微波消解-HG-AFS测定大米中痕量砷

Determination of Trace Arsenic in Rice by Microwave Digestion-HG-AFS

研究了微波消解 -氢化物发生 -原子荧光光谱法测定大米中痕量砷的方法。建立了大米用微波消解的最佳分析条件 ,试验了酸、预还原剂用量等对测定砷的影响 ,并讨论了大米中其他伴生元素对测定的干扰情况 ,确定了原子荧光光谱仪的参数设置和最佳氢化反应条件。检出限为 0 .0 4 ng/m L。此法测定标准物质大米粉 (GBW0 85 0 2 )中砷的含量 ,其结果与证书值相吻合 ,相对标准偏差为 2 .5 % ,回收率为 93.9%—115 .0 %。

Trace arsenic in rice was determined by microwave digestion-HG-AFS.The experimental conditions of microwave digestion of samples and of hydride generation atomic fluorescence spectrometry for determination were optimized.The effect of the medium acid and amount of reducing agent on determination of arsenic and the interference from element formed hydride compound and coexistent elements in rice were discussed.The detection limit was 0.04ng/mL.The method was used to determine arsenic in reference materials(rice flour,GBW 08502),which shows a good agreement with standard value.The RSD was 2.5%,and the recovery of lead was 93.9%-115.0%.