A high-sensitivity UPLC-MS/MS method for simultaneous determination and confirmation of triptolide in zebrafish embryos

A high‐sensitivity ultra‐performance liquid‐chromatography (UPLC) coupled with tandem mass spectrometric method was developed for simultaneous quantification and confirmation of triptolide in both zebrafish embryos and the aqueous‐exposure solution on a tandem quadrupole mass spectrometer (TQ‐MS). This was achieved by performing quantification using the multiple reaction monitoring (MRM) acquisition with simultaneous characterization of the MRM peak using product ion confirmation (PIC) acquisition as it elutes from the chromatographic system. Separation was achieved on a 1.7 µm C₁₈ UPLC column using 0.1% formic acid water–acetonitrile mobile phase with a cycle time of 6 min. The linear range of 0.115–360 ng/mL, and lower limits of detection of 0.02 ng/mL and quantification of 0.064 ng/mL were established. This method was successfully applied to determine the time course of triptolide absorption by zebrafish embryos and the amount of triptolide remaining in the culture medium after administration of two triptolide dosages at three time points. This coupled MRM with PIC approach could provide both qualitative and quantitative results without the need for repetitive analyses. This resulted in the reduction of further confirmative experiments and analytical time, and ultimately increased laboratory productivity. Copyright © 2010 John Wiley & Sons, Ltd.     

UPLC-MS/MS method for the determination of acrylic acid in tap water

Abstract

A simple and rapid method employing ultra-high performance liquid chromatography tandem mass spectrometry has been developed for the direct determination of acrylic acid in tap water for the first time. The method worked on a ultra-high-performance liquid chromatography system and utilized the direct injection of 10?μL volumes. Aqueous samples were filtered with 0.22?μm membrane after diluting with the acetonitrile without any further pretreatment. The separation was accomplished by using a HILIC column with a gradient elution program. Acetonitrile and ammonium acetate solution (pH = 7) were applied in the method as the mobile phase. Acrylic acid- d₃ was used as the internal standard in the quantification process. The method provided good recovery from 102.8% to 104.4%, good precision with intraday relative standard deviations in a range of 2.3% and 5.1%. The limit of quantification for the method was 45?μg/L. The possible structures of qualitative ion and quantitative ion of acrylic acid were proposed in this work with the help of the product ion spectra of acrylic acid and its corresponding isotopic standards. This study provided a reliable and quantitative method that could be used for daily monitoring of water quality.     

UPLC-MS/MS determination of doxazosine in human plasma

A sensitive, selective and rapid method for the analysis of doxazosine (DOX) in human plasma based on ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) is described. DOX and tamsulosin, used as an internal standard (IS), were extracted by liquid-liquid extraction, and the chromatography was performed on a C18 UPLC column packed with 1.7 μm particles. The total run time was 2 min. Detection was achieved by the multiple reaction monitoring of the following transitions: m/z 452→344 and m/z 409→228 for DOX and IS, respectively. Transitions of m/z 452→247 and m/z 409→271 were also collected for confirmation purposes. The calibration curve based on peak area ratio was linear up to at least 100 ng ml⁻¹, with a detection limit of 0.02 ng ml⁻¹ (a signal-to-noise ratio of 3). The method showed satisfactory reproducibility, and the short-term stability of the analyte was assessed. The method was successfully applied to the analysis of DOX in human plasma.     

UPLC-MS/MS测定蛋白胨中17种游离氨基酸

建立了超高效液相色谱-串联质谱(UPLC-MS/MS)测定蛋白胨中17种游离氨基酸的方法.样品经水溶解定量稀释后,无需衍生直接进样.17种游离氨基酸经过Syncronis C18色谱柱分离,采用含有0.1％(V/V)甲酸的5％(V/V)甲醇水溶液进行等度洗脱,在电喷雾离子源、正离子模式下,采用多反应监测模式进行监测,外...     

A high-throughput multicomponent screening method for diuretics, masking agents, central nervous system (CNS) stimulants and opiates in human urine by UPLC-MS/MS

A simple and rapid multicomponent screening method of 130 substances for direct injections of urine samples has been developed. The fully automated method based on ultra-performance liquid chromatography (UPLC) and tandem mass spectrometry (MS/MS) is used for three different classes of doping agents: diuretics, central nervous system stimulants (CNS stimulants) and opiates. The samples are diluted with buffer containing internal standards (IS) by a pipetting robot system into 96-well plates. Samples are injected on a reversed phase sub 2-microm particle column connected to a fast polarity switching and rapid scanning tandem mass spectrometer with an electrospray interface. The software used to evaluate the results produced reports containing a small-sized window for each component and a data table list with flags to indicate any adverse analytical findings in the sample. The report can also be processed automatically using an application software, which interpret the data and indicate if there is a suspicious sample. One 96-well plate can be analyzed within 16 h.     

LC‐MS/MS method for the determination of haemanthamine in rat plasma,bile and urine and its application to a pilot pharmacokinetic study

Evidence gathered in various studies points to the fact that haemanthamine, an isoquinoline alkaloid, has multiple medicinally interesting characteristics, including antitumor, antileukemic, antioxidant, antiviral, anticonvulsant and antimalarial activity. This work presents, for the first time, a universal LC‐MS/MS method for analysis of haemanthamine in plasma, bile and urine which has been verified in a pilot pharmacokinetic experiment on rats. Chromatographic separation was performed on a pentafluorophenyl core–shell column in gradient elution mode with a mobile phase consisting of acetonitrile–methanol–ammonium formate buffer. A sample preparation based on liquid–liquid extraction with methyl tert‐butyl ether was employed with ambelline used as an internal standard. Quantification was performed using LC‐MS‐ESI(+) in Selected Reaction Monitoring mode. The method was validated according to the European Medicines Agency guideline in a concentration range of 0.1–10 μmol/L in plasma, bile and urine. The concentration–time profiles of haemanthamine in plasma, bile and urine after a single i.v. bolus of 10 mg/kg have been described for the first time. The presented study addresses the lack of information on haemanthamine pharmacokinetics and also introduces a new universal method of haemanthamine analysis in complex biological matrices. Copyright © 2015 John Wiley & Sons, Ltd.     

UPLC-MS/MS法快速筛查尿液中30种滥用药物

基于超高液相色谱-串联四极杆/线性离子阱质谱(QTRAP UPLC-MS/MS),建立了尿液中30种滥用药物的筛查方法.采用蛋白沉淀法处理尿液样品,实现对多类别滥用药物的高效提取.采用分段多反应监测(sMRM)联合信息依赖性采集(IDA)与增强离子扫描(EPI)模式,结合EPI谱库检索匹配确证检出物信息,并引入内标辅助...     

Multi-residue method for the determination of chlorinated phenol metabolites in urine

Electron-capture-gas chromatographic (EC-GC) methods for the determination of chlorinated phenol metabolites of hexachlorobenzene (HCB) and pentachlorophenol (PCP) in urine are presented. After extraction the sample was reacted with diazomethane to produce the methyl ether of each metabolite prior to determination by EC-GC. An acid alumina column was used for cleanup and separation of methylated phenols into groups. Average recoveries of greater than 80% were obtained from urine fortified with known amounts of the phenol metabolites under investigation. A level of 1 ppb¹ was established as minimum detection limit for each phenol metabolite. Previously unreported urinary metabolites of HCB and PCP were found as a result of a rat feeding study. Levels of chlorinated phenol residues from (a) human general population and (b) a worker occupationally exposed to PCP are also included.     

LC/MS determination of bisphenol A in river water using a surface-modified molecularly-imprinted polymer as an on-line pretreatment device

A new analytical method for the determination of bisphenol A (BPA) by LC/MS was developed and applied to environmental water samples. Quantitative MS detection of BPA was carried out in the negative mode. In order to preconcentrate the target compound yet prevent serious contamination of the water samples from the experimental environment, we employed column switching HPLC coupled with a pretreatment column of surface-modified molecularly-imprinted polymers. The recovery of BPA from a spiked environmental water sample was 102% and the repeatability of actual determinations of water samples containing 20 ng/L of BPA was 5.4% RSD. By modifying the surfaces of the molecularly-imprinted polymer particles packed in the pretreatment column, interference from the water samples was effectively removed, resulting in a significant increase in sensitivity and more reliable results. This method was successfully applied to the trace determination of BPA in environmental water samples using LC/MS.     

Automated high-throughput method using solid-phase microextraction-liquid chromatography-tandem mass spectrometry for the determination of ochratoxin A in human urine

A new automated, high-throughput method for the determination of ochratoxin A (OTA) in human urine samples has been optimized and validated using solid-phase microextraction coupled to liquid chromatography-tandem mass spectrometry (SPME-LC-MS/MS). High-throughput was achieved by simultaneous preparation of up to 96 samples using multi-fiber SPME device and multi-well plates. A carbon-tape coating was chosen for the first time as the best extracting phase for this contaminant. The proposed method required only minimal sample pre-treatment to adjust sample pH to 3.0 using a dilution (1:1) with 0.5M phosphate-buffered saline. A simple gradient guaranteed a good chromatographic separation from matrix interferences in only 8min. Relative recovery (%), precision and linearity validation results met Food and Drug Administration acceptance criteria at three concentration levels (1, 10, and 50ng/mL), indicating excellent performance of the proposed method. Limits of detection and quantitation were 0.3 and 0.7ng/mL in urine, respectively. OTA determination in urine is a good marker for human exposure to this mycotoxin. It is also less invasive than blood analysis. This method is fully automated and the SPME technique is simpler, less time-consuming and cheaper compared with most widely adopted clean-up procedures for OTA extraction from urine.     

Development and validation of an LC‐MS/MS method for simultaneous quantitative analysis of free and conjugated bisphenol A in human urine

Bisphenol A (BPA) is an environmental endocrine‐disrupting chemicals that is widely used in common consumer products. There is an increasing concern regarding human exposure to BPA owing to the potential adverse effects associated with its estrogenic activity. For assessing environmental exposure to BPA, it is essential to have a sensitive, accurate and selective analytical method, especially one that can detect low BPA levels in complex sample matrices. In this study, we developed and validated an accurate, sensitive, and robust liquid chromatography–tandem mass spectrometry method for simultaneous quantification of free BPA and BPA β‐d ‐glucuronide (BPA‐gluc) concentrations in human urine with only a single injection. Calibration curves were linear over a concentration range of 1–100 ng/mL for BPA and 10–1000 ng/mL for BPA‐gluc. The levels of the analytes were determined quantitatively with HPLC/ESI‐MS/MS by using negative electrospray ionization in the select ion monitoring mode and a pentaflouraphenyl propyl column. The validated method was applied to the analysis of spot urine specimens collected from randomly selected healthy human subjects. Copyright © 2013 John Wiley & Sons, Ltd.     

超高效液相色谱串联质谱快速测定饮用水中9种N-亚硝胺的新方法

N-亚硝胺是潜在的人类致癌物,是近年来关注的一类饮用水消毒副产物,同时也是环境分析研究的热点.本文建立了超高效液相色谱(UPLC)串联质谱快速测定饮用水中9种N-亚硝胺的新方法,讨论了色谱柱和流动相对分离9种N-亚硝胺的影响,优化了多级反应质谱(MRM,MS/MS)条件.二甲基亚硝胺-d6为贮存和回收率内标,亚硝基二丙...     

A sensitive and validated LC-MS/MS method for high-throughput determination of pomalidomide in human plasma and pharmacokinetic studies

Pomalidomide is an immunomodulatory agent （IMiD） that has been approved by the US Food and Drug Administration （FDA） for clinical treatment of patients with multiple myeloma.In this work,we developed a sensitive and validated LC-MS/MS method for high-throughput determination of pomalidomide over the range of 1.006–100.6 ng/m L （R²=0.9991） in human plasma and pharmacokinetic studies.A liquid-liquid extraction method using ethyl acetate was applied to extract pomalidomide and afatinib （...     

Development and validation of the quantitative determination of avapritinib in rat plasma by a bioanalytical method of UPLC-MS/MS

Avapritinib, an orally consumed, highly selective inhibitor of platelet-derived growth factor receptor alpha (PDGFRA), is approved in the USA for PDGFRA exon 18 (including D842V) mutant gastrointestinal stromal tumour (GIST). The research conducted investigates an advanced reliable and fast UPLC-MS/MS method that could verify and determine avapritinib concentration in plasma of rats. An addition of acetonitrile was incorporated along with the plasma sample in order to precipitate protein with the analyte separated from the matrix by a gradient elution procedure on a Waters Acquity UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 μm). The active stage in mobile phase consists of a mixture of 0.1% formic acid in water and acetonitrile with a 0.40 mL/min flow rate. UPLC-MS/MS detection was done employing a mode of multiple reaction monitoring (MRM), and the ion transitions of avapritinib and imatinib (internal standard, IS) was m/z 499.10 → 482.09, and m/z 494.30 → 394.20, respectively. This method has good linearity within 2–4000 ng/mL of avapritinib calibration range and a lower limit of quantification (LLOQ) of 2 ng/mL verified. Avapritinib precisions in both intra-day and inter-day were below 15% with the determined accuracy of ?12.9% to 12.0%. The recoveries, stabilities, and matrix effect of avapritinib and IS were credible. 30 mg/kg avapritinib was administered as a single dose orally to rats. The determination of avapritinib level in pharmacokinetic studies was accomplished by efficiently applying a newly optimized UPLC-MS/MS assay.     

A novel and sensitive UPLC–MS/MS method to determine mequitazine in rat plasma and urine: Validation and its application to pharmacokinetic studies

The aim of this study was to develop an analytical method to determine mequitazine in rat plasma and urine. Mequitazine was separated by UPLC–MS/MS equipped with a Kinetex core–shell C₁₈ column (50 × 2.1 mm, 1.7 μm) using 0.1% (v/v) aqueous formic acid and acetonitrile containing 0.1% (v/v) formic acid as a mobile phase by gradient elution at a flow rate of 0.3 mL/min. Quantitation of this analysis was performed on a triple quadrupole mass spectrometer employing electrospray ionization technique operating in multiple reaction monitoring positive ion mode. Mass transitions were m/z 323.3 → 83.1 for mequitazine and 281.3 → 86.3 for imipramine as internal standard. Liquid–liquid extraction with ethyl acetate and protein precipitation with methanol were used for sample extraction. Chromatograms showed that the method had high resolution, sensitivity and selectivity without interference from plasma constituents. Calibration curves for mequitazine in rat plasma and urine were 0.02–200 ng/mL, showing excellent linearity with correlation coefficients (r²) >0.99. Both intra‐ and inter‐day precisions (CV%) were within 4.08% for rat plasma and urine. The accuracies were 99.58–102.03%. The developed analytical method satisfied the criteria of international guidance. It could be successfully applied to pharmacokinetic studies of mequitazine after oral and intravenous administration to rats.     

Detection and quantification of traces of bisphenol A and bisphenol S in paper samples using analytical pyrolysis-GC/MS

In this paper a simplified method based on analytical pyrolysis gas chromatography mass spectrometry (Py-GC/MS) for the detection and quantification of bisphenol A and bisphenol S in paper samples is presented. The method enables a direct analysis of the samples without tedious sample preparation. As the analytes are thermally desorbed, a solvent extraction is not needed. The method is applicable to small samples of ~120 μg. The limits of detection are below 1 mg kg(-1) for bisphenol A and for bisphenol S. The limits of quantification are about 1.3 mg kg(-1). Several validation characteristics of the method developed like standard error of calibration, limit of determination, linearity, and accuracy are given. To prove the accuracy of the method, interferences and matrix dependencies were also investigated. The influence of the pyrolysis crucibles, a special effect of analytical pyrolysis, was additionally investigated. It was found that the impact of the crucibles on the results is significant and one cause for matrix effects.     

A validated LC‐MS/MS method for rapid determination of brazilin in rat plasma and its application to a pharmacokinetic study

Brazilin is a major homoisoflavonoid component isolated from the dried heartwood of traditional Chinese medicine Caesalpinia sappan L., which is a natural red pigment used for histological staining. Herein a sensitive, specific and rapid analytical LC‐MS/MS method was established and validated for brazilin in rat plasma. After a simple step of protein precipitation using acetonitrile, plasma samples were analyzed using an LC‐MS/MS system. Brazilin and the IS (protosappanin B) were separated on a Diamonsil C₁₈ analytical column (150 × 4.6 mm, 5 µm) using a mixture of water and 10 mm ammonium acetate in methanol (20:80, v/v) as mobile phase at a flow rate of 0.6 mL/min. The method was sensitive with a lower limit of quantitation of 10.0 ng/mL, with good linearity (r² ≥ 0.99) over the linear range 10.0–5000 ng/mL. All the validation data, such as accuracy and precision, matrix effect, extraction recovery and stability tests were within the required limits. The assay method was successfully applied to evaluate the pharmacokinetics parameters of brazilin after an oral dose of 100 mg/kg brazilin in rats. Copyright © 2013 John Wiley & Sons, Ltd.     

Simultaneous determination of tofacitinib and its principal metabolite in beagle dog plasma by UPLC-MS/MS and its application in pharmacokinetics

The main objective of our current study is to develop and validate an accurate and direct ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method to simultaneously detect plasma concentrations of tofacitinib and its metabolite M9, and to study the pharmacokinetic profiles of the two compounds in beagle dogs. After rapid precipitation of protein by adding acetonitrile, the chromatographic separation of tofacitinib was completed, as well as M9 and upadacitinib (internal standard, IS) by using an Acquity BEH C18 (1.7 μm, 2.1 mm × 50 mm) column. A Xevo TQ-S triple quadrupole tandem mass spectrometer was employed to determine their concentrations under the positive ion pattern. Selective reaction monitoring (SRM) was used with ion transitions at m/z 313.12 → 148.97 for tofacitinib, m/z 329.10 → 137.03 for M9, and m/z 380.95 → 255.97 for IS, respectively. This assay demonstrated excellent linearity, and the ranges of calibration curves for both tofacitinib and M9 were 0.5–400 ng/mL. The new UPLC-MS/MS assay can reach the values (0.5 ng/mL) of lower limit of quantification (LLOQ) for both tofacitinib and M9. Both intra-day and inter-day accuracy of all analytes ranged from ?12.0% to 14.3%, while the precision was ≤13.2%. The recovery rate of all analytes was >88.5%, and more importantly there was no conspicuous matrix effect. In addition, the stability was consistent with the quantificative requirements of plasma samples under all conditions. Finally, the assay on UPLC-MS/MS is able to be employed to determine the pharmacokinetic characteristics of tofacitinib and its metabolite M9 in the plasma of beagle dogs after taking orally a dose of tofacitinib at 2 mg/kg.