Chen K L, Amarasiriwardena C J, Christiani D C
Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA.
Biol Trace Elem Res. 1999 Feb;67(2):109-25. doi: 10.1007/BF02784067.
The analysis of trace elements in biological samples will extend our understanding of the impact that environmental exposure to these elements has on human health. Measuring arsenic content in nails has proven useful in studies evaluating the chronic body burden of arsenic. In this study, we developed methodology with inductively coupled plasma-mass spectrometry (ICP-MS) for the determination of total arsenic in nails. We assessed the utility of the washing procedures for removing surface contamination. Four types of preanalysis treatments (water bath, sonication, water bath plus sonication, and control) after sample decomposition by nitric acid were compared to evaluate the digestion efficiencies. In addition, we studied the stability of the solution over 1 wk and the effect of acidity on the arsenic signal. Arsenic content in the digested solution was analyzed by using Ar-N2 plasma with Te as the internal standard. The results suggest that washing once with 1% Triton X-100 for 20 min for cleaning nail samples prior to ICP-MS analysis is satisfactory. Repeated measurement analysis of variance revealed that there was no significant difference among the various sample preparation techniques. Moreover, the measurements were reproducible within 1 wk, and acidity seemed to have no substantial influence on the arsenic signal. A limit of detection (on the basis of three times the standard deviation of the blank measurement) of 7 ng As/g toenail was achieved with this system, and arsenic recoveries from reference materials (human hair and nails) were in good agreement (95-106% recovery) with the certified/reference values of the standard reference materials. ICP-MS offers high accuracy and precision, as well as high-throughput capacity in the analysis of total arsenic in nail samples.
对生物样品中的微量元素进行分析，将拓展我们对于环境中这些元素暴露对人类健康影响的理解。在评估砷的慢性身体负担的研究中，测量指甲中的砷含量已被证明是有用的。在本研究中，我们开发了一种使用电感耦合等离子体质谱法（ICP-MS）测定指甲中总砷的方法。我们评估了清洗程序去除表面污染物的效用。比较了硝酸分解样品后四种类型的分析前处理（水浴、超声处理、水浴加超声处理和对照）以评估消解效率。此外，我们研究了溶液在1周内的稳定性以及酸度对砷信号的影响。使用以碲为内标的氩-氮等离子体分析消解溶液中的砷含量。结果表明，在进行ICP-MS分析之前，用1% Triton X-100清洗指甲样品一次20分钟就足够了。重复测量方差分析表明，各种样品制备技术之间没有显著差异。此外，测量在1周内具有可重复性，酸度似乎对砷信号没有实质性影响。该系统实现了7 ng As/g趾甲的检测限（基于空白测量标准偏差的三倍），并且从标准参考物质（人发和指甲）中回收的砷与标准参考物质的认证/参考值高度一致（回收率为95-106%）。ICP-MS在分析指甲样品中的总砷时具有高准确性、高精度以及高通量能力。
