微波消解-氢化物发生原子荧光光谱法测定婴儿配方乳粉中硒含量

Determination of Selenium in Infant formulas by Microwave Digestion-Hydride Generation Atomic Fluorescence Spectrometry

建立微波消解-氢化物发生原子荧光光谱法测定婴儿配方乳粉中硒含量的方法。对还原剂、载流、预还原条件、铁氰化钾掩蔽效果、乳粉标准物质消解液及还原剂存放时间进行了研究。结果表明,在还原剂为1.0 g/100 mL KBH4-0.5 g/100 mL NaOH溶液,载流为8%盐酸,消解完全后的残留液中加5.0 mL 6 mol/L盐酸溶液后90℃加热至溶液体积约1 mL,不添加铁氰化钾做掩蔽剂,硒的线性回归方程为I=38.440 4C+1.362 7,线性范围为1.0~10 ng/mL,相关系数为1.000。方法检出限为0.084 ng/mL,加标回收率为90.4%~109%,相对标准偏差为2.9%(n=6)。乳粉标物消解液室温保存有效时间为3 d,还原剂避光冷藏保存有效时间至少1周。本方法与国标法相比具有简便高效、节约试剂、更有利于操作人员身体健康和环境保护等优点,可以用来快速准确检测婴儿配方乳粉中硒含量。

A method for the determination of selenium in infant formulas was developed using microwave digestionhydride generation atomic fluorescence spectrometry. Effects of reagents, pre-reducing methods, the presence or absence of potassium ferricyanide, and reserving time of the sample digestion solution of certified reference material and the reducing agent on the test results of selenium were studied. Under the appropriate reagent and pre-reducing condition, without using potassium ferricyanide as masking agent, the linear regression equation was I = 38.440 4C+1.362 7 in the linear range of 1.0–10 ng/mL(r = 1.000 0). The limit of detection(LOD) was 0.084 ng/mL, and the recovery rate of selenium from spiked samples was 90.4%–109%, with relative standard deviation(RSD) of 2.9%(n = 6). The digestion solution of the certified reference material GBW10017(GSB-8 milk powder) could be stored at room temperature for three days before determination and the reducing agent was valid within at least one week under refrigeration. The method was characterized by simple operation, high efficiency, reagent-saving, easy operation and no pollution, and was suitable for rapid and accurate determination of selenium in infant formulas.