Profiling ABA metabolites in Nicotiana tabacum L. leaves by ultra-performance liquid chromatography-electrospray tandem mass spectrometry

We have developed a simple method for extracting and purifying (+)-abscisic acid (ABA) and eight ABA metabolites - phaseic acid (PA), dihydrophaseic acid (DPA), neophaseic acid (neoPA), ABA-glucose ester (ABAGE), 7′-hydroxy-ABA (7′-OH-ABA), 9′-hydroxy-ABA (9′-OH-ABA), ABAaldehyde, and ABAalcohol - before analysis by a novel technique for these substances, ultra-performance liquid chromatography-electrospray ionisation tandem mass spectrometry (UPLC-ESI-MS/MS). The procedure includes addition of deuterium-labelled standards, extraction with methanol-water-acetic acid (10:89:1, v/v), simple purification by Oasis^® HLB cartridges, rapid chromatographic separation by UPLC, and sensitive, accurate quantification by MS/MS in multiple reaction monitoring modes. The detection limits of the technique ranged between 0.1 and 1 pmol for ABAGE and ABA acids in negative ion mode, and 0.01-0.50 pmol for ABAGE, ABAaldehyde, ABAalcohol and the methylated acids in positive ion mode. The fast liquid chromatographic separation and analysis of ABA and its eight measured derivatives by UPLC-ESI-MS/MS provide rapid, accurate and robust quantification of most of the substances, and the low detection limits allow small amounts of tissue (1-5 mg) to be used in quantitative analysis. To demonstrate the potential of the technique, we isolated ABA and its metabolites from control and water-stressed tobacco leaf tissues then analysed them by UPLC-ESI-MS/MS. Only ABA, PA, DPA, neoPA, and ABAGE were detected in the samples. PA was the most abundant analyte (ca. 1000 pmol/g f.w.) in both the control and water-stressed tissues, followed by ABAGE and DPA, which were both present at levels ca. 5-fold lower. ABA levels were at least 100-fold lower than PA concentrations, but they increased following the water stress treatment, while ABAGE, PA, and DPA levels decreased. Overall, the technique offers substantial improvements over previously described methods, enabling the detailed, direct study of diverse ABA metabolites in small amounts of plant tissue.     

高效液相色谱-串联质谱法同时测定人尿液中7种邻苯二甲酸酯代谢物

建立了同时检测人尿液中7种邻苯二甲酸酯代谢物的高效液相色谱-串联三重四极杆质谱法。尿液经酶水解后,采用萃取柱净化,以2%(v/v)甲酸甲醇溶液为洗脱剂,经苯基柱分离,以0.1%(v/v)乙酸水溶液和0.1%(v/v)乙酸乙腈溶液为流动相进行梯度洗脱,采用电喷雾离子源负离子模式和多反应监测模式采集信号,用同位素内标法进行定量分析。尿液中7种邻苯二甲酸酯代谢物在0.2~200.0 μg/L范围内定量离子的相对峰面积比值与质量浓度均呈良好线性关系(r≥0.99976);检出限(LOD)为13.43~80.21 ng/L,定量限为44.77~267.37 ng/L; 3个水平的加标回收率为88.8%~108.9%,日内和日间精密度均不大于17.05%。该方法可同时准确、灵敏、简便地测定人尿液中7种邻苯二甲酸酯代谢物的暴露水平。     

Application of molecular-secondary-ion mass spectrometry for drug metabolism studies. I. Direct analysis of conjugates by thin-layer chromatography-secondary-ion mass spectrometry

Molecular-secondary-ion mass spectrometry (SIMS) is a suitable method for the analysis of nonvolatile substances such as conjugated metabolites of drugs. We have developed a simple method for the direct SIMS measurement of conjugates following thin-layer chromatography without any extraction procedure. After separation with a butanol-acetic acid-ethanol-water (3:1:1:1, v/v) system, the spot was cut out and attached to a SIMS probe. The conjugates of p-nitrophenol and 4-hydroxyantipyrine were measured. The quantitative application of the method is also discussed, using deuterium-labelled internal standards for p-nitrophenol conjugates.     

An automated method for the simultaneous determination of pravastatin, 3-hydroxy isomeric metabolite, pravalactone and fenofibric acid in human plasma by sensitive liquid chromatography combined with diode array and tandem mass spectrometry detection

In this study, a sensitive and selective method based on liquid chromatography combined with diode array and tandem mass spectrometry detection (LC-DAD-MS/MS) was developed for the simultaneous quantitative determination of fenofibric acid, pravastatin and its main metabolites in human plasma. In this method, an automated solid-phase extraction (SPE) on disposable extraction cartridges (DECs) is used to isolate the compounds from the biological matrix and to prepare a cleaner sample before injection and analysis in the LC-DAD-MS/MS system. On-line LC-DAD-MS/MS system using an atmospheric pressure ionization (TurboIonSpray) was then developed for the simultaneous determination of pravastatin, 3-hydroxy isomeric metabolite (3-OH metab), pravalactone and fenofibric acid. The separation is obtained on an endcapped dodecyl silica based stationary phase using a mobile phase consisting of a mixture of acetonitrile, methanol and 5mM ammonium acetate solution (30:30:40, v/v/v). Sulindac and triamcinolone were used as internal standards (ISs). The detection of the fenofibric acid and sulindac was achieved by means of a DAD system. The MS/MS ion transitions monitored were m/z 442.2-->269.1, 442.2-->269.1, 424.3-->183.0 and 435.2-->397.2 for pravastatin, 3-OH metab, pravalactone and triamcinolone, respectively. The method was validated regarding stability, selectivity, extraction efficiency, response function, trueness, precision lower limit of quantitation and matrix effect. The limits of quantitation (LOQs) were around 0.50 ng/ml for pravastatin, 0.25 ng/ml for 3-OH metab, 0.05 ng/ml for pravalactone and 0.25 microg/ml for fenofibric acid.     

Measurement of catecholamines, their precursor and metabolites in human urine and plasma by solid-phase extraction followed by high-performance liquid chromatography with fluorescence derivatization

A high-performance liquid chromatographic method is described for the determination in human urine and plasma of catecholamines, their precursor and metabolites [amino compounds (norepinephrine, epinephrine, dopamine, normetanephrine, metanephrine, 3-methoxytyramine and L-DOPA), acidic compounds (3,4-dihydroxymandelic acid, 3,4-dihydroxyphenylacetic acid, vanillylmandelic acid and homovanillic acid) and alcoholic compounds (3,4-dihydroxyphenylethyleneglycol and 4-hydroxy-3-methoxyphenylethyleneglycol)]. Urine (0.5 ml) containing 3,4-dihydroxybenzylamine and 4-hydroxy-3-methoxycinnamic acid (internal standards) is deproteinized with perchloric acid, and the resulting solution is fractionated by solid-phase extraction on a strong cation-exchange resin cartridge (Toyopak IC-SP S) into two fractions (amine fraction and acid-alcohol fraction), which include 3,4-dihydroxybenzylamine and 4-hydroxy-3-methoxycinnamic acid, respectively. Plasma (0.7 ml) is deproteinized in the presence of 3,4-dihydroxybenzylamine (internal standard) in the same manner, and the resulting solution is directly used as an acid-alcohol fraction, while an amine fraction is obtained as for urine. Each fraction is subjected to the previously established ion-pair reversed-phase chromatography with post-column derivatization involving coulometric oxidation followed by fluorescence reaction with 1,2-diphenylethylenediamine. The detection limits, at a signal-to-noise ratio of 5, of the compounds measured in urine are 300 pmol/ml for the two mandelic acids, 2-7 pmol/ml for the other acidic and alcoholic compounds, 12 pmol/ml for L-DOPA and 0.6-2 pmol/ml for the other amino compounds; the corresponding values for plasma samples are 80, 0.5-3, 10 and 0.6-3 pmol/ml, respectively.     

Quantitative analysis of metabolites in complex biological samples using ion-pair reversed-phase liquid chromatography-isotope dilution tandem mass spectrometry

A rapid, sensitive and selective ion-pair reversed-phase liquid chromatography-electrospray ionization isotope dilution tandem mass spectrometry (IP-LC-ESI-ID-MS/MS) was developed for quantitative analysis of free intracellular metabolites in cell cultures. As an application a group of compounds involved in penicillin biosynthesis pathway of Penicillium chrysogenum cells, such as penicillin G (PenG), 6-aminopenicillanic acid (6-APA), benzylpenicilloic acid (PIO), ortho-hydroxyphenyl acetic acid (o-OH-PAA), phenylacetic acid (PAA), 6-oxopipeidine-2-carboxylic acid (OPC), 8-hydroxypenicillic acid (8-HPA), L-alpha-(delta-aminoadipyl)-L-alpha-cystenyl-D-alpha-valine (ACV) and isopenicillin N (IPN) were chosen. (13)C-labeled analogs of the metabolites were added to the sample solutions as internal standards (I.S.). Sample mixtures were analyzed without any sample pretreatment. No extraction recovery check was needed because I.S. was added to the cell samples before extraction process. The method showed excellent precision (relative standard deviation (RSD)相似文献   

Quantification of metronidazole in healthy subjects' feces using an LC–MS/MS method

A highly selective and sensitive liquid chromatography–tandem mass spectrometry (LC MS/MS) method was developed for the quantification of metronidazole (MTZ) in human feces. The analyte was recovered from feces after liquid–liquid extraction with ethyl acetate and separated on Waters Symmetry® C₁₈ (100 × 4.6 mm, 5μm) column using 0.1% formic acid in water and acetonitrile (40:60, v/v) as the mobile phase. A stable‐deuterated internal standard metronidazole‐d4 (MTZ‐d4) was used in the study. Mass analysis was performed on a triple quadrupole mass spectrometer in the positive electrospray ionization mode. A linear response function of MTZ was established in the concentration range of 0.50–250 ng/g, based on dry mass. The mean extraction recovery of MTZ (97.28%) and MTZ‐d4 (96.76%) from spiked feces samples was consistent at higher as well as lower concentrations. Post‐column infusion analysis showed no ion‐suppression/enhancement effects and the mean IS‐normalized matrix factor ranged from 0.986 to 1.013. Spiked feces samples stored at −20 and − 70°C for long‐term stability were stable for at least 3 months, while extracted samples (dry and wet extracts) were stable up to 24 h. The method was applied to determine MTZ in feces of 12 healthy Indian subjects.     

Matrix Solid Phase Dispersion‐Accelerated Solvent Extraction for Determination of OCP Residues in Fish Muscles

A rapid, sensitive and accurate matrix solid phase dispersion‐accelerated solvent extraction (MSPD‐ASE) method for selective determination of sixteen organochlorine pesticide (OCP) residues in fish samples has been developed and validated. 2 g fresh fish muscle was dispersed with 10 g anhydrous sodium sulfate and 2 g acid alumina thoroughly, and loaded into the stainless‐steel extraction cell containing 6 g of acid alumina and 10 g anhydrous sodium sulfate. The temperature 60 °C and two extraction cycles of 5 min gave adequate extraction efficiency using DCM‐hexane (3:7, v/v) mixture as solvent. Not only the lipids, but also other co‐extracts, which peaks mostly located in the forepart of chromatograms and maybe interfere the identification or quantitation of analytes, were eliminated exhaustively, while analytes were extracted selectively. Sixteen OCPs were identified by retention time of standards and quantified using mirex as internal standards. These detected OCPs were confirmed by GC‐MS in real samples. The performance of proposed method was evaluated and validated: the detection limits were 0.008‐0.05 ng g^‐1, relative standard deviations were 1.9‐5.0%, and recoveries were 91.0‐104.1% spiked at 10 ng g^‐1 level. The accuracy and precision of proposed method were equal to or better than that of traditional Soxhlet extraction method.     

Simultaneous extraction and analysis by high performance liquid chromatography coupled to diode array and mass spectrometric detectors of bixin and phenolic compounds from annatto seeds

This study was designed to identify and quantify the carotenoids and phenolic compounds from annatto seeds using high performance liquid chromatography coupled to diode array and mass spectrometer detectors (HPLC-DAD-MS/MS). Furthermore, using response surface methodology, an optimized procedure for simultaneous extraction of these compounds was established. In addition to bixin, known to be the main carotenoid in annatto seeds, hypolaetin and a caffeoyl acid derivative were identified as the main phenolic compounds. The optimized procedure involved 15 extractions using acetone:methanol:water (50:40:10, v/v/v) as solvent, a solid-liquid ratio of 1:9 (m/v) and an extraction time of 5 min. Validation data indicated that the HPLC method proposed provided good linearity, sensitivity, procedure accuracy, system precision and suggested its suitability for the simultaneous analysis of phenolic compounds and carotenoids in annatto seeds.     

液相色谱-串联质谱法测定蜂产品中吡虫啉及其3种代谢物

建立了蜂蜜和蜂花粉中吡虫啉及其代谢物吡虫啉烯烃、吡虫啉脲、6-氯烟酸的液相色谱-串联质谱(LC-MS/MS)检测方法.在QuEChERS方法基础上,针对目标物化学性质和样品杂质情况,对提取溶液的pH值、提取次数、净化材料等参数进行了优化.最终以5％甲酸-乙腈溶液提取两次,无水MgSO4、NaCl盐析分层,提取液经增强型脂类去除材料(EMR)净化,以LC-MS/MS进行测定,基质外标法进行定量分析.结果表明,蜂蜜和蜂花粉中吡虫啉、吡虫啉烯烃、吡虫啉脲、6-氯烟酸的平均加标回收率为86.0％～111.5％, 相对标准偏差在1.7％～9.6％之间, 检出限分别为0.20, 3.50, 0.40和14.00 μg/kg,定量限分别为0.60, 11.64, 1.20和45.00 μg/kg.本方法分析速度快、灵敏度高、重现性好,适用于蜂蜜和蜂花粉中吡虫啉及其3种代谢物的快速测定.     

超高效液相色谱-三重四极杆质谱法测定人尿中9种邻苯二甲酸酯代谢物

建立了人尿中9种邻苯二甲酸酯（PAE）代谢物的超高效液相色谱-三重四极杆质谱（UPLC-MS/MS）测定方法。2 mL尿液样本酶解2 h后,经强阴离子固相萃取净化处理;选用Waters ACQUITY UPLC BEH Phenyl色谱柱（100 mm×2.1 mm,1.7 μ m）,以0.1%（体积分数）乙酸乙腈和0.1%（体积分数）乙酸水溶液为流动相进行梯度洗脱;在负离子电喷雾多反应监测模式（MRM）下测定9种PAE代谢物含量。8种PAE代谢物在0.39~200 μ g/L范围内、1种PAE代谢物在1.17~600 μ g/L范围内线性关系良好,相关系数均大于0.995。方法检出限为0.06~0.85 μ g/L,定量限为0.20~2.80 μ g/L。3个加标水平的加标回收率为84.1%~122%,精密度为4.5%~14.3%;日内精密度不高于9.3%,日间精密度不高于10.1%;基质效应和稳定性符合分析要求。应用该方法测定50份人尿液样本,邻苯二甲酸单环已酯（MCHP）和邻苯二甲酸单苄酯（MBZP）的检出率分别为0和44.0%,其余7种PAE代谢物的检出率为100%。该方法操作简单、定量准确、稳定性好,适用于人尿中9种PAE代谢物的定量分析。     

Metabolomics study of cured tobacco using liquid chromatography with mass spectrometry: Method development and its application in investigating the chemical differences of tobacco from three growing regions

Cured tobacco is an important plant material. Component studies are a big challenge for its significantly diverse chemical properties and vastly different concentrations. In this work, liquid chromatography with quadrupole time‐of‐flight mass spectrometry was used to perform a metabolomics study of cured tobacco owing to its efficient separation and detection of semipolar metabolites. A solvent of methanol/water (8:2, v/v) and 30 min of ultrasound time were found to be optimal to perform extraction. 95, 92, and 93% of metabolite features had within 20% of coefficient of variation for repeatability, intraday and interday precision analysis, respectively, indicating a good stability of the method developed. 113 metabolites were identified in cured tobacco based on accurate mass, retention time, and MS/MS fragments. The developed method was applied to a metabolomics study of cured tobacco from three growing regions. Forty three metabolites were found to be contributed to the classification. It is shown that the developed method can be applied to metabolomics analysis of plant materials.     

加速溶剂萃取-超高效液相色谱-串联质谱快速测定棉花中残留的8种脱叶剂

采用加速溶剂萃取结合超高效液相色谱-串联质谱(UPLC-MS/MS)技术,建立了一种快速提取和测定棉花中8种脱叶剂(噻苯隆、脱叶磷、甲基苯噻隆、脱落酸、氟酮唑草酯、敌草隆、百草枯、嘧草硫醚)的分析方法。样品经提取、浓缩,乙腈-水溶液(1:9, v/v)溶解,采用Acquity UPLC^® HSS T3柱(50 mm×2.1 mm, 1.8 μ m)分离,以乙腈-0.05%(v/v)甲酸水溶液为流动相,梯度洗脱,电喷雾正离子模式多反应监测,外标法定量。该方法在0.01~0.3 mg/L范围内线性关系良好(r >0.99),在添加含量水平为0.1、0.5、1.0 mg/kg时,平均回收率范围为(84.18±8.04)%~(95.99±6.76)%,相对标准偏差(RSD)为7.04%~10.60%,方法检出限(LOD)为0.8~29 μ g/kg,方法定量限(LOQ)为2.5~96 μ g/kg。该方法操作简便、快捷、灵敏、准确,适合棉花中8种脱叶剂的确证和定量测定。     

Determination of oxanilic and sulfonic acid metabolites of acetochlor in soils by liquid chromatography-electrospray ionisation mass spectrometry

An analytical method is presented that describes the extraction and quantification of oxanilic and sulfonic acid metabolites of the herbicide acetochlor in soil samples. Experiments were performed on 50 g of soil using a solvent extraction technique with an acetonitrile-water (60:40) mixture in an acidic medium. Analysis was carried out by reversed-phase liquid chromatography and detection by electrospray ionisation mass spectrometry in single ion monitoring and negative modes. Four different soil matrices were spiked in triplicate with standards of each degradation compound at three concentration levels between 2 and 80 microg/kg. The average recoveries range from 90 to 120% for both the metabolites, with relative standard deviations lower than 15%. The limits of quantification are about 1 and 2 microg/kg for the ethanesulfonic acid and the oxanilic acid metabolites, respectively. The method has been applied to soils and solids recovered from the deeper unsaturated zone of a small French catchment closely monitored as part of the European project "Pesticides in European Groundwaters: detailed study of Aquifers and Simulation of possible Evolution scenarios (PEGASE)".     

Simultaneous Determination of Methadone,Heroin, Cocaine and their Metabolites in Urine by GC‐MS

Abstract

A gas chromatographic‐mass spectrometric (GC‐MS) method for the determination of methadone, heroin, cocaine, and their metabolites in urine using Selected Ion Monitoring (SIM) was developed. Following a liquid‐liquid extraction with Toxitubes A^® and using their deuterated analogs as internal standards, the analytes were derivatized with 99:1 (v/v) N,O‐bis‐trimethylsilyl‐trifluoroacetamide/trimethylchlorosilane and injected by hand, in the splitless mode, at 240°C and a purging time of 0.75 min. The mass selective detector was kept at 300°C and molecules were ionized in the electron impact mode, using an energy of 70 eV. The detector response was linear for all drugs studied over the range 50–1000 ng/mL.     

Analysis of polycyclic aromatic hydrocarbons in pine needles by gas chromatography-mass spectrometry: comparison of different extraction and clean-up procedures

Three extraction methodologies (Soxhlet, ultrasonic and pressurized liquid extraction) and several clean-up procedures (Florisil, silica and alumina in cartridges or glass column format) were tested and compared to extract 16 US Environmental Protection Agency (EPA) polycyclic aromatic hydrocarbons (PAHs) from Pinus pinea L. needles. Quantification was done by gas chromatography with mass spectrometry, by internal standard method using five deuterated PAH surrogate standards. Among the several extraction and clean-up procedures tested, ultrasonic extraction followed by alumina cartridge clean-up was the preferred method, yielding recoveries between 72 and 100% and limits of detection between 0.22 and 0.71 ng/g dry weight. The performance of the method was tested to determine PAHs in naturally contaminated samples.     

High-performance liquid chromatographic analysis of secoisolariciresinol diglucoside and hydroxycinnamic acid glucosides in flaxseed by alkaline extraction

A HPLC method was developed for the analysis of secoisolariciresinol diglucoside (SDG) and hydroxycinnamic acid glucosides in milled defatted flaxseed flour. Direct extraction by 1 M NaOH for 1 h at 20 degrees C resulted in a higher yield than that obtained by hydrolysis of alcoholic extracts. An internal standard, o-coumaric acid, was used and the method was found to be easy, fast, and with good repeatability. On dry matter basis, different samples of flaxseeds varied considerably in their content of (+)-SDG (11.9-25.9 mg/g), (-)-SDG (2.2-5.0 mg/g), p-coumaric acid glucoside (1.2-8.5 mg/g), and ferulic acid glucoside (1.6-5.0 mg/g).     

Simultaneous micro-determination of nicotinamide and its major metabolites, N1-methyl-2-pyridone-5-carboxamide and N1-methyl-4-pyridone-3-carboxamide, by high-performance liquid chromatography

A simultaneous micro-determination of nicotinamide and its major metabolites, N1-methyl-2-pyridone-5-carboxamide (2-py) and N1-methyl-4-pyridone-3-carboxamide (4-py) by high-performance liquid chromatography is described. The method employs a 7-ODS-L (250 mm X 4.6 mm I.D., particle size 7 microns) column eluted with 10 mM potassium dihydrogenphosphate-acetonitrile (96:4, v/v; pH adjusted to 3.0 by the addition of concentrated phosphoric acid) at a flow-rate of 1.0 ml/min. The UV detector was set at 260 nm. The detection limits for nicotinamide, 2-py and 4-py were 10 pmol (1.22 ng), 2 pmol (304 pg) and 2 pmol (304 pg), respectively, at a signal-to-noise ratio 5:1. Isonicotinamide was used as an internal standard. The technique was applied to the analysis of rat and human urines. The total analysis time was ca. 15 min.     

Liquid chromatography–mass spectrometry for analysis of a novel β2‐adrenoceptor agonist trantinterol and its metabolites in beagle dog urine

A liquid chromatography–tandem mass spectrometry method was developed for the identification of metabolites of trantinterol, a novel β₂‐adrenoceptor agonist, in beagle dog urine. The separation of metabolites was performed on a reversed‐phase C₈ column using 0.1% formic acid in water and methanol (70 : 30, v/v) as the mobile phase. The structural information and elemental information of metabolites were acquired by an electrospray ionization tandem mass spectrometer and a quadrupole time‐of‐flight mass spectrometer, respectively. A total of 13 metabolites were detected and characterized on the basis of their tandem MS/MS fragmentation patterns. The accurate masses of nine metabolites were determined and two metabolites were further confirmed by comparing with reference standards. The metabolic pathways of trantinterol in beagle dog are proposed. Copyright © 2009 John Wiley & Sons, Ltd.     

Novel human lens metabolites from normal and cataractous human lenses

4-(2-Aminophenyl)-4-oxobutanoic acid, 4-(2-amino-3-hydroxyphenyl)-4-oxobutanoic acid and glutathionyl-kynurenine have been identified as novel metabolites in normal and cataractous human lenses following total synthesis and comparison with authentic human lens samples. Their structures are consistent with those derived from the major human lens UV filters kynurenine and 3-hydroxykynurenine, and it is proposed that these compounds also play a role as UV filters. These metabolites were isolated in pmol/mg levels (dry mass) in lenses. 4-(2-Amino-3-hydroxyphenyl)-4-oxobutanoic acid and glutathionyl-kynurenine were found to be unstable at physiological pH. Other potential metabolites, glutathionyl-3-hydroxykynurenine, kynurenine yellow and 3-hydroxykynurenine yellow, were not detected in either normal or cataractous lenses.