电感耦合等离子体质谱法测定谷物中重金属含量的方法研究

采用微波消解技术,建立电感耦合等离子体质谱法测定谷物中重金属As,Pb,Hg,Cd含量的方法.完善前处理条件,优化仪器工作参数,选取72Ge,115In,209Bi作为内标元素,有效克服基体效应及仪器波动影响,利用干扰校正方程技术,消除多原子离子干扰.测定元素标准曲线相关系数均在0.999 9以上,各元素检出限在0.000 6～0.016 mg·L-1之间,回收率在90％～110％之间,方法的精密度在5％以内,用国家标准物质评价了方法准确性,用标准溶液进行了共存离子干扰试验.研究表明,该方法线性范围宽、精密度好、准确性高,适用于快速测定谷物中重金属元素As,Pb,Hg,Cd.

Research of Heavy Metals Determination in Cereals by Inductively Coupled Plasma Mass Spectrometry

The present paper established the determination method of heavy metals such as As, Pb, Hg and Cd in cereals by inductively coupled plasma mass spectrometry (ICP-MS) with microwave digestion. The pretreatment conditions were improved and the instrument operating parameters were optimized. 72Ge, 115In and 209Bi were selected as the internal standard elements to overcome the matrix effects and instrument fluctuations effectively. Interference correction equations were used to eliminate the interference of polyatomic ions. Satisfactory linearity of standard curves was obtained with elemental correlation coefficients over 0.999 9. The detection limits were in the range of 0.000 6～0.016 mg·L-1, the recoveries of samples were 90%～110%, and the RSD was within 5%. The accuracy of the method was evaluated with national standard reference materials and the interference test was experimented using standard solution. Studies have shown that the method is suitable for rapid determination of heavy metals As, Pb, Hg and Cd in cereals with wide linear range, good precision and high accuracy.