Chan Kwok Chu, Yip Yiu Chung, Chu Hei Shing, Sham Wing Cheong
The Government Laboratory of the Hong Kong Special Administrative Region, 7/F, Homantin Government Offices, 88 Chung Hau St, Homantin, Kowloon, Hong Kong.
J AOAC Int. 2006 Mar-Apr;89(2):469-79.
A method was developed for high-throughput determinations of 7 elements in food samples, namely antimony (Sb), arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), mercury (Hg), and tin (Sn). The samples were digested by closed-vessel microwave-assisted digestion using concentrated nitric acid (HNO3) as the medium, followed by microwave- assisted evaporation to concentrate the sample solutions before dilution to the desired volume. The microwave-assisted evaporation procedure effectively reduced the final acid concentration to around 8% before analysis by inductively coupled plasma-mass spectrometry (ICP-MS). This reduction allows determination by ICP-MS to proceed without further sample dilution, which would affect the detection limit. The method was validated, and method recoveries for As, Cd, Cr, Pb, and Hg were within the certified ranges of the chosen certified reference materials. Recoveries of the 7 elements from spiked samples ranged from 93.1 to 103.6%. The standard uncertainties of precision for the 7 elements were between 3.1 and 4.3%. Interlaboratory comparison studies for As, Cd, and Pb gave z-scores ranging from -0.2 to 0.3.
开发了一种用于高通量测定食品样品中7种元素的方法，这7种元素分别是锑（Sb）、砷（As）、镉（Cd）、铬（Cr）、铅（Pb）、汞（Hg）和锡（Sn）。样品采用密闭容器微波辅助消解，以浓硝酸（HNO₃）为介质进行消解，然后进行微波辅助蒸发以浓缩样品溶液，再稀释至所需体积。微波辅助蒸发程序在通过电感耦合等离子体质谱法（ICP-MS）分析前有效地将最终酸浓度降低至约8%。这种降低使得通过ICP-MS进行测定时无需进一步稀释样品，否则会影响检测限。该方法经过验证，砷、镉、铬、铅和汞的方法回收率在所选有证标准物质的认证范围内。加标样品中7种元素的回收率在93.1%至103.6%之间。7种元素精密度的标准不确定度在3.1%至4.3%之间。砷、镉和铅的实验室间比对研究给出的z分数在-0.2至0.3之间。
