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1.
The use of two modes for mass spectrometry (MS) detection with an ion trap instrument, selected ion storage (SIS) and tandem mass spectrometry (MS/MS), are compared for the solid-phase microextraction (SPME)–gas chromatography (GC) coupled to mass spectrometry (GC-MS) determination of 16 priority organochlorine pesticides (OCPs) in drinking water samples at the ultratrace levels (ng?L?1) required by official guidelines in the European legislation. Experimental parameters investigated for the SPME sample preparation were: the type of coating (100?µm polydimethylsiloxane, PDMS, and 65?µm poly(dimethylsiloxane)–divinylbenzene, PDMS/DVB), SPME modality, extraction and desorption times and desorption temperature and the methanol percentage in the SPME working solution. Under the calculated optimal conditions two methodologies were developed, one for SIS and the other for MS/MS modes. The detection limits, precision and accuracy were evaluated for both alternatives and were appropriate to the official guidelines requirements. The SPME–GC-MS(SIS) methodology offered LODs from 0.2–6.6?ng?L?1, precision below 13% and recoveries between 83 and 110%. The SPME–GC–MS/MS methodology provided limits of detection (LODs) ranging from 0.3 to 7.6 ng?L?1, % RSD were ≤14% and recoveries of 79–108% were achieved. After the results observed within an Interlaboratory Exercise, the latest MS methodology was selected for the pursued analysis in real drinking water samples. Also, the good results in this round-robin exercise validate the proposed SPME–GC–MS/MS methodology.  相似文献   

2.
A simple and sensitive gas chromatography/tandem mass spectrometry (GC/MS/MS) method is described for the detection of anabolic steroids, usually found in keratin matrix at very low concentrations. Hair samples from seven athletes who spontaneously reported their abuse of anabolic steroids, and in a single case cocaine, were analyzed for methyltestosterone, nandrolone, boldenone, fluoxymesterolone, cocaine and its metabolite benzoylecgonine. Anabolic steroids were determinate by digestion of hair samples in 1 m NaOH for 15 min at 95 degrees C. After cooling, samples were purificated by solid-phase and liquid-liquid extraction, then anabolic steroids were converted to their trimethylsilyl derivative and finally analyzed by GC/MS/MS. For detection of cocaine and benzoylecgonine, hair samples were extracted with methanol in an ultrasonic bath for 2 h at 56 degrees C then overnight in a thermostatic bath at the same temperature. After the incubation, methanol was evaporated to dryness, and benzoylecgonine was converted to its trimethylsilyl derivative prior of GC/MS/MS analysis. Results obtained are in agreement with the athletes' reports, confirming that hair is a valid biological matrix to establish long-term intake of drugs.  相似文献   

3.
Four different commercial sorbents for solid-phase extraction have been evaluated for the extraction of a group of acidic pharmaceuticals in terms of selectivity and capacity: Oasis hydrophilic-lipophilic balance (HLB), Oasis MAX (strong anion exchange), Oasis WAX (weak anion exchange) and a commercial available molecularly imprinted polymer specific for non-steroidal anti-inflammatory drugs. Among the sorbents studied, molecularly imprinted polymer proved to be very effective in the reduction of matrix interferences and the selective extraction of acidic pharmaceuticals, such as salicylic acid, ibuprofen, fenoprofen, diclofenac and naproxen, among others, from effluent wastewater samples. Moreover, molecularly imprinted solid-phase extraction protocol was applied to liquid chromatography coupled to tandem mass spectrometry (MS/MS) with the purpose of evaluating the clean-up effect on ion suppression/enhancement when the complexity of the samples increases and a reduction of this effect was observed. Molecularly imprinted solid-phase extraction followed by liquid chromatography coupled to ultraviolet detection and liquid chromatography coupled to tandem mass spectrometry validation methodologies with effluent wastewaters were developed, obtaining recoveries between 70 and 85% and limits of detection at low levels of μg/L (0.15-1 μg/L) and ng/L (0.5-2 ng/L), respectively. The final application of molecularly imprinted solid-phase extraction and liquid chromatography coupled to MS/MS detection showed the presence of acidic pharmaceuticals studied in this work in effluent wastewaters (相似文献   

4.
A liquid chromatography/tandem mass spectrometry (LC-MS/MS) method, characterized by complete automation and high-throughput, was developed for the determination of colistin A and B in human plasma. All sample preparation procedures were performed by using 2.2 mL 96-deep-well plates, whereas robotic liquid-handling workstations were utilized for all liquid transfer steps, including solid-phase extraction (SPE). The whole preparation procedure was very rapid, whereas the method had a very short chromatographic run time of just 2 min. Sample analysis was performed by reversed phase LC-MS/MS, with positive electrospray ionization, using multiple reaction monitoring. The absence of available purified colistin A and B standards led to the development of a novel LC method with evaporative light-scattering detector for the determination of their stoichiometries in the standard mixture, along with its purity. The proposed bioanalytical method was fully validated and it was proven to be selective, accurate, precise, reproducible and suitable for the determination of colistin A and B in human plasma. It was applied successfully to a pharmacokinetic study for the determination of both analytes in samples of patients.  相似文献   

5.
Here we developed a highly sensitive, fast and reliable liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the detection and analysis of 16 different polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs that have been identified as carcinogens and classified according to their biological potency. Comparison to standard analysis procedures based on gas chromatography-mass spectrometry (GC-MS) instrumentation demonstrated an improved easiness of sample preparation and sensitivity of detection achieved with the new LC-MS/MS method employing an atmospheric pressure photoionization (APPI) source attached to an API 4000 mass spectrometer (LC-APPI-MS/MS). The favorable outcome could be confirmed by analyzing complex mixtures such as certain Standard Reference Materials (SRMs) obtained from the National Institute of Standards & Technology (NIST), i.e., SRM 1975 and SRM 2975, and several diesel exhaust soots provided by the German automobile industry. Certified concentrations of individual analytes provided by NIST not only could be confirmed, but additional extremely potent carcinogens such as several isomeric hexacyclic dibenzopyrenes (DBPs), 5-methylchrysene (5-MC), and others have been detected in these crude samples in a concentration range down to below 1 ng g(-1) raw material.  相似文献   

6.
The suitability of liquid chromatography tandem mass spectrometry (LC-MS/MS) and gas chromatography mass spectrometry (GC-MS) for the elucidation of fluoxymesterone metabolism has been evaluated. Electrospray ionization (ESI) and collision induced dissociation (CID) fragmentation in LC-MS/MS and electron impact spectra (EI) in GC-MS have been studied for fluoxymesterone and two commercially available metabolites. MS(n) experiments and accurate mass measurements performed by an ion-trap analyser and a QTOF instrument respectively have been used for the elucidation of the fragmentation pathway. The neutral loss scan of 20 Da (loss of HF) in LC-MS/MS has been applied for the selective detection of fluoxymesterone metabolites. In a positive fluoxymesterone doping control sample, 9 different analytes have been detected including the parent compound. Seven of these metabolites were also confirmed by GC-MS including 5 previously unreported metabolites. On the basis of the ionization, the CID fragmentation, the accurate mass of the product ions and the EI spectra of these analytes, a tentative elucidation as well as a proposal for the metabolic pathway of fluoxymesterone has been suggested. The presence of these compounds has also been confirmed by the analysis of five other positive fluoxymesterone urine samples.  相似文献   

7.
Quantitative analysis of liquid chromatography (LC)-mass spectrometry (MS) and tandem mass spectrometry (MS/MS) data is essential to many proteomics studies. We have developed MASIC(2) to accurately measure peptide abundances and LC elution times in LC-MS/MS analyses. This software program uses an efficient processing algorithm to quickly generate mass specific selected ion chromatograms from a dataset and provides an interactive browser that allows users to examine individual chromatograms with a variety of options.  相似文献   

8.
A multiresidue method based on extraction with ethyl acetate has been used at the Swedish National Food Administration since 1989 to monitor pesticide residues in fruit and vegetables. The method has been continuously adjusted, resulting in simple and quick analyses of pesticide residues. To recover basic pesticides, the addition of an alkali is necessary. The addition of sodium hydrogen carbonate has been shown to recover all pesticides effectively without any degradation. The liquid chromatography (LC) with tandem mass spectrometry (MS/MS) technique has made it possible to analyse more polar pesticides and to replace many single methods. The latest development in the multiresidue method, comprising the use of gas chromatography (GC) with MS/MS, has further improved the analysis by replacing the conventional GC detectors. The need for cleanup has been reduced or eliminated entirely. Consequently, the method has been simplified in a way that makes it possible to recover all included analytes in many different matrices in one single extraction and to detect them either with GC-MS/MS or with LC-MS/MS.  相似文献   

9.
A rapid, specific and reliable isocratic high-performance liquid chromatography combined with quadrupole time-of-flight electrospray ionization tandem mass spectrometry (LC/Q-TOF-ESI-MS/MS) method has been developed and validated for the identification and characterization of stressed degradation products of metoprolol. Metoprolol, an anti-hypertensive drug, was subjected to hydrolysis (acidic, alkaline and neutral), oxidation, photolysis and thermal stress, as per ICH-specified conditions. The drug showed extensive degradation under oxidative and hydrolysis (acid and base) stress conditions. However, it was stable to thermal, neutral and photolysis stress conditions. A total of 14 degradation products were observed and the chromatographic separation of the drug and its degradation products was achieved on a C(18) column (4.6 × 250 mm, 5 μm). To characterize degradation products, initially the mass spectral fragmentation pathway of the drug was established with the help of MS/MS, MS(n) and accurate mass measurements. Similarly, fragmentation pattern and accurate masses of the degradation products were established by subjecting them to LC-MS/QTOF analysis. Structure elucidation of degradation products was achieved by comparing their fragmentation pattern with that of the drug. The degradation products DP(2) (m/z 153) and DP(14) (m/z 236) were matched with impurity B, listed in European Pharmacopoeia and British Pharmacopoeia, and impurity I, respectively. The LC-MS method was validated with respect to specificity, linearity, accuracy and precision.  相似文献   

10.
母乳中多种含卤持久性有机污染物的联合检测方法   总被引:1,自引:0,他引:1  
建立了母乳中多种含卤持久性有机污染物(POPs)的联合检测方法,目标化合物主要包括六溴环十二烷(HBCDs)、多溴联苯醚(PBDEs)、多氯联苯(PCBs)和有机氯农药(OCPs)等.样品的前处理采用液液萃取、凝胶渗透色谱(GPC)净化和固相萃取(SPE)等技术,目标化合物经气相色谱-质谱联用仪(GC-MS)、液相色谱-三重四极杆串联质谱联用仪(LC-MS/MS)和气相色谱-三重四极杆串联质谱联用仪(GC-MS/MS)等进行检测.样品通过GPC除去脂肪,然后经SPE柱进一步净化并进行多组分分离,极大程度地减小了生物样品中复杂基质的干扰,适合样品量相对较小的人体样本中多种超痕量POPs的分析.应用灵敏度高、选择性更好的GC-MS/MS对样品中的PCBs和OCPs等进行分析,进一步降低基质的干扰.方法经过小牛血清加标实验验证,稳定可靠.POPs的加标回收率分别为88.7%~98.8%(PBDEs), 88.5%~92.5%(HBCDs), 67.9%~82.3%(PCBs)和81.7%~116.1%(OCPs),方法检出限分别为0.13~1.8 pg/mL(PBDEs), 0.31~1.2 pg/mL(HBCDs), 0.22~1.4 pg/mL(PCBs)和0.20~1.5 pg/mL(OCPs).采用本方法对潍坊地区20例母乳样品进行分析,结果显示,潍坊市母乳中HBCDs, PBDEs, PCBs、HCHs和DDTs的中值浓度分别为2.86, 7.76, 8.84、140和503 ng/g 脂重,此浓度水平与国内其它地区人群相当.  相似文献   

11.
Hyphenated mass spectrometric techniques, particularly gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectrometry (LC/MS), are indispensable tools in clinical and forensic toxicology and in doping control owing to their high sensitivity and specificity. They are used for screening, library-assisted identification and quantification of drugs, poisons and their metabolites, prerequisites for competent expertise in these fields. In addition, they allow the study of metabolism of new drugs or poisons as a basis for developing screening procedures in biological matrices, most notably in urine, or toxicological risk assessment. Concepts and procedures using GC/MS and LC/MS techniques in the areas of analytical toxicology and the role of mass spectral libraries are presented and discussed in this feature article. Finally, perspectives of their future position are discussed.  相似文献   

12.
The Quick Easy Cheap Effective Rugged and Safe multiresidue method (QuEChERS) has been validated for the extraction of 80 pesticides belonging to various chemical classes from various types of representative commodities with low lipid contents. A mixture of 38 pesticides amenable to gas chromatography (GC) were quantitatively recovered from spiked lemon, raisins, wheat flour and cucumber, and determined using gas chromatography-tandem mass spectrometry (GC-MS/MS). An additional mixture of 42 pesticides were recovered from oranges, red wine, red grapes, raisins and wheat flour, using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for determination. The pesticides chosen for this study included many of the most frequently detected ones and/or those that are most often found to violate the maximum residue limit (MRL) in food samples, some compounds that have only recently been introduced, as well as a few other miscellaneous compounds. The method employed involved initial extraction in a water/acetonitrile system, an extraction/partitioning step after the addition of salt, and a cleanup step utilizing dispersive solid-phase extraction (D-SPE); this combination ensured that it was a rapid, simple and cost-effective procedure. The spiking levels for the recovery experiments were 0.005, 0.01, 0.02 and 0.2 mg kg(-1) for GC-MS/MS analyses, and 0.01 and 0.1 mg kg(-1) for LC-MS/MS analyses. Adequate pesticide quantification and identity confirmation were attained, even at the lowest concentration levels, considering the high signal-to-noise ratios, the very good accuracies and precisions, as well as the good matches between the observed ion ratios. Mean recoveries mostly ranged between 70 and 110% (98% on average), and relative standard deviations (RSD) were generally below 10% (4.3% on average). The use of analyte protectants during GC analysis was demonstrated to provide a good alternative to the use of matrix-matched standards to minimize matrix-effect-related errors. Based on these results, the methodology has been proven to be highly efficient and robust and thus suitable for monitoring the MRL compliance of a wide range of commodity/pesticide combinations.  相似文献   

13.
The widespread use of highly active antiretroviral treatments has dramatically changed the prognosis of people living with HIV (PLWH). However, such treatments have to be taken lifelong raising issues regarding the maintenance of both therapeutic effectiveness and long‐term tolerability. Recently approved or investigational antiretroviral drugs present considerable advantages, allowing once daily oral dosage along with activity against resistant variants (eg, bictegravir and doravirine) and also parenteral intramuscular administration that facilitates treatment adherence (eg, long‐acting injectable formulations such as cabotegravir and rilpivirine). Still, there remains a risk of insufficient or exaggerated circulating exposure due to absorption issues, abnormal elimination, drug‐drug interactions, and others. In this context, a multiplex ultra‐high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC‐MS/MS) bioassay has been developed for the monitoring of plasma levels of bictegravir, cabotegravir, doravirine, and rilpivirine in PLWH. A simple and convenient protein precipitation was performed followed by direct injection of the supernatant into the UHPLC‐MS/MS system. The four analytes were eluted in less than 3 minutes using a reversed‐phase chromatography method coupled with triple quadrupole mass spectrometry detection. This bioassay was fully validated following international guidelines and achieved good performances in terms of trueness (94.7%‐107.5%), repeatability (2.6%‐11%), and intermediate precision (3.0%‐11.2%) over the clinically relevant concentration ranges (from 30 to 9000 ng/mL for bictegravir, cabotegravir, and doravirine and from 10 to 1800 ng/mL for rilpivirine). This sensitive, accurate, and rapid UHPLC‐MS/MS assay is currently applied in our laboratory for routine therapeutic drug monitoring of the oral drugs bictegravir and doravirine and is also intended to be applied for the monitoring of cabotegravir/rilpivirine levels in plasma from PLWH receiving once monthly or every 2‐month intramuscular injection of these long‐acting antiretroviral drugs.  相似文献   

14.
Like many new designer drugs of abuse, synthetic cannabinoids (SC) have structural or positional isomers which may or may not all be regulated under law. Differences in acute toxicity may exist between isomers which impose further burden in the fields of forensic toxicology, medicine and legislation. Isomer differentiation therefore becomes crucial from these standpoints as new designer drugs continuously emerge with just minor positional modifications to their preexisting analogs. The aim of this study was to differentiate the positional isomers of JWH‐081. Purchased standard compounds of JWH‐081 and its positional isomers were analyzed by gas chromatography‐electron ionization‐mass spectrometry (GC‐EI‐MS) first in scan mode to investigate those isomers who could be differentiated by EI scan spectra. Isomers with identical or near‐identical EI spectra were further subjected to GC‐tandem mass spectrometry (MS/MS) analysis with appropriate precursor ions. EI scan was able to distinguish 3 of the 7 isomers: 2‐methoxy, 7‐methoxy and 8‐methoxy. The remaining isomers exhibited near‐identical spectra; hence, MS/MS was performed by selecting m/z 185 and 157 as precursor ions. 3‐Methoxy and 5‐methoxy isomers produced characteristic product ions that enabled the differentiation between them. Product ion spectrum of 6‐methoxy isomer resembled that of JWH‐081; however, the relative ion intensities were clearly different from one another. The combination of EI scan and MS/MS allowed for the regioisomeric differentiation of the targeted compounds in this study. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

15.
色谱保留时间在蛋白质组研究中的应用   总被引:1,自引:0,他引:1  
邵晨  高友鹤 《色谱》2010,28(2):128-134
液相色谱与串联质谱联用(LC-MS/MS)技术是蛋白质组学研究中的常见方法。保留时间作为独立于质谱信息的参数已经被用于蛋白质的鉴定和定量工作中。在多肽鉴定领域,多肽的色谱保留时间预测与常规的二级串联质谱数据库搜索算法结合可以提高鉴定的可信度。鉴定的灵敏度也可以通过匹配多次LC-MS实验中具有相同精确质量数和保留时间的峰而提高。另一方面,由于色谱条件的微小改变即会引起保留时间的变化,因此对多次实验结果进行保留时间比对是进行非标记定量的不可或缺的步骤。另外,联合保留时间偏移和质量数信息还可以进行蛋白质翻译后修饰(post-translational modification, PTM)的鉴定。  相似文献   

16.
Liquid chromatography coupled to tandem mass spectrometry has been compared to shotgun analysis with the objective of finding the best compromise for a single run analysis of whole cell phospholipids. Hydrophilic interaction liquid chromatography (HILIC), normal phase (NP), and reversed phase (RP) liquid chromatography were evaluated with reference phospholipids belonging to phosphatidic acid (PA), phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), phosphatidylinositol (PI), and phosphatidylserine (PS) classes. NP-HPLC- and RP-HPLC-ESI-MS/MS were applied to yeast phospholipidome analysis, using a wild-type strain and two strains defective for acyltransferases that are known to be involved in de novo phospholipid synthesis or phospholipid remodeling. The MRM mode was used for relative quantitation of individual compounds based on reference phospholipids bearing fatty acid chains with an odd number of carbon atoms. Combined LC-MS/MS was found superior to shotgun analysis, leading to a larger number of quantified species than shotgun analysis. Finally, RP-HPLC-MS/MS was the preferred method for its higher selectivity, robustness, and better repeatability.  相似文献   

17.
A simple and accurate liquid chromatography coupled with tandem mass spectrometry method was developed for determination and in vivo pharmacokinetic studies of vitexin rhamnoside in rat plasma. After protein precipitation using methanol, the analytes were separated by a Luna C(18) column with an isocratic elution and analyzed by mass spectrometry in multiple reaction monitoring mode using the respective negative ion at m/z 577.2-293.0 for vitexin rhamnoside and m/z 593.2-413.0 for internal standard (IS) vitexin glucoside. The method was validated systematically within the concentration range 5-5000 microg/L (R > 0.996) and the lower limit of quantitation was 5 microg/L. Acceptable precision and accuracy were acquired for concentrations over the standard curve range. It was further applied to assess pharmacokinetics and bioavailability of vitexin rhamnoside after intravenous and oral administration to rats. The oral bioavailability of vitexin rhamnoside was only 3.57%, which indicated that vitexin rhamnoside had poor absorption or underwent extensive first-pass metabolism. Practical utility of this new LC/MS/MS method was confirmed in pilot pharmacokinetic studies in rats following both intravenous and oral administration.  相似文献   

18.
Solvent front position extraction procedure was used to prepare biological samples containing selected antihypertensive drugs (ramipril, lercanidipine, indapamide, valsartan, hydrochlorothiazide, perindopril, and nebivolol). Substances separated from the biological matrix components (bovine serum albumin) were quantified by means of liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Sample preparation process was performed with the use of a prototype horizontal chamber with a moving pipette driven by a 3D printer mechanism enabling a controlled eluent flow velocity. Application of this device was advantageous for simultaneous preparation of several samples for further quantitative analysis, with a synchronized reduction of manual operations and solvent consumption. Quantitative results obtained for the majority of the investigated antihypertensive drugs in a complex biological matrix were satisfactory. The values of the %RSD were around 5% for six of the seven substances (with the exception of indapamide). The method exhibits a suitable accuracy (the relative error percentage was below 10% for most drugs). The values of LOD and LOQ were in the range of 1.19 µg/L–8.53 µg/L and 3.61 µg/L–25.8 µg/L, respectively.  相似文献   

19.
建立高效液相色谱–串联质谱法(HPLC–MS/MS)测定动物源性食品中玉米赤霉烯酮及其5种代谢产物(α-玉米赤霉烯醇、β-玉米赤霉烯醇、α-玉米赤霉醇、β-玉米赤霉醇、玉米赤霉酮)残留量。在样品中加入4种同位素内标(13C18–玉米赤霉烯酮,D7–α-玉米赤霉烯醇,D7–β-玉米赤霉烯醇,D5–α-玉米赤霉醇)后,经β-葡萄糖苷酶/硫酸酯酶酶解,用叔丁基甲基醚萃取,取上清液氮吹至近干后用三氯甲烷复溶,再用氢氧化钠溶液反向萃取,以HLB固相萃取柱净化后,用HPLC–MS/MS检测。结果表明,玉米赤霉烯酮及其代谢产物在1.0~100.0μg/L范围内线性关系良好,相关系数均大于0.996,方法的检出限为0.04~0.13μg/kg,定量限为0.11~0.43μg/kg。在1.0、4.0、10.0μg/kg三种加标浓度水平下,回收率为77.7%~105.5%,测定结果的相对标准偏差为4.8%~9.8%(n=6)。该方法准确、可靠,灵敏度高,适用于动物源性食品中玉米赤霉烯酮及其代谢产物的定量分析。  相似文献   

20.
建立了顶空固相微萃取-气相色谱串联质谱检测葡萄酒中主要的痕量木塞污染物——2,4,6-三氯苯甲醚(TCA)的方法。通过优化萃取时间、温度、盐浓度、pH值等固相微萃取处理条件,采用2,4,6-三氯甲苯(TCT)为内标进行定量,气相色谱离子阱质谱法测定。选取TCA母离子和子离子分别为m/z210和m/z195,TCT的母离子和子离子为m/z195和m/z159。方法的定量下限(LOQ)为2.0 ng/L,回收率为71%-98%。该法操作简单、快速,适用于葡萄酒中痕量TCA残留的快速检测。  相似文献   

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