超声提取-ICP-MS法测定土壤中有效态铅和镉

Measurement of Available Lead and Cadmium in Soil by ICP-MS with Ultrasonic Extraction

本实验以DTPA为提取剂,建立了超声提取-电感耦合等离子体质谱（ICP-MS）测定土壤中有效态铅和镉的方法。实验考察了超声提取时间、溶液稀释倍数、测定条件等因素,并对基体干扰的消除进行了对比研究。在优化的ICP-MS条件下,有效态铅和镉在1~200μg/L浓度范围内线性关系良好,方法检出限分别为0.019mg/kg、0.001 4mg/kg,相对标准偏差小于6%（n=6）。用国家土壤标准物质进行方法精密度和准确度验证,相对误差小于5%（n=6）,该测定结果与国家标准方法（GB/T 23739—2009）一致,经t检验表明两者无显著性差异。该方法简便快捷、检出限低,具有良好的准确度和精密度,可满足大批量农业土壤污染调查样品中有效态铅和镉的分析要求。

According to determination of available forms of lead and cadmium in soil,the contents of lead and cadmium were directly determined with DTPA as extracted by inductively coupled plasma-mass spectrometry（ICP-MS）.The effects of ultrasonic extraction time,dilution time of extraction agent and the analytical conditions were investigated,and the elimination of matrix interference was compared.The results show that the available lead and cadmium have good linearity in the concentrations of1-200μg/L,and the detection limits of the method are 0.019mg/kg and 0.001 4mg/kg,respectively,the relative standard deviation is less than 6%.The accuracy and precisionof the method were verified by analyzing national standard reference materials.There was no significant difference between this method and the national standard method（GB/T 23739-2009）by t test,the relative standard deviation is less than 5%.This method has characteristics of convenient,low detection limit,high accuracy and good precision,which can be applied to determine available forms of lead and cadmium in large batches agricultural pollution soil.