超声辅助-王水提取法在测定土壤中重金属元素的应用

建立了超声辅助王水消解土壤样品的前处理方法,并结合电感耦合等离子体原子发射光谱法(ICP-AES)和电感耦合等离子体质谱法(ICP-MS)对土壤样品中铜、锌、镍、铁、锰、铅、砷、汞、铬、镉等10种元素进行测定。通过试验确定王水用量为5mL、超声水浴温度为80℃、超声提取时间为45min的超声提取条件。在优化的仪器条件下,按照实验方法测得的土壤样品中10种元素的校准曲线线性相关系数为0.9996~0.9999;各元素的检出限为0.0021~0.23mg/kg,各元素的测定下限为0.0070~0.78mg/kg。按照实验方法(超声王水提取-ICP-AES/ICP-MS)测定土壤样品中铜、锌、镍、铁、锰、铅、砷、汞、铬、镉,测定结果的相对标准偏差(RSD,n=6)为0.39%~7.8%;除铁、锰的提取值较小外,其他元素的测定结果与采用国标方法(GB 15618—1995、GB/T 22105.1—2008)得到的测定值基本一致;按照实验方法测定土壤标准物质GBW07404、GBW07406、GBW07407、GBW07427中铜、锌、镍、锰、铅、砷、汞、铬、镉,除了锰由于其在原土中主要以氧化物结合态存在,测定结果偏低以外,其他元素测定值与认定值相吻合。

Application of ultrasonic-assisted aqua regia extraction inthe determination of heavy metal elements in soil

The soil samples were pretreated by ultrasound-assisted aqua regia digestion. Then the contents of ten elements (including copper, zinc, nickel, iron, manganese, lead, arsenic, mercury, chromium and cadmium) in soil sample were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). The ultrasound-assisted extraction conditions were listed as follows: the dosage of aqua regia was 5mL, the ultrasound water bath temperature was 80℃, and the ultrasound-assisted extraction time was 45min. Under the optimized instrumental conditions, the linear correlation coefficients of calibration curves for ten elements in soil samples were between 0.9996 and 0.9999 in experiments. The detection limits of elements were between 0.0021mg/kg and 0.23mg/kg. The low limit of determination of elements varied from 0.0070mg/kg to 0.78mg/kg. The contents of copper, zinc, nickel, iron, manganese, lead, arsenic, mercury, chromium and cadmium in soil sample were determined according to the experimental method (ultrasound-assisted aqua regia extraction-ICP-AES/ICP-MS). The relative standard deviations (RSD, n=6) of determination results were between 0.39% and 7.8%. The extraction values of iron and manganese were relatively low, while the determination results of other elements were basically consistent with those obtained by national standard method (GB 15618-1995 and GB/T 22105.1-2008). The proposed method was applied for the determination of copper, zinc, nickel, manganese, lead, arsenic, mercury, chromium and cadmium in certified reference materials of soil (GBW07404, GBW07406, GBW07407 and GBW07427). Except for manganese (it mainly existed in the form of oxides in original soil, and the determination results were lower), the found results of other elements were consistent with the certified values.