微波等离子体炬质谱直接分析水中镉的研究

建立了一种测量水中痕量镉的质谱电离新方法。以微波等离子体炬(MPT)为离子源,结合质谱仪器可直接分析水样而无需任何样品预处理。水样直接通过雾化器雾化形成气溶胶,气溶胶经加热冷却循环及浓硫酸干燥后,由MPT中心管道引入等离子体,产生的离子采用四极杆质谱仪(QMS)检测,得到镉的MPT特征质谱。根据镉的特征质谱进行定量分析。结果表明,114Cd的信号强度与溶液中镉离子浓度在300~3 000ng/L范围内呈良好线性关系,相关系数可达0.994 96,检出限(LOD)为72.7 ng/L。对实际水样(自来水、太湖湖水、赣州龙南井水、矿泉水)进行分析,加标回收率为90.6%~112.2%,10次测量的相对标准偏差(RSD,n=10)为7.1%~21.5%,单个样品测试可在2~3 min内完成。因此,MPT质谱法对水中有害金属镉的快速测量具有一定优势,作为传统ICP质谱检测的有力补充,可以发展成为在线分析方法,应用于环境水、生活水质量监控等领域。     

基于微波等离子体炬串联质谱鉴别蜂蜜和糖浆

采用微波等离子体炬串联质谱(Microwave plasma torch mass spectrometry,MPT-MS)技术,在无需样品预处理的条件下,建立了快速鉴别3种蜂蜜和4种糖浆的方法。在正离子模式下,蜂蜜和糖浆直接由MPT产生的火焰离子化,生成的离子采用四极杆质谱仪(QM)检测,得到蜂蜜和糖浆的质谱信息,采用化学计量学方法进一步对质谱数据进行分析。结果表明,MPT-MS结合化学计量学的方法,可以快速鉴别蜂蜜和糖浆,主成分分析(PCA)显示PC1、PC2和PC3的总贡献率达91.2%;聚类分析(CA)显示当临界值为7时,除紫云英蜜和菊粉糖浆外,可以有效的区分蜂蜜和糖浆;偏最小二乘判别分析(PLS-DA)显示蜂蜜和糖浆可以被有效区分;判别分析(DA)显示蜂蜜和糖浆的判别准确率为100%。本方法无需样品预处理,具有分析速度快、信息提取准确和识别精度高等优点,可用于蜂蜜与主要掺假糖浆的鉴别。     

两种微波等离子体炬质谱测定水中铅的对比研究

建立了一种新型的能够灵敏分析水中痕量铅的质谱方法,以微波等离子体炬(MPT)为离子源,可无需样品预处理而直接分析水样。样品经雾化和去溶后由MPT的中心管道引入等离子体,离子由国产的四极杆质谱仪(Q-MS)检测,得到铅的MPT特征质谱。定量结果表明,该方法的检出限为20 ng/L,线性范围为200~1 000 ng/L,相对标准偏差(RSD)为5.3%;所得定量指标优于相同条件下商用的线性离子阱质谱(LTQ-MS)测试结果,且四极杆质谱仪上所得的铅离子特征质谱信号更简单、易归属,无需复杂的多级串联质谱加以确认。这种MPT可与国产质谱仪器相结合发展成为一种低成本的现场检测铅的质谱仪器,在环境监控、饮用水检验等方面具有一定的应用价值。     

合成产物PEPAMP及其副产物的电喷雾串联质谱分析

PEPAMP是应用于工业循环水中的新一代高效阻垢剂.采用电喷雾电离质谱和质谱/质谱技术分析了合成产物,注射泵直接进样,正离子方式检测,方法简便、快速.通过EI-MS技术获得了目标产物PEPAMP及主要副产物的准分子离子峰,通过ESI-MS-MS技术获得了其碎片信息,并对目标化合物及主要副产物进行了精确质量测定,确定了目标化合物及主要副产物的结构.     

微波等离子体常压解吸电离质谱法快速检测化学药剂中的活性成分

构建了一种新型电离源--微波等离子体常压解吸电离源, 等离子体由微波等离子体炬产生, 工作气体为Ar气, 微波频率为2450 MHz, 该离子源可在大气压下产生稳定的等离子体. 将该电离源与具有大气压接口的Corsair API-TOF型飞行时间质谱仪结合, 实现了化学药剂中单一或多种主要活性成分的快速分析, 在手动进样条件下, 检测速度可达每小时360次. 在微波等离子体环境下, 活性物质成盐时母体化合物上结合的酸性物质可被直接除掉, 谱图中主要离子为母体化合物的准分子离子[M+H]⁺, 便于识别. 微波等离子体常压解吸电离质谱法无需化学试剂, 具有实时、 快速及无污染等特点, 为药剂研发及化学工业提供了一种新的检测技术.     

苦参生物碱电喷雾质谱分析

用电喷雾离子阱质谱(ESI-ITMS)研究了苦参碱和氧化苦参碱一级质谱电离规律和二级质谱裂解规律。实验结果显示,苦参碱和氧化苦参碱电喷雾一级质谱中均易产生聚合及加合离子,二级质谱中易产生环逐步裂解碎片离子,即结构相似的苦参碱和氧化苦参碱具有相似的电喷雾质谱行为。苦参碱的特征碎片为m/z148和150,氧化苦参碱的特征碎片为m/z248([M H-17] )、m/z247([M H-18] )以及m/z148、m/z150。对苦参对照药材的甲醇提取物进行了电喷雾质谱分析,由一级质谱的准分子离子及其二级质谱碎裂信息对各已知组分进行了结构认证。     

三唑仑苯二氮(艹卓)类药物的电喷雾质谱裂解特征

采用电喷雾/四极杆飞行时间质谱(ESI-QqTOF)联用技术,对3种三唑仑苯二氮(艹卓)类药物进行CID研究,并以质子化准分子离子[M+H]+作为内标物,对碎片离子进行了准确质量测定,确认了这些碎片离子的元素组成,探讨了该类化合物的质谱裂解规律.研究发现,它们的ESI-MS2(源内)和ESI-MS3质谱分别生成脱去N2分子、HCN或CH3CN分子和Cl原子的碎片离子,其中m/z 205为3种药物共有的碎片离子,这些特征可用于三唑仑苯二氮(艹卓)类药物的体内代谢转化和定量研究.     

解析电喷雾电离质谱成像技术在口红类化妆品物证检验中的应用北大核心CSCD

目前法庭科学物证检验中对化妆品类物证的研究较少,检测手段多以色谱检测为主,样品前处理过程复杂,且难以进行准确定性.据此,以口红类化妆品为例,提出了适合口红成分分析的解析电喷雾电离质谱成像检测方法,并用于检测30种不同品牌口红样品,根据正、负离子模式下得到的准分子离子及碎片离子质荷比,对比不同档次口红成分和质谱数据的差异,初步建立适用于刑事技术的口红质谱信息数据库.该方法重复性好、定性能力强,无需复杂的样品前处理即可对口红中的主要成分进行快速定性检测,一方面可应用于口红产品的真伪鉴别,另一方面可对实际案件中口红残留物证进行比对检验,从而为刻画嫌疑人及确定侦查方向提供思路.     

潮湿空气微波放电离子形成动力学

利用微波放电电离质谱装置，通过水蒸气与空气混合气体（潮湿空气）的微波放电，同时获得了化学电离质谱探测技术中常用的三种重要母体离子H3O＋、NO＋和.结合潮湿空气中主要成分N2、O2以及水蒸气各自微波放电后的质谱探测结果，对潮湿空气微波放电后上述三种离子产生的动力学过程进行了分析，并给出了各种离子的形成机制.这些离子 分子反应过程在计算机模拟中得到了进一步的证实.     

表面解吸常压化学电离质谱快速分析六味地黄丸

采用新型表面解吸常压化学电离(Surface Desorption Atmospheric Pressure Chemical Ionization, SDAPCI)质谱法, 在敞开环境下, 对潮湿的空气进行电晕放电产生试剂离子, 进而在六味地黄丸表面发生解吸电离过程, 在无需复杂预处理的前提下对六味地黄丸中的待测物进行离子化, 从而获得了六味地黄丸在正负离子模式下的化学指纹图谱, 并利用主成分分析法对质谱指纹数据进行处理, 可对6个厂家生产的多个批次产品进行较好的区分. 结果表明, SDAPCI-MS技术能够快速测定六味地黄丸的剂型和生产厂家信息, 并能够对目标组分做多级串联质谱鉴定, 发现痕量目标组分. 研究方法可望应用于中成药药品生产质量控制和成品检测等领域.     

An easy and simple kilowatt-MPT-MS-based metal elements analysis method for rapid environmental water monitoring: An example from Poyang Lake of China

A powerful analytical method based on microwave plasma torch/mass spectrometry (MPT-MS) was developed to rapidly detect mental elements in environmental water from Poyang lake in China. With minimum or uncomplicated sample manipulation, raw water samples were ionized by MPT for subsequent LTQ-MS analysis under negative ion mode. Typical potential contamination sources such (e.g., iron, cobalt, and nickel) were detected and identified by collision-induced dissociated (CID) experiment. It was found that the three metallic elements were formed as [M(NO_x)_mO_n]⁻, which was universal; thus, they could be target ions. For the given elements, their limits of detection (LOD) were assessed as 0.09 μg•L⁻¹ for iron ion, 0.03 μg•L⁻¹ for cobalt ion, and 0.33 μg^.L⁻¹ for nickel ion under the optimized conditions; good determination coefficient (R² ≥ 0.99) and the relative standard deviation (RSD, 2.0–11%, n = 11) were obtained. For current actual samples under testing, short analysis time for a single sample (less than 1 min), the average levels for iron, cobalt, and nickel, reached allowable concentrations of national standards, which also suggested this method is practically effective and usable. Moreover, possible ionization mechanism of metallic elements in MPT source was also discussed in this work, which may provide insight and useful information for the metal organics derived from water environment or metabonomics by MPT-MS. On the whole, this study lays a solid basis for the in-site mass spectrometry analysis of aqueous samples in relevant fields.     

Microwave plasma torch mass spectrometry for some rare earth elements

Rare earth elements (REEs) have been widely applied in modern industry and material science due to their special chemical properties and luminescence properties, but their environment pollution problem has also attracted attention. How to trace and control impact of REEs on environment and develop highly sensitive methods for REEs analysis have practical significance. Microwave plasma torch (MPT) is a kind of simple, low power consumption (～200 W) and easily operated plasma generators. When it was coupled with varied mass spectrometers as ion source of mass spectrometry (MS), i.e. MPT-MS can use for the analysis of metal elements in aqueous with the remarkable advantage of only minimal or even no simple pretreatment, and can meet comprehensive requirements of environmental control and water quality monitoring. MPT-MS have also an ability to carry out online real-time monitoring and analysis of water environment. Compared with the traditional ICP-MS, it can obtain more effective information and has higher sensitivity (the detection limit is at sub-ppb level). This paper reviews common methods and research progress of REEs analysis in recent years. Practical applications and advantages of MPT in the analysis of REEs are briefly summarized. Specifically, this paper introduces some work recently done in our group on analysis of REEs by the MPT, including analysis of metal elements distribution in water samples in local Poyang Lake, and general rules of formation and behavior of complex metal ions in the MPT plasma are also proposed afterwards. Through the practically dealing with the Poyang Lake case by the MPT, hopefully this would interest more academia into this area so as to speed up development of the MPT itself.     

Microwave plasma torch analytical atomic spectrometry

The microwave plasma torch (MPT), as a relative new source, has found extensive use in atomic spectrometry. In this review, the fundamental features and characteristics of the MPT are summarized and compared with other kinds of analytical atomic sources, such as the more popularly used inductively coupled plasma (ICP), the direct current plasma (DCP), as well as other kinds of microwave plasmas (MWPs). Since the MPT offers some attractive features, it has been used as an excitation source for atomic emission spectrometry (MPT-AES), including the atomic emission detection (AED) for gas chromatography (GC), liquid chromatography (LC) and supercritical fluid chromatography (SFC). Also, it has been used either as an ionization source for atomic mass spectrometry (MPT-AMS) or an atomization source for atomic fluorescence spectrometry (MPT-AFS). The historical development and recent improvements in these MPT atomic spectrometric techniques are evaluated with emphasis on the analytical advantages and limitations. In addition, the future research directions and the application prospects of MPT atomic spectrometry (MPT-AS) are discussed.     

Direct desorption/ionization of analytes by microwave plasma torch for ambient mass spectrometric analysis

Ambient ionization is the new revolution in mass spectrometry (MS). A microwave plasma produced by a microwave plasma torch (MPT) at atmospheric pressure was directly used for ambient mass spectrometric analysis. H₃O⁺ and NH₄⁺ and their water clusters from the background are formed and create protonated molecules and ammoniated molecules of the analytes. In the full‐scan mass spectra, both the quasi‐molecular ions of the analytes and their characteristic ionic fragments are obtained and provide evidence of the analyte. The successful detection of active compounds in both medicine and garlic proves that MPT has the efficient desorption/ionization capability to analyze solid samples. The obtained decay curve of nicotine in exhaled breath indicates that MPT‐MS is a useful tool for monitoring gas samples in real time. These results showed that the MPT, with the advantages of stable plasma, minimal optimization, easy, solvent‐free operation, and no pretreatment, is another potential technique for ambient MS. Copyright © 2013 John Wiley & Sons, Ltd.     

Gas chromatography/mass spectrometry determination of amphetamine-related drugs and ephedrines in plasma, urine and hair samples after derivatization with 2,2,2-trichloroethyl chloroformate

A new analytical approach, based on derivatization with 2,2,2-trichloroethyl chloroformate and gas chromatography/mass spectrometry (GC/MS), was investigated for qualitative and quantitative analyses of a large range of amphetamine-related drugs and ephedrines in plasma, urine and hair samples. Sample preparation involved alkaline extraction of analytes from biological samples using Extrelut columns, after addition of the internal standard 3,4-methylenedioxypropylamphetamine (MDPA), and subsequent derivatization to produce 2,2,2-trichloroethylcarbamates. GC/MS analyses, in splitless mode using a slightly polar 30-m capillary column, were performed with quadrupole or ion trap instruments. MS acquisition modes were electron ionization (EI) in full-scan or selected ion monitoring (SIM) modes (quadrupole), and full-scan MS or MS/MS modes with chemical ionization (CI) conditions (ion trap). EI spectra of 2,2,2-trichloroethylcarbamates showed variably abundant molecular ions as well as abundant diagnostic fragment ions, both characterized by ion clusters reflecting the isotope distribution of three chlorine atoms in the derivatized molecules. CI spectra showed abundant protonated molecules. Quantitative studies using EI SIM conditions gave recoveries in the range 74-89%, linear response over ranges of 10-2000 ng/mL (plasma and urine) and 0.20-20 ng/mg (hair), with corresponding limits of detection in the ranges 2-5 ng/mL and 0.1-0.2 ng/mg. Potential applications (following full method validation) include clinical and forensic toxicology, as well as doping control.     

单糖衍生物的电喷雾质谱裂解规律研究

以1-(2-萘基)-3-甲基-5-吡唑啉酮(NMP)作单糖标识剂, 经在线串联的LC-ESI-MS建立了单糖衍生物的电喷雾质谱裂解方法.衍生物在质谱裂解中糖类化合物特有的规范信息.借助糖类化合物在ESI-MS条件下表现出的分子离子峰m/z [M H] , 及在ESI-MS/MS条件下呈现出的特征碎片离子峰m/z 473, 可有效地确定出单糖类化合物的组成. 尽管一些脂肪醛和芳香醛也能同时被标识, 然而在质谱条件下不产生m/z 473的特征碎片离子峰, 且它们的洗脱远在糖类组分之后, 因此不干扰糖类化合物的分离和结构确定.通过建立的LC-ESI-MS方法, 对水解蜂花粉中的单糖进行了分析.结果表明: 水解的蜂花粉中含甘露糖(Man)、半乳糖醛酸(GalUA)、葡萄糖醛酸(GlcUA)、鼠李糖(Rha)、葡萄糖 (Glc)、半乳糖(Gal)、阿拉伯糖(Ara)、木糖(Xyl)和岩藻糖(Fuc).本方法为环境样品中单糖类化合物的确定提供了准确、可靠的技术手段.     

Desorption sonic spray ionization for (high) voltage-free ambient mass spectrometry

Sonic spray ionization is shown to create a supersonic cloud of charged droplets able to promote efficient desorption and ionization of drugs directly from the surfaces of commercial drug tablets at ambient conditions. Compared with desorption electrospray ionization (DESI), desorption sonic spray ionization (DeSSI) is advantageous since it uses neither heating nor high voltages at the spray capillary. DeSSI therefore provides a more friendly environment in which to perform ambient mass spectrometry (MS). DeSSI-MS is herein evaluated for the analysis of drug tablets, and found to be, in general, as sensitive as DESI-MS. The (high) voltage-free DeSSI method provides, however, cleaner mass spectra with less abundant solvent cluster ions and with enough abundant analyte signal for tandem mass spectrometry (MS/MS). These features may therefore facilitate the DeSSI-MS detection of low molar mass components or impurities, or both. The higher-velocity supersonic DeSSI spray also facilitates matrix penetration thus providing more homogenous sampling and longer lasting ion signals.     

Self-aspirating atmospheric pressure chemical ionization source for direct sampling of analytes on surfaces and in liquid solutions

A self-aspirating heated nebulizer probe is described and demonstrated for use in the direct analysis of analytes on surfaces and in liquid samples by atmospheric pressure chemical ionization (APCI) mass spectrometry. Functionality and performance of the probe as a self-aspirating APCI source is demonstrated using reserpine and progesterone as test compounds. The utility of the probe to sample analytes directly from surfaces was demonstrated first by scanning development lanes of a reversed-phase thin-layer chromatography plate in which a three-component dye mixture, viz., Fat Red 7B, Solvent Green 3, and Solvent Blue 35, was spotted and the components were separated. Development lanes were scanned by the sampling probe operated under computer control (x, y plane) while full-scan mass spectra were recorded using a quadrupole ion trap mass spectrometer. In addition, the ability to sample the surface of pharmaceutical tablets (viz., Extra Strength Tylenol and Evista tablets) and to detect the active ingredients (acetaminophen and raloxifene, respectively) selectively was demonstrated using tandem mass spectrometry (MS/MS). Finally, the capability to sample analyte solutions from the wells of a 384-well microtiter plate and to perform quantitative analyses using MS/MS detection was illustrated with cotinine standards spiked with cotinine-d3 as an internal standard.     

Chemical profile of meta-chlorophenylpiperazine (m-CPP) in ecstasy tablets by easy ambient sonic-spray ionization, X-ray fluorescence, ion mobility mass spectrometry and NMR

Meta-chlorophenylpiperazine (m-CPP) is a new illicit drug that has been sold as ecstasy tablets. Easy ambient sonic-spray ionization mass spectrometry (EASI-MS) and X-ray fluorescence spectrometry (XRF) are shown to provide relatively simple and selective screening tools to distinguish m-CPP tablets from tablets containing amphetamines (mainly 3,4-methylenedioxymethamphetamine (MDMA)). EASI-MS detects the active ingredients in their protonated forms: [m-CPP + H](+) of m/z 197, [MDMA + H](+) of m/z 194, and [2MDMA + HCl + H](+) of m/z 423 and other ions from excipients directly on the tablet surface, providing distinct chemical fingerprints. XRF identifies Cl, K, Ca, Fe, and Cu as inorganic ingredients present in the m-CPP tablets. In contrast, higher Cl concentrations and a more diverse set of elements (P, Cl, Ca, Fe, Cu, Zn, Pt, V, Hf, Ti, Pt, and Zr) were found in MDMA tablets. Principal component analysis applied to XRF data arranged samples in three groups: m-CPP tablets (four samples), MDMA tablets (twenty three samples), and tablets with no active ingredients (three samples). The EASI-MS and XRF techniques were also evaluated to quantify m-CPP in ecstasy tablets, with concentrations ranging from 4 to 40 mg of m-CPP per tablets. The m-CPP could only be differentiated from its isomers (o-CPP and for the three isomers p-CPP) by traveling wave ion mobility mass spectrometry and NMR measurements.