固相基底电喷雾电离质谱的原理及应用

实际样品的直接质谱分析是质谱技术发展的重要趋势.固相基底电喷雾电离质谱是使用固相材料(如金属材料、多孔材料)承载样品进行电离的一类技术,可以直接分析各种形态的样品(如液态样品、黏性样品、固体样品、生物组织等),具有不同于传统毛细管电喷雾电离质谱的分析特性.近年来,固相基底电喷雾电离质谱受到越来越多的关注,并且已广泛地应用于生物、化学、药学以及食品等领域.本文着重介绍了几种典型固相基底电喷雾电离技术的原理及其应用,并且讨论了固相基底和溶剂在其中的作用以及固相基底电喷雾电离质的未来发展趋势.     

软电离质谱在烟草化学中的应用进展

综述了软电离质谱技术原理和特点,及其在烟草及烟气中有害成分分析测定、实时在线卷烟烟气测定、致香物质的分离与鉴定、农残测定等方面展望了其在烟草化学中的应用,主要包括化学电离质谱、电喷雾电离质谱、大气压化学电离质谱、激光解吸电离质谱、单光子电离质谱等技术(引用文献54篇)。     

电喷雾质谱在手性识别和分析中的应用

近年来电喷雾质谱以其快速、灵敏、简便、样品用量少等特点被越来越多地应用于手性分析研究中。本文综述了目前电喷雾质谱法在手性识别和分析中的应用,包括常用的分析方法及常用的质谱手性选择剂,并对其发展进行了展望。     

质谱技术的新进展及其在生命科学中的应用

近年来,一系列质谱软电离技术得到了新的发展.这些包括电喷雾电离(Electrospray Ionization ESI)和基质辅助激光解吸电离(Matrix-assisted Laser Desorption/ionization MALDI)等.这些软电离技术的发展不但使质谱技术发生了突破性的革新,而且使质谱技术在生命科学中的应用得到了前所未有的扩展.质谱技术所能提供的精确分子量和分子结构信息及其微量鉴定的特点,使得它成为蛋白质组研究中两大支撑技术之一.其中电喷雾质谱更由于其易于与常规的高分辨率分离方法如高效液相色谱和毛细管电泳等实现在线连用而在多肽混合物的分析中得到了广泛的应用.因为在多肽混合物的高灵敏度分析中,将多肽与其他杂质分离对于获得准确的分析结果至关重要.     

质谱及色谱-质谱联用技术在多糖结构分析中的应用

综述了从1968-2010年间质谱及色谱-质谱联用分析法在多糖结构分析中的应用,包括电子轰击质谱、化学电离质谱、快原子轰击质谱、电喷雾质谱、基质辅助激光解吸离子化质谱、气相色谱-质谱、液相色谱-质谱和毛细管电泳-质谱法(引用文献42篇)。     

计算机辅助确定LC-MS中的分子离子的初步研究

LC-MS联用技术灵敏度高、专属性好、样品处理简单、快速,而且多级质谱能够提供丰富的化合物结构信息.同时,电喷雾离子化(ESI)是一种软电离技术,特别适合热不稳定炸药及耐热炸药的分析,有关电喷雾电离质谱对炸药的分析已有若干报道.     

苯丙氨酸取代的丝氨酸八聚体离子的红外光解离光谱及其在手性分析中的应用

通过电喷雾电离的方法,结合质谱-红外解离光谱技术对苯丙氨酸取代的丝氨酸八聚体团簇离子的红外解离光谱手性效应进行了研究,获得了相应的团簇离子在2 700~3 600 cm~(-1)的红外解离光谱。实验结果显示,苯丙氨酸取代的丝氨酸八聚体团簇离子均存在明显的同手性优势。通过比较相应红外解离光谱图的差异或在特定波长处的红外解离质谱均可实现苯丙氨酸单元的手性区分。     

质谱技术在糖类结构分析中的应用

综述了电子轰击、化学电离、快原子轰击、电喷雾离子化、基质辅助激光解吸、串联质谱等质谱技术在糖类结构分析中的应用。引用文献共53篇。     

芹菜素的电喷雾萃取电离串联质谱

采用实验室自制的电喷雾萃取电离源(EESI),结合串联质谱(MSn)技术,对芹菜素这一典型的黄酮类活性化合物的质谱行为进行了研究。实验表明,在正、负离子检测模式下,该化合物均能得到较好的EESI-MS信号,且在负离子检测模式下灵敏度更高。通过对比芹菜素的EESI-MS和电喷雾电离质谱(ESI-MS)谱图发现,芹菜素在EESI-MS和ESI-MS中的裂解规律相似,但是EESI是一种比ESI更软的电离模式。根据对芹菜素EESI-MS特征碎片离子的分析,提出了芹菜素在EESI-MS中裂解的基本规律,为EESI-MS技术用于分析、鉴定复杂基质中痕量芹菜素奠定了理论和实验基础。     

引言

<正>质谱是一种按照离子的质荷比对不同大小的离子进行分离和检测的方法,测出离子准确质量即可确定相应化合物组成。早期的质谱法主要用于元素的同位素分析、小分子的分子量测定、化学式的确定及结构鉴定等。质谱在生命科学中的应用归功于两个软离子源的出现,即电喷雾电离源(ESI)和基质辅助激光解吸电离源(MALDI),这两种技术所具有的高灵敏度和高质量检测范围,使得质谱检测生物大分子变得更加容易,质谱学由此进入了生物质谱的新时代。2004年,美国普渡大学Cooks教授在ESI离子源研究的基础上,发展了一种电喷雾解吸离子化(DESI)技术,该技术无需复杂的样品前处理、     

Quantitative chiral analysis of phthaloylglutamic acid and related analogs by a single ratio kinetic method using electrospray ionization and matrix-assisted laser desorption techniques

A rapid method for quantitative chiral analysis of phthaloylglutamic acid and its dimethyl ester by Cook's kinetic method is demonstrated using electrospray ionization (ESI) and matrix-assisted laser desorption techniques. Transition-metal-bound complex ions containing the chiral phthaloylglutamic acid and its dimethyl ester are generated by ESI mass spectrometry and subjected to collision-induced dissociation. The ratio of the two competitive dissociation rates is related to the enantiomeric composition of the drug mixture. A seven-point calibration curve, derived from the kinetic method, allowed rapid quantitation of the enantiomeric excess of drug mixtures. In this paper, matrix-assisted laser desorption/ionization (MALDI) coupled with the linear ion trap (LIT) technique is evaluated for its applicability as a complementary technique to ESI for chiral discrimination and quantitation.     

Chiral amines as reagents for HPLC-MS enantioseparation of chiral carboxylic acids

Mass spectrometry (MS) has become a popular analytical technique because of its high sensitivity and specificity. Therefore, the use of a chiral derivatization reagent for the MS detection seems to be efficient for the enantiomeric separation of racemates. However, the number of chiral reagents for the liquid chromatography (LC)-tandem mass spectrometry (MS/MS) analysis is very limited. The applicability of commercially available chiral amines as the derivatization reagents for the enantiomeric separation of chiral carboxylic acids is reported in this paper by using non-steroidal anti-inflammatory drugs (NSAIDs), i.e. ibuprofen, flurbiprofen, and loxoprofen. The efficiency of the chiral reagents was evaluated in terms of tagging easiness, separation by reversed-phase chromatography, and detection sensitivity by electrospray ionization (ESI)-MS/MS. Among the tested eight chiral amines, i.e. (R)-(+)-4-(3-aminopyrrolidin-1-yl)-7-(N,N-dimethylaminosulfonyl)-2,1,3-benzoxadiazole (DBD-APy), (S)-(+)-1-(2-pyrrolidinylmethyl)-pyrrolidine (PMP), L-prolinamide, (3R)-(-)-1-benzyl-3-aminopyrrolidine, (S)-(+)-1-cyclohexyl-ethylamine, (3R)-(+)-3-(trifluoroacetamido)-pyrrolidine (TFAP), (R)-(-)-1-aminoindan (AI), and (S)-(+)-tetrahydrofurfuryl-amine, DBD-APy, PMP, AI, and TFAP could be used as the chiral reagents for the enantiomeric separation of the NSAIDs. The Rs values and the detection limits of the derivatives were in the range of 1.29-3.85 and 0.57-0.96 fmol, respectively. These four reagents were applied for the determination of the NSAIDs in rat plasma.     

Letter: steric effects in electrospray-tandem mass spectrometry of 11betanitrates of estrane series

The fragmentation of [M+Na](+) ions produced from steroid 11beta-nitrates during electrospray/ionization (ESI) was studied by using ion trap MS/MS technique. The [M+Na](+) ions eliminate NO(2) and HNO(3) for epimers bearing 9beta and 9alpha substituents, respectively. As the main fragmentation pathways are determined mainly by the configuration at C-9 and alternative fragmentation does not practically occur, this offers the possibility for the determination of the configuration at chiral C-9 centre in the estrane 11beta-nitrate series by ESI mass spectrometry.     

电喷雾电离质谱在化学中应用新进展

电喷雾电离质谱(ESI-MS)是本世纪发展的非常重要的质谱,具有无碎片的特点,可分析检测非挥发性的、极性的、热不稳定的化合物。评述了ESI-MS在富勒烯化学、无机配合物、簇合物、有机化学反应,金属有机化合物及超分子化学中的应用进展。     

Comparison of APPI, APCI and ESI for the LC-MS/MS analysis of bezafibrate, cyclophosphamide, enalapril, methotrexate and orlistat in municipal wastewater

The applicability of three different ionization techniques: atmospheric pressure photoionization (APPI), atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI) was tested for the liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of five target pharmaceuticals (cyclophosphamide, methotrexate, bezafibrate, enalapril and orlistat) in wastewater samples. Performance was compared both by flow injection analysis (FIA) and on-column analysis in deionized water and wastewater samples. A column switching technique for the on-line extraction and analysis of water samples was used. For both FIA and on-column analysis, signal intensity and signal-to-noise (S/N) ratio of the target analytes in the three sources were studied. Limits of detection and matrix effects during the analysis of wastewater samples were also investigated. ESI generated significantly larger peak areas and higher S/N ratios than APCI and APPI in FIA and in on-column analysis. ESI was proved to be the most suitable ionization method as it enabled the detection of the five target compounds, whereas APCI and APPI ionized only four compounds.     

Electrospray Ionization Mass Spectrometry: A Powerful Platform for Noble‐Metal Nanocluster Analysis

Electrospray ionization mass spectrometry (ESI‐MS) is an analytical technique that measures the mass of a sample through “soft” ionization. Recent years have witnessed a rapid growth of its application in noble‐metal nanocluster (NC) analysis. ESI‐MS is able to provide the mass of a noble‐metal NC analyte for the analysis of their composition (n, m, q values in a general formula [M_nL_m]^q), which is crucial in understanding their properties. This review attempts to present various developed techniques for the determination of the composition of noble metal NCs by ESI‐MS. Additionally, advanced applications that use ESI‐MS to further understand the reaction mechanism, complexation behavior, and structure of noble metal NCs are introduced. From the comprehensive applications of ESI‐MS on noble‐metal NCs, more possibilities in nanochemistry can be opened up by this powerful technique.     

Exploring the chemical profile of designer drugs by ESI(+) and PSI(+) mass spectrometry—An approach on the fragmentation mechanisms and chemometric analysis

The consumption of design drugs, frequently known as new psychoactive substances (NPS), has increased considerably worldwide, becoming a severe issue for the responsible governmental agencies. These illicit substances can be defined as synthetic compounds produced in clandestine laboratories in order to act as analogs of schedule drugs mimetizing its chemical structure and improving its pharmacological effects while hampering the control and making regulation more complicated. In this way, the development of new methodologies for chemical analysis of NPS drugs is indispensable to determine a novel class of drugs arising from the underground market. Therefore, this work shows the use of high‐resolution mass spectrometry Fourier transform ion cyclotron resonance mass spectrometry (FT‐ICR MS) applying different ionization sources such as paper spray ionization (PSI) and electrospray ionization (ESI) in the evaluation of miscellaneous of seized drugs samples as blotter paper (n = 79) and tablet (n = 100). Also, an elucidative analysis was performed by ESI(+)MS/MS experiments, and fragmentation mechanisms were proposed to confirm the chemical structure of compounds identified. Besides, the results of ESI(+) and PSI(+)‐FT‐ICR MS were compared with those of GC–MS, revealing that ESI(+)MS showed greater detection efficiency among the methodologies employed in this study. Moreover, this study stands out as a guide for the chemical analysis of NPS drugs, highlighting the differences between the techniques of ESI(+)‐FT‐ICR MS, PSI(+)‐FT‐ICR MS, and GC–MS.     

Chiral and isomeric analysis by electrospray ionization and sonic spray ionization using the fixed-ligand kinetic method

The fixed-ligand version of the kinetic method has been used for chiral and for isomeric analysis by studying the dissociation kinetics of transition metal-bound trimeric cluster ions ([(M(II) + L(fixed)-H)(ref*)(An)](+), where M(II) is a transition metal, L fixed is a fixed (non-dissociating) ligand, ref* is a reference ligand and An is the analyte. The trimeric cluster ions are readily generated by electrospray ionization (ESI) or sonic spray ionization (SSI). The size of the fixed ligand, L- Phe-Gly-L-P he-Gly, is chosen based on previous results but with the inclusion of aromatic functionality to increase chiral recognition. Improved chiral/isomeric differentiation results from enhanced chiral/isomeric interactions (metal-ligand and ligand-ligand) due to the fixed ligand. As shown in the cases of chiral dipeptides (D-Ala-D-Ala/L-Ala-L-Ala), sugars (D/L-glucose, D/L-mannose) and isomeric tetrapeptides (L-Ala-Gly-Gly-Gly/Gly-Gly -Gly-L-Ala), improved chiral/isomeric discrimination by factors from three to six were obtained by the fixed ligand procedure. Chiral recognition is independent of the concentrations of the analyte, the reference ligand, the fixed ligand and the transition metal salt, a great advantage for practical applications. In addition to increased chiral distinction, the simplified dissociation kinetics also contribute to improved accuracy in chiral quantification, in comparison with data obtained by investigating the dissociation kinetics of simple trimeric cluster ions [M(II)(ref*)2(An) H](+). Accurate determination of enantiomeric excess (ee) is demonstrated by enantiomeric quantification of D-Ala-D-Ala/L-Ala-L-Ala down to 2% ee. Both ESI and SSI allow chiral quantification with similar accuracies. The performance of chiral analysis experiments is not limited to ion trapping devices such as quadrupole ion trap mass spectrometers by a hybrid quadrupole-time of flight (Q-ToF) mass spectrometer is shown to provide an alternative choice. The fixed-ligand kinetic method is not restricted to any particular kinds of isomers and, hence, represents a general procedure for improving molecular recognition and chiral analysis in the gas phase.     

Matrix effect in bio-analysis of illicit drugs with LC-MS/MS: Influence of ionization type, sample preparation, and biofluid

The purpose of the present work was to evaluate the synergistic effect of ionization type, sample preparation technique, and bio-fluid on the presence of matrix effect in quantitative liquid chromatography (LC)-MS/MS analysis of illicit drugs by post-column infusion experiments with morphine (10-microg/mL solution). Three bio-fluids (urine, oral fluid, and plasma) were pretreated with four sample preparation procedures [direct injection, dilution, protein precipitation, solid-phase extraction (SPE)] and analyzed by both LC-electrospray ionization (ESI)-MS/MS and LC-atmospheric pressure chemical ionization (APCI)-MS/MS. Our results indicated that both ionization types showed matrix effect, but ESI was more susceptible than APCI. Sample preparation could reduce (clean up) or magnify (pre-concentrate) matrix effect. Residual matrix components were specific to each bio-fluid and interfered at different time points in the chromatogram. We evaluated matrix effect in an early stage of method development and combined optimal ionization type and sample preparation technique for each bio-fluid. Simple dilution of urine was sufficient to allow for the analysis of the analytes of interest by LC-APCI-MS/MS. Acetonitrile protein precipitation provided both sample clean up and concentration for oral fluid analysis, while SPE was necessary for extensive clean up of plasma prior to LC-APCI-MS/MS.     

Targeted lipidomics using electron capture atmospheric pressure chemical ionization mass spectrometry

There is an increasing need to be able to conduct quantitative lipidomics analyses as a complement to proteomics studies. The highest specificity for proteomics analysis can be obtained using methodology based on electrospray ionization (ESI) or atmospheric pressure chemical ionization (APCI) coupled with liquid chromatography/tandem mass spectrometry (LC/MS/MS). For lipidomics analysis it is often necessary to be able to separate enantiomers and regioisomers. This can be very challenging when using methodology based on conventional reversed-phase chromatography. Normal-phase chromatography using chiral columns can provide dramatic improvements in the resolution of enantiomers and regioisomers. However, conventional ESI- and APCI-MS/MS has limited sensitivity, which makes it difficult to conduct studies in cell culture systems where only trace amounts of non-esterified bioactive lipids are present. The use of electron capture APCI-MS/MS overcomes this problem. Enantiomers and regioisomers of diverse bioactive lipids can be quantified using stable isotope dilution methodology coupled with normal-phase chiral chromatography and electron capture APCI-MS/MS. This methodology has allowed a lipidomics profile from rat epithelial cells maintained in culture to be delineated and allowed the effect of a non-selective lipoxygenase inhibitor to be assessed.