis and adequate staging are crucial for the choice of adequate treatment in prostate cancer (PC). Morphologic and functional imaging modalities, such as CT and MRI, have had limited accuracy in the diagnosis and nodal staging of PC. Molecular PET/CT imaging with 11 C- or 18 F-choline-labeled derivatives is increasingly being used, but its role in the diagnosis and initial staging of PC is controversial because of limitations in sensitivity and specificity for the detection of primary PC. For T staging, functional MRI is superior to 11 C- or 18 F-choline PET/CT. For N staging, 11 C- or 18 F-choline PET/CT can provide potentially useful information that may influence treatment planning. For the detection of bone metastases, 11 C- or 18 F-choline PET/CT has had promising results; however, in terms of cost-effectiveness, the routine use of 11 C- or 18 F-choline PET/CT is still debatable. 11 C- or 18 F-choline PET/CT might be used in high-risk PC before radiation treatment planning, potentially affecting this planning (e.g., regarding dose escalation). This review provides an overview of the diagnostic accuracy and limitations of 11 C- or 18 F-choline PET/CT in the diagnosis and staging of PC. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

D.C. Municipal Separate Storm Sewer System (MS4)

EPA Pesticide Factsheets

This permit covers all areas within the jurisdictional boundary of the District of Columbia served by, or otherwise contributing to discharges from, the Municipal Separate Storm Sewer System (MS4) owned or operated by the District of Columbia.

Serum apolipoprotein A-1 quantification by LC–MS with a SILAC internal standard reveals reduced levels in smokers

PubMed Central

Wang, Qingqing; Zhang, Suhong; Guo, Lili; Busch, Christine M; Jian, Wenying; Weng, Naidong; Snyder, Nathaniel W; Rangiah, Kannan; Mesaros, Clementina; Blair, Ian A

2015-01-01

Background: Absolute quantification of protein biomarkers such as serum apolipoprotein A1 by both immunoassays and LC–MS can provide misleading results. Results: Recombinant ApoA-1 internal standard was prepared using stable isotope labeling by amino acids in cell culture with [13C615N2]-lysine and [13C915N1]-tyrosine in human cells. A stable isotope dilution LC–MS method for serum ApoA-1 was validated and levels analyzed for 50 nonsmokers and 50 smokers. Conclusion: The concentration of ApoA-1 in nonsmokers was 169.4 mg/dl with an 18.4% reduction to 138.2 mg/dl in smokers. The validated assay will have clinical utility for assessing effects of smoking cessation and therapeutic or dietary interventions in high-risk populations. PMID:26394123

Solubility of α-Tocopheryl Succinate in Supercritical Carbon Dioxide Using Offline HPLC-MS/MS Analysis

PubMed Central

Hybertson, Brooks M.

2010-01-01

The solubility of the vitamin E-related compound α-tocopheryl succinate in supercritical carbon dioxide was measured at pressures ranging from (15.0 to 30.0) MPa and temperatures of (40 and 50) °C using a simple microsampling type apparatus with a 100.5 μL sample loop to remove aliquots and collect them in ethanol for off line analysis. α-Tocopheryl succinate concentrations in the collected samples were measured using HPLC-MS/MS analysis. The solubility of α-tocopheryl succinate in supercritical carbon dioxide ranged from mole fractions of 0.28 × 10−5 at 15.0 MPa and 50 °C to 2.56 × 10−5 at 30.0 MPa and 50 °C. PMID:20953319

The Counterarc to MS 1512-cB58 and a Companion Galaxy

NASA Astrophysics Data System (ADS)

Teplitz, Harry I.; Malkan, Matthew A.; McLean, Ian S.

2004-06-01

We present near-infrared spectra of ``A2,'' the primary counterarc to the gravitationally lensed galaxy MS 1512-cB58. The spectra show redshifted Hα, [N II], [O III], and Hβ at z=2.729+/-0.001. We observe the same Hα/[O III] ratio as cB58, which together with the redshift confirms that A2 is indeed another image of a single background galaxy. Published lensing reconstruction reports that A2 is a magnification of the entire source, while cB58 is an image of only a part. At marginal significance, A2 shows higher line-to-continuum ratios than cB58 (by a factor of ~2), suggesting a nonuniform ratio of young to old stars across the galaxy. We observe a second emission-line source in the slit. This object, ``W5,'' is predicted to be a lensed image of another galaxy at a redshift similar to cB58. W5 is blueshifted from cB58 by ~400 km s-1 and has a significantly lower Hα/[O III] ratio, confirming that it is an image of a different background galaxy in a group with cB58. The Hα emission line in W5 implies a star formation rate of 6 Msolar yr-1 (H0=70 km s-1 Mpc-1, ΩM=0.3,ΩΛ=0.7), after correcting for lensing magnification. Data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

A high-throughput mass spectrometry assay to simultaneously measure intact insulin and C-peptide.

PubMed

Taylor, Steven W; Clarke, Nigel J; Chen, Zhaohui; McPhaul, Michael J

2016-04-01

Measurements of fasting levels of insulin and C-peptide are useful in documenting insulin resistance and may help predict development of diabetes mellitus. However, the specific insulin and C-peptide levels associated with specific degrees of insulin resistance have not been defined, owing to marked variability among immunoassays and lack of standardization. Herein, we describe a multiplexed liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for intact insulin and C-peptide. Insulin and C-peptide were enriched from patient sera using monoclonal antibodies immobilized on magnetic beads and processed on a robotic liquid handler. Eluted peptides were analyzed by LC-MS/MS. Bovine insulin and a stable isotopically-labeled (13C/15N) C-peptide were utilized as internal standards. The assay had an analytical measurement range of 3 to 320 μIU/ml (18 to 1920 pmol/l) for insulin and 0.11 to 27.2 ng/ml (36 to 9006 pmol/l) for C-peptide. Intra- and inter-day assay variation was less than 11% for both peptides. Of the 5 insulin analogs commonly prescribed to treat diabetes, only the recombinant drug insulin lispro caused significant interference for the determination of endogenous insulin. There were no observed interferences for C-peptide. We developed and validated a high-throughput, quantitative, multiplexed LC-MS/MS assay for intact insulin and C-peptide. Copyright © 2016 Elsevier B.V. All rights reserved.

Quantitation of Tenofovir and Emtricitabine in Dried Blood Spots (DBS) with LC-MS/MS

PubMed Central

Zheng, Jia-Hua; Guida, Louis A; Rower, Caitlin; Castillo-Mancilla, Jose; Meditz, Amie; Klein, Brandon; Kerr, Becky Jo; Langness, Jacob; Bushman, Lane; Kiser, Jennifer; Anderson, Peter L.

2013-01-01

A reversed-phase high performance liquid chromatographic (LC), tandem mass spectrometry (MS/MS) assay for the determination of tenofovir (TFV) and emtricitabine (FTC) in dried blood spots (DBS) from human whole blood was developed and validated. Whole blood samples were spotted, dried, and a 3mm punch was extracted with methanol for analysis by LC-MS/MS utilizing stable isotope labeled internal standards. The assay was validated over the range of 2.5ng/mL to 1,000ng/mL for TFV and 2.5ng/mL to 5,000ng/mL for FTC. The method was accurate (within ± 15% of control) and precise (coefficient of variation ≤ 15%) for hematocrit concentrations ranging from 25% to 76%; using edge punches versus center punches; and spot volumes of 10µL to 50µL. Analytes were stable for five freeze/thaw cycles and up to 6 days at room temperature, whereas long-term storage required −20°C or −80°C. Comparison of TFV and FTC in DBS versus plasma yielded r2 ≥ 0.96, indicating that DBS can be used as a plasma alternative for pharmacokinetic analyses in vivo. PMID:24055850

Prescriptive Oriented Drug Analysis of Multiple Sclerosis Disease by LC-UV in Whole Human Blood.

PubMed

Suneetha, A; Rajeswari, Raja K

2016-02-01

As a polytherapy treatment, multiple sclerosis disease demands prescriptions with more than one drug. Polytherapy is sometimes rational for drug combinations chosen to minimize adverse effects. Estimation of drugs that are concomitantly administered in polytherapy is acceptable as it shortens the analytical timepoints and also the usage of biological matrices. In clinical phase trials, the withdrawal of biofluids is a critical issue for each analysis. Estimating all the coadminsitered drugs in a single shot will be more effective and economical for pharmaceuticals. A single, simple, rapid and sensitive high-performance liquid chromatography assay method has been developed with UV detection and fully validated for the quantification of 14 drugs (at random combinations) used in the treatment of multiple sclerosis disease. The set of combinations was based on prescriptions to patients. Separations were achieved on an X-Terra MS C18 (100 × 3.9 mm, 5 µm) column. The analytes were extracted from 50 µL aliquots of whole human blood with protein precipitation using acetonitrile. All the drugs were sufficiently stable during storage for 24 h at room temperature and for 23 days at 2-8°C. The percentage recoveries of all drugs were between 90 and 115%, with RSD values <10.6%. This method has been shown to be reproducible and sensitive and can be applied to clinical samples from pharmacokinetic studies and also a useful tool in studying the drug interaction studies. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Simultaneous determination of acetaminophen and dihydrocodeine in human plasma by UPLC-MS/MS: Its pharmacokinetic application.

PubMed

Qiu, Xiangjun; Lou, Dan; Su, Ding; Liu, Zebin; Gao, Pengtao; Zhang, Nan-sheng

2015-06-15

An ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed and validated to determine acetaminophen (AAP) and dihydrocodeine (DHC) in human plasma simultaneously. Plasma samples were prepared using protein precipitation with acetonitrile, the two analytes and the internal standard midazolam were separated on an Acquity UPLC BEH C18 column and mass spectrometric analysis was performed using a QTrap5500 mass spectrometer coupled with an electro-spray ionization (ESI) source in the positive ion mode. The MRM transitions of m/z 151.2→110.0 and m/z 302.3→199.2 were used to quantify for AAP and DHC, respectively. The linearity of this method was found to be within the concentration range of 50-10000ng/mL for AAP, and 1-100ng/mL for DHC in human plasma, respectively. The lower limit of quantification (LLOQ) was 50ng/mL and 1ng/mL for AAP and DHC in human plasma, respectively. The relative standard deviations (RSD) of intra and inter precision were less than 10% for both AAP and DHC. The analysis time of per sample was 1.0min. The developed and validated method was successfully applied to a pharmacokinetic study of AAP (500mg) with DHC (20mg) capsule in Chinese healthy volunteers (N=20). Copyright © 2015 Elsevier B.V. All rights reserved.

Analysis of coffee for the presence of acrylamide by LC-MS/MS.

PubMed

Andrzejewski, Denis; Roach, John A G; Gay, Martha L; Musser, Steven M

2004-04-07

A variety of popular instant, ground, and brewed coffees were analyzed using a modified liquid chromatography-tandem mass spectrometry (LC-MS/MS) method specifically developed for the determination of acrylamide in foods. Coffee test portions were spiked with 13C3-labeled acrylamide as an internal standard prior to their extraction and cleanup. Ground coffees (1 g) and instant coffees (0.5 g) were extracted by shaking with 9 mL of water for 20 min. Brewed coffee test portions (9 mL) were taken through the cleanup procedure without further dilution with extraction solvent. Coffee test portions were cleaned up by passing 1.5 mL first through an Oasis HLB (hydrophilic/lipophilic copolymer sorbent) solid phase extraction (SPE) cartridge and then a Bond Elut-Accucat (cation and anion exchange sorbent) SPE cartridge. The cleaned up extracts were analyzed by positive ion electrospray LC-MS/MS. The MS/MS data was used to detect, confirm, and quantitate acrylamide. The limit of quantitation of the method was 10 ng/g for ground and instant coffees and 1.0 ng/mL for brewed coffee. The levels of acrylamide ranged from 45 to 374 ng/g in unbrewed coffee grounds, from 172 to 539 ng/g in instant coffee crystals, and from 6 to 16 ng/mL in brewed coffee.

Optimization of fatty alcohol biosynthesis pathway for selectively enhanced production of C12/14 and C16/18 fatty alcohols in engineered Escherichia coli

PubMed Central

2012-01-01

Background With the increasing stress from oil price and environmental pollution, aroused attention has been paid to the microbial production of chemicals from renewable sources. The C12/14 and C16/18 alcohols are important feedstocks for the production of surfactants and detergents, which are widely used in the most respected consumer detergents, cleaning products and personal care products worldwide. Though bioproduction of fatty alcohols has been carried out in engineered E. coli, several key problems have not been solved in earlier studies, such as the quite low production of C16/18 alcohol, the lack of optimization of the fatty alcohol biosynthesis pathway, and the uncharacterized performance of the engineered strains in scaled-up system. Results We improved the fatty alcohol production by systematically optimizing the fatty alcohol biosynthesis pathway, mainly targeting three key steps from fatty acyl-acyl carrier proteins (ACPs) to fatty alcohols, which are sequentially catalyzed by thioesterase, acyl-coenzyme A (CoA) synthase and fatty acyl-CoA reductase. By coexpression of thioesterase gene BTE, acyl-CoA synthase gene fadD and fatty acyl-CoA reductase gene acr1, 210.1 mg/L C12/14 alcohol was obtained. A further optimization of expression level of BTE, fadD and acr1 increased the C12/14 alcohol production to 449.2 mg/L, accounting for 75.0% of the total fatty alcohol production (598.6 mg/L). In addition, by coexpression of thioesterase gene ‘tesA, acyl-CoA synthase gene fadD and fatty acyl-CoA reductase gene FAR, 101.5 mg/L C16/18 alcohol was obtained, with C16/18 alcohol accounting for 89.2% of the total fatty alcohol production. Conclusions To our knowledge, this is the first report on selective production of C12/14 and C16/18 alcohols by microbial fermentation. This work achieved high-specificity production of both C12/14 and C16/18 alcohols. The encouraging 598.6 mg/L of fatty alcohols represents the highest titer reported so far. In

A sensitive LC-MS/MS method for the quantification of febuxostat in human plasma and its pharmacokinetic application.

PubMed

Vaka, Venkata Rami Reddy; Inamadugu, Jaswanth Kumar; Pilli, Nageswara Rao; Ramesh, Mullangi; Katreddi, Hussain Reddy

2013-11-01

An improved, simple and highly sensitive LC-MS/MS method has been developed and validated for quantification of febuxostat with 100 μL human plasma using febuxostat-d7 as an internal standard (IS) according to regulatory guidelines. The analyte and IS were extracted from human plasma via liquid-liquid extraction using diethyl ether. The chromatographic separation was achieved on a Zorbax C18 column using a mixture of acetonitrile and 5 mm ammonium formate (60:40, v/v) as the mobile phase at a flow rate of 0.5 mL/min. The total run time was 5.0 min and the elution of febuxostat and IS occurred at 1.0 and 1.5 min, respectively. A linear response function was established for the range of concentrations 1-6000 ng/mL (r > 0.99). The precursor to product ion transitions monitored for febuxostat and IS were m/z 317.1 → 261.1 and 324.2 → 262.1, respectively. The intra- and inter-day precisions (%RSD) were within 1.29-9.19 and 2.85-7.69%, respectively. The proposed method was successfully applied to pharmacokinetic studies in humans. Copyright © 2013 John Wiley & Sons, Ltd.

Metabolite fingerprinting of Camptotheca acuminata and the HPLC-ESI-MS/MS analysis of camptothecin and related alkaloids.

PubMed

Montoro, Paola; Maldini, Mariateresa; Piacente, Sonia; Macchia, Mario; Pizza, Cosimo

2010-01-20

The major phytochemical constituents, namely, alkaloids, flavonoids and ellagic acid derivatives, of leaves of Camptotheca acuminata were identified using high performance liquid chromatography (HPLC) coupled with electrospray mass spectrometry (ESI-MS) in extracts of plants cultivated in Italy and collected at different growth stages. Alkaloids related to camptothecin were identified and quantified by HPLC coupled with ESI-tandem mass spectrometry (MS/MS) employing, respectively, an ion trap and a triple quadrupole mass analyser. The fragmentation patterns of alkaloids related to camptothecin were analysed and a specific Multiple Reaction Monitoring HPLC-MS/MS method was developed for the quantitative determination of these constituents. The described method provides high sensitivity and specificity for the characterisation and quantitative determination of the alkaloids in C. acuminata.

Quantification of Lignin and Its Structural Features in Plant Biomass Using 13C Lignin as Internal Standard for Pyrolysis-GC-SIM-MS.

PubMed

van Erven, Gijs; de Visser, Ries; Merkx, Donny W H; Strolenberg, Willem; de Gijsel, Peter; Gruppen, Harry; Kabel, Mirjam A

2017-10-17

Understanding the mechanisms underlying plant biomass recalcitrance at the molecular level can only be achieved by accurate analyses of both the content and structural features of the molecules involved. Current quantification of lignin is, however, majorly based on unspecific gravimetric analysis after sulfuric acid hydrolysis. Hence, our research aimed at specific lignin quantification with concurrent characterization of its structural features. Hereto, for the first time, a polymeric 13 C lignin was used as internal standard (IS) for lignin quantification via analytical pyrolysis coupled to gas chromatography with mass-spectrometric detection in selected ion monitoring mode (py-GC-SIM-MS). In addition, relative response factors (RRFs) for the various pyrolysis products obtained were determined and applied. First, 12 C and 13 C lignin were isolated from nonlabeled and uniformly 13 C labeled wheat straw, respectively, and characterized by heteronuclear single quantum coherence (HSQC), nuclear magnetic resonance (NMR), and py-GC/MS. The two lignin isolates were found to have identical structures. Second, 13 C-IS based lignin quantification by py-GC-SIM-MS was validated in reconstituted biomass model systems with known contents of the 12 C lignin analogue and was shown to be extremely accurate (>99.9%, R 2 > 0.999) and precise (RSD < 1.5%). Third, 13 C-IS based lignin quantification was applied to four common poaceous biomass sources (wheat straw, barley straw, corn stover, and sugar cane bagasse), and lignin contents were in good agreement with the total gravimetrically determined lignin contents. Our robust method proves to be a promising alternative for the high-throughput quantification of lignin in milled biomass samples directly and simultaneously provides a direct insight into the structural features of lignin.

40 CFR Appendix 8 to Subpart A of... - Reference C16-C18 Internal Olefin Drilling Fluid Formulation

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Reference C16-C18 Internal Olefin Drilling Fluid Formulation 8 Appendix 8 to Subpart A of Part 435 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS OIL AND GAS EXTRACTION POINT SOURCE CATEGORY...

40 CFR Appendix 8 to Subpart A of... - Reference C16-C18 Internal Olefin Drilling Fluid Formulation

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Reference C16-C18 Internal Olefin Drilling Fluid Formulation 8 Appendix 8 to Subpart A of Part 435 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS OIL AND GAS EXTRACTION POINT SOURCE CATEGORY...

Pharmacokinetics of Caffeic Acid, Ferulic Acid, Formononetin, Cryptotanshinone, and Tanshinone IIA after Oral Administration of Naoxintong Capsule in Rat by HPLC-MS/MS.

PubMed

Li, Jin; Bai, Yang; Bai, Yun; Zhu, Ruichao; Liu, Wei; Cao, Jun; An, Mingrui; Tan, Zhijing; Chang, Yan-Xu

2017-01-01

Naoxintong capsule (NXTC) was a famous patent medicine of Traditional Chinese Medicine (TCM) to treat cerebrovascular diseases in China. An LC-MS/MS method was developed for simultaneous determination of 11 major ingredients (paeoniflorin, ecdysterone, amygdalin, mulberroside A, caffeic acid, ferulic acid, salvianolic acid B, astragaloside IV, formononetin, cryptotanshinone, and tanshinone IIA) in NXTC in rat plasma. All analytes were separated on an Eclipse plus C 18 column using a gradient mobile phase system of acetonitrile-0.1% formic acid aqueous solution. The lower limits of quantification of 11 ingredients were between 0.075 and 10 ng mL -1 . The precision was less than 15% and the accuracies were between 85% and 115%. The results showed that caffeic acid, ferulic acid, formononetin, cryptotanshinone, and tanshinone IIA could be detected after oral administration of NXTC. The validated method was successfully applied to pharmacokinetic study of the caffeic acid, ferulic acid, formononetin, cryptotanshinone, and tanshinone IIA in rats after oral administration of NXTC at single and triple dose.

18. BLUEPRINT, RR BRIDGE Tombigbee R. MISSISSIPPI, CLAY CO., WAVERLY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

18. BLUEPRINT, RR BRIDGE Tombigbee R. MISSISSIPPI, CLAY CO., WAVERLY 1.5 mi. S of MS 50 Detail: 'Georgia Pacific Rwy. -- Tombigbee River Bridge Elevation' with river profile, May 16, 1888. Credit: Columbus and Greenville Rr, Columbus, Ms. DWG = S-3-342. Sarcone Photography, Columbus, Ms Sep 1978. - Bridges of the Upper Tombigbee River Valley, Columbus, Lowndes County, MS

Simultaneous determination of phenolic acids and flavonoids in Chenopodium formosanum Koidz. (djulis) by HPLC-DAD-ESI-MS/MS.

PubMed

Hsu, B Y; Lin, S W; Inbaraj, B Stephen; Chen, B H

2017-01-05

A high performance liquid chromatography-diode array detection-tandem mass spectrometry method (HPLC-DAD-MS/MS) was developed for simultaneous determination of phenolic acids and flavonoids in djulis (Chenopodium formosanum Koidz.), a traditional Chinese herb reported to possess vital biological activities. A high yield of phenolic acids and flavonoids was attained by employing 50% ethanol in water as the extraction solvent and shaking in a 60°C water bath for 3h. A total of 8 phenolic acids and 14 flavonoids were separated and identified within 55min by using a Poroshell 120 EC-C18 column with detection at 280nm, flow rate at 0.8mL/min, column temperature at 35°C, and a gradient solvent system of 0.1% formic acid in water and acetonitrile. Two internal standards caffeic acid and kaempferol-3-O-rutinoside were used for quantitation of phenolic acids and flavonoids in djulis respectively. The amounts of phenolic acids ranged from 11.5±0.8μg/g (caffeoyl-putrescine-derivative (2)) to 1855.3±16.9μg/g (hydroxylphenylacetic acid pentoside), while the flavonoids ranged from 19.93±2.29μg/g (quercetin-3-O-(coumaryl)-rutinoside-pentoside (1)) to 257.3±2.05μg/g (rutin-O-pentoside (2)). A high recovery (89.68-97.20%) and high reproducibility was obtained for both phenolic acids and flavonoids with the relative standard deviation (RSD) for the latter ranging from 0.09-8.22% (intra-day variability) and 0.80-8.48% (inter-day variability). This method may be applied to determination of both phenolic acids and flavonoids in food products and Chinese herbs. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparative pharmacokinetic profiles of selected irreversible tyrosine kinase inhibitors, neratinib and pelitinib, with apigenin in rat plasma by UPLC-MS/MS.

PubMed

Maher, Hadir M; Alzoman, Nourah Z; Shehata, Shereen M; Abahussain, Ashwag O

2017-04-15

Neratinib (NER) and pelitinib (PEL) are irreversible tyrosine kinase inhibitors (TKIs) that have been recently employed in cancer treatment. Apigenin (API), among other flavonoids, is known to have antioxidant, anti-proliferative, and carcinogenic effect. API can potentiate the antitumor effect of chemotherapeutic agents and/or alleviate the side effects of many anticancer agents. Since TKIs are mostly metabolized by CYP3A4 enzymes and that API could alter the enzymatic activity, potential drug interactions could be expected following their co-aministration. In the present study, a bioanalytical UPLC-MS/MS method has been developed and validated for the quantification of NER and PEL in rat plasma, using domperidone (DOM) as an internal standard. Sample preparation was carried out using solid phase extraction (SPE) with C18 cartridges with good extraction recovery of not less than 92.42% (NER) and 89.73% (PEL). Chromatographic analysis was performed on a Waters BEH C18 column with a mobile phase composed of acetonitrile and water, (70:30, v/v), each with 0.1% formic acid. Quantitation was performed using multiple reaction monitoring (MRM) of the transitions from protonated precursor ions [M+H] + , at m/z 557.30 (NER), m/z 468.21 (PEL), and at m/z 426.27 (DOM), to selected product ions at m/z 112.05 (NER), m/z 395.22 (PEL), and at m/z 175.18 (DOM). The method was fully validated as per the FDA guidelines over the concentration range of 0.5-200ng/mL with very low lower limit of quantification (LLOQ) of 0.5ng/mL for both NER and PEL. The intra- and inter-day assay precision and accuracy were evaluated for both drugs and the calculated values of percentage relative standards deviations (%RSD) and relative errors (%E r ) were within the acceptable limits (<15%) for concentrations other than LLOQ and 20% for LLOQ. The applicability of the method was extended to study the possibility of drug interactions following the oral co-administration of NER/PEL with API. Thus, this

A validated UPLC-MS/MS method for the analysis of linezolid and a novel oxazolidinone derivative (PH027) in plasma and its application to tissue distribution study in rabbits.

PubMed

Hedaya, Mohsen A; Thomas, Vidhya; Abdel-Hamid, Mohamed E; Kehinde, Elijah O; Phillips, Oludotun A

2017-01-01

Linezolid is the first approved oxazolidinone antibacterial agent, whereas PH027 is a novel compound of the same class that exhibits good in vitro antibacterial activity. The objective of this study was to develop an UPLC-MS/MS assay for the analysis of linezolid and PH027 in plasma and to apply the method for comparative pharmacokinetic and tissue distribution studies of both compounds. Plasma samples and calibrators were extracted with diethyl ether after addition of the internal standard solution. After evaporation of the ether layer, the residue was reconstituted in mobile phase and injected into UPLC-MS/MS. The mobile phase consisted of 2mM ammonium acetate buffer solution and acetonitrile (70:30) at a flow rate of 0.2ml/min. Separation was achieved using UPLC BEH C 18 column, and quantitative determination of the analytes was performed using multiple-reaction monitoring (MRM) scanning mode. The method was validated by analyzing quality control tissue homogenate samples, and was applied to analyze tissue homogenate samples obtained following IV injections of linezolid and PH027 in rabbits. The developed UPLC-MS/MS method was linear in the concentration range of 50-5000ng/ml. Validation of the method proved that the method's precision, selectivity and stability were all within the acceptable limits. Linezolid and PH027 concentrations were accurately determined in the quality control tissue homogenate samples, and analysis of samples obtained following IV administration of the two compounds showed that the tissue to plasma concentration ratio of PH027 was higher than that of linezolid probably due to its higher lipophilicity. The developed UPLC-MS/MS method for the analysis of linezolid and PH027 in rabbit's plasma can accurately determine the concentrations of these compounds in different tissues. Copyright © 2016 Elsevier B.V. All rights reserved.

/sup 18/O + /sup 12/C fusion-evaporation reaction

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

Heusch, B; Beck, C; Coffin, J P

1980-01-01

A study of the /sup 18/O + /sup 12/C fusion evaporation reaction has been undertaken for 2 reasons: to make a systematic study of the formation cross section for each individual evaporation residue over a broad excitation energy region in the compound nucleus /sup 30/Si:30 to 62 MeV; and to compare all results to fusion-evaporation calculations done in the framework of the Hauser-Feschbach statistical model.

Development and validation of a sensitive UHPLC-MS/MS method for the simultaneous analysis of tramadol, dextromethorphan chlorpheniramine and their major metabolites in human plasma in forensic context: application to pharmacokinetics.

PubMed

Heneedak, Hala M; Salama, Ismail; Mostafa, Samia; El-Kady, Ehab; El-Sadek, Mohamed

2015-07-01

The prerequisites for forensic confirmatory analysis by LC/MS/MS with respect to European Union guidelines are chromatographic separation, a minimum number of two MS/MS transitions to obtain the required identification points and predefined thresholds for the variability of the relative intensities of the MS/MS transitions (MRM transitions) in samples and reference standards. In the present study, a fast, sensitive and robust method to quantify tramadol, chlorpheniramine, dextromethorphan and their major metabolites, O-desmethyltramadol, dsmethyl-chlorpheniramine and dextrophan, respectively, in human plasma using ibuprofen as internal standard (IS) is described. The analytes and the IS were extracted from plasma by a liquid-liquid extraction method using ethyl acetate-diethyl-ether (1:1). Extracted samples were analyzed by ultra-high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS). Chromatographic separation was performed by pumping the mobile phase containing acetonitrile, water and formic acid (89.2:11.7:0.1) for 2.0 min at a flow rate of 0.25 μL/min into a Hypersil-Gold C18 column, 20 × 2.0 mm (1.9 µm) from Thermoscientific, New York, USA. The calibration curve was linear for the six analytes. The intraday precision (RSD) and accuracy (RE) of the method were 3-9.8 and -1.7-4.5%, respectively. The analytical procedure herein described was used to assess the pharmacokinetics of the analytes in 24 healthy volunteers after a single oral dose containing 50 mg of tramadol hydrochloride, 3 mg chlorpheniramine maleate and 15 mg of dextromethorphan hydrobromide. Copyright © 2014 John Wiley & Sons, Ltd.

A UPLC-MS/MS method for simultaneous determination of five flavonoids from Stellera chamaejasme L. in rat plasma and its application to a pharmacokinetic study.

PubMed

Li, Yun-Qing; Li, Cheng-Jian; Lv, Lei; Cao, Qing-Qing; Qian, Xian; Li, Si Wei; Wang, Hui; Zhao, Liang

2018-06-01

Stellera chamaejasme L. has been used as a traditional Chinese medicine for the treatment of scabies, tinea, stubborn skin ulcers, chronic tracheitis, cancer and tuberculosis. A sensitive and selective ultra-high liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the simultaneous determination of five flavonoids (stelleranol, chamaechromone, neochamaejasmin A, chamaejasmine and isochamaejasmin) of S. chamaejasme L. in rat plasma. Chromatographic separation was accomplished on an Agilent Poroshell 120 EC-C 18 column (2.1 × 100 mm, 2.7 μm) with gradient elution at a flow rate of 0.4 mL/min and the total analysis time was 7 min. The analytes were detected using multiple reaction monitoring in positive ionization mode. The samples were prepared by liquid-liquid extraction with ethyl acetate. The UPLC-MS/MS method was validated for specificity, linearity, sensitivity, accuracy and precision, recovery, matrix effect and stability. The validated method exhibited good linearity (r ≥ 0.9956), and the lower limits of quantification ranged from 0.51 to 0.64 ng/mL for five flavonoids. The intra- and inter-day precision were both <10.2%, and the accuracy ranged from -11.79 to 9.21%. This method was successfully applied to a pharmacokinetic study of five flavonoids in rats after oral administration of ethyl acetate extract of S. chamaejasme L. Copyright © 2018 John Wiley & Sons, Ltd.

Carbon Isotope Characterization of Organic Intermediaries in Hydrothermal Hydrocarbon Synthesis by Pyrolysis-GC-MS-C-IRMS

NASA Technical Reports Server (NTRS)

Socki, Richard A.; Fu, Qi; Niles, Paul B.

2010-01-01

We report results of experiments designed to characterize the carbon isotope composition of intermediate organic compounds produced as a result of mineral surface catalyzed reactions. The impetus for this work stems from recently reported detection of methane in the Martian atmosphere coupled with evidence showing extensive water-rock interaction during Martian history. Abiotic formation by Fischer-Tropsch-type (FTT) synthesis during serpentinization reactions may be one possible process responsible for methane generation on Mars, and measurement of carbon and hydrogen isotopes of intermediary organic compounds can help constrain the origin of this methane. Of particular interest within the context of this work is the isotopic composition of organic intermediaries produced on the surfaces of mineral catalysts (i.e. magnetite) during hydrothermal experiments, and the ability to make meaningful and reproducible isotope measurements. Our isotope measurements utilize a unique analytical technique combining Pyrolysis-Gas Chromatograph-Mass Spectrometry-Combustion-Isotope Ratio Mass Specrometry (Py-GC-MS-C-IRMS). Others have conducted similar pyrolysis-IRMS experiments on low molecular weight organic acids (Dias, et al, Organic Geochemistry, 33 [2002]). Our technique differs in that it carries a split of the pyrolyzed GC-separated product to a Thermo DSQ-II quadrupole mass spectrometer as a means of making qualitative and semi-quantitative compositional measurements of the organic compounds. A sample of carboxylic acid (mixture of C1 through C6) was pyrolyzed at 100 XC and passed through the GC-MS-C-IRMS (combusted at 940 XC). In order to test the reliability of our technique we compared the _13C composition of different molecular weight organic acids (from C1 through C6) extracted individually by the traditional sealed-tube cupric oxide combustion (940 XC) method with the _13C produced by our pyrolysis technique. Our data indicate that an average 4.3. +/-0.5. (V

Intracerebral microdialysis coupled to LC-MS/MS for the determination tramadol and its major pharmacologically active metabolite O-desmethyltramadol in rat brain microdialysates.

PubMed

Liu, Mingzhou; Wang, Peng; Yu, Xuming; Dong, Guicheng; Yue, Jiang

2017-08-01

A rapid and sensitive method involving liquid chromatography electrospray tandem mass spectrometry (LC-ESI-MS/MS) coupled to an intracerebral microdialysis technique was developed for the determination and pharmacokinetic investigation of tramadol and its major active metabolite O-desmethyltramadol (ODT) in rat brain. The microdialysis samples were separated on a C18 column and eluted with a mobile phase of acetonitrile-water-formic acid (50:50:0.1; v/v/v) at a flow rate of 0.3 mL/min. The ESI-MS/MS spectra were performed in electrospray positive ion mode, and the analytes were detected by multiple reaction monitoring (MRM) of the transitions m/z [M + H] + 264.3 → 58.2 for tramadol, m/z [M + H] + 250.3 → 58.3 for ODT, and m/z [M + H] + 379.4 → 264.0 for ambroxol (internal standard; IS). The total run time was 4.0 min. A lower limit of quantitation (LLOQ) was achieved as 1 ng/mL for tramadol and 0.5 ng/mL for ODT, with excellent linearity over a concentration range of 1 ~ 500 ng/mL (r > 0.99) for tramadol and 0.5 ~ 50 ng/mL for ODT (r > 0.99), respectively. The proposed method was successfully applied to the pharmacokinetic studies of tramadol and ODT in rat brain. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Second-order standard addition for deconvolution and quantification of fatty acids of fish oil using GC-MS.

PubMed

Vosough, Maryam; Salemi, Amir

2007-08-15

In the present work two second-order calibration methods, generalized rank annihilation method (GRAM) and multivariate curve resolution-alternating least square (MCR-ALS) have been applied on standard addition data matrices obtained by gas chromatography-mass spectrometry (GC-MS) to characterize and quantify four unsaturated fatty acids cis-9-hexadecenoic acid (C16:1omega7c), cis-9-octadecenoic acid (C18:1omega9c), cis-11-eicosenoic acid (C20:1omega9) and cis-13-docosenoic acid (C22:1omega9) in fish oil considering matrix interferences. With these methods, the area does not need to be directly measured and predictions are more accurate. Because of non-trilinear conditions of GC-MS data matrices, at first MCR-ALS and GRAM have been used on uncorrected data matrices. In comparison to MCR-ALS, biased and imprecise concentrations (%R.S.D.=27.3) were obtained using GRAM without correcting the retention time-shift. As trilinearity is the essential requirement for implementing GRAM, the data need to be corrected. Multivariate rank alignment objectively corrects the run-to-run retention time variations between sample GC-MS data matrix and a standard addition GC-MS data matrix. Then, two second-order algorithms have been compared with each other. The above algorithms provided similar mean predictions, pure concentrations and spectral profiles. The results validated using standard mass spectra of target compounds. In addition, some of the quantification results were compared with the concentration values obtained using the selected mass chromatograms. As in the case of strong peak-overlap and the matrix effect, the classical univariate method of determination of the area of the peaks of the analytes will fail, the "second-order advantage" has solved this problem successfully.

Development and validation of an LC-MS/MS analysis for simultaneous determination of delphinidin-3-glucoside, cyanidin-3-glucoside and cyanidin-3-(6-malonylglucoside) in human plasma and urine after blood orange juice administration.

PubMed

Giordano, Lucia; Coletta, Walter; Rapisarda, Paolo; Donati, Maria Benedetta; Rotilio, Domenico

2007-12-01

Blood orange juice has a high content in anthocyanins, especially represented by delphinidin-3-glucoside (D3G), cyanidin-3-glucoside (C3G) and cyanidin-3-(6-malonylglucoside) (CMG). An LC-MS/MS method for the simultaneous determination of D3G and C3G in human plasma and urine was developed and validated. After sample preparation by SPE, chromatographic separation was performed with an RP-C(18) column, using a water/methanol linear gradient. The quantitation of target compounds was determined by multiple reaction monitoring (MRM) mode, using ESI. The method showed good selectivity, sensitivity (LOD = 0.05 and 0.10 ng/mL for C3G in plasma and urine, respectively; LOD = 0.10 ng/mL for D3G in plasma and urine), linearity (0.20-200 ng/mL; r >or= 0.998), intra- and interday precision and accuracy (C3G and CMG levels in human plasma and urine after the ingestion of a single dose (500 mL) of blood orange juice.

Metabolic signatures and risk of type 2 diabetes in a Chinese population: an untargeted metabolomics study using both LC-MS and GC-MS.

PubMed

Lu, Yonghai; Wang, Yeli; Ong, Choon-Nam; Subramaniam, Tavintharan; Choi, Hyung Won; Yuan, Jian-Min; Koh, Woon-Puay; Pan, An

2016-11-01

Metabolomics has provided new insight into diabetes risk assessment. In this study we characterised the human serum metabolic profiles of participants in the Singapore Chinese Health Study cohort to identify metabolic signatures associated with an increased risk of type 2 diabetes. In this nested case-control study, baseline serum metabolite profiles were measured using LC-MS and GC-MS during a 6-year follow-up of 197 individuals with type 2 diabetes but without a history of cardiovascular disease or cancer before diabetes diagnosis, and 197 healthy controls matched by age, sex and date of blood collection. A total of 51 differential metabolites were identified between cases and controls. Of these, 35 were significantly associated with diabetes risk in the multivariate analysis after false discovery rate adjustment, such as increased branched-chain amino acids (leucine, isoleucine and valine), non-esterified fatty acids (palmitic acid, stearic acid, oleic acid and linoleic acid) and lysophosphatidylinositol (LPI) species (16:1, 18:1, 18:2, 20:3, 20:4 and 22:6). A combination of six metabolites including proline, glycerol, aminomalonic acid, LPI (16:1), 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid and urea showed the potential to predict type 2 diabetes in at-risk individuals with high baseline HbA1c levels (≥6.5% [47.5 mmol/mol]) with an AUC of 0.935. Combined lysophosphatidylglycerol (LPG) (12:0) and LPI (16:1) also showed the potential to predict type 2 diabetes in individuals with normal baseline HbA1c levels (<6.5% [47.5 mmol/mol]; AUC = 0.781). Our findings show that branched-chain amino acids and NEFA are potent predictors of diabetes development in Chinese adults. Our results also indicate the potential of lysophospholipids for predicting diabetes.

Determination of arsenic species and arsenosugars in marine samples by HPLC-ICP-MS.

PubMed

Hirata, Shizuko; Toshimitsu, Hideki

2005-10-01

Arsenic-speciation analysis in marine samples was performed by high-pressure liquid chromatography (HPLC) with ICP-MS detection. Separation of eight arsenic species--As(III), MMA, DMA, As(V), AB, TMAO, AC and TeMAs(+)--was achieved on a C(18) column with isocratic elution (pH 3.0), under which conditions As(III) and MMA co-eluted. The entire separation was accomplished in 15 min. The HPLC-ICP-MS detection limits for the eight arsenic species were in the range 0.03-0.23 microg L(-1) based on 3 sigma for the blank response (n=5). The precision was calculated to be 2.4-8.0% (RSD) for the eight species. The method was successfully applied to several marine samples, e.g. oysters, fish, shrimps, and marine algae. Low-power microwave digestion was employed for extraction of arsenic from seafood products; ultrasonic extraction was employed for the extraction of arsenic from seaweeds. Separation of arsenosugars was achieved on an anion-exchange column. Concentrations of arsenosugars 2, 3, and 4 in marine algae were in the range 0.18-9.59 microg g(-1).

Mechanisms linking metabolism of Helicobacter pylori to 18O and 13C-isotopes of human breath CO2

PubMed Central

Som, Suman; De, Anulekha; Banik, Gourab Dutta; Maity, Abhijit; Ghosh, Chiranjit; Pal, Mithun; Daschakraborty, Sunil B.; Chaudhuri, Sujit; Jana, Subhra; Pradhan, Manik

2015-01-01

The gastric pathogen Helicobacter pylori utilize glucose during metabolism, but the underlying mechanisms linking to oxygen-18 (18O) and carbon-13 (13C)-isotopic fractionations of breath CO2 during glucose metabolism are poorly understood. Using the excretion dynamics of 18O/16O and 13C/12C-isotope ratios of breath CO2, we found that individuals with Helicobacter pylori infections exhibited significantly higher isotopic enrichments of 18O in breath CO2 during the 2h-glucose metabolism regardless of the isotopic nature of the substrate, while no significant enrichments of 18O in breath CO2 were manifested in individuals without the infections. In contrast, the 13C-isotopic enrichments of breath CO2 were significantly higher in individuals with Helicobacter pylori compared to individuals without infections in response to 13C-enriched glucose uptake, whereas a distinguishable change of breath 13C/12C-isotope ratios was also evident when Helicobacter pylori utilize natural glucose. Moreover, monitoring the 18O and 13C-isotopic exchange in breath CO2 successfully diagnosed the eradications of Helicobacter pylori infections following a standard therapy. Our findings suggest that breath 12C18O16O and 13C16O16O can be used as potential molecular biomarkers to distinctively track the pathogenesis of Helicobacter pylori and also for eradication purposes and thus may open new perspectives into the pathogen’s physiology along with isotope-specific non-invasive diagnosis of the infection. PMID:26039789

Anticancer Activities of C18-, C19-, C20-, and Bis-Diterpenoid Alkaloids Derived from Genus Aconitum.

PubMed

Ren, Meng-Yue; Yu, Qing-Tian; Shi, Chun-Yu; Luo, Jia-Bo

2017-02-13

Cancer is one of the most common lethal diseases, and natural products have been extensively studied as anticancer agents considering their availability, low toxicity, and economic affordability. Plants belonging to the genus Aconitum have been widely used medically in many Asian countries since ancient times. These plants have been proven effective for treating several types of cancer, such as lung, stomach, and liver cancers. The main effective components of Aconitum plants are diterpenoid alkaloids-which are divided into C 18 -, C 19 -, C 20 -, and bis-diterpenoid alkaloids-are reportedly some of the most promising, naturally abundant compounds for treating cancer. This review focuses on the progress of diterpenoid alkaloids with different structures derived from Aconitum plants and some of their derivatives with potential anticancer activities. We hope that this work can serve as a reference for further developing Aconitum diterpenoid alkaloids as anticancer agents.

[Simultaneous determination of repaglinide and pravastatin sodium in rat plasma by LC-ms/MS and its application on pharmacokinetic interactions study].

PubMed

Ma, Yan-Rong; Zhou, Yan; Zhang, Guo-Qiang; Rao, Zhi; Huang, Jing; Wei, Yu-hui; Wu, Xin-An

2014-01-01

The study aims to establish a method for simultaneous determination of repaglinide and pravastatin sodium in rat plasma by LC-MS/MS and to study its pharmacokinetic interactions. Eighteen male SD rats were divided into repaglinide group, pravastatin sodium group and co-administration group. Blood samples were collected at different times after oral administration. Repaglinide and pravastatin sodium in rat plasma were separated by Agilent HC-C18 with the mobile phase consisting of methanol-0.1% formic acid (80 : 20). Detection and quantification were performed by using ESI-MS. The detector was operated in selected Reaction-monitoring mode at m/z 453.3-->230.1 for repaglinide, m/z 447.2-->327.4 for pravastatin sodium and m/z 285.1-->192.9 for diazepam as the internal standard. The calibration curve obtained was linear (R2>0.99) over the concentration range of 9.77-10,000 ng.mL-1 for repaglinide and 4.88-625 ng.mL-1 for pravastatin sodium. Compared with the single administration group, Cmax and AUC0-6h of repaglinide increased significantly (P<0.05) and tmax of pravastatin sodium prolonged (P<0.05) in co-administration group. The method is found to be simple, sensitive and accurate for determining the concentration of repaglinide and pravastatin sodium in rat plasma. There exists pharmacokinetic interactions in the co-administration of repaglinide and pravastatin sodium.

UFLC-ESI-MS/MS analysis of multiple mycotoxins in medicinal and edible Areca catechu.

PubMed

Liu, Hongmei; Luo, Jiaoyang; Kong, Weijun; Liu, Qiutao; Hu, Yichen; Yang, Meihua

2016-05-01

A robust, sensitive and reliable ultra fast liquid chromatography combined with electrospray ionization tandem mass spectrometry (UFLC-ESI-MS/MS) was optimized and validated for simultaneous identification and quantification of eleven mycotoxins in medicinal and edible Areca catechu, based on one-step extraction without any further clean-up. Separation and quantification were performed in both positive and negative modes under multiple reaction monitoring (MRM) in a single run with zearalanone (ZAN) as internal standard. The chromatographic conditions and MS/MS parameters were carefully optimized. Matrix-matched calibration was recommended to reduce matrix effects and improve accuracy, showing good linearity within wide concentration ranges. Limits of quantification (LOQ) were lower than 50 μg kg(-1), while limits of detection (LOD) were in the range of 0.1-20 μg kg(-1). The accuracy of the developed method was validated for recoveries, ranging from 85% to 115% with relative standard deviation (RSD) ≤14.87% at low level, from 75% to 119% with RSD ≤ 14.43% at medium level and from 61% to 120% with RSD ≤ 13.18% at high level, respectively. Finally, the developed multi-mycotoxin method was applied for screening of these mycotoxins in 24 commercial samples. Only aflatoxin B2 and zearalenone were found in 2 samples. This is the first report on the application of UFLC-ESI(+/-)-MS/MS for multi-class mycotoxins in A. catechu. The developed method with many advantages of simple pretreatment, rapid determination and high sensitivity is a proposed candidate for large-scale detection and quantification of multiple mycotoxins in other complex matrixes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Unassigned MS/MS Spectra: Who Am I?

PubMed

Pathan, Mohashin; Samuel, Monisha; Keerthikumar, Shivakumar; Mathivanan, Suresh

2017-01-01

Recent advances in high resolution tandem mass spectrometry (MS) has resulted in the accumulation of high quality data. Paralleled with these advances in instrumentation, bioinformatics software have been developed to analyze such quality datasets. In spite of these advances, data analysis in mass spectrometry still remains critical for protein identification. In addition, the complexity of the generated MS/MS spectra, unpredictable nature of peptide fragmentation, sequence annotation errors, and posttranslational modifications has impeded the protein identification process. In a typical MS data analysis, about 60 % of the MS/MS spectra remains unassigned. While some of these could attribute to the low quality of the MS/MS spectra, a proportion can be classified as high quality. Further analysis may reveal how much of the unassigned MS spectra attribute to search space, sequence annotation errors, mutations, and/or posttranslational modifications. In this chapter, the tools used to identify proteins and ways to assign unassigned tandem MS spectra are discussed.

Tequila authenticity assessment by headspace SPME-HRGC-IRMS analysis of 13C/12C and 18O/16O ratios of ethanol.

PubMed

Aguilar-Cisneros, Blanca O; López, Mercedes G; Richling, Elke; Heckel, Frank; Schreier, Peter

2002-12-18

By use of headspace SPME sampling and a PLOT column, on-line capillary gas chromatography-isotope ratio mass spectrometry was employed in the combustion (C) and the pyrolysis (P) modes (HRGC-C/P-IRMS) to determine the delta(13)C(VPDB) and delta(18)O(VSMOW) values of ethanol in authentic (n = 14) and commercial tequila samples (n = 15) as well as a number of other spirits (n = 23). Whereas with delta(13)C(VPDB) values ranging from -12.1 to -13.2 per thousand and from -12.5 to -14.8 per thousand similar variations were found for 100% agave and mixed tequilas, respectively, the delta(18)O(VSMOW) data differed slightly within these categories: ranges from +22.1 to +22.8 per thousand and +20.8 to +21.7 per thousand were determined for both the authentic 100% agave and mixed products, respectively. The data recorded for commercial tequilas were less homogeneous; delta(13)C(VPDB) data from -10.6 to -13.9 per thousand and delta(18)O(VSMOW) values from +15.5 to +22.7 per thousand were determined in tequilas of both categories. Owing to overlapping data, attempts to differentiate between white, rested, and aged tequilas within each of the two categories failed. In addition, discrimination of tequila samples from other spirits by means of delta(13)C(VPDB) and delta(18)O(VSMOW) data of ethanol was restricted to the products originating from C(3) as well as C(4)/CAM raw materials.

Rapid determination of caffeoylquinic acid derivatives in Cynara scolymus L. by ultra-fast liquid chromatography/tandem mass spectrometry based on a fused core C18 column.

PubMed

Shen, Qing; Dai, Zhiyuan; Lu, Yanbin

2010-10-01

An ultra-fast high-performance LC-ESI-MS/MS method was developed for the analysis and quantification of caffeoylquinic acid derivatives, including chlorogenic acid, 1,3-di-O-caffeoylquinic acid (cynarin) and 1,5-di-O-caffeoylquinic acid, in artichoke (Cynara scolymus L.) heads and leaves. The rapid separation (less than 4  min) was achieved based on a Halo fused core C18-silica column (50  mm × 2.1  mm id, 2.7  μm). The target compounds were detected and quantified by a triple-quadrupole mass spectrometer in multiple-reaction monitoring mode. The calibration function is linear from 0.06 to 2800  ng/mL for chlorogenic acid, 0.3-3000  ng/mL for cynarin and 0.24-4800  ng/mL for 1,5-di-O-caffeoylquinic acid, respectively. The average recoveries ranged from 92.1 to 113.2% with RSDs ≤6.5%. Moreover, four batches of artichoke head and leaf extracts were analyzed using the established method. The results indicated that the Halo fused core column provided much faster separations and higher sample throughput without sacrificing column ruggedness and reliability, and triple-quadrupole MS provided extraordinarily lower LOQs for most of the target analytes. Comparing to conventional quantitative approaches, the established method was fast, sensitive and reliable for the determination of caffeoylquinic acid derivatives in artichoke.

Data-independent MS/MS quantification of neuropeptides for determination of putative feeding-related neurohormones in microdialysate.

PubMed

Schmerberg, Claire M; Liang, Zhidan; Li, Lingjun

2015-01-21

Food consumption is an important behavior that is regulated by an intricate array of neuropeptides (NPs). Although many feeding-related NPs have been identified in mammals, precise mechanisms are unclear and difficult to study in mammals, as current methods are not highly multiplexed and require extensive a priori knowledge about analytes. New advances in data-independent acquisition (DIA) MS/MS and the open-source quantification software Skyline have opened up the possibility to identify hundreds of compounds and quantify them from a single DIA MS/MS run. An untargeted DIA MS(E) quantification method using Skyline software for multiplexed, discovery-driven quantification was developed and found to produce linear calibration curves for peptides at physiologically relevant concentrations using a protein digest as internal standard. By using this method, preliminary relative quantification of the crab Cancer borealis neuropeptidome (<2 kDa, 137 peptides from 18 families) was possible in microdialysates from 8 replicate feeding experiments. Of these NPs, 55 were detected with an average mass error below 10 ppm. The time-resolved profiles of relative concentration changes for 6 are shown, and there is great potential for the use of this method in future experiments to aid in correlation of NP changes with behavior. This work presents an unbiased approach to winnowing candidate NPs related to a behavior of interest in a functionally relevant manner, and demonstrates the success of such a UPLC-MS(E) quantification method using the open source software Skyline.

Quantification of Lignin and Its Structural Features in Plant Biomass Using 13C Lignin as Internal Standard for Pyrolysis-GC-SIM-MS

PubMed Central

2017-01-01

Understanding the mechanisms underlying plant biomass recalcitrance at the molecular level can only be achieved by accurate analyses of both the content and structural features of the molecules involved. Current quantification of lignin is, however, majorly based on unspecific gravimetric analysis after sulfuric acid hydrolysis. Hence, our research aimed at specific lignin quantification with concurrent characterization of its structural features. Hereto, for the first time, a polymeric 13C lignin was used as internal standard (IS) for lignin quantification via analytical pyrolysis coupled to gas chromatography with mass-spectrometric detection in selected ion monitoring mode (py-GC-SIM-MS). In addition, relative response factors (RRFs) for the various pyrolysis products obtained were determined and applied. First, 12C and 13C lignin were isolated from nonlabeled and uniformly 13C labeled wheat straw, respectively, and characterized by heteronuclear single quantum coherence (HSQC), nuclear magnetic resonance (NMR), and py-GC/MS. The two lignin isolates were found to have identical structures. Second, 13C-IS based lignin quantification by py-GC-SIM-MS was validated in reconstituted biomass model systems with known contents of the 12C lignin analogue and was shown to be extremely accurate (>99.9%, R2 > 0.999) and precise (RSD < 1.5%). Third, 13C-IS based lignin quantification was applied to four common poaceous biomass sources (wheat straw, barley straw, corn stover, and sugar cane bagasse), and lignin contents were in good agreement with the total gravimetrically determined lignin contents. Our robust method proves to be a promising alternative for the high-throughput quantification of lignin in milled biomass samples directly and simultaneously provides a direct insight into the structural features of lignin. PMID:28926698

Determination of pseudoprotodioscin in rat plasma by UPLC-MS/MS: Assay development and application to pharmacokinetic study.

PubMed

Liao, Min; Chen, Xiao; Chen, Jiefeng; Liu, Mengping; Wang, Junyi; Chen, Zuanguang; Xie, Zhiyong; Yao, Meicun

2016-07-15

An original and sensitive ultraperformance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) method for the determination of pseudoprotodioscin (PPD) in rat plasma was developed and validated. Digitoxin was applied as an internal standard. Plasma samples were processed by acetonitrile-mediated plasma protein precipitation and chromatographed using a step gradient program on a C18 column (2.1×50mm i.d., 1.7μm). The mobile phase was comprised of acetonitrile and 0.1mmolL(-1) aqueous lithium acetate mixed with 0.03% formic acid at the flow rate of 0.2mLmin(-1). Multiple reaction monitoring (MRM) transitions were performed for detection and lithium adduct ions were employed with a significant improvement of the response of the analytes in electrospray positive ionization mode. The concentration range of calibration curve was linear over the range 2-5000ngmL(-1). The intra- and inter-day precisions were all less than 11.5% and accuracies were within the range of 94.1-103.5%, and the analytes exhibited no severe matrix effect. The validated method was successfully applied in the pharmacokinetics of PPD after intragastric (50mgkg(-1)) and intravenous (4mgkg(-1)) administration in rats. PPD showed rapid excretion and with bioavailability of simply about 5.7% in rats. Copyright © 2015 Elsevier B.V. All rights reserved.

UPLC-MS-MS Method for the Determination of Vilazodone in Human Plasma: Application to a Pharmacokinetic Study.

PubMed

El-Bagary, Ramzia; Hashem, Hanaa; Fouad, Marwa; Tarek, Sally

2016-09-01

A sensitive, rapid and simple liquid chromatographic-electrospray ionization tandem mass spectrometric (LC-ESI-MS-MS) method was developed for the quantitative determination of vilazodone in human plasma and for the study of the pharmacokinetic behavior of vilazodone in healthy Egyptian volunteers. With escitalopram as internal standard (IS), liquid-liquid extraction was used for the purification and preconcentration of analytes from human plasma matrix using diethyl ether. The separation was performed on an Acquity UPLC BEH shield RP C18 column (1.7 µm, 2.1 × 150 mm). Isocratic elution was applied using methanol-0.2% formic acid (90:10, v/v). Detection was performed on a triple-quadrupole tandem mass spectrometer with multiple reaction monitoring mode via an electrospray ionization source at m/z 442.21 → 155.23 for vilazodone and m/z 325.14 → 109.2 for escitalopram. Linear calibration curves were obtained over the range of 1-200 ng/mL with the lower limit of quantification at 1 ng/mL. The intra- and inter-day precision showed relative standard deviation ≤3.3%. The total run time was 1.5 min. This method was successfully applied for clinical pharmacokinetic investigation, and a preliminary metabolic study was also carried out. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Laser Spectroscopy Monitoring of 13C18O16O and 12C17O16O of Atmospheric Carbon Dioxide

NASA Astrophysics Data System (ADS)

Shorter, J. H.; Nelson, D. D.; Ono, S.; McManus, J. B.; Zahniser, M. S.

2017-12-01

One of the main challenges to making accurate predictions of future changes in CO2 concentration is the capability to determine what fraction of human produced CO2 remains in the atmosphere. We present our progress in the application of Tunable Infrared Laser Direct Absorption Spectroscopy (TILDAS) to the measurement of the primary clumped (13C18O16O) as well as 17O (12C17O16O) isotopologues of atmospheric CO2, as a tracer of its sources and sinks. We expect unique isotopologue signals in CO2 from high-temperature combustion sources, plants, soils, and air-sea exchange processes. High sampling frequency (a few minutes for each sample vs. reference cycle) achieved by a TILDAS instrument is expected to enable us to document local heterogeneous sources and temporal variations. The TILDAS is equipped with a newly developed 400-meter absorption cell. We designed a dual pressure measurement technique in which the clumped isotopologue, 13C18O16O, and 13C16O16O are first measured at 30 torr cell pressure. This is followed by measurement of 12C17O16O, 12C18O16O and 12C16O16O at lower ( 5 torr) cell pressure. Isotopologue ratios are compared between reference and sample gases. Preliminary tests demonstrated a precision approaching 0.03 ‰ for the ratio 13C18O16O/13C16O16O and 0.08‰ for Δ13C18O16O value (1σ repeatability for 4 min sample vs. reference cycle). Sample size for a single analysis is approximately 100 mL of air (1.6μmol of CO2). Given the previously observed range of variations for Δ13C18O16O and Δ17O values as large as 0.6 to 0.3 ‰, respectively, TILDAS offers a novel approach for real time monitoring of atmospheric CO2 isotopologues. It was found that achieving better than 0.1‰ requires careful matching of CO2 mixing ratios between reference and sample air. A primary cause of pressure and mixing ratio dependence is inaccurate baseline fitting (analogous to abundance sensitivity or pressure baseline for IRMS). Given that mixing ratios of atmospheric

ANALYSIS OF POLYMORPHISMS IN THE INTERLEUKIN 18 GENE PROMOTOR (-137 G/C AND -607 C/A) IN PATIENTS INFECTED WITH HEPATITIS C VIRUS FROM THE BRAZILIAN AMAZON.

PubMed

Santos, Kemper Nunes dos; Almeida, Marcella Kelly Costa de; Fecury, Amanda Alves; Costa, Carlos Araújo da; Martins, Luísa Caricio

2015-01-01

The hepatitis C virus has been recognized as the leading cause of chronic liver disease in the world. Host genetic factors have been implicated in the persistence of hepatitis C virus infection. Single nucleotide polymorphisms at positions -607 C/A (rs1946518) and -137 G/C (rs187238) in the IL-18 gene promoter have been suggested to be associated with delayed hepatitis C virus clearance and persistence of the disease. Identify these polymorphisms in a population infected with hepatitis C virus from the Brazilian Amazon region. In a cross-sectional analytical study conducted in Belém, Pará, Brazil, 304 patients infected with hepatitis C virus were divided into two groups: group A, patients with persistent infection; group B, patients with spontaneous clearance. The control group consisted of 376 volunteers not infected with hepatitis C virus. Samples were analyzed by RT-PCR for the detection of viral RNA and by RFLP-PCR to evaluate the presence of the -137 G/C and -607 C/A IL-18 gene promoter polymorphisms. Comparison of polymorphism allele frequencies between the patient and control groups showed a higher frequency of allele C at position -607 among patients (P=0.02). When the association between the polymorphisms and viral infection was analyzed, patients carrying genotype C/A at position -607 were found to be at higher risk of persistent hepatitis C virus infection (P=0.03). The present results suggest a possible role of the -607 IL-18 gene promoter polymorphism in the pathogenesis of hepatitis C virus infection.

Highly sensitive LC-MS/MS-ESI method for determination of phenelzine in human plasma and its application to a human pharmacokinetic study.

PubMed

Kallem, Raja Reddy; Jillela, Bhupathi; Ravula, Arun Reddy; Samala, Ramakrishna; Andy, Adinarayana; Ramesh, Mullangi; Rao, Jvln Seshagiri

2016-06-01

A selective, sensitive and rapid LC-MS/MS method has been developed and validated for quantification of the phenelzine (PZ) in 200μL of human plasma using hydroxyzine (HZ) as an internal standard (IS) as per regulatory guidelines. The sample preparation involved the derivatization of PZ using pentaflurobenzaldehyde followed by solid phase extraction process to extract PZ and HZ from human plasma. LC-MS/MS was operated under the multiple reaction-monitoring mode (MRM) using the electro spray ionization technique in positive ion mode and the transitions of m/z 305.1→105.1 and m/z 375.3→201.1 were used to measure the derivative of PZ and IS, respectively. The total run time was 3.5min and the elution of PZ and HZ occurred at 2.53, and 1.92min, respectively; this was achieved with a mobile phase consisting of 10mM ammonium acetate: acetonitrile (20:80, v/v) at a flow rate of 1.0mL/min on an Ace C18 column with a split ratio of 70:30. The developed method was validated in human plasma with a lower limit of quantitation 0.51ng/mL. A linear response function was established for the range of concentrations 0.51-25.2ng/mL (r>0.995) for PZ. The intra- and inter-day precision values met the acceptance criteria. PZ was stable in the battery of stability studies viz., stock solution, bench-top, auto-sampler, long-term and freeze/thaw cycles. The developed assay method was applied to an oral bioequivalence study in humans. Copyright © 2016 Elsevier B.V. All rights reserved.

Identification and quantification of 5,6,7,8-tetrahydro-2-(2-phenylethyl)chromones in Chinese eaglewood by HPLC with diode array detection and MS.

PubMed

Li, Jun; Chen, Dong; Jiang, Yong; Zhang, Qian; Zhang, Liang; Tu, Peng-Fei

2013-12-01

A sensitive and reliable HPLC coupled with diode array detection and MS method was developed and validated for the first time to simultaneously identify and quantify eight characteristic 5,6,7,8-tetrahydro-2-(2-phenylethyl)chromones (THPECs) in Chinese eaglewood. Chromatographic separation was performed on a Zorbax SB C18 column with a gradient of acetonitrile/0.1% formic acid/water as the mobile phase. The MS fragmentation behavior of THPECs was characterized as the successive neutral loss of two molecules of H2 O ([M+H-18-18](+) ) and then two molecules of CO ([M+H-18-18-28-28](+) ), which could be used to differentiate Chinese eaglewood from counterfeits. Validation of the developed analytical method showed good linearity, satisfactory precision, and good recovery. The established method was successfully applied to the simultaneous determination of eight THPECs in ten batches of Chinese eaglewood, which could be used as a tool for the quality control of Chinese eaglewood. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparison of enzyme kinetics of warfarin analyzed by LC-MS/MS QTrap and differential mobility spectrometry.

PubMed

Shaik, Abdul Naveed; Grater, Richard; Lulla, Mukesh; Williams, David A; Gan, Lawrence L; Bohnert, Tonika; LeDuc, Barbara W

2016-01-01

Warfarin is an anticoagulant used in the treatment of thrombosis and thromboembolism. It is given as a racemic mixture of R and S enantiomers. These two enantiomers show differences in metabolism by CYPs: S-warfarin undergoes 7 hydroxylation by CYP2C9 and R-warfarin by CYP3A4 to form 10 hydroxy warfarin. In addition, warfarin is acted upon by different CYPs to form the minor metabolites 3'-hydroxy, 4'-hydroxy, 6-hydroxy, and 8-hydroxy warfarin. For analysis, separation of these metabolites is necessary since all have the same m/z ratio and similar fragmentation pattern. Enzyme kinetics for the formation of all of the six hydroxylated metabolites of warfarin from human liver microsomes were determined using an LC-MS/MS QTrap and LC-MS/MS with a differential mobility spectrometry (DMS) (SelexION™) interface to compare the kinetic parameters. These two methods were chosen to compare their selectivity and sensitivity. Substrate curves for 3'-OH, 4'-OH, 6-OH, 7-OH, 8-OH and 10-OH warfarin formation were generated to determine the kinetic parameters (Km and Vmax) in human liver microsomal preparations. The limit of quantitation (LOQ) for all the six hydroxylated metabolites of warfarin were in the range of 1-3nM using an LC-MS/MS QTrap method which had a run time of 22min. In contrast, the LOQ for all the six hydroxylated metabolites using DMS interface technology was 100nM with a run time of 2.8min. We compare these two MS methods and discuss the kinetics of metabolite formation for the metabolites generated from racemic warfarin. In addition, we show inhibition of major metabolic pathways of warfarin by sulfaphenazole and ketoconazole which are known specific inhibitors of CYP2C9 and CYP3A4 respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

Soyuz Ms_06 Post LAnding VF 2-28-18_623721_hires

NASA Image and Video Library

2018-03-01

Expedition 54 Commander Alexander Misurkin of Roscosmos and Flight Engineers Mark Vande Hei and Joe Acaba of NASA were greeted in a traditional ceremony at the airport in Karaganda, Kazakhstan Feb. 28, a few hours after landing in their Soyuz MS-06 spacecraft in Kazakhstan near the town of Dzhezkazgan. After the ceremony, Misurkin returned to his training base in Star City, Russia, while Vande Hei and Acaba flew back to their homes in Houston on a NASA jet. The trio spent almost six months in space.

Structure of the c-Ki-ras gene in a rat fibrosarcoma induced by 1,8-dinitropyrene.

PubMed Central

Tahira, T; Hayashi, K; Ochiai, M; Tsuchida, N; Nagao, M; Sugimura, T

1986-01-01

Restriction enzyme maps were made of the region around exons 1 and 2 of activated c-Ki-ras of a fibrosarcoma (1,8-DNP2) induced in a rat by 1,8-dinitropyrene. Nucleotide sequence analysis revealed that activated c-Ki-ras shows a G----T transversion in codon 12 and consequently encodes cysteine instead of glycine in normal rat c-Ki-ras. PMID:3023884

Identification of hydroxycinnamoylquinic acids of arnica flowers and burdock roots using a standardized LC-DAD-ESI/MS profiling method.

PubMed

Lin, Long-Ze; Harnly, James M

2008-11-12

A screening method using LC-DAD-ESI/MS was developed for the identification of common hydroxycinnamoylquinic acids based on direct comparison with standards. A complete standard set for mono-, di-, and tricaffeoylquinic isomers was assembled from commercially available standards, positively identified compounds in common plants (artichokes, asparagus, coffee bean, honeysuckle flowers, sweet potato, and Vernonia amygdalina leaves) and chemically modified standards. Four C18 reversed phase columns were tested using the standardized profiling method (based on LC-DAD-ESI/MS) for 30 phenolic compounds, and their elution order and retention times were evaluated. Using only two columns under standardized LC condition and the collected phenolic compound database, it was possible to separate all of the hydroxycinnamoylquinic acid conjugates and to identify 28 and 18 hydroxycinnamoylquinic acids in arnica flowers (Arnica montana L.) and burdock roots (Arctium lappa L.), respectively. Of these, 22 are reported for the first time.

HPLC determination of cefprozil in tablets using monolithic and C18 silica columns.

PubMed

Can, Nafiz O

2011-08-01

Cefprozil (CPZ) is a second-generation semi-synthetic cephalosporin antibiotic that commonly exists as the mixture of Z and E diastereoisomers, at the ratio of approximately 9:1. A novel reversed-phase HPLC method for the determination of CPZ in tablets was described. The separation of CPZ diastereoisomers and caffeine (internal standard) was carried out by applying the same analytical and instrumental conditions on two stationary phases, which have different surface chemistries. The columns used in the study were monolithic silica Merck Chromolith Performance RP-18e and conventional C18 silica Phenomenex Synergi Hydro RP columns. In total, 10 μL aliquots of samples were injected into the system and eluted using water-acetonitrile (90:10, v/v) solution, which was pumped through the column at a flow rate of 1.0 mL/min. The analyte peaks were detected at 200 nm using diode array detector with high specificity. CPZ diastereoisomers and caffeine were measured within 13 min using the C18 column, whereas <5 min was required for the monolithic one. Validation studies were performed according to official recommendations. Value of a monolithic column for the assay of diastereoisomers in pharmaceutical tablets was evaluated for the first time and found as a powerful alternative to highly efficient C18 columns. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

LC-MS/MS assay for the quantitation of the tyrosine kinase inhibitor neratinib in human plasma.

PubMed

Kiesel, Brian F; Parise, Robert A; Wong, Alvin; Keyvanjah, Kiana; Jacobs, Samuel; Beumer, Jan H

2017-02-05

Neratinib is an orally available tyrosine kinase inhibitor targeting HER2 (ERBB2) and EGFR (ERBB). It is being clinically evaluated for the treatment of breast and other solid tumors types as a single agent or in combination with other chemotherapies. In support of several phase I/II clinical trials investigating neratinib combinations, we developed and validated a novel LC-MS/MS assay for the quantification of neratinib in 100μL of human plasma with a stable isotopic internal standard. Analytes were extracted from plasma using protein precipitation and evaporation of the resulting supernatant followed by resuspension. Chromatographic separation was achieved using an Acquity UPLC BEH Shield RP18 column and a gradient methanol-water mobile phase containing 10% ammonium acetate. An ABI 4000 mass spectrometer and electrospray positive mode ionization were used for detection. The assay was linear from 2 to 1,000ng/mL and proved to be accurate (98.9-106.5%) and precise (<6.2%CV), and met the FDA guidance for bioanalytical method validation. This LC-MS/MS assay will be an essential tool to further define the pharmacokinetics of neratinib. Copyright © 2016 Elsevier B.V. All rights reserved.

Deposition of single and layered amorphous fluorocarbon films by C8F18 PECVD

NASA Astrophysics Data System (ADS)

Yamauchi, Tatsuya; Mizuno, Kouichiro; Sugawara, Hirotake

2008-10-01

Amorphous fluorocarbon films were deposited by plasma-enhanced chemical vapor deposition (PECVD) using C8F18 in closed system at C8F18 pressures 0.1--0.3 Torr, deposition times 1--30 min and plasma powers 20--200 W@. The layered films were composed by repeated PECVD processes. We compared `two-layered' and `intermittently deposited' films, which were made by the PECVD, respectively, with and without renewal of the gas after the deposition of the first layer. The interlayer boundary was observed in the layered films, and that of the intermittently deposited films showed a tendency to be clearer when the deposition time until the interruption of the PECVD was shorter. The film thickness increased linearly in the beginning of the PECVD and it turned down after 10--15 min, that was similar between the single and intermittently deposited films. It was considered that large precursors made at a low decomposition degree of C8F18 contributed to the film deposition in the early phase and that the downturn was due to the development of the C8F18 decomposition. This explanation on the deposition mechanism agrees qualitatively with our experimental data of pressure change and optical emission spectra during the deposition. This work is supported by Grant-in-Aid from Japan Society for the Promotion of Science.

[Pharmacokinetics of scopolamine hydrobromide oral disintegrative microencapsule tablets in Beagle dogs determined with LC-MS/MS].

PubMed

Xia, Tian; Liu, De-Ding; Shi, Li-Fu; Hu, Jin-Hong

2011-08-01

The study aims to elucidate the characteristics of pharmacokinetics of scopolamine hydrobromide oral disintegrative microencapsule tablets in healthy Beagle dogs. Chromatographic separation was performed on a C18 column (100 mm x 3.0 mm, 3.5 microm) with methanol - 2 mmol x L(-1) ammonium formate (25 : 75) as the mobile phase. A trip-quadrupole tandem mass spectrum with the electrospray ionization (ESI) source was applied and positive ion multiple reaction monitoring mode was operated. Six Beagle dogs were randomly devided into two groups. They received oral single dose of scopolamine hydrobromide oral disintegrative microencapsule tablets 0.6 mg (test tablet) or scopolamine hydrobromide normal tablets (reference tablet). Plasma samples were collected at designed time. Plasma concentration of scopolamine hydrobromide was determined by LC-MS/MS and pharmacokinetic parameters were calculated. The pharmacokinetic parameters of test tablet vs reference tablet were as follows: C(max): (8.16 +/- 0.67) ng x mL(-1) vs (3.54 +/- 0.64) ng x mL(-1); t1/2: (2.83 +/- 0.45) h vs (3.85 +/- 0.82) h; t(max): (1.25 +/- 0.27) h vs (0.42 +/- 0.09) h; AUC(0-12h): (25.06 +/- 3.75) h x ng x mL(-1) vs (9.59 +/- 1.02) h x ng x mL(-1); AUC(0-infinity): (26.30 +/- 3.92) h x ng x mL(-1) vs (10.80 +/- 1.45) h x ng x mL(-1); MRT(0-12h): (3.38 +/- 0.34) h vs (3.86 +/- 0.26) h; MRT(0-infinity): (3.98 +/- 0.63) h vs (5.37 +/- 1.00) h. The absorption rate and AUC of test tablet is different from that of reference tablet. The bioavailability of test tablet is better than those of reference tablet.

High-Throughput Quantitation of Neonicotinoids in Lyophilized Surface Water by LC-APCI-MS/MS.

PubMed

Morrison, Lucas M; Renaud, Justin B; Sabourin, Lyne; Sumarah, Mark W; Yeung, Ken K C; Lapen, David R

2018-05-21

Background : Neonicotinoids are among the most widely used insecticides. Recently, there has been concern associated with unintended adverse effects on honeybees and aquatic invertebrates at low parts-per-trillion levels. Objective : There is a need for LC-MS/MS methods that are capable of high-throughput measurements of the most widely used neonicotinoids at environmentally relevant concentrations in surface water. Methods : This method allows for quantitation of acetamiprid, clothianidin, imidacloprid, dinotefuran, nitenpyram, thiacloprid, and thiamethoxam in surface water. Deuterated internal standards are added to 20 mL environmental samples, which are concentrated by lyophilisation and reconstituted with methanol followed by acetonitrile. Results : A large variation of mean recovery efficiencies across five different surface water sampling sites within this study was observed, ranging from 45 to 74%. This demonstrated the need for labelled internal standards to compensate for these differences. Atmospheric pressure chemical ionization (APCI) performed better than electrospray ionization (ESI) with limited matrix suppression, achieving 71-110% of the laboratory fortified blank signal. Neonicotinoids were resolved on a C18 column using a 5 min LC method, in which MQL ranged between 0.93 and 4.88 ng/L. Conclusions : This method enables cost effective, accurate, and reproducible monitoring of these pesticides in the aquatic environment. Highlights : Lyophilization is used for high throughput concentration of neonicotinoids in surface water. Variations in matrix effects between samples was greatly reduced by using APCI compared with ESI. Clothianidin and thiamethoxam were detected in all samples with levels ranging from below method quantitation limit to 65 ng/L.

Adsorption behaviors of neutral and ionizable compounds on hybrid stationary phases in the absence (BEH-C18) and the presence (CSH-C18) of immobile surface charges.

PubMed

Gritti, Fabrice; Guiochon, Georges

2013-03-22

The adsorption behaviors of a neutral (caffeine) and a positively charged compound (nortriptylinium) are investigated on two RPLC/hybrid stationary phases, eluted with a low ionic strength buffer (phosphate buffer, W(S)pH 2.63, I=10mM). The first phase, bridge ethylene hybrid (BEH), is neutral at all pHs whereas the second, charged surface hybrid (CSH), contains a protonated ligand at W(W)pH <7. The band profiles of these two compounds eluted by mixture of acetonitrile and water were recorded under overloaded conditions. The adsorption isotherms of the neutral compound on both columns were well accounted for by a heterogeneous Linear-Langmuir (LL) model, which has an adsorption-desorption equilibrium constants about twice larger for caffeine on the CSH than on the BEH, due to charge-dipole interactions. In contrast, at low loadings (0.3 and 1.2μL, C=30g/L), the adsorption isotherm of the charged compound can be accounted for by a homogeneous electrostatically modified Langmuir (EML) or by a heterogeneous bi-EML implicit isotherms onto the CSH and BEH adsorbent, respectively. Electrostatic repulsions definitely account the lesser retention of the ionizable compound on CSH than on BEH. This is explained by the surface potential of CSH-C18 at 20mV and by the subsequent decrease of the equilibrium constant of weak adsorption sites (C18 environment) and removal of the strong adsorption sites (accessible silanols). At the highest sample loadings (5 and 20μL, C=30g/L), the EML and the bi-EML isotherms failed because some adsorbate-adsorbate interactions take place when bulk concentrations exceed 0.2g/L. The experimental data were then successively fitted to an empirical heterogeneous Langmuir-Moreau (LM) explicit isotherm. The best saturation capacities of the empirical heterogeneous LM isotherm is consistent with the manufacturer's estimate of the surface concentration of residual silanols onto the BEH- and CSH-C18 endcapped adsorbent (<0.1μmol/m(2)). Copyright �

Using in situ GC-MS for analysis of C2-C7 volatile organic acids in ambient air of a boreal forest site

NASA Astrophysics Data System (ADS)

Hellén, Heidi; Schallhart, Simon; Praplan, Arnaud P.; Petäjä, Tuukka; Hakola, Hannele

2017-01-01

An in situ method for studying gas-phase C2-C7 monocarboxylic volatile organic acids (VOAs) in ambient air was developed and evaluated. Samples were collected directly into the cold trap of the thermal desorption unit (TD) and analysed in situ using a gas chromatograph (GC) coupled to a mass spectrometer (MS). A polyethylene glycol column was used for separating the acids. The method was validated in the laboratory and tested on the ambient air of a boreal forest in June 2015. Recoveries of VOAs from fluorinated ethylene propylene (FEP) and heated stainless steel inlets ranged from 83 to 123 %. Different VOAs were fully desorbed from the cold trap and well separated in the chromatograms. Detection limits varied between 1 and 130 pptv and total uncertainty of the method at mean ambient mixing ratios was between 16 and 76 %. All straight chain VOAs except heptanoic acid in the ambient air measurements were found with mixing ratios above the detection limits. The highest mixing ratios were found for acetic acid and the highest relative variations for hexanoic acid. In addition, mixing ratios of acetic and propanoic acids measured by the novel GC-MS method were compared with proton-mass-transfer time-of-flight mass spectrometer (PTR-TOFMS) data. Both instruments showed similar variations, but differences in the mixing ratio levels were significant.

A UPLC-MS/MS method for qualification of quercetin-3-O-β-D-glucopyranoside-(4→1)-α-L-rhamnoside in rat plasma and application to pharmacokinetic studies.

PubMed

Yao, Xin; Zhou, Guisheng; Tang, Yuping; Li, Zhenhao; Su, Shulan; Qian, Dawei; Duan, Jin-Ao

2013-03-07

A sensitive and accurate ultra-performance liquid chromatography coupled with triple quadrupole mass (UPLC-MS/MS) method was developed for the determination of quercetin-3-O-β-D-glucopyranoside-(4→1)-α-L-rhamnoside (QGR) in rat plasma using rutin as internal standard. Chromatographic separation was achieved on a Acquity BEH C18 column (100 mm × 2.1 mm, 1.7 μm) with a gradient elution of acetonitrile and 0.10% formic acid (v/v) at a flow rate of 0.4 mL/min. QGR and rutin were detected using electrospray negative ionization mass spectrometry in the multiple reaction monitoring (MRM) mode. The method demonstrated good linearity and did not show any endogenous interference with the QGR and rutin peaks. This method was successfully applied to a pharmacokinetic study of QGR in rats after intravenous (20 mg/kg) and oral (40 mg/kg) administration, and the results showed that the compound was poorly absorbed, with an absolute bioavailability of approximately 3.41%.

[UPLC-MS/MS determination of content of three iridoids of xingnaojing oral preparation in rat brains and study on their brain pharmacokinetics].

PubMed

Xu, Pan; Du, Shou-Ying; Lu, Yang; Bai, Jie; Liu, Hui-Min; Du, Qiu; Chen, Zhen-Zhen; Wang, Zhen

2014-06-01

To establish a UPLC-MS/MS method for the simultaneous determination of geniposide, genipin 1-O-beta-D-gentiobioside and geniposidic acid in rat brains and study the brain pharmacokinetics of the three iridoid glycosides in stroke rat after the oral administration of Xingnaojing. In this experiment, brain samples were precipitated with protein for twice. Acquity BEH C18 column was adopted, with acetonitrile-0.1% formic acid-water as the mobile phase for gradient elution. ESI source was adopted for mass spectra; multiple reaction monitoring (MRM) was conducted to detect negative ions. The time for sample analysis was 3.5 min. the results showed good linear relations among the three iridoid glycosides, with the extraction recovery between 99.6% and 114.3%, good intra- and inter-day precisions and accuracies and stability in line with the requirements. The t1/2 and MRT in the three components were similar in brains of stroke rats. Geniposide and genipin 1-O-beta-D-gentiobioside showed double peaks; where as geniposidic acid showed a single peak. In conclusion, the method is so specific, sensitive, accurate and reliable that it can be used to study the brain pharmacokinetics of Xingnaojing oral preparation.

Microdose study of a P-glycoprotein substrate, fexofenadine, using a non-radioisotope-labelled drug and LC/MS/MS.

PubMed

Yamazaki, A; Kumagai, Y; Yamane, N; Tozuka, Z; Sugiyama, Y; Fujita, T; Yokota, S; Maeda, M

2010-04-01

Fexofenadine is a P-glycoprotein substrate of low bioavailability. It is primarily excreted into faeces as a parent drug via biliary excretion. The predictability from microdose data for the drug absorbed via transporters such as P-glycoprotein is not known. Therefore, this study assessed the predictability of therapeutic-dose pharmacokinetics of fexofenadine from microdosing data using non-radioisotope-labelled drug and liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS). In a single dose, randomized, two-way crossover study, eight subjects received a microdose (100 microg) or a therapeutic dose (60 mg) of fexofenadine. Blood samples were collected until 12 h after dosing, and assayed using LC/MS/MS. Plasma concentration-time curves of fexofenadine between microdose and therapeutic dose were similar. The mean +/- SD of C(max) normalized to 60 mg dose after microdose and therapeutic dose were 379 +/- 147 and 275 +/- 145 ng/mL respectively. The mean AUC(last) normalized to 60 mg dose after microdose and therapeutic dose were 1914 +/- 738 and 1431 +/- 432 ng/h/mL respectively. The mean dose-adjusted C(max) and AUC(last) after microdose were higher compared with those after therapeutic dose. Individual plots of C(max) and AUC(last) normalized to 60 mg dose, were similar for microdose and therapeutic dose. None of the pharmacokinetic parameters were statistically different using anova. Overall, the microdose pharmacokinetics profile was similar to, and hence predictive of, that of the therapeutic dose. For the P-glycoprotein substrate fexofenadine, the predictability of therapeutic-dose pharmacokinetics from microdose data was good. A microdose study using a non-radioisotope-labelled drug and LC/MS/MS is convenient, and has the potential to aid the early selection of drug candidates.

In-Depth Lipidomic Analysis of Molecular Species of Triacylglycerides, Diacylglycerides, Glycerophospholipids, and Sphingolipids of Buttermilk by GC-MS/FID, HPLC-ELSD, and UPLC-QToF-MS

PubMed Central

Castro-Gómez, Pilar; Montero, Olimpio; Fontecha, Javier

2017-01-01

Buttermilk, a byproduct of butter manufacturing, has gained considerable attention due to its high concentration of polar lipids as phospho- and sphingolipids from the milk fat globule membrane (MFGM). These polar lipids (PLs) are essential components of all cellular membranes and exert a variety of indispensable metabolic, neurological, and intracellular signaling processes. Despite its importance, there are few research studies that report a comprehensive characterization of the lipid molecular species of MFGM that could contribute to a better understanding of their putative healthful activities. In this study, procedures such as pressurized liquid extraction of polar and nonpolar lipids and their fractionation by flash chromatography have been carried out. The obtained fractions were submitted to an exhaustive characterization from a lipidomic point of view. The characterization includes new data about the identification and quantification of triacylglycerides (TAG), diacylglycerides (DAG), and phospho- and sphingolipids using different chromatographic techniques. The fatty acid profile was comparable to that of the milk fat but with a highly diverse composition of fatty acids. Molecular species have also been determined by using ultra-high performance liquid chromatography/quadruple-time-of-flight mass spectrometry (UPLC/QToF-MS). The TAG (16:0/16:0/6:0) and TAG (16:0/16:0/8:0) were the predominant saturated TAG species and TAG (14:0/18:1/16:0) and TAG (16:0/16:0/18:1) presented the highest content of monounsaturated TAG species. Furthermore; over 30 molecular species of phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), and phosphatidylinositol (PI) could be identified within PL, with PC (16:0/18:1) being the most abundant species. Whereas C16:0 was found to be the preferred FA in TAGs, it was C18:1 in PLs. Several ganglioside species have also been characterized with d18:1 ceramide moiety and secondary acyl chains ranging from C

Analysis of emerging organic contaminants in water, fish and suspended particulate matter (SPM) in the Joint Danube Survey using solid-phase extraction followed by UHPLC-MS-MS and GC-MS analysis.

PubMed

Loos, Robert; Tavazzi, Simona; Mariani, Giulio; Suurkuusk, Gert; Paracchini, Bruno; Umlauf, Gunther

2017-12-31

In the third Joint Danube Survey (JDS3), emerging organic contaminants were analysed in the dissolved water phase of samples from the Danube River and its major tributaries. Analyses were performed using solid-phase extraction (SPE) followed by ultra-high-pressure liquid chromatography triple-quadrupole mass spectrometry (UHPLC-MS-MS) and gas chromatography-mass spectrometry (GC-MS). The polar organic compounds analysed by UHPLC-MS-MS were 1H-benzotriazole, methylbenzotriazoles, carbamazepine, 10,11-dihydro-10,11-dihydroxy-carbamazepine, diclofenac, sulfamethox-azole, 2,4-D (2,4-dichlorophenoxyacetic acid), MCPA (2-methyl-4-chlorophenoxyacetic acid), metolachlor, cybutryne (irgarol), terbutryn, DEET (N,N-diethyl-m-toluamide), and several perfluoroalkyl acids (C 6 -C 9 ; C 8 =perfluorooctanoic acid (PFOA)) and perfluorooctansulfonic acid (PFOS). In addition, several organophosphorus flame retardants were analysed by GC-MS. The most relevant compounds identified in the 71 water samples, in terms of highest median and maximum concentrations, were 1H-benzotriazole, tris(1-chloro-2-propyl)phosphate (TCPP), methylbenzotriazoles, carbama-zepine and its metabolite, DEET, sulfamethoxazole, tris(isobutyl)phosphate (TiBP), tris(2-chloroethyl)phosphate (TCEP), PFOA, PFOS and diclofenac. The concentrations of these compounds in the samples were generally below the environmental quality standard (EQS) threshold values, with the exception of PFOS, the concentration of which exceeded the annual average water EQS limit of 0.65ng/L along the whole river, and also exceeded the fish biota EQS of 9.1μg/kg. In addition, the proposed EQS for diclofenac, of 0.1μg/L, was exceeded in the Arges River in Romania (255ng/L). Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

(18)F-FACBC (anti1-amino-3-(18)F-fluorocyclobutane-1-carboxylic acid) versus (11)C-choline PET/CT in prostate cancer relapse: results of a prospective trial.

PubMed

Nanni, Cristina; Zanoni, Lucia; Pultrone, Cristian; Schiavina, Riccardo; Brunocilla, Eugenio; Lodi, Filippo; Malizia, Claudio; Ferrari, Matteo; Rigatti, Patrizio; Fonti, Cristina; Martorana, Giuseppe; Fanti, Stefano

2016-08-01

To compare the accuracy of (18)F-FACBC and (11)C-choline PET/CT in patients radically treated for prostate cancer presenting with biochemical relapse. This prospective study enrolled 100 consecutive patients radically treated for prostate cancer and presenting with rising PSA. Of these 100 patients, 89 were included in the analysis. All had biochemical relapse after radical prostatectomy (at least 3 months previously), had (11)C-choline and (18)F-FACBC PET/CT performed within 1 week and were off hormonal therapy at the time of the scans. The two tracers were compared directly in terms of overall positivity/negativity on both a per-patient basis and a per-site basis. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy were calculated for both the tracers; follow-up at 1 year (including correlative imaging, PSA trend and pathology when available) was considered as the standard of reference. In 51 patients the results were negative and in 25 patients positive with both the tracers, in eight patients the results were positive with (18)F-FACBC but negative with (11)C-choline, and in five patients the results were positive with (11)C-choline but negative with (18)F-FACBC. Overall in 49 patients the results were false-negative (FN), in two true-negative, in 24 true-positive (TP) and in none false-positive (FP) with both tracers. In terms of discordances between the tracers: (1) in one patient, the result was FN with (11)C-choline but FP with (18)F-FACBC (lymph node), (2) in seven, FN with (11)C-choline but TP with (18)F-FACBC (lymph node in five, bone in one, local relapse in one), (3) in one, FP with (11)C-choline (lymph node) but TP with (18)F-FACBC (local relapse), (4) in two, FP with (11)C-choline (lymph nodes in one, local relapse in one) but FN with (18)F-FACBC, and (5) in three, TP with (11)C-choline (lymph nodes in two, bone in one) but FN with (18)F-FACBC. With (11)C-choline and (18)F-FACBC, sensitivities

Metabolite profiling in Trigonella seeds via UPLC-MS and GC-MS analyzed using multivariate data analyses.

PubMed

Farag, Mohamed A; Rasheed, Dalia M; Kropf, Matthias; Heiss, Andreas G

2016-11-01

Trigonella foenum-graecum is a plant of considerable value for its nutritive composition as well as medicinal effects. This study aims to examine Trigonella seeds using a metabolome-based ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) in parallel to gas chromatography-mass spectrometry (GC-MS) coupled with multivariate data analyses. The metabolomic differences of seeds derived from three Trigonella species, i.e., T. caerulea, T. corniculata, and T. foenum-graecum, were assessed. Under specified conditions, we were able to identify 93 metabolites including 5 peptides, 2 phenolic acids, 22 C/O-flavonoid conjugates, 26 saponins, and 9 fatty acids using UPLC-MS. Several novel dipeptides, saponins, and flavonoids were found in Trigonella herein for the first time. Samples were classified via unsupervised principal component analysis (PCA) followed by supervised orthogonal projection to latent structures-discriminant analysis (OPLS-DA). A distinct separation among the investigated Trigonella species was revealed, with T. foenum-graecum samples found most enriched in apigenin-C-glycosides, viz. vicenins 1/3 and 2, compared to the other two species. In contrast to UPLC-MS, GC-MS was less efficient to classify specimens, with differences among specimens mostly attributed to fatty acyl esters. GC-MS analysis of Trigonella seed extracts led to the identification of 91 metabolites belonging mostly to fatty acyl esters, free fatty acids followed by organic acids, sugars, and amino acids. This study presents the first report on primary and secondary metabolite compositional differences among Trigonella seeds via a metabolomics approach and reveals that, among the species examined, the official T. foenum-graecum presents a better source of Trigonella secondary bioactive metabolites.

Multi-residue determination of seventeen sulfonamides and five tetracyclines in fish tissue using a multi-stage LC-ESI-MS/MS approach based on advanced mass spectrometric techniques.

PubMed

Dasenaki, Marilena E; Thomaidis, Nikolaos S

2010-07-05

A strategy was newly developed to rapidly screen seventeen sulfonamides and five tetracyclines in a single run from fish tissues using ultra-high performance liquid chromatography (UHPLC) coupled with comprehensive mass spectrometric approaches, including precursor-ion scan and data dependent scan. The product ions for precursor-ion scanning were selected by studying the MS/MS fragmentation of the analytes. All sulfonamides share the same diagnostic product ion at m/z 156 in positive MS/MS scan, while for tetracycline antibiotics the diagnostic product ion was proved to be at m/z 153.8. Further characterization of each compound was performed using a data dependent scan. Separation was performed on a Zorbax Eclipse Plus C18 column with a gradient elution using acetonitrile - 0.1% formic acid mobile phase at a flow rate of 0.1 mL min(-1). This approach has proven to be a powerful, highly selective, and sensitive tool for rapid screening and detection of non-targeted components in fish tissue and requires a minimum sample preparation such as one generic extraction step with MeOH:ACN 50:50 (v/v) acidified with 0.05% formic acid. The method has also been applied successfully to porcine and poultry meat. The validation of such a screening method was performed for the first time according to Commission Decision 2002/657/EC and satisfactory method performance characteristics were achieved. Copyright 2010 Elsevier B.V. All rights reserved.

Simultaneous determination of erlotinib and tamoxifen in rat plasma using UPLC-MS/MS: Application to pharmacokinetic interaction studies.

PubMed

Maher, Hadir M; Alzoman, Nourah Z; Shehata, Shereen M

2016-08-15

Tamoxifen (TAM) is a non-steroidal estrogen receptor antagonist that enhances erlotinib (ERL)-induced cytotoxicity in the treatment of NSCLC. ERL and TAM are metabolized by CYP3A4 enzymes. In addition, both drugs have the potential of altering the enzymatic activity through either inhibition (ERL) or induction (TAM). Thus it was expected that pharmacokinetics (PK) drug-drug interactions (DDIs) could be encountered following their co-administration. In this respect, a bioanalytical UPLC-MS/MS method has been developed and validated for the simultaneous determination of ERL and TAM in rat plasma samples, using ondansetron (OND) as an internal standard (IS). Plasma samples were prepared using mixed mode cationic solid phase extraction (SPE) STRATA™ -X-C 33μm cartridges with good extraction recovery of both drugs from rat plasma (Er% from -13.92 to -3.32). The drugs were separated on a Waters BEH™ C18 column with an isocratic elution using a mobile phase composed of a mixture of acetonitrile and water, each with 0.15% formic acid, in the ratio of 80: 20, v/v. Quantitation was carried out using the positive ionization mode with multiple reaction monitoring (MRM) at m/z 394.20>278.04 (ERL), m/z 372.25>72.01 (TAM), and m/z 294.18>170.16 (OND). The method was fully validated as per the FDA guidelines over the concentration range of 0.2-50ng/mL with very low lower limit of quantification (LLOQ) of 0.2ng/mL for both ERL and TAM. The intra- and inter-day assay precision (in terms of relative standard deviation, RSD) and accuracy (in terms of percentage relative error, % Er) were evaluated for both drugs and the calculated values evaluated at four different concentration levels were within the acceptable limits (<15%) for concentrations other than LLOQ and 20% for LLOQ. The method was successfully applied to the study of possible PK-DDI following the oral administration of ERL and TAM in a combination, compared to their single administration. Copyright © 2016 Elsevier B

Rapid determination of alkaloids in Macleaya cordata using ionic liquid extraction followed by multiple reaction monitoring UPLC-MS/MS analysis.

PubMed

Li, Linqiu; Huang, Mingyuan; Shao, Junli; Lin, Bokun; Shen, Qing

2017-02-20

The ultrasonic-assisted extraction (UAE) and ionic liquid based dispersive liquid-liquid microextraction (IL-DLLME) have been successfully applied in extracting of six alkaloids from M. cordata. 1-hexyl-3-methylimidazolium tetrafluoroborate ([C 6 MIM][BF 4 ]) aqueous solution was used as extraction solvent. The target analytes in raw material were deposited into a single drop of 1-hexyl-3-methylimidazolium hexafluorophosphate ([C 6 MIM][PF 6 ]), which was in situ formed by mixing [C 6 MIM][BF 4 ] and potassium hexafluorophosphate ([K][PF 6 ]. Afterwards, the extract was analyzed by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) in multiple-reaction monitoring (MRM) mode. The proposed method was fully validated in terms of linearity (0.9983-0.9992), LOD (0.080ngmL -1 ), LOQ (0.25ngmL -1 ), intra-day precision (<5.46%), inter-day precision (<6.36%), and recovery (86.42-112.48%). The results indicate that the approach of combining IL-DLLME with UPLC-MS/MS is powerful and practical for analyzing alkaloids in M. cordata., and it also has great potential for comprehensive quality control of other herbal medicines. Copyright © 2016 Elsevier B.V. All rights reserved.

Identification and determination of the saikosaponins in Radix bupleuri by accelerated solvent extraction combined with rapid-resolution LC-MS.

PubMed

Yang, Yun-Yun; Tang, You-Zhi; Fan, Chun-Lin; Luo, Hui-Tai; Guo, Peng-Ran; Chen, Jian-Xin

2010-07-01

A method based on accelerated solvent extraction combined with rapid-resolution LC-MS for efficient extraction, rapid separation, online identification and accurate determination of the saikosaponins (SSs) in Radix bupleuri (RB) was developed. The RB samples were extracted by accelerated solvent extraction using 70% aqueous ethanol v/v as solvent, at a temperature of 120 degrees C and pressure of 100 bar, with 10 min of static extraction time and three extraction cycles. Rapid-resolution LC separation was performed by using a C(18) column at gradient elution of water (containing 0.5% formic acid) and acetonitrile, and the major constituents were well separated within 20 min. A TOF-MS and an IT-MS were used for online identification of the major constituents, and 27 SSs were identified or tentatively identified. Five major bioactive SSs (SSa, SSc, SSd, 6''-O-acetyl-SSa and 6''-O-acetyl-SSd) with obvious peak areas and good resolution were chosen as benchmark substances, and a triple quadrupole MS operating in multiple-reaction monitoring mode was used for their quantitative analysis. A total of 16 RB samples from different regions of China were analyzed. The results indicated that the method was rapid, efficient, accurate and suitable for use in the quality control of RB.

[Determination and pharmacokinetics of main components for Psoralea corylifolia-Myristica fragrants drug pair by using UPLC-MS/MS].

PubMed

Gao, Jia-Rong; Xu, Shuang-Zhi; Han, Yan-Quan; Wei, Liang-Bing; Jiang, Hui; Song, Jun-Mei; Xue, Xue

2017-05-01

To conduct multiple-reaction monitoring(MRM) quantitative analysis with ultra-high performance liquid chromatography coupled with mass spectrometry method(UPLC-MS/MS), determine the concentrations of psoralen, isopsoralen, bakuchiol and dehydrodiisoeugenol in plasma under positive iron mode with chloramghenicol as internal standard, and investigate the pharmacokinetics process of the main components before and after oral administration of drug pair Psoralea corylifolia -Myristica fragrants. Thirty-six SD rats were randomly divided into three group(A, B, C) and received P. corylifolia extract, P. corylifolia-M. fragrants extract, and M. fragrants extract respectively by intragastric administration. The plasma samples were collected at different time points. In the plasma samples, psoralen, isopsoralen, bakuchiol and dehydrodiisoeugenol showed good linear relationship within concentration rages of 0.098 125 to 39.25, 0.084 37 to 33.75, 0.046 875 to 18.75, and 0.11 to 2.2 mg•L⁻¹ respectively. The precision and stability results showed that the determination method of plasma concentration for such compositions was stable and reliable. The pharmacokinetic parameters obtained by DAS 2.0 showed varying differences before and after compatibility. According to the experimental results, the compatibility of P. corylifolia and M. fragrants can significantly impact the pharmacokinetic process of main components, expand their distribution and accelerate their metabolism and elimination in vivo. Copyright© by the Chinese Pharmaceutical Association.

Specific determination of bromate in bread by ion chromatography with ICP-MS.

PubMed

Akiyama, Takumi; Yamanaka, Michiko; Date, Yukiko; Kubota, Hiroki; Nagaoka, Megumi Hamano; Kawasaki, Yoko; Yamazaki, Takeshi; Yomota, Chikako; Maitani, Tamio

2002-12-01

A sensitive method for detecting bromate in bread by ion chromatography with inductively-coupled plasma mass spectrometry (IC/ICP-MS) was developed. Bromate was extracted from bread with water. The clean-up procedure included a 0.2 micron filter, a C18 cartridge for defatting, a silver cartridge to remove halogen anions, a centrifugal ultrafiltration unit to remove proteins, and a cation-exchange cartridge to remove silver ions. A 500 microL sample solution was applied to IC/ICP-MS. The detection limit and the quantitation limit of bromate in the solution were 0.3 ng/mL and 1.0 ng/mL, expressed as HBrO3, respectively, which corresponded to 2 ng/g and 5 ng/g, respectively, in bread. Recovery of bromate was about 90%, and the CV was about 2%. Based on the detection limit in solution and recovery from bread, the detection limit of bromate in bread was estimated to be 2 ng/g.

Development and application of a UPLC-MS/MS method for the pharmacokinetic study of 10-hydroxy camptothecin and hydroxyethyl starch conjugate in rats.

PubMed

Li, Guofei; Cai, Cuifang; Ren, Tianyang; Tang, Xing

2014-01-01

With the purpose to carry out the pharmacokinetic studies of 10-hydroxy camptothecin (10-HCPT) and hydroxyethyl starch (10-HCPT-HES) conjugate, an ultraperformance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method has been developed and validated. The analytes, 10-HCPT and the internal standard, Diphenhydramine hydrochloride were extracted with ethyl acetate-isopropanol (95:5, v/v) and separated on an ACQUITY UPLC™ BEH C18 column using a mobile phase composed of acetonitrile and water (containing 0.1% formic acid) with a linear gradient program. With positive ion electrospray ionization (ESI), the analytes were monitored on a triple quadrupole mass spectrometer in the multiple reaction monitoring (MRM) mode. Linear calibration curves were obtained over the concentration ranges of 0.5-2500ng/mL. The intra- and inter-day precisions were less than 9.8% and 10.8%, respectively. The accuracy was within 12.1%. The mean recoveries of 10-HCPT at three concentrations of 2.5, 100, 2000ng/mL were higher than 87.2%. Commercial 10-HCPT injection and 10-HCPT-HES conjugate were administered intravenously at an equal dose of 10-HCPT at 0.5mg/kg. The biological half-life of conjugate was increased significantly from 10min to 3.15h and the bioavailability was 40 times higher than 10-HCPT injection. Consequently, the proposed UPLC-ESI-MS/MS method was proved to be sensitive, specific and reliable to analyze 10-HCPT in biological samples; 10-HCPT and HES conjugate is a promising strategy for delivery of 10-HCPT with prolonged half time and improved bioavailability. Copyright © 2013 Elsevier B.V. All rights reserved.

Simple and rapid quantification of vancomycin in serum, urine and peritoneal/pleural effusion via UHPLC-MS/MS applicable to personalized antibiotic dosing research.

PubMed

Javorska, Lenka; Krcmova, Lenka Kujovska; Solich, Petr; Kaska, Milan

2017-08-05

Management of the therapy of life-threatening bacterial infection is extremely based on an optimal antibiotic treatment. Achieving the correct vancomycin dosage in blood and target tissues can be complicated in special situations, e.g., where large fluid sequestration and/or acute renal failure occur. A UHPLC-MS/MS method operating in electrospray (ESI) positive ion mode was applied for the determination of vancomycin in serum, urine and peritoneal/pleural effusion. Sample pretreatment was composed of dilution and simple protein precipitation where only a small volume (50μL) of serum, urine or peritoneal/pleural effusion was required. The separation of vancomycin was performed on a Meteoric Core C18 BIO column (100×4.6mm, 2.7μm) by gradient elution with 0.1% formic acid in water and acetonitrile. The total time of analysis was 4.5min. The method was found to be linear in the range of 2-60μM (or 0.5-10μM) for serum, 0.27-10μM (or 2-60μM) for peritoneal/pleural effusion and 25-300μM for urine, which was adequate for the determination of vancomycin in patient samples. The intra- and inter-day precision was below 8% RSD, and accuracy was from 89 to 104%. The UHPLC/MS-MS method offers a fast and reliable approach to determine vancomycin concentrations in three different human body fluid samples (serum, urine and peritoneal/pleural effusion) with a simple sample pretreatment that was the same for all selected specimens. This method should be applicable to large sample series in clinical (pharmacokinetic/pharmacodynamic) studies. Copyright © 2017 Elsevier B.V. All rights reserved.

Analysis of phytochemical variations in dioecious Tinospora cordifolia stems using HPLC/QTOF MS/MS and UPLC/QqQLIT -MS/MS.

PubMed

Bajpai, Vikas; Singh, Awantika; Chandra, Preeti; Negi, M P S; Kumar, Nikhil; Kumar, Brijesh

2016-01-01

The stem of dioecious Tinospora cordifolia (Menispermaceae) is a commonly used traditional Ayurvedic medicine in India having several therapeutic properties. To develop and validate LC-MS methods for the identification and simultaneous quantitation of various secondary metabolites and to study metabolomic variations in the stem of male and female plants. Ethanolic extract of stems were analysed by HPLC/ESI-QTOF-MS/MS for rapid screening of bioactive phytochemicals. High resolution MS and MS/MS in positive ESI mode were used for structural investigation of secondary metabolites. An UPLC/ESI-QqQ(LIT) -MS/MS method in MRM mode was developed and validated for the simultaneous quantitation of five bioactive alkaloids. Identification and characterisation of 36 metabolites including alkaloids, sesquiterpenes and phytoecdysteroids were performed using LC-MS and MS/MS techniques. The bioactive alkaloids such as jatrorrhizine, magnoflorine, isocorydine, palmatine and tetrahydropalmatine were successfully quantified in male and female plants. The mean abundances of magnoflorine jatrorrhizine, and oblongine were significantly (P < 0.05) higher in male plants while mean abundances of tetrahydropalmatine, norcoclaurine, and reticuline were significantly (P < 0.05) higher in female plants. Phytochemicals in the stem of male and female Tinospora cordifolia showed significant qualitative and quantitative variations. LC-MS and MS/MS methods can be used to differentiate between male and female plants based on their chemical profiles and quantities of the marker bioactive alkaloids. This chemical composition difference was also evident during vegetative stage when there were no male and female flowers. Copyright © 2015 John Wiley & Sons, Ltd.

Interaction Between Cytochrome c and the Hapten 2,4-Dinitro-fluorobenzene by Electrospray Ionization Mass Spectrometry

NASA Astrophysics Data System (ADS)

Wu, Bo; Chu, Yan-qiu; Dai, Zhao-yun; Ding, Chuan-fan

2008-06-01

Allergic contact dermatitis is a delayed hypersensitivity reaction, which results from skin exposure to low molecular weight chemicals such as haptens. To clarify the pathogenic mechanism, electrospray ionization mass spectrometry (ESI-MS) and hydrogen/deuterium (H/D) exchange, as well as UV spectroscopy, were applied to determine the interaction between the model protein cytochrome c (cyt c) and the hapten 2,4-dinitro-fluorobenzene (DNFB). The ESI-MS results demonstrate that the conformation of cyt c can change from native folded state into partially unfolded state with the increase of DNFB. The equilibrium state H/D exchange followed by ESI-MS further confirms the above results. UV spectroscopy indicates that the strong-field coordination between iron of heme (prosthetic group) and His18 or Met80 of cyt c is not obviously affected by the hapten.

Simultaneous quantification of reparixin and paclitaxel in plasma and urine using ultra performance liquid chromatography-tandem mass spectroscopy (UHPLC-MS/MS): Application to a preclinical pharmacokinetic study in rats.

PubMed

Malhi, Sarandeep; Stesco, Nicholas; Alrushaid, Samaa; Lakowski, Ted M; Davies, Neal M; Gu, Xiaochen

2017-03-01

A liquid chromatography-tandem mass spectroscopy (LC-MS/MS) assay was developed and validated to simultaneously quantify anticancer drugs reparixin and paclitaxel in this study. The compounds were extracted from plasma and urine samples by protein precipitation with acetone (supplemented with 0.1% formic acid). Chromatographic separation was achieved using a C18 column, and drug molecules were ionized using dual ion source electrospray and atmospheric pressure chemical ionization (DUIS: ESI-APCI). Reparixin and paclitaxel were quantified using negative and positive multiple reaction monitoring (MRM) mode, respectively. Stable isotope palcitaxel-D5 was used as the internal standard (IS). The assay was validated for specificity, recovery, carryover and sample stability under various storage conditions; it was also successfully applied to measure drug concentrations collected from a pharmacokinetic study in rats. The results confirmed that the assay was accurate and simple in quantifying both reparixin and paclitaxel in plasma and urine with minimal sample pretreatment. Copyright © 2016 Elsevier B.V. All rights reserved.

Testing for nandrolone metabolites in urine samples of professional athletes and sedentary subjects by GC/MS/MS analysis.

PubMed

Gambelunghe, Cristiana; Sommavilla, Marco; Rossi, Ruggero

2002-12-01

The concentrations of nandrolone metabolites, 19-norandrosterone (19-NA) and 19-noretiocholanolone (19-NE) were analysed in urine samples of professional athletes doing intense physical activity and sedentary subjects to verify if there was endogenous production of nandrolone and if there was any link between physical effort and the urinary metabolites of the steroid. We collected 18 urine samples from professional footballers age range 20-30 years, all from the same team, and 18 urine samples from males not doing any physical activity, age range 20-30 years. Neither group used nandrolone. Qualitative and quantitative analyses of urinary nandrolone metabolites were carried out by GC/MS followed by GC/MS/MS to confirm positive samples. This technique has been demonstrated to be an excellent analytical approach for the determination of anabolic steroids at very low detection limits in complex matrices such as urine. In five urine samples from professional footballers traces of 19-NA were detected. No trace of 19-NA was found in the group of sedentary subjects and no trace of 19-NE was found in any urine sample. The absence of nandrolone metabolites in sedentary subjects supports the hypothesis that the presence of 19-NA and 19-NE could be linked to physical effort even though the origin is not yet clear. Copyright 2002 John Wiley & Sons, Ltd.

Application of gas chromatography-mass spectrometry/combustion/isotope ratio mass spectrometry (GC-MS/C/IRMS) to detect the abuse of 17β-estradiol in cattle.

PubMed

Janssens, Geert; Mangelinckx, Sven; Courtheyn, Dirk; Prévost, Stéphanie; De Poorter, Geert; De Kimpe, Norbert; Le Bizec, Bruno

2013-07-31

Although the ability to differentiate between endogenous steroids and synthetic homologues on the basis of their (13)C/(12)C isotopic ratio has been known for over a decade, this technique has been scarcely implemented for food safety purposes. In this study, a method was developed using gas chromatography-mass spectrometry/combustion/isotope ratio mass spectrometry (GC-MS/C/IRMS) to demonstrate the abuse of 17β-estradiol in cattle, by comparison of the (13)C/(12)C ratios of the main metabolite 17α-estradiol and an endogenous reference compound (ERC), 5-androstene-3β,17α-diol, in bovine urine. The intermediate precisions were determined as 0.46 and 0.26‰ for 5-androstene-3β,17α-diol and 17α-estradiol, respectively. This is, to the authors' knowledge, the first reported use of GC-MS/C/IRMS for the analysis of steroid compounds for food safety issues.

Biotransformation and detectability of the new psychoactive substances N,N-diallyltryptamine (DALT) derivatives 5-fluoro-DALT, 7-methyl-DALT, and 5,6-methylenedioxy-DALT in urine using GC-MS, LC-MSn, and LC-HR-MS/MS.

PubMed

Michely, Julian A; Brandt, Simon D; Meyer, Markus R; Maurer, Hans H

2017-02-01

Derivatives of N,N-diallyltryptamine (DALT) can be classified as new psychoactive substances. Biotransformation and detectability of 5-fluoro-DALT (5-F-DALT), 7-methyl-DALT (7-Me-DALT), and 5,6-methylenedioxy-DALT (5,6-MD-DALT) are described here. Their metabolites detected in rat urine and pooled human liver microsomes were identified by liquid chromatography (LC)-high resolution (HR)-tandem mass spectrometry (MS/MS). In addition, the human cytochrome-P450 (CYP) isoenzymes involved in the main metabolic steps were identified and detectability tested in urine by the authors' urine screening approaches using GC-MS, LC-MS n , or LC-HR-MS/MS. Aromatic and aliphatic hydroxylations, N-dealkylation, N-oxidation, and combinations could be proposed for all compounds as main pathways. Carboxylation after initial hydroxylation of the methyl group could also be detected for 7-Me-DALT and O-demethylenation was observed for 5,6-MD-DALT. All phase I metabolites were extensively glucuronidated or sulfated. Initial phase I reactions were catalyzed by CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP3A4, and CYP3A5. Rat urine samples were analyzed following two different low-dose administrations. GC-MS was not able to monitor consumption reliably, but all three compounds are predicted to be detectable in cases of overdose. The LC-MS n and LC-HR-MS/MS approaches were suitable for detecting an intake of all three compounds mainly via their metabolites. However, after the lowest dose, a reliable monitoring could only be achieved for 5-F-DALT via LC-MS n and LC-HR-MS/MS and for 7-Me-DALT via LC-HR-MS/MS. The most abundant targets in both LC-MS screenings were one of two hydroxy-aryl metabolites and both corresponding glucuronides for 5-F-DALT, one N-deallyl hydroxy-aryl, the carboxy, and one dihydroxy-aryl metabolite for 7-Me-DALT, and the demethylenyl metabolite, its oxo metabolite, and glucuronide for 5,6-MD-DALT.

siMS Score: Simple Method for Quantifying Metabolic Syndrome.

PubMed

Soldatovic, Ivan; Vukovic, Rade; Culafic, Djordje; Gajic, Milan; Dimitrijevic-Sreckovic, Vesna

2016-01-01

To evaluate siMS score and siMS risk score, novel continuous metabolic syndrome scores as methods for quantification of metabolic status and risk. Developed siMS score was calculated using formula: siMS score = 2*Waist/Height + Gly/5.6 + Tg/1.7 + TAsystolic/130-HDL/1.02 or 1.28 (for male or female subjects, respectively). siMS risk score was calculated using formula: siMS risk score = siMS score * age/45 or 50 (for male or female subjects, respectively) * family history of cardio/cerebro-vascular events (event = 1.2, no event = 1). A sample of 528 obese and non-obese participants was used to validate siMS score and siMS risk score. Scores calculated as sum of z-scores (each component of metabolic syndrome regressed with age and gender) and sum of scores derived from principal component analysis (PCA) were used for evaluation of siMS score. Variants were made by replacing glucose with HOMA in calculations. Framingham score was used for evaluation of siMS risk score. Correlation between siMS score with sum of z-scores and weighted sum of factors of PCA was high (r = 0.866 and r = 0.822, respectively). Correlation between siMS risk score and log transformed Framingham score was medium to high for age groups 18+,30+ and 35+ (0.835, 0.707 and 0.667, respectively). siMS score and siMS risk score showed high correlation with more complex scores. Demonstrated accuracy together with superior simplicity and the ability to evaluate and follow-up individual patients makes siMS and siMS risk scores very convenient for use in clinical practice and research as well.

{sup 13}CO/C{sup 18}O Gradients across the Disks of Nearby Spiral Galaxies

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

Jiménez-Donaire, María J.; Cormier, Diane; Bigiel, Frank

We use the IRAM Large Program EMPIRE and new high-resolution ALMA data to measure {sup 13}CO(1-0)/C{sup 18}O(1-0) intensity ratios across nine nearby spiral galaxies. These isotopologues of {sup 12}CO are typically optically thin across most of the area in galaxy disks, and this ratio allows us to gauge their relative abundance due to chemistry or stellar nucleosynthesis effects. Resolved {sup 13}CO/C{sup 18}O gradients across normal galaxies have been rare due to the faintness of these lines. We find a mean {sup 13}CO/C{sup 18}O ratio of 6.0 ± 0.9 for the central regions of our galaxies. This agrees well with resultsmore » in the Milky Way, but differs from results for starburst galaxies (3.4 ± 0.9) and ultraluminous infrared galaxies (1.1 ± 0.4). In our sample, the {sup 13}CO/C{sup 18}O ratio consistently increases with increasing galactocentric radius and decreases with increasing star formation rate surface density. These trends could be explained if the isotopic abundances are altered by fractionation; the sense of the trends also agrees with those expected for carbon and oxygen isotopic abundance variations due to selective enrichment by massive stars.« less

First Nuclear DNA C-values for 18 Eudicot Families

PubMed Central

HANSON, LYNDA; BOYD, AMY; JOHNSON, MARGARET A. T.; BENNETT, MICHAEL D.

2005-01-01

• Background and Aims A key target set at the second Plant Genome Size Workshop, held at the Royal Botanic Gardens, Kew in 2003, was to produce first DNA C-value data for an additional 1 % of angiosperm species, and, within this, to achieve 75 % familial coverage overall (up from approx. 50 %) by 2009. The present study targeted eudicot families for which representation in 2003 (42·5 %) was much lower than monocot (72·8 %) and basal angiosperm (69·0 %) families. • Methods Flow cytometry or Feulgen microdensitometry were used to estimate nuclear DNA C-values, and chromosome counts were obtained where possible. • Key Results First nuclear DNA C-values are reported for 20 angiosperm families, including 18 eudicots. This substantially increases familial representation to 55·2 % for angiosperms and 48·5 % for eudicots. • Conclusions The importance of targeting specific plant families to improve familial nuclear DNA C-value representation is reconfirmed. International collaboration will be increasingly essential to locate and obtain material of unsampled plant families, if the target set by the second Plant Genome Size Workshop is to be met. PMID:16239248

Free amino acid profiling in the giant puffball mushroom (Calvatia gigantea) using UPLC-MS/MS.

PubMed

Kıvrak, İbrahim; Kıvrak, Şeyda; Harmandar, Mansur

2014-09-01

Wild edible and medicinal mushroom, Calvatia gigantea, was quantitatively analyzed for the determination of its free amino acids using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The concentrations of total free amino acids, essential and non-essential amino acids were 199.65 mg/100 g, 113.69 mg/100 g, and 85.96 mg/100 g in C. gigantea, respectively. This study showed that C. gigantea, so called a giant puffball mushroom, has free amino acids content. The essential amino acids: tryptophan, isoleucine, valine, phenylalanine, leucine, threonine, lysine, histidine, methionine, and the non-essential amino acids: tyrosine, 4-hyrdroxy proline, arginine, proline, glycine, serine, alanine, glutamine, glutamic acid, aspargine, aspartic acid were detected. Copyright © 2014 Elsevier Ltd. All rights reserved.

Pulmonary NO and C18O2 uptake during pressure-induced lung expansion in rabbits.

PubMed

Heller, Hartmut; Schuster, Klaus-Dieter

2007-01-01

In artificially ventilated animals we investigated the dependence of the pulmonary diffusing capacities of nitric oxide (NO) and doubly 18O-labeled carbon dioxide (DLNO, DLC18O2) on lung expansion with respect to ventilator-driven increases in intrapulmonary pressure. For this purpose we applied computerized single-breath experiments to 11 anesthetized paralyzed rabbits (weight 2.8-3.8 kg) at various alveolar volumes (45-72 ml) by studying the almost entire inspiratory limb of the respective pressure/volume curves (intrapulmonary pressure: 6-27 cmH2O). The animals were ventilated with room air, employing a computerized ventilatory servo-system that we designed to maintain mechanical ventilation and to execute the particular lung function tests automatically. Each single-breath maneuver was started from residual volume (13.5+/-2 ml, mean+/-SD) by inflating the rabbit lungs with 35-55 ml indicator gas mixture containing 0.05% NO in N2 or 0.9% C18O2 in N2. Alveolar partial pressures of NO and C18O2 were measured by respiratory mass spectrometry. Values of DLNO and DLC18O2 ranged between 1.55 and 2.49 ml/(mmHg min) and 11.7 and 16.6 ml/(mmHg min), respectively. Linear regression analyses yielded a significant increase in DLNO with simultaneous increase in alveolar volume (P<0.005) and intrapulmonary pressure (P<0.023) whereas DLC18O2 was not improved. Our results suggest that the ventilator-driven lung expansion impaired the C18O2 blood uptake conductance, finally compensating for the beneficial effect of the increase in alveolar volume on DLC18O2 values.

Exploring the 13CO/C18O abundance ratio towards Galactic young stellar objects and HII regions