建立了采用微波消解,基体改进剂辅助石墨炉原子吸收光谱法测定蛋白质粉中镉的方法。研究了样品中磷酸二氢铵的质量浓度,灰化温度以及原子化温度对吸光度的影响。在单因素试验的基础上,通过响应曲面法优化确定了最佳测定条件为:磷酸二氢铵的质量浓度为3.51 mg/mL、灰化温度为564℃、原子化温度为1 893℃。在此条件下,测定蛋白质粉中镉的含量为0.238μg/g,精密度为2.77%,检出限为0.21 ng/mL,加标平均回收率为99.5%,相对标准偏差为2.82%。

An effective method was developed for determination of cadmium in protein powder by microwave digestion-GFAAS with matrix modifier.The effects of NH4H2PO4 mass concentration in tested sample,ashing temperature and atomizing temperature on absorption was discussed.The optimal determination conditions were found by response surface methodology as follows: NH4H2PO4 mass concentration 3.51 mg/mL;ashing temperature 564℃;and atomizing temperature 1 893℃.Under the above conditions,the content of cadmium in protein powder was 0.238 μg/g,the precision relative standard deviation was 2.77%,the detection limit was 0.21 ng/mL,and the average recovery of cadmium in protein powder was 99.5% with a relative standard deviation of 2.82%.