高压微波消解-电感耦合等离子体质谱(ICP-MS)法测定小米样品中铜铅锌镉铬镍砷

Determination of Copper,Lead,Zinc,Cadmium,Chromium,Nickel,Arsenic in Millet by Inductively Coupled Plasma Mass Spectrometrywith High-pressure Microwave Digestion

准确测定小米中的重金属对控制和提高食品安全具有非常重要的意义。采用高压微波消解法,以HNO3-H2O2体系处理样品,选择52Cr、60Ni、63Cu、66Zn、75As、111Cd、208Pb为测量同位素,采用He气模式的碰撞反应池技术测定Cr和As,采用仪器自带干扰校正公式对Cd的测定结果进行校正,建立了电感耦合等离子体质谱(ICP-MS)法测定小米样品中Cu、Pb、Zn、Cd、Cr、Ni、As的方法。重点对溶样条件进行了优化,结果表明在优化的实验条件下,校准曲线的相关系数均不小于0.999,检出限为0.000 5~0.01μg/g,测定下限为0.002~0.4μg/g。按照实验方法对小米成分分析标准物质中Cu、Pb、Zn、Cd、Cr、Ni、As平行测定12次,各元素测定值与认定值基本一致,相对标准偏差(RSD)均在7.0%以内。采用实验方法对蔚县小米样品进行分析,结果表明,方法灵敏度高、重现性好、定量准确,可用于大批量小米样品的测定。

Accurate determination of heavy metals in millet is very important to control and improve food safety.The samples were treated by high-pressure microwave digestion in HNO 3-H 2 O 2 system.A method for the determination of heavy metals in millet samples by electrical coupled plasma mass spectrometry(ICP-MS)has been developed.52 Cr,60 Ni,63 Cu,66 Zn,75 As,111 Cd,208 Pb were selected as the measured isotopes.The isobaric interference of 111 Cd,52 Cr,75 As are corrected by the online calibration equation and collision/reaction interface mode.Under the optimized experimental conditions,the correlation coefficient of the calibration curve is higher than 0.999,with the detection limit ranges from 0.0005 to 0.01μg/g,and the low limit of determination from 0.002 to 0.4μg/g.The proposed method was applied for the 12 times parallel determination of Cu,Pb,Zn,Cd,Cr,Ni in the composition analysis standard substances of millet.The analytical results were basically consistent with the certified values,with the relative standard deviations(RSD)less than 7.0%.The millet samples of Yuxian were analyzed by experimental methods.The method has high sensitivity good reproducibility and accurate quantification,it can be used for the determination of large quantities of millet samples.