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硒作为生命的必需元素已越来越为人们所重视，目前，市场上各种食品日渐增多，富硒奶粉也应运而生，建立快速、灵敏、准确的检测分析方法是产品质量的必要保证。以往痕量硒的测定大都采用荧光分析法，气相色谱法等，但这些方法均较费时，费力，且所用试剂费用较高．硒的极谱法规定虽有报道，但都用于矿石、合金及生物样品的分析，而奶粉中痕量硒的规定还未见提道。本实验采用电化学分析系统２７３Ａ型（美国ＥＧ＆ＧＰｒｉｎｃｅｔｏｎＡｐｐｌｉｅｄＲｅｓｅａｒｃｈＣｏｒｐｏｒａｔｉｏｎ，１９９２年出品）对微分脉冲催化极谱法应用于奶粉中痕量硒的测定进行了研究，实验采用正交设计选择最佳条件；检测极限０．１ｎｇ／ｍｌ，线性范围０．５～５ｎｇ／ｍｌ，回收率９５．７～９９．４％．变异系数４．６％，方法的灵敏度较其它方法有较大提高。
As an essential element of life, selenium has been paid more and more attention by people. At present, all kinds of foods on the market are increasing day by day. Se-enriched milk powder also came into being. The establishment of fast, sensitive and accurate detection and analysis methods is the necessary guarantee of product quality. Most of the previous determination of trace selenium using fluorescence analysis, gas chromatography, etc., but these methods are more time-consuming and laborious, and the reagent costs higher. Polarographic determination of selenium has been reported, but are used for the analysis of ores, alloys and biological samples, but the provisions of trace amounts of selenium in milk have not been mentioned. In this study, the differential pulse catalytic polarography was applied to the determination of trace selenium in milk powder by electrochemical analysis system type 273A (American EG & GP, Princeton Applied Research Corporation, 1992). The optimal conditions were selected by orthogonal design. The detection limit .1ng / ml, the linear range of 0.5 ~ 5ng / ml, the recovery rate of 95.7 ~ 99.4%. The coefficient of variation is 4.6%, the sensitivity of the method is greatly improved compared with other methods.