联用技术应用于元素形态分析的新进展

扼要介绍了近年来报道的有关联用技术应用于生物体中硒、砷和镉等化学形态的研究成果。最常用的形态分析技术是高效液相色谱-电感耦合等离子体质谱联用技术(HPLC-ICP-MS)。毛细管电泳-电感耦合等离子体质谱联用技术(CE-ICP-MS)也开始受到重视。由于HPLC-ICP-MS和CE-ICP-MS均不能提供化合物的分子结构信息,因此在缺少标准物的情况下电喷雾离子质谱(ESI-MS)是不可缺少的形态分析工具。ESI-MS被应用于鉴定硒酵母中的硒-腺苷-高半胱氨酸和海藻中一种新的砷糖。反向高效液相色谱(RP-HPLC)与毛细管电泳分离结合ICP-MS和ESI-MS平行检测,已用于表征金属硫蛋白(MTs)中的金属络合物。由于ESI-MS的灵敏度低,且易受试样中基体的干扰,因此分析物在分析前须经多次分离、纯化和富集以保证分析结果的可靠性。

Recent Advances in the Elemental Speciation by Hyphenated Techniques

This paper introduces briefly the original papers published on the speciation of selenium, arsenic and cadmium in bio-materials by the use of hyphenated techniques. The most frequently applied hyphenated systems for elemental speciation are the coupling of high performance liquid chromatography (HPLC) with inductively coupled plasma mass spectrometry (ICP-MS), but capillary electro-phoresis (CE) becomes more and more popular as an on line separation technique. Since HPLC-ICP-MS and CE-ICP-MS do not provide structure information of unknown compounds and their authentic standards are rarely available, electrospray mass spectrometry (ESI-MS) is an invaluable tool for the identification and a prerequisite for further characterization of a compound in speciation analysis. Recently, ESI-MS has been used to identify Se-adenosylhomecysteine in an extract of selenized yeast and a new arsenic sugar in algae. Reversed phase HPLC and CE with parallel ICP-MS and ESI-MS have been applied for the characterization of metal complexes with metallothioneins. The insufficient sensitivity and vulnerability to matrix interference of ESI-MS can be overcome by the approach involving isolation, purification and concentration of the analyte detected.