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一、方法原理GB/T7917.2-1987化妆品中砷含量测定方法有银盐法(定量法)、砷斑法(半定量法)两种。银盐法测定砷含量显色梯度明显,线性好,准确度高。化妆品经灰化或消解,在碘化钾和氯化亚锡的作用下,样液中五价砷被还原为三价砷,三价砷与新生态氢反应生成砷化氢气体。通过乙酸铅棉花去除硫化氢干扰,然后与溶于三乙醇胺一氯仿中的二乙氨基二硫代甲酸银作用,生成棕红色胶态银,比色定量。钴、镍、汞、银、铂、铬和钼可干扰砷化氢的发生,但化妆品中这些金属含量低或没有不会产生干扰。因此测定重现性好,比色效果明显。
First, the principle of method GB / T7917.2-1987 Determination of arsenic in cosmetics are silver salt method (quantitative method), arsenic stain method (semi-quantitative method) two. Determination of arsenic by silver color method obvious color gradient, good linearity, high accuracy. Ashing or digestion of cosmetics, under the action of potassium iodide and stannous chloride, pentavalent arsenic in sample solution is reduced to trivalent arsenic, and trivalent arsenic reacts with new ecological hydrogen to generate arsine gas. Through the lead acetate cotton to remove hydrogen sulfide interference, and then dissolved in triethanolamine-chloroform of silver diethyldithiocarbamate role, the formation of brown colloidal silver, colorimetric. Cobalt, nickel, mercury, silver, platinum, chromium and molybdenum can interfere with arsine formation, but these metals in cosmetics have low or no disruption. Therefore, good reproducibility of measurement, the colorimetric effect is obvious.