全反射X射线荧光光谱法测定面霜中的铅砷汞镉

摘要

建立悬浮液制样全反射X射线荧光光谱法快速测定面霜中限用元素铅、砷、汞、镉的含量.通过合成水-四氢呋喃-甲醇-Triton X-100混合溶剂分散样品,制备均匀的悬浮液;添加共聚维酮防止汞元素在测试液烘干过程中的损失和沉积物的扩散;内标法以镓(Ga)为内标元素实现定量分析.共聚维酮能够固化测试液,使沉积物变厚,基体变复杂,造成解谱不准,谱线重叠时结果偏差较大,经过对测试液的稀释偏差得到控制.该方法对铅、砷、汞、镉的精密度(RSD,n=11)分别小于12.7%、7.4%、11.8%、13.5%,检出限分别为0.014 μg· mL-1、0.013μg·mL-1、0.015μg·mL-1、0.310μg·mL-1,测定结果与标准物质和标准方法的测定结果一致.%A method for the determination of trace elements such as lead,arsenic,mercury and cadmium in face cream by total re-flection X ray fluorescence spectrometry with suspension sampling was developed.The samples were dispersed by water-tetrahydro-furan-methanol-Triton X-100 mixed solvent and a homogeneous suspension was obtained;poly(1-vinylpyrrolidone-co-vinyl acetate) is added to the test solution to prevent the loss of the mercury element and to reduce the diffusion of the sediment on the carrier dur-ing the drying process;the internal standard element gallium(Ga)to achieve the quantitative analysis.The povidone can solidify the test solution,but thickens the sediment and the matrix becomes more complex.It will cause the resolution of the spectrum is not ac-curate,and the result will be larger when the line is overlapped.The precision of the method of lead,arsenic,mercury and cadmium (RSD,n=11)were less than 12.7%,7.4%,11.8%,13.5%,the limit of detection were 0.014 g·mL-1,0.013 g·mL-1,0.015 g ·mL-1,0.310 g·mL-1.The measurement results were consistent with the reference method.