凝胶渗透色谱净化-气相色谱/串联质谱分析蘑菇中的36种农药残留

建立了用凝胶渗透色谱净化-气相色谱/串联质谱分析蘑菇中36种农药残留的方法。蘑菇中的待测农药组分在30 ℃条件下用乙酸乙酯提取,高速匀浆后通过凝胶渗透色谱净化;选用填料为中性多孔的聚苯乙烯二乙烯基苯微球体的S-X3玻璃柱(22 g,19 cm×2 cm)作为凝胶渗透色谱净化柱,流动相为乙酸乙酯-环己烷(体积比为1∶1)溶液,流速5 mL/min;收集第7~15 min流出的液体用气相色谱-三重四极杆串联质谱仪测定。在0.01~1.0 mg/L的质量浓度范围内,各种农药标准溶液的线性相关系数均大于0.99。在样品中添加36种农药(添加水平为0.01,0.05,0.10 mg/kg)的混合标准溶液,平均回收率为72.6%~117.1%,相对标准偏差为2.0%~10.8%(n=5),最低检出限为 0.1~0.7 μg/kg,最低定量限为 0.2~2 μg/kg。     

Evaluation of multiple alternative instrument platforms for targeted and non‐targeted dioxin and furan analysis

The use of gas chromatography coupled to high‐resolution magnetic sector mass spectrometers (GC‐HRMS) is well established for dioxin and furan analysis. However, the use of gas chromatography coupled to triple quadrupole (MS/MS) and time of flight (TOF) mass spectrometers with atmospheric pressure ionization (API) and traditional electron ionization (EI) for dioxin and furan analysis is emerging as a viable alternative to GC‐HRMS screening. These instruments offer greater versatility in the lab for a wider range of compound identification and quantification as well as improved ease of operation. The instruments utilized in this study included 2 API‐MS/MS, 1 traditional EI‐MS/MS, an API‐quadrupole time of flight mass spectrometer (API‐QTOF), and a EI‐high‐resolution TOF (EI‐HRTOF). This study compared these 5 instruments to a GC‐HRMS using method detection limit (MDLs) samples for dioxin and furan analysis. Each instrument demonstrated acceptable MDL values for the 17 chlorinated dioxin and furans studied. The API‐MS/MS instruments provide the greatest overall improvement in MDL value over the GC‐HRMS with a 1.5 to 2‐fold improvement. The API‐QTOF and EI‐TOF demonstrate slight increases in MDL value as compared with the GC‐HRMS with a 1.5‐fold increase. The 5 instruments studied all demonstrate acceptable MDL values with no MDL for a single congener greater than 5 times that for the GC‐HRMS. All 5 instruments offer a viable alternative to GC‐HRMS for the analysis of dioxins and furans and should be considered when developing new validated methodologies.     

High‐throughput metabolic stability studies in drug discovery by orthogonal acceleration time‐of‐flight (OATOF) with analogue‐to‐digital signal capture (ADC)

Screening assays capable of performing quantitative analysis on hundreds of compounds per week are used to measure metabolic stability during early drug discovery. Modern orthogonal acceleration time‐of‐flight (OATOF) mass spectrometers equipped with analogue‐to‐digital signal capture (ADC) now offer performance levels suitable for many applications normally supported by triple quadruple instruments operated in multiple reaction monitoring (MRM) mode. Herein the merits of MRM and OATOF with ADC detection are compared for more than 1000 compounds screened in rat and/or cryopreserved human hepatocytes over a period of 3 months. Statistical comparison of a structurally diverse subset indicated good agreement for the two detection methods. The overall success rate was higher using OATOF detection and data acquisition time was reduced by around 20%. Targeted metabolites of diazepam were detected in samples from a CLint determination performed at 1 µM. Data acquisition by positive and negative ion mode switching can be achieved on high‐performance liquid chromatography (HPLC) peak widths as narrow as 0.2 min (at base), thus enabling a more comprehensive first pass analysis with fast HPLC gradients. Unfortunately, most existing OATOF instruments lack the software tools necessary to rapidly convert the huge amounts of raw data into quantified results. Software with functionality similar to open access triple quadrupole systems is needed for OATOF to truly compete in a high‐throughput screening environment. Copyright © 2010 John Wiley & Sons, Ltd.     

Use of a quadrupole linear ion trap mass spectrometer in metabolite identification and bioanalysis

A new type of quadrupole linear ion trap mass spectrometer, Q TRAP trade mark LC/MS/MS system (Q TRAP trade mark ), was evaluated for its performance in two studies: firstly, the in vitro metabolism of gemfibrozil in human liver microsomes, and, secondly, the quantification of propranolol in rat plasma. With the built-in information-dependent-acquisition (IDA) software, the instrument utilizes full scan MS in the ion trap mode and/or constant neutral loss scans as survey scans to trigger product ion scan (MS(2)) and MS(3) experiments to obtain structural information of drug metabolites 'on-the-fly'. Using this approach, five metabolites of gemfibrozil were detected in a single injection. This instrument combines some of the unique features of a triple quadrupole mass spectrometer, such as constant neutral loss scan, precursor ion scan and multiple reaction monitoring (MRM), together with the capability of a three-dimensional ion trap. Therefore, it becomes a powerful instrument for metabolite identification. The fast duty cycle in the ion trap mode allows the use of full product ion scan for quantification. For the quantification of propranolol, both MRM mode and full product ion scan in the ion trap mode were employed. Similar sensitivity, reproducibility and linearity values were established using these two approaches. The use of the product ion scan mode for quantification provided a convenient tool in selecting transitions for improving selectivity during the method development stage.     

Application of gas and liquid chromatography coupled to time‐of‐flight mass spectrometry in pesticides: Multiresidue analysis

Analysis of pesticide residues in water and food matrices is an active research area closely related to food safety and environmental issues. In this aspect mass spectrometry (MS) coupled to gas chromatography (GC) and liquid chromatography (LC) has been increasingly used in the analysis of pesticide residues in water and food. The increasing interest in application of high‐resolution mass spectrometry with time‐of‐flight (TOF) and hybrid triple quadrupole TOF in pesticide analysis is due to its capability of performing both targeted and nontargeted analysis. This article discusses an overview of the application of GC‐TOF‐MS and LC‐TOF‐MS in water and food matrices.     

Development of a mass spectrometric hydroxyl‐position determination method for the hydroxyindole metabolites of JWH‐018 by GC‐MS/MS

One of the many issues of designer drugs of abuse like synthetic cannabinoids (SCs) such as JWH‐018 is that details on their metabolism has yet to be fully elucidated and that multiple metabolites exist. The presence of isomeric compounds poses further challenges in their identification. Our group has previously shown the effectiveness of gas chromatography‐electron ionization‐tandem mass spectrometry (GC‐EI‐MS/MS) in the mass spectrometric differentiation of the positional isomers of the naphthoylindole‐type SC JWH‐081, and speculated that the same approach could be used for the metabolite isomers. Using JWH‐018 as a model SC, the aim of this study was to differentiate the positional isomers of its hydroxyindole metabolites by GC‐MS/MS. Standard compounds of JWH‐018 and its hydroxyindole metabolite positional isomers were first analyzed by GC‐EI‐MS in full scan mode, which was only able to differentiate the 4‐hydroxyindole isomer. Further GC‐MS/MS analysis was performed by selecting m/z 302 as the precursor ion. All four isomers produced characteristic product ions that enabled the differentiation between them. Using these ions, MRM analysis was performed on the urine of JWH‐018 administered mice and determined the hydroxyl positions to be at the 6‐position on the indole ring. GC‐EI‐MS/MS allowed for the regioisomeric differentiation of the hydroxyindole metabolite isomers of JWH‐018. Furthermore, analysis of the fragmentation patterns suggests that the present method has high potential to be extended to hydroxyindole metabolites of other naphthoylindole type SCs in identifying the position of the hydroxyl group on the indole ring. Copyright © 2016 John Wiley & Sons, Ltd.     

High‐throughput determination of Sudan Azo‐dyes within powdered chili pepper by paper spray mass spectrometry

A high‐throughput mass spectrometric method is presented for the simultaneous detection of Sudan I, II, III, IV and Para‐Red azo‐dyes in foodstuff. The method is based on the use of paper spray mass spectrometry (MS) and deuterium‐labeled internal standards on a triple‐quadrupole instrument. A detailed assay of each azo‐dye was performed by the isotope dilution method, through the precursor ion scan approach, using deuterium‐labeled internal standards. The gas‐phase breakdown pattern of each labeled and unlabeled analogue displays the naphthoic moiety as a common fragment. Sudan dyes can be determined above the threshold of 1 ppm. Paper spray allows for a wide range of analytes and samples to be investigated by MS in the open air and without sample preparation and bypassing chromatography. Copyright © 2013 John Wiley & Sons, Ltd.     

High‐throughput UHPLC–MS/MS method for the detection,quantification and identification of fifty‐five anabolic and androgenic steroids in equine plasma

Anabolic and androgenic steroids (AASs) are synthetic substances related to the primary male sex hormone, testosterone. AASs can be abused in both human and equine sports and, thus, are banned by the International Olympic Committee and the Association of Racing Commissioners International (ARCI). Enforcement of the ban on the use of AASs in racehorses during competition requires a defensible and robust method of analysis. To address this requirement, a high‐throughput ultra high‐performance liquid chromatography–mass spectrometric (UHPLC–MS) method was developed for the detection, quantification and confirmation of 55 AASs in equine plasma. AASs were recovered from equine plasma samples by liquid–liquid extraction with methyl tert‐butyl ether (MTBE). Analytes were chromatographically separated on a sub‐2 µm particle size C₁₈ column with a mobile phase gradient elution and detected by selected‐reaction monitoring (SRM) on a triple quadrupole mass spectrometer. AASs with isobaric precursor ions were either chromatographically resolved or mass spectrometrically differentiated by unique precursor‐to‐product ion transitions. A few of them that could not be resolved by both approaches were differentiated by intensity ratios of three major product ions. All the epimer pairs, testosterone and epitestosterone, boldenone and epiboldenone, nandrolone and epinandrolone, were chromatographically base‐line separated. The limit of detection and that of quantification was 50 pg/ml for most of the AASs, and the limit of confirmation was 100–500 pg/ml. Full product ion spectra of AASs at concentrations as low as 100–500 pg/ml in equine plasma were obtained using the triple quadrupole instrument, to provide complementary evidentiary data for confirmation. The method is sensitive and selective for the detection, quantification and confirmation of multiple AASs in a single analysis and will be useful in the fight against doping of racehorses with AASs. Copyright © 2010 John Wiley & Sons, Ltd.     

Detection of buffalo mozzarella adulteration by an ultra‐high performance liquid chromatography tandem mass spectrometry methodology

Over the past years, LC–MS‐based approaches have gained a growing interest in food analysis by using different platforms and methodologies. In particular, enhanced selectivity and sensitivity of multiple reaction monitoring (MRM) scan function offer powerful capabilities in detecting and quantifying specific analytes within complex mixtures such as food matrices. The MRM approach, traditionally applied in biomedical research, is particularly suitable for the detection of food adulteration and for the verification of authenticity to assure food safety and quality, both recognized as top priorities by the European Union Commission. Increasingly stringent legislation ensure products safety along every step ‘from farm to fork’, especially for traditional foods designed with the Protected Designation of Origin certification. Therefore, there is a growing demand of new methodologies for defining food authenticity in order to preserve their unique traits against frauds. In this work, an ultra performance liquid chromatopgraphy‐electrospray ionization‐tandem mass spectrometry (MS/MS) methodology based on MRM has been developed for the sensitive and selective detection of buffalo mozzarella adulteration. The targeted quantitative analysis was performed by monitoring specific transitions of the phosphorylated β‐casein f33‐48 peptide, identified as a novel species‐specific proteotypic marker. The high sensitivity of MRM‐based MS and the wide dynamic range of triple quadrupole spectrometers have proved to be a valuable tool for the analysis of food matrices such as dairy products, thus offering new opportunities for monitoring food quality and adulterations. Copyright © 2012 John Wiley & Sons, Ltd.     

Determination of multiple pesticide residues in teas by gas chromatography with accurate time‐of‐flight mass spectrometry

In this work, gas chromatography tandem with electron ionization and full‐scan high‐resolution mass spectrometry with a time‐of‐flight mass analyzer was evaluated for analyzing pesticide residues in teas. The relevant aspects for mass spectrometry analysis, including the resolution and mass accuracy, acquisition rate, temperature of ion source, were investigated. Under acquisition condition in 2‐GHz extended dynamic range mode, accurate mass spectral library including 184 gas chromatography detectable pesticides was established and retrieval parameters were optimized. The mass spectra were consistent over a wide concentration range (three orders) with good match values to those of NIST (EI‐quadrupole). The methodology was verified by the validation of 184 pesticides in four tea matrices. A wide linear range (1–1000 μg/kg) was obtained for most compounds in four matrices. Limit of detection, limit of quantification, and limit of identification values acquired in this study could satisfy the requirements for maximum residue levels prescribed by the European Community. Recovery studies were performed at three concentrations (10, 50, and 100 μg/kg). Most of the analytes were recovered at an acceptable range of 70–120% with relative standard deviations ≤ 20% in four matrices. The potential extension of qualitative screening scope makes gas chromatography tandem with electron ionization and mass spectrometry with a time‐of‐flight mass analyzer a more powerful tool compared with gas chromatography with tandem mass spectrometry.     

A reliable analytical approach based on gas chromatography coupled to triple quadrupole and time‐of‐flight mass analyzers for the determination and confirmation of polycyclic aromatic hydrocarbons in complex matrices from aquaculture activities

The potential of gas chromatography coupled to tandem mass spectrometry (GC/MS/MS) with a triple quadrupole analyzer (QqQ) has been investigated for the quantification and reliable identification of sixteen polycyclic aromatic hydrocarbons (PAHs) from the EPA priority list in animal and vegetable samples from aquaculture activities, whose fat content ranged from 5 to 100%. Matrices analyzed included fish fillet, fish feed, fish oil and linseed oil. Combining optimized saponification and solid‐phase extraction led to high efficiency in the elimination of interfering compounds, mainly fat, from the extracts. The developed procedure minimized the presence of these interfering compounds in the extracts and provided satisfactory recoveries of PAHs. The excellent sensitivity and selectivity of GC/(QqQ)MS/MS in selected reaction monitoring (SRM) allowed to reach limits of detection at pg/g levels. Two SRM transitions were acquired for each analyte to ensure reliable identification of compounds detected in samples. Confirmation of positive findings was performed by GC coupled to high‐resolution time‐of‐flight mass spectrometry (GC/TOFMS). The accurate mass information provided by GC/TOFMS in full acquisition mode together with its high mass resolution makes it a powerful analytical tool for the unequivocal confirmation of PAHs in the matrices tested. The method developed was applied to the analysis of real‐world samples of each matrix studied with the result of detecting and confirming the majority of analytes at the µg/kg level by both QqQ and TOF mass spectrometers. Copyright © 2009 John Wiley & Sons, Ltd.     

多重反应监测(MRM):靶标蛋白质定量的新方法

多重反应监测(multiple reaction monitoring,MRM)是针对靶标分子的一种质谱分析技术.该技术采用三重四级杆质谱仪,检测靶标分子的母离子和子离子的质谱响应信号,从而获取较灵敏和高重现性的定性和定量信息,近年来在蛋白质组学领域得到了广泛应用.与全谱性的蛋白质组学分析不同,MRM注重有限目标的蛋白质定量测定,因此,它在蛋白质分析检测领域中的应用极有发展潜力.在临床检验中,酶联免疫吸附测定(enzyme linked immunosorbent assay,ELISA)是蛋白质定量分析的常规技术,但是ELISA在多重蛋白质生物标志物的测定方面具有一定限制.随着蛋白质组学的深入进行,MRM的定量分析优势可否应用于临床检测已提至日程,世界范围内多个研究团队一直致力于推动这一领域的发展,也取得了令人瞩目的成就.本文简单介绍了MRM技术的原理、优势及发展前景等,同时,对其在蛋白质组学研究及临床应用中的潜力进行了讨论.     

SIM/GC/ITD测定土样中ppt级多氯二苯并二噁英

本文介绍了以选择离子检测方式的气相色谱-离子阱检测器(SIM/GC/ITD)分析土样中ppt级多氯二苯并-对-二噁英的方法。该法所用仪器简单,操作简便,净化效率和回收率高。当组分浓度在ppt～ppb范围、母体组成在很大范围变动时,也有较好的重复性。     

Development of two‐dimensional gas chromatography (GC×GC) coupled with Orbitrap‐technology‐based mass spectrometry: Interest in the identification of biofuel composition

Comprehensive gas chromatography (GC) has emerged in recent years as the technique of choice for the analysis of volatile and semivolatile compounds in complex matrices. Coupling it with high‐resolution mass spectrometry (MS) makes a powerful tool for identification and quantification of organic compounds. The results obtained in this study showed a significant improvement by using GC×GC‐EI‐MS in comparison with GC‐EI‐MS; the separation of chromatogram peaks was highly improved, which facilitated detection and identification. However, the limitation of Orbitrap mass analyzer compared with time‐of‐flight analyzer is the data acquisition rate; the frequency average was about 25 Hz at a mass resolving power of 15.000, which is barely sufficient for the proper reconstruction of the narrowest chromatographic peaks. On the other hand, the different spectra obtained in this study showed an average mass accuracy of about 1 ppm. Within this average mass accuracy, some reasonable elemental compositions can be proposed and combined with characteristic fragment ions, and the molecules can be identified with precision. At a mass resolving power of 7.500, the scan rate reaches 43 Hz and the GC×GC‐MS peaks can be represented by more than 10 data points, which should be sufficient for quantification. The GC×GC‐MS was also applied to analyze a cellulose bio‐oil sample. Following this, a highly resolved chromatogram was obtained, allowing EI mass spectra containing molecular and fragment ions of many distinct molecules present in the sample to be identified.     

Review of the Sampling and Pretreatment Methods for Dioxins Determination in Solids,Liquids and Gases

The analytical requirements for the determination of dioxins (e.g. PCDD, PCDF) are unique in comparison with those for other routinely monitored chemicals: dioxins are measured in parts per trillion (ppt) and lower levels in technical and environmental samples, whereas other organics are measured in parts per million (ppm) or parts per billion (ppb). The ultra‐trace analysis of dioxins requires a high sample enrichment obtainable by the use of efficient extraction methods and highly selective purification/fractionation techniques. Furthermore, highly sensitive equipment (e.g. high resolution gas chromatography ‐ HRGC) with detection levels in the ppt range must be used to isolate and separate a huge number of dioxin congeners. The quantification of the dioxins by a high resolution mass detector (HRMS) requires the use of internal and labeled standards. This paper reviews and compares the classic and modern pretreatment methods, namely extraction and clean‐up, that are currently used in dioxin analysis in industrial samples and that were improved or developed in the last 25 years. In addition, the standard methods for dioxin sampling from an emission source (flue or stack gas) are examined and compared with new, automated techniques.     

Advances in the determination of degradation intermediates of personal care products in environmental matrixes: a review

In this review, recent methods developed for the determination of degradation intermediates of personal care products in environmental matrixes focusing on the extraction and determination steps are discussed. The five classes of personal care products evaluated are stimulants, fragrances, sunscreens, antimicrobials, and insect repellents. Methods are critically reviewed in terms of the analytical steps involved in the analysis, sample pretreatment, separation, and detection as well as the different confirmation strategies employed. Preconcentration from aqueous matrixes was performed by solid-phase extraction, liquid–liquid extraction, or solid-phase microextraction, allowing the simultaneous extraction of parent compounds and their degradation intermediates. Following the extraction and cleanup steps, the identification and quantification of degradation intermediates of personal care products at environmental levels (i.e., parts per trillion to parts per billion range) is usually performed by using mass spectrometry techniques such as single quadrupole mass spectrometry and more recently by time-of-flight mass spectrometry or tandem mass spectrometry. The main scope of this review is to critically evaluate the current state of the art of the analytical techniques used and to identify the research needs in the determination of degradation intermediates of personal care products in environmental matrixes.     

Identification of NTBC metabolites in urine from patients with hereditary tyrosinemia type 1 using two different mass spectrometric platforms: triple stage quadrupole and LTQ‐Orbitrap

The objective of our work was to identify known and unknown metabolites of the drug NTBC (2‐(2‐nitro‐4‐trifluoromethylbenzoyl)‐1,3‐cyclohexanedione) in urine from patients during the treatment of hereditary tyrosinemia type 1 (HT‐1) disease, a severe inborn error of tyrosine metabolism. Two different mass spectrometric techniques, a triple stage quadrupole and an LTQ‐Orbitrap (Fourier transform mass spectrometry (FTMS)), were used for the identification and the structural elucidation of the detected metabolites. Initially, the mass spectrometric (MS) approach consisted of the precursor ion scan detection of the selected product ions, followed by the corresponding collision‐induced dissociation (CID) fragmentation analysis (MS²) for the targeted selected reaction monitoring (SRM) mode. Subsequently, accurate and high‐resolution full scan and MS/MS measurements were performed on the possible metabolites using the LTQ‐Orbitrap. Final confirmation of the identified metabolites was achieved by measuring commercially supplied or laboratory‐synthesized standards. Altogether six metabolites, including NTBC itself, were extracted, detected and identified. In addition, two new NTBC metabolites were unambiguously identified as amino acid conjugates, namely glycine‐NTBC and β‐alanine‐NTBC. These identifications were based on their characteristics of chromatographic retention times, protonated molecular ions, elemental compositions, product ions (using CID and higher‐energy C‐trap dissociation (HCD) techniques) and synthesized references. The applied MS strategy, based on two different MS platforms (LC/MS/MS and FTMS), allowed the rapid identification analysis of the drug metabolites from human extracts and could be used for pharmaceutical research and drug development. Copyright © 2010 John Wiley & Sons, Ltd.     

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.     

Comprehensive two-dimensional gas chromatography coupled to a rapid-scanning quadrupole mass spectrometer: principles and applications

The principles, practicability and potential of comprehensive two-dimensional (2D) gas chromatography coupled to a rapid-scanning quadrupole mass spectrometer (GC x GC-qMS) for the analysis of complex flavour mixtures in food, allergens in fragrances and polychlorinated biphenyls (PCBs) were studied. With a scan speed of 10,000 amu/s, monitoring over a mass range of up to 200 atomic mass unit (amu) can be achieved at an acquisition frequency of 33 Hz. Extending this mass range and/or increasing the data acquisition frequency results in a loss of spectral quality. Optimal parameter settings allow, next to unambiguous identification/confirmation of target compounds on the basis of high-quality mass spectra, fully satisfactory quantification (three to four modulations per peak) with linear calibration plots and detection limits in the low-pg level. The potential of time-scheduled data acquisition to increase the effective mass range within one GC x GC run was also explored. The analyses, with baseline separation of the flavours, allergens and PCB target compounds, took less than 30 min.