Tirez Kristof, Scharf Holger, Calzolari Domenico, Cleven Rob, Kisser Monika, Lück Detlef
Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol, Belgium.
J Environ Monit. 2007 Jul;9(7):749-59. doi: 10.1039/b706724k. Epub 2007 Jun 1.
A European standard for the determination of Cr(vi) in solid material has been elaborated in the framework of an international co-operation and finally validated in the course of an interlaboratory comparison. The procedure is based on the alkaline digestion prescribed by EPA method 3060A followed by ion chromatography and determines an operationally defined content of Cr(vi), including water-soluble and insoluble chromates. A preliminary robustness study was carried out in order to compare different extraction methodologies and to study the equivalency of different analytical methods for the determination of Cr(vi) in alkaline extracts of soil and waste materials. During an interlaboratory validation trial with 19 European laboratories a set of 4 samples (2 soil and 2 waste samples) was analysed to determine performance characteristics for different combinations of digestion and detection methods. With the procedures prescribed by the new European standard (EN 15192) acceptable results were obtained for both soil samples and one of the waste samples (sludge). However, for the second waste sample (fly ash) a large deviation in analytical results was observed. This indicates that particularly for waste materials a possible occurrence of strong matrix effects has to be considered and supplementary quality control data are needed in order to assess the validity of analytical results. The accuracy of the determination of Cr(vi) in solid matrices remains a challenging field in terms of maximum extraction efficiency and minimum species interconversion.
在国际合作框架内制定了一项用于测定固体材料中六价铬的欧洲标准，并最终在实验室间比对过程中得到验证。该程序基于美国环境保护局（EPA）方法3060A规定的碱性消解，随后进行离子色谱分析，测定的是六价铬的操作定义含量，包括水溶性和不溶性铬酸盐。开展了一项初步稳健性研究，以比较不同的提取方法，并研究不同分析方法对土壤和废物材料碱性提取物中六价铬测定的等效性。在由19个欧洲实验室参与的实验室间验证试验中，分析了一组4个样品（2个土壤样品和2个废物样品），以确定不同消解和检测方法组合的性能特征。采用新欧洲标准（EN 15192）规定的程序，土壤样品和其中一个废物样品（污泥）均获得了可接受的结果。然而，对于第二个废物样品（粉煤灰），分析结果出现了较大偏差。这表明，特别是对于废物材料，必须考虑可能出现的强烈基体效应，并且需要补充质量控制数据以评估分析结果的有效性。就最大提取效率和最小物种间转化而言，固体基质中六价铬测定的准确性仍然是一个具有挑战性的领域。
