电喷雾解吸电离质谱快速测定吴茱萸中生物碱

生物碱是许多中草药的活性有效成分,其含量的多少和种类的差异是导致中草药品质差异的重要因素.本文利用电喷雾解吸电离质谱(DESI-MS)能够在不需要样品预处理的前提下进行复杂基体样品分析的特点,采用酸性甲醇-水混合溶液作为喷雾试剂,在优化了的实验条件下快速获得了吴茱萸的DESI-MS指纹谱图,然后利用串联质谱对其中有重要活性的5种生物碱进行了结构鉴定.实验表明,基于固体表面解吸电离质谱分析的方法不需要萃取-分离手续,单个样品测定时间不超过1.5 min,大幅度提高了分析速度,有望在药品品质的在线监测和工艺过程控制中发挥重要作用.     

电喷雾萃取电离质谱法分析莲子中的生物碱

在无需样品预处理的前提下,直接对莲子醇提液进行电喷雾萃取电离质谱(EESI-MS)检测,并对其中可能存在的生物碱母离子进行串联质谱分析确认,通过主成分分析(PCA)对不同贮藏时间莲子的醇提液进行区分.研究结果表明,电离电压、离子传输管温度和样品进样流速的最佳条件分别为3.5 kV,250℃和5μL/min;串联质谱结果表明莲子醇提液中存在莲心碱、甲基莲心碱、莲心季铵碱、荷叶碱及O-去甲基荷叶碱等生物碱.PCA可将不同贮藏时间的莲子明显区分在二维平面的不同区域.本方法无需样品预处理,可用于复杂基体样品中生物碱的快速鉴定,与化学计量学结合可对不同新陈度的莲子样品进行有效区分.     

高效液相色谱-电喷雾质谱同时测定人体尿液中黄蝶呤与异黄蝶呤

建立了高效液相色谱-电喷雾质谱(HPLC-ESI-MS)法同时测定人体尿液中黄蝶呤与异黄蝶呤的分析方法.尿样经离心、过膜后直接进样,采用电喷雾质谱进行定性和定量.结果表明,黄蝶呤与异黄蝶呤含量分别在0.0204～2.04μg/mL和0.0202～ 2.02 μg/mL范围内与色谱峰面积呈良好的线性关系,线性相关系数r2...     

高效液相色谱/电喷雾飞行时间质谱分析太子参中环肽类化合物

采用高效液相色谱/电喷雾飞行时间质谱联用方法(HPLC/ESI-TOFMS)分析太子参中的环肽类化合物。实验采用反相C18色谱柱,二元线性梯度洗脱,分离并检测了太子参中6种环肽类化合物;通过与电喷雾飞行时间质谱联用获得了这几种化合物的准确分子量信息,由于ESI-TOFMS具有高分辨率,能够测定化合物精确的分子质量而不降低灵敏度,对6种环肽类化合物成分进行了定性鉴定。该方法简便、快速、准确。     

电喷雾内部萃取电离质谱直接分析蒜瓣组织的研究

固态复杂基体样品的直接电离一般仅发生在样品浅层表面,对固体内部深层物质的质谱分析往往需将样品破碎后才能进行。本研究以蒜瓣样品为例,无需样品预处理,带电的甲醇溶液以2μL/min持续流经蒜瓣深层组织,内部组织中的化学物质选择性地溶解到流动液中,并在蒜瓣组织的尖端形成电喷雾,产生相应气态离子供后续质谱分析。在正离子检测模式下,实验记录了两种蒜瓣样品(共24个)、经不同方式贮存加工后的同种蒜瓣样品(共36个)在m/z 50~2000范围内的化学指纹谱图,并将指纹谱图数据进行主成分分析( PCA),获得了令人满意的分组结果。研究表明,电喷雾内部萃取电离质谱( iEESI-MS)可以直接获取蒜瓣内部组织生物化学信息,鉴定蒜瓣组织中重要的化学成分(如蒜氨酸、蒜素、精氨酸、多糖等),快速识别蒜瓣组织中代谢组分的变化。本方法无需样品预处理、操作简单、分析速度快(单个样品分析时间小于2 min),最大程度避免了生物组织分析过程中活性物质受环境作用(如酸解、空气氧化等)的降解,有望为生物组织样品的代谢组学研究提供一种直接、快速的质谱分析方法。     

尿样及动物组织中甲氧苄氨嘧啶残留量的高效液相色谱-串联质谱测定法

采用微量化样品前处理技术,以固相萃取为净化方法,电喷雾正离子多反应监测方式建立了尿样及动物组织中甲氧苄氨嘧啶残留量的液相色谱-串联质谱联用测定法.检出限为0.1 ng/g,线性范围均大于3个数量级,线性方程的相关系数大于0.999,组织样品和尿样的回收率分别为89%和93%.     

水样中痕量黑索今的快速质谱法检测

近年来,以RDX为代表的痕量爆炸物检测已经是反恐斗争和国土安全领域的重要课题[1]。本实验将醋酸作为辅助试剂直接添加到待分析水样中,采用电喷雾电离直接进样,在正离子检测模式下,建立了直接快速测定水样中衡量RDX的电喷雾质谱分析方法。在样品流量为10.0μL/m in,喷雾电压为5.0 kV,毛细管温度为200℃条件下获得的RDX的检出限为0.001μg/L,线性范围为0.005~100μg/L。对天然湖水、矿泉水和自来水中添加的衡量RDX的回收率分别在92%~108%之间。单个样品分析(含串联质谱分析)所需时间不超过2 m in。     

芍药苷的电喷雾串联质谱研究

采用电喷雾串联质谱(ESI-MSn)技术, 结合H/D交换方法, 在正、负离子检测模式下对白芍药材中主要成分芍药苷的质谱裂解规律进行了系统研究. 实验结果表明, 该化合物在正、负离子模式下均得到较好的质谱信息, 且在正离子模式下, 电喷雾质谱分析的灵敏度更高. 同时获得了其质谱裂解规律, 为白芍中其它化合物的分析鉴定提供了有效的质谱方法.     

高效液相色谱-四极杆飞行时间质谱分析紫甘蓝和羽衣甘蓝中花色苷

应用高效液相色谱-电喷雾/四极杆飞行时间串联质谱联用技术分析了紫甘蓝和羽衣甘蓝中的花色苷成分.选用Agilent TC-C18色谱柱(250 mm×4.6 mm×5 μm),二元线性梯度洗脱,柱后流出液采用电喷雾四极杆飞行时间质谱的正、负离子模式进行检测.根据一级质谱的分子离子和二级质谱碎片离子,获得化合物的准确分子量...     

芦笋中化学成分的内部萃取电喷雾电离质谱检测

选择芦笋(Asparagus Officinalis L)新鲜茎块和两种干燥茎块为代表性植物组织样品,建立了一种直接检测芦笋中多种化学成分的内部萃取电喷雾电离质谱(iEESI-MS)分析方法。在正离子检测模式下,选择甲醇(CH₃OH)作萃取溶剂,在无需样品预处理的条件下对芦笋组织样品进行直接质谱分析,获得了组织样品在m/z 50~1000范围内的化学指纹谱图,并通过目标离子的碰撞诱导解离(CID)实验,鉴定了对药物和自然产品研发具有重要意义的糖类、氨基酸、生物碱以及芦丁等多种代表性的营养成分。 本方法具有无需样品预处理、样品耗量少、操作简便、分析速度快(单个样品的分析时间少于1 min)等优点,为食源性植物组织样品的快速分析提供了一种质谱分析新方法。     

The rapid identification of drug metabolites using capillary liquid chromatography coupled to an ion trap mass spectrometer

Capillary liquid chromatography (LC) using a 320 microns column and a flow rate of 10 microL/min has been coupled to an ion trap mass spectrometer using electrospray ionisation (ESI) to enable the rapid and effective identification of metabolites in urine, following oral administration of a novel human neutrophil elastase inhibitor, GW311616. Metabolites were identified from their mass (MS) spectra and tandem (MS/MS) mass spectra using minimal sample (1 microL of urine) and no sample pretreatment. Sensitivity assessment has shown that both molecular weight and structural information is obtainable on as little as 5 pg of compound, making the capillary LC/ion trap system as described an ideal analytical tool for the detection and characterisation of low level metabolites in biofluids (particularly when sample volume is limited). This level of detection was unattainable using a triple quadrupole mass spectrometer operating in full-scan mode, although 200 fg on column was detected using selected reaction monitoring target analysis.     

溶液中蛋白质的气液荷电萃取电离质谱研究

利用自主研制的气液荷电萃取电离装置实现了溶液中蛋白组分的荷电萃取电离直接质谱分析.系统考察了所用气体种类、气泡路径长度、溶液电压、气压等条件对溶液中溶菌酶等蛋白荷电萃取电离的影响,以期得到最佳蛋白质信号.在以CO2为萃取气体、气泡路径长度32 cm、溶液电压+2 kV、气压0.05 MPa条件下,溶菌酶在水、纯水稀释200倍尿液、未稀释尿液中的浓度分别为1×10-8 mol/L、1×10-7 mol/L、1×10-5 mol/L时获得谱图信噪比(S/N≥3)类似,信号强度不受样品管内径大小影响,所用尿液最小体积为6 mL,但对珍稀样品可进一步减少用量.与ESI-MS相比,本方法获得更多低价态蛋白质离子,对溶液中的小分子基体、无机盐具有更强的耐受性,且辣根过氧化物酶经气液苛电萃取电离能保留53.9%活度.本方法具有无需复杂样品预处理、无化学试剂污染的特点,有望为分析复杂基质中蛋白质提供一种新方法.     

Simultaneous determination of serotonin and creatinine in urine by combining two ultrasound-assisted emulsification microextractions with on-column stacking in capillary electrophoresis

This article describes the development of a rapid, simple, and sensitive analytical approach for the simultaneous determination of serotonin (5‐hydroxytryptamine) and creatinine in urine samples by combining two ultrasound‐assisted emulsification microextractions (USAEMEs) in series with on‐column stacking in CE. This serial USAEME procedure comprises analytes extraction from the donor solution (urine with K₂CO₃ additive) to an organic solvent followed by a back‐extraction from the organic phase into a small volume of hydrochloric acid. After 15 min of sample pretreatment, the acidic acceptor solution was analyzed directly on CE in the mode of capillary zone electrophoresis. The adoption of HCl as the acceptor phase not only provided effective back‐extraction but also facilitated pH‐mediated on‐column stacking in CE analysis. About 360‐fold sensitivity enhancement was achieved for serotonin detection. The limits of detection were 7.9 nM for serotonin and 13.3 μM for creatinine, respectively. Satisfactory results were obtained with respect to precision and recovery. The proposed method has been demonstrated to be convenient and effective for the analysis of real urine samples. We believe that two USAEMEs in series will find wide applications in simplified sample pretreatment prior to CE analysis.     

Development and validation of an isotope-dilution electrospray ionization tandem mass spectrometry method with an on-line sample clean-up device for the quantitative analysis of the benzene exposure biomarker S-phenylmercapturic acid in human urine

An isotope-dilution electrospray ionization tandem mass spectrometry (ESI-MS/MS) method with an on-line sample clean-up device, for the quantitative analysis of human urine for the benzene exposure biomarker S-phenylmercapturic acid (SPMA), was developed and validated. The sample clean-up system was constructed from an autosampler, a reversed-phase C18 trap cartridge, a two-position switching valve, and controlling computer software and hardware. The sample clean-up system was interfaced via 1/20 splitting to the ESI source of a triple-quadrupole mass spectrometer using negative ion mode and multiple reaction monitoring for SPMA and the isotope-labeled internal standard. A strategy was adopted to acquire pooled blank urine matrix and quality control samples spiked with standards. Validated procedures and data on method specificity, detection limits, standard curves, precision and recovery, sample storage stability, and inter-laboratory comparison are presented. The analytical system was fully automated. No tedious manual sample clean-up procedures are required. With the selectivity and the sensitivity provided by ESI-MS/MS detection, the analytical system can be used for high-throughput and accurate determination of SPMA levels in human urine samples, as a biomarker for environmental as well as occupational benzene exposure.     

基于敞开式直接电离质谱技术的尿液中毒品检测北大核心CSCD

尿液作为一种易于获取的体内毒品检材,在吸毒人员快速筛查中被广泛应用。针对传统快速筛查技术存在假阳性率高、定量能力不足以及实验室质谱技术在快速检测中存在前处理复杂、检测耗时长、使用环境苛刻等问题,该文提出了一种基于敞开式直接电离质谱技术的生物样本快速检测方法。该研究采用探针式电喷雾离子源与便携式质谱仪联用快速检测平台,优化了喷雾电压和质谱入口毛细管温度,开发了高效快速的前处理技术。基于该平台和前处理技术,5种常规毒品(甲基苯丙胺、氯胺酮、可卡因、O^(6)-单乙酰吗啡和3,4-亚甲双氧甲基苯丙胺)的尿液加标溶液的检出限为0.5~30 ng/mL,且其中4种毒品定量检测的线性相关系数大于0.99。除此之外,5种常规毒品在3个不同水平下的加标回收率为56.1%~103.7%,多次检测结果的相对标准偏差为9.0%~27.8%,说明联用检测平台与前处理方法结合可以达到良好的准确度。为了进一步检验该联用仪器的实战能力,测试了某社区戒毒康复中心40份阳性和110份阴性实际尿液样本,总体检测的准确率接近99%,且通过一次进样在20 s内可同时检测多种毒品。该研究成果有利于推动快速检测技术的发展,促进敞开式直接电离质谱仪技术的推广应用,提升一线执法服务水平。     

Portable electrospray ionization mass spectrometry (ESI-MS) for analysis of contaminants in the field

Hitherto analysis of chemicals in the field using mass spectrometry (MS) has been limited to analysis of non-polar and thermally stabile organic compounds using either a direct gas leak or a membrane inlet as MS interface. Recently, Professor R. Graham Cooks’ group demonstrated that miniature mass spectrometers operating at elevated pressures (>0.13?Pa (1?·?10^?3??Torr)) can be combined with electrospray ionization (ESI) for analysis of polar as well as thermally labile organic compounds. We present a simple miniaturized ESI unit for analysis of small liquid samples using miniature mass spectrometry. The ESI unit operates without pumps and supplementary sheath gases, which makes it very simple to handle in the field. 20–30?µL of sample solution is simply dropped into a small cavity in the ESI unit, where after the spray is initiated by applying high voltage to it. The miniaturized ESI unit was tested in combination with a miniature mass spectrometer (the Mini 10 developed by Professor R. Graham Cooks, Purdue University, IN) and we found that common herbicides (Atrazine, Prometryne, Terbutryne and Triadimefone) could be detected with detection limits around 1?mg?L^?1 and with a quantitative reproducibility of +/?30%. These characteristics, although high for environmental samples, are comparable to detection limits obtained with other ESI units used with miniature mass spectrometers and represent an early step forward towards a future field instrument. A major advantage of the capillary spray cell is its direct compatibility with micro extraction techniques for sample pre-concentration.     

CE Determination of Creatinine and Uric Acid in Saliva and Urine During Exercise

A simple and reliable method based on capillary electrophoresis with electrochemical detection (CE–ED) was applied to study the effect of aerobic exercises on creatinine and uric acid concertration in saliva and urine. The pH value, the running buffer concentration, the SDS concentration, separation voltage, injection time and the potential applied to the working electrode were investigated to find the optimum conditions. The detection limits (S/N = 3) for creatinine and uric acid were 3.6 μmol L^?1 and 0.86 μmol L^?1, respectively. This method was successfully used in the rapid analysis of creatinine and uric acid in saliva samples. After aerobic exercises, creatinine concentration decreased, and uric acid concentration increased in saliva. In urine, the concentrations of creatinine and uric acid both increased after exercise.     

Chromatographic Properties of Ethanol/Water Mobile Phases on Silica Based Monolithic C18

A simple and reliable method based on capillary electrophoresis with electrochemical detection (CE–ED) was applied to study the effect of aerobic exercises on creatinine and uric acid concertration in saliva and urine. The pH value, the running buffer concentration, the SDS concentration, separation voltage, injection time and the potential applied to the working electrode were investigated to find the optimum conditions. The detection limits (S/N = 3) for creatinine and uric acid were 3.6 μmol L⁻¹ and 0.86 μmol L⁻¹, respectively. This method was successfully used in the rapid analysis of creatinine and uric acid in saliva samples. After aerobic exercises, creatinine concentration decreased, and uric acid concentration increased in saliva. In urine, the concentrations of creatinine and uric acid both increased after exercise.

     

Electrospray ionization mass spectrometry fingerprinting of perfumes: Rapid classification and counterfeit detection

A fast procedure to classify perfumes and identify counterfeit samples is described. Dilution of a few microL of the sample in a 1:1 methanol/water solution is followed by detection of its major polar components via direct infusion electrospray ionization mass spectrometry (ESI-MS) in the positive ion mode. As proof-of-principle cases, three famous brands of perfumes were used. The ESI+-MS fingerprints of authentic samples were very characteristic, showing distinctive sets of polar markers for each sample. Principal component analysis (PCA) placed samples of the three perfume brands in well-defined groups. Counterfeit samples were also clearly detected owing to contrasting ESI-MS fingerprints, with PCA placing these samples far away from the authentic samples.     

Determination of two oxy-pyrimidine metabolites of diazinon in urine by gas chromatography/mass selective detection and liquid chromatography/electrospray ionization/mass spectrometry/mass spectrometry

An analytical method was developed for the determination in urine of 2 metabolites of diazinon: 6-methyl-2-(1-methylethyl)-4(1H)-pyrimidinone (G-27550) and 2-(1-hydroxy-1-methylethyl)-6-methyl-4(1H)-pyrimidinone (GS-31144). Two of the urine sample preparation procedures presented rely on gas chromatography/mass selective detection (GC/MSD) in the selected ion monitoring mode for determination of G-27550. For fast sample preparation and a limit of quantitation (LOQ) of 1.0 ppb, urine samples were purified by using ENV+ solid-phase extraction (SPE) columns. For analyte confirmation at an LOQ of 0.50 ppb, classical liquid/liquid partitioning was used before further purification in a silica SPE column. An SPE sample preparation procedure and liquid chromatography/electrospray ionization/mass spectrometry/mass spectrometry (LC/ESI/MS/MS) were used for both G-27550 and GS-31144. The limit of detection was 0.01 ng for G-27550 with GC/MSD, and 0.016 ng when LC/ESI/MS/MS was used for both G-27550 and GS-31144. The LOQ was 0.50 ppb for G-27550 when GC/MSD and the partitioning/SPE sample preparation procedure were used, and 1.0 ppb for the SPE only sample preparation procedure. The LOQ was 1.0 ppb for both analytes when LC/ESI/MS/MS was used.