毛细管电泳-电感耦合等离子体质谱联用技术及其元素形态分析的新进展

元素的形态与它的毒性和生物活性密切相关。近年来,毛细管电泳与电感耦合等离子体质谱联用(CE-ICP-MS)技术成为元素形态分析的有力手段,得到了迅速发展。本工作阐述了CE-ICP-MS联用的各种接口方式,并讨论了几种接口及雾化器装置的优点和不足;综述了近几年采用CE-ICP-MS联用技术对痕量元素形态分析的新进展,对CE-ICP-MS联用技术在元素形态分析上的潜力、限制及发展趋势作了讨论。     

ICP-MS相关联用技术在食品元素形态分析中的应用及进展

电感耦合等离子体质谱（ICP-MS）技术凭借其低检出限、多元素同时分析等优点,广泛应用于食品中的元素分析。随着分析技术的发展,以及元素的不同形态在物理、化学、营养、毒理等方面的显著差异,元素形态分析已经引起分析工作者的广泛关注。本工作对近年来ICP-MS技术与各种分离手段联用,在食品中砷、硒及锡等元素形态分析中的应用进行了综述,指出了ICP-MS 相关联用技术应用于食品元素形态分析时存在的问题,并对其未来的发展趋势进行了展望。     

总砷超标食用菌样品中砷形态分布研究

目的:研究总砷超标食用菌样品中砷的形态分布,对食用菌中总砷含量与食用安全性的关系及其限量规定进行探讨。方法:从2010年深圳口岸进出口食用菌批量监测的各种食用菌样品中选择总砷超标的几类样品,采用液相色谱-氢化物发生-原子荧光光谱联用技术(LC-HGAFS)分析了不同种类食用菌样品中的砷形态,准确测定了总无机砷与总砷含量。结果:形态分析方法能够准确定性定量食用菌中的总无机砷含量,而食用菌中总砷含量和总无机砷含量并不存在对应关系。干香菇中总砷和总无机砷含量均较高,食用安全风险较高;而蘑菇中总砷含量高,但总无机砷含量却很低,主要以一甲基砷等无毒砷形态存在,可以放心食用。结论:食用菌中砷形态分布测定能更科学地体现砷超标和食用安全性的关系。我国现行食用菌卫生标准仅规定了总砷限量指标,建议对该标准进行修订。     

DevelopmentofPhotocatalyst-BasedICP-MSCouplingTechniquesforDeterminationofTraceElementsandTheirSpecies

It is well known that the speciation, or chemical form, of metals governs its fate, toxicity, mobility, and bioavailability in environmental and biological systems. To assess these chemical properties and to accurately gauge their impact on human health and the environment, metals need to be characterized at the atomic level. To attain new information about environmental and biological effects of trace elements, new methodologies or modify conventional analytical methods is deemed as vital factor for the progress of bio- and environmental- studies. In view of the limitation on the analytical capability of single instrumental technique, analytical chemists can seldom rely on a single instrumental technique to analyze a sample with complicated matrix and analyte species with a variety of physico-chemical form. It is thus necessary to develop a technique which can fulfill ultratrace analyses of metal species down to the sub-g/L concentration range in complicated samples. Accordingly, the most important features of an analytical tool suitable for meeting the requirement of modern bio-analytical works are shorter temporal resolution, good selectivity and high sensitivity. For ultratrace elements measurements, ICP coupled with Mass Spectrometry (ICP-MS) has been considered as first priority option. Although the analytical sensitivity has been significantly improved by the technical advances in ICP-MS, instrumental limitations, such as difficulties in differentiating elemental species and removing matrix interferences caused by the concomitant salt, still remain in advanced analytical technologies. To satisfy the analytical requirements, the potency of hyphenating analytical separation techniques to mass spectrometers has been recognized. Basically, according to Hirschfeld1, the advantages brought about by coupling techniques are increasing the differentiating and separating power of analytical methods and synergism between methods. However, the design of the analytical system is difficult, owing to the complex composition of the real-world sample, the diversity of physicochemical forms of the element, their lability and low concentrations. For overcoming the abovementioned problems, attempts to couple ICP-MS with various types of chromatography for separation, as well as on-line sample pretreatment techniques for signal enhancement and matrix removal have been made. To expand the analytical capability, in this study, we developed several hyphenated systems by integrating the alternative photo-redox characteristic of nano-TiO₂ into the interfacing device to convert both inorganic and organic metal-containing species to gaseous products that are favor for ICP-MS determination. Based on our experimental results, this presentation will describe the studied hyphenated methods which have been proven feasible for the analyses of trace elements and their chemical species in environmental and biological systems.     

High irradiance laser ionization orthogonal time-of-flight mass spectrometry: a versatile tool for solid analysis

This article reviews the development of and applications for high irradiance laser ionization orthogonal time-of-flight mass spectrometry (LI-O-TOFMS). LI-O-TOFMS has solved the bottleneck problems in traditional high irradiance laser ionization mass spectrometry, which allows the instrument to acquire explicit spectra with high resolution. A buffer-gas-assisted ion source effectively reduces the kinetic energy of the ions and suppresses the multiply charged ion interference. The pulse train data acquisition technique was applied to reduce the spectrum interference from multiply charged ions and polyatomic ions according to the temporal profiles of different ion packets in the repelling region. Relatively high laser irradiance (≥10(10) W/cm(2)) is preferable for achieving uniform relative sensitivities for different elements in the samples of different matrices. LI-O-TOFMS has been used in the standardless, semiquantitative analysis of solids, which is proved to be a fast and convenient technique for solid sample analysis. By increasing the laser irradiance and reducing the buffer gas pressure, the determination of nonmetallic elements in solids can also be achieved without losing spectral explicity. Recent applications, such as elemental analysis of a single egg cell and acquiring elemental, fragmental, and molecular information of chemicals, were given to demonstrate the potential of the new technique. All of these results reveal that LI-O-TOFMS is an advanced tool in the elemental analysis of solids in terms of modern mass spectrometry.     

离子色谱氢化物发生原子荧光法测定地下水中砷形态

采用离子色谱氢化物发生原子荧光联用法(IC-HGAFS)测定四种砷形态,并优化了各种实验参数。整套分析系统的最小检出量为As(III)0.020ng,MMA 0.045ng,DMA0.043ng,As(V)0.166ng,相对标准偏差(n=6)小于3%,在10~200 ng/mL的浓度范围内线性关系均大于0.999。用此方法测量地下水的4种砷形态加和的总量与用HG-AFS测得的总砷值相一致,表明本方法切实可行。本系统结构简单、稳定性好,非常适合用于检测砷形态。     

SRTXRF Analysis in Different Pharmaceutical Forms of Diclofenac Sodium

Abstract

The quality of medicine depends upon the production processes and on chemical, physical, and physical‐chemical properties of the drug (i.e., the active ingredient) and pharmaceutical excipients used in the formulation. The presence of impurities can inhibit the process of dissolution of medicine and the formulation components, among them metals, can be associated with the clinical effectiveness and bioavailability. The purpose of this work was to verify the presence of trace metals in different batches and pharmaceutical forms of diclofenac sodium using synchrotron radiation total reflection X‐ray fluorescence analysis (SRTXRF). Different batches of medicines from six laboratories were analyzed. The results indicated variation in individual masses of the commercial medicine and in the nature and concentrations of the trace elements detected. Elements measured include Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, and Sr. The SRTXRF shows high sensitivity for the elements considered; it is, therefore, ideal for elemental characterization in solid pharmaceutical products.     

EnhancingElementalCompositionDeterminationbyEmpiricalRules

A new approach to enhancing the performance of elemental composition determination of true unknowns beyond high mass and spectral accuracy was evaluated. Three chemical empirical rules on upper limits and ratios of elements were tested for their effectiveness in filtering out false positive formulas with low resolution mass spectrometry data. The rule on elements’ upper limits was the most effective one in eliminating false positives.     

高功率激光电离飞行时间质谱技术

对于传统的高功率激光质谱存在的关键问题,如离子动能分散、多价离子和多原子离子干扰、基体效应和分馏效应等,高功率激光电离飞行时间质谱(LI-TOF MS)通过仪器结构设计及实验条件的优化等可以很好地解决。目前,LI-TOF MS的应用包括地质和金属样品中元素的定性和无标样半定量分析、非金属元素的测定、元素表面成像分析和薄层的深度剖析、液体残渣分析、复杂生物材料中元素组成的确定,甚至对于有机金属化合物也可以同时获得分子、碎片和元素信息。本工作综述了LI-TOF MS技术的发展历程,分析了其在不同领域中的优势,并对其应用领域拓展的新方向和仪器的改进目标进行了展望。     

蔬菜中砷形态的液相色谱-原子荧光联用分析

本文研究高压液相色谱-氢化物发生原子荧光(HPLC-HGAFS)测定蔬菜中砷形态前处理的方法。研究提取溶剂、水浴温度、水浴时间等因素的影响,采用正交优化,明确砷形态化合物(As~Ⅲ,DMA)分离分析的条件。研究HPLC-HGAFS联用技术来测定蔬菜样品中不同形态的砷的分析方法。该法具有操作简便、灵敏度高、准确度高、基体干扰少、节省试剂等特点,可以对蔬菜样品中砷形态进行定量分析。     

傅立叶变换离子回旋共振质谱仪在石油组成分析中的应用

傅立叶变换离子回旋共振质谱仪(FT-ICR MS)是一种具有超高质量分辨能力的质谱仪,在石油组分相对分子质量范围(200～1 000 u)内,其分辨率能够达到几十万甚至上百万,这种分辨能力可以精确地确定由C、H、S、N、O以及它们主要同位素所组成的各种元素组合,真正从分子元素组成层次上研究石油组成。电喷雾(ESI)电离源可以从高浓度复杂烃类基质中选择性地电离石油组分中微量的杂原子极性化合物,ESI与FT-ICR MS相结合已经成为重质油非烃化合物分析的一种重要手段。本文介绍了FT-ICR MS的基本原理及近年来的发展趋势,石油组分的电离化方法及数据处理技术,综述了近期利用FT-ICR MS对石油组成取得的新认识,以及该仪器手段在石油有机地球化学、油田化学、炼油化工等领域的应用情况。尽管在重质油组成定量分析方面还存在一些技术问题,FT-ICR MS无疑将成为石油化学研究和石油工业生产过程的重要检测工具。     

电感耦合等离子体质谱测定硫的方法研究及应用进展

硫是矿石、化石燃料、蛋白质等的重要组成元素,与人类生活密切相关。近年来,随着质谱技术的发展,电感耦合等离子体质谱(ICP-MS)已成为硫测量和研究的重要手段,并在环境监测、食品安全、生命科学、环境地球化学等研究中显示出良好的应用前景。本工作综述了ICP-MS用于硫元素总量、多种形态、硫同位素测量技术方面的最新研究进展。     

Ⅱ型糖尿病患者与健康男性血清中19种微量元素含量对比

微量元素代谢在糖尿病患者中可能发生了改变,这些元素在糖尿病发病机制和发展中起特定的作用。本工作研究了年龄区间50~60岁男性Ⅱ型糖尿病患者（95例）与健康人对照组（91例）的血清微量元素含量的差异。采用微波消解法对血清中19种微量元素进行前处理,稀释25倍,选择电感耦合等离子体质谱法（ICP-MS）进行检测。该方法的检测限、精密度和重复性良好,符合血清微量元素的检测要求。相比于对照组,糖尿病患者血清中锰、钴、铜、钡和铅元素的含量相对较高,钒、锌、砷、锑和钨元素的含量相对较低,而铬、铁、镍、硒、钼、镉、锡、汞和铊元素的含量在糖尿病患者和健康对照组中无显著统计学差异。结果表明,与糖尿病密切相关的10种微量元素在年龄区间50~60岁男性糖尿病患者与健康人之间存在显著统计学差异。该结论可为进一步研究与微量元素缺乏或者过量相关的糖尿病发病机制和发展过程提供数据支持。     

激光溅射电离飞行时间质谱用于矿样分析的研究及技术比较

将自行研制的激光溅射电离飞行时间质谱仪（LAI-TOFMS）用于辉绿岩（GBW07123）、石榴石和硅化木3种矿物样品的直接分析,初步讨论了元素含量和元素相对含量的计算方法,计算过程中选Mn作参考元素,并将LAI-TOFMS与电感耦合等离子体质谱（ICP-MS）、X射线荧光光谱（XRF）在样品分析过程和分析结果方面进行比较。LAI-TOFMS中,元素含量是通过相对灵敏系数（RSC）和Mn的含量计算得到,元素的相对含量与元素的相对原子质量及其质谱峰的强度有关;对于ICP-MS和XRF,元素的相对含量是待测元素和Mn含量的比值。初步研究表明：LAI-TOFMS, ICP-MS和XRF 3种分析方法测得的元素含量和元素相对含量结果相对符合较好。此外,由于具有样品前处理简单、几乎不污染样品、样品消耗量少等优点,LAI-TOFMS能够提高矿物样品的分析检测效率。     

微波消解-ICP-MS法同时测定营养素补充剂中20种元素

建立了微波消解-电感耦合等离子体质谱(ICP-MS)法测定营养素补充剂中铜、铁、锌、锰、钙、镁、钾、磷、锶、钼、镍、钒、硒、锡、铬、铅、镉、砷、汞和锑共20种营养及有害元素的分析方法。通过对微波消解条件、质谱条件的优化、内标物的选择,克服高盐复杂基体对痕量元素测定的干扰,选择高浓度元素的低丰度质量数扩大线性范围。结果表明,铜、锌、铁、锰、钙、镁、钾、磷在0~50mg/L、汞在0~10μg/L、其他元素在0~50μg/L线性良好,相关系数在0.9992~1.0000之间,方法检出限为0.021μg/kg~21μg/kg,方法精密度为0.8%~5.7%。用该方法测定国家标准物质奶粉GBW(E)10017和芹菜GBW10048,测定结果与标准值无显著差异。方法简便、快速,可实现多种样品中含量在1%以下的主、微量元素同时测定。     

Interstellar dust laser explorer: a new instrument for elemental and isotopic analysis and imaging of interstellar and interplanetary dust

We present the performance characteristics of a time-of-flight secondary ion mass spectrometer designed for 157 nm laser postionization of sputtered neutrals for high sensitivity elemental and isotopic analyses. The instrument was built with the aim of analyzing rare element abundances in micron to submicron samples such as interstellar grains and cometary dust. Relative sensitivity factors have been determined for secondary ion mass spectrometry which show an exponential dependency against the first ionization potential. This allows elemental abundances to be measured with errors below 25% for most major elements. The accuracy for isotope ratios, where isotopes can be resolved from isobaric interferences, is usually limited only by counting statistics. In laser secondary neutral mass spectrometry, the spatial and temporal overlaps between the laser and sputtered neutral atoms are modeled and predictions of total detection efficiency and isotopic and elemental fractionation are compared with experimental data. Relative sensitivity factors for laser-ionized secondary neutrals from a stainless steel standard are found to vary less than 3% above saturation laser pulse energy enabling more accurate quantification.     

电感耦合等离子体质谱法在临床样品分析中的应用

本文对近年来电感耦合等离子体质谱法（ICP-MS）在临床样品微量元素及形态分析中的应用进行了综述，讨论了应用ICP-MS技术测定临床样品微量元素的三种处理和分析方法（直接稀释法，湿法消解法和微波消解法），列举了部分含量测定的实例。介绍了联用技术高效液相色谱（HPLC）、气相色谱（GC）、超临界流体色谱（SFC）和毛细管电泳（CE）在形态分析中的应用，指出了现存的问题，探讨了可能的解决方案。     

Proteome analysis in the study of the bacterial heat-shock response

In recent years, it has become clear that, in addition to the regulation of the expression of specific genes, there are global regulatory systems that control the simultaneous expression of a large number of genes in response to a variety of environmental stresses. The first of these global control systems, and of substantial importance, is the heat-shock response. The heat-shock response is characterized by the induction of a large set of proteins (heat-shock proteins-HSPs) upon shifts to higher temperature and upon exposure to conditions in which proteins are denatured (i.e., alcohols, heavy metals). The heat-shock response is universal and many of the heat-shock proteins are highly conserved among species. In bacteria, the heat-shock response has been studied extensively in several Gram-positive bacteria (Bacillus subtilis) and in the Gram-negative bacteria (i.e., Escherichia coli, Agrobacterium tumefaciens). The first recognition of the molecular abundance of the bacterial heat-shock proteins took place with the introduction of high-resolution two-dimensional polyacrylamide gels (2D gels) to analyze complex mixtures of cellular proteins. Two-dimensional gels, followed by mass spectrometry, were used to define the heat-shock stimulons in several bacteria, and to study the regulatory elements that control the heat-shock response. Here, we review the heat-shock response and its regulation in bacteria. The review will emphasize the use of proteome analysis in the study of this response, and will point out those open questions that can be investigated with proteomics, including mass spectrometry techniques.     

五氧化铀的电喷雾萃取电离串联质谱法制备与表征

Negatively charged organic uranyl species (HOUO₂OH), prepared with uranyl acetate using extractive electrospray ionization multiple-stage tandem mass spectrometry, reacted with oxygen to yield a novel UO₅ anion species in the gas phase. The molecular structure of UO₅ was confirmed by using collision-induced dissociation (CID) mass spectrometry experiments. The effects of experimental parameters on the yield of UO₅ anion were experimentally evaluated. The data have shown that the electron cloud radius (r) of the polyatom anion (e.g., HOUO₂OH) was tunable within the range r_inert≤r_Reactive≤r_{decomposition} by changing the collision energy of CID. This mechanism can be further used to catalyze a certain type of chemical reactions.     

原子吸收光谱法在元素形态分析方面的应用

元素形态分析已成为AAS发展的一个热点,是分析化学的一个重要发展领域。 本文评述了近年来原子吸收光谱法在元素形态分析方面的应用进展,包括化学法分析元 素形态,氢化物发生法分析元素形态,色谱-原子吸收光谱联用分析元素形态。