Svete P, Milacic R, Mitrovic B, Pihlar B
Department of Environmental Sciences, Jozef Stefan Institute, Jamova, Ljubljana, Slovenia.
Analyst. 2001 Aug;126(8):1346-54. doi: 10.1039/b101867l.
Analytical procedures were developed for the speciation of Zn using fast protein liquid chromatography (FPLC), flame atomic absorption spectrometry (FAAS) and convective interaction media (CIM) fast monolithic chromatography with FAAS and electrospray (ES)-MS-MS detection. The investigation was performed on synthetic solutions (2 microg cm-3 Zn) of hydrated Zn2+ species and Zn complexes with citrate, oxalate and EDTA (ligand-to-Zn molar ratio 100:1) over a pH range from 5.4 to 7.4. It was found that Zn interacts with various buffers and the careful adjustment of the pH with diluted solutions of KOH is, therefore, required. FPLC separations were carried out on a Mono Q HR 5/5 strong anion-exchange column, applying an aqueous 1 mol dm(-3) NH4NO3 linear gradient elution over 15 min, at a flow rate of 1.0 cm3 min(-1). The separated Zn species were determined in 1.0 cm3 eluate fractions "off line" by FAAS. Speciation of Zn was also performed on a weak anion-exchange CIM DEAE fast monolithic disc by applying an aqueous 0.4 mol dm(-3) NH4NO3 linear gradient elution over 7.5 min, at a flow rate of 2.0 cm3 min(-1) and determination of the separated Zn species in 1.0 cm3 eluate fractions "off line" by FAAS. Zn-binding ligands in separated fractions were also characterized by electrospray (ES)-MS-MS analysis. The CIM DEAE disc was found to be more efficient in the separation of negatively charged Zn complexes than the Mono Q FPLC column. On the CIM DEAE disc Zn-citrate was separated from both Zn-oxalate and from Zn-EDTA. All these species were also separated from hydrated Zn2+, which was eluted with the solvent front. This method has an advantage over commonly used analytical techniques for the speciation of Zn which are only able to distinguish between labile and strong Zn complexes. Good repeatability of the measurements (RSD 2-4%), tested for six parallel determinations (2 microg cm(-3) Zn) of Zn-EDTA, Zn-citrate and Zn-oxalate was found at a pH of 6.4 on a CIM DAEA disc. The limit of detection (3s) for the separated Zn species was 10 ng cm(-3). The proposed analytical procedure was applied to the speciation of Zn in aqueous soil extracts and industrial waste water from a lead and zinc mining area.
开发了用于锌形态分析的分析方法，该方法采用快速蛋白质液相色谱（FPLC）、火焰原子吸收光谱法（FAAS）以及配有FAAS和电喷雾（ES）-MS-MS检测的对流相互作用介质（CIM）快速整体柱色谱法。对水合Zn2+物种以及与柠檬酸盐、草酸盐和乙二胺四乙酸（EDTA）形成的锌配合物（配体与锌的摩尔比为100:1）的合成溶液（2μg cm-3锌）在pH值为5.4至7.4的范围内进行了研究。发现锌与各种缓冲剂相互作用，因此需要用氢氧化钾稀释溶液仔细调节pH值。FPLC分离在Mono Q HR 5/5强阴离子交换柱上进行，采用1 mol dm(-3)硝酸铵水溶液线性梯度洗脱15分钟，流速为1.0 cm3 min(-1)。分离出的锌物种通过FAAS在1.0 cm3洗脱液馏分中“离线”测定。锌的形态分析也在弱阴离子交换CIM DEAE快速整体柱盘上进行，采用0.4 mol dm(-3)硝酸铵水溶液线性梯度洗脱7.5分钟，流速为2.0 cm3 min(-1)，并通过FAAS在1.0 cm3洗脱液馏分中“离线”测定分离出的锌物种。分离馏分中的锌结合配体也通过电喷雾（ES）-MS-MS分析进行了表征。发现CIM DEAE柱盘在分离带负电荷的锌配合物方面比Mono Q FPLC柱更有效。在CIM DEAE柱盘上，柠檬酸锌与草酸锌和乙二胺四乙酸锌都被分离。所有这些物种也与水合Zn2+分离，水合Zn2+随溶剂前沿洗脱。该方法相对于常用的锌形态分析技术具有优势，后者只能区分不稳定和稳定的锌配合物。在CIM DAEA柱盘上，在pH值为6.4时，对锌-乙二胺四乙酸、锌-柠檬酸盐和锌-草酸盐进行六次平行测定（2μg cm-3锌），测量的重复性良好（相对标准偏差为2-4%）。分离出的锌物种的检测限（3s）为10 ng cm(-3)。所提出的分析方法应用于水相土壤提取物和铅锌矿区工业废水中锌的形态分析。
