超声王水浸提-电感耦合等离子体质谱(ICP-MS)法测定土壤中汞的含量

Determination of Mercury Content in Soil by Inductively Coupled Plasma Mass Spectrometry(ICP-MS)with Ultrasonic Aqua Regia Leaching

为建立了一种适合土壤中汞含量测定的方法,通过考察样品前处理中使用的王水体积、超声温度、超声时间和超声功率以及测定过程中的干扰消除等因素对测定的影响,确定了0.1 g土壤样品中加入5 mL的王水溶液,放入超声波清洗器中在功率400 W、60℃水浴下超声浸提30 min的前处理方法;电感耦合等离子体质谱仪通过^(209)Bi作为内标,仪器采用KED模式消除质谱干扰;提出了将金溶液与内标试剂共同配制,从而形成在线冲洗消除记忆效应的方法。结果表明:汞浓度在0~20μg/L内线性良好,相关系数R=0.99946;方法检出限为1.5μg/kg,方法定量下限为6μg/kg;通过测定值与认定值对比分析可知测定结果均在认证值范围内,方法准确度较高;RSD为2.1%~3.4%(n=6),方法精密度较高,满足分析要求。超声王水浸提-电感耦合等离子体质谱法测定土壤中的汞含量,前处理易操作,普适性强,准确度和精确度均满足检测要求,可适用于大批量土壤汞含量测定工作。

In order to establish a method suitable for the determination of mercury content in soil,the effects of aqua regia volume,ultrasonic temperature,ultrasonic time,ultrasonic power used in sample pretreatment and interferences elimination during the determination were investigated.The pretreatment method of adding 5 mL of aqua regia solution to 0.1 g of soil sample and placing it in an ultrasonic cleaner at a power of 400 W and a water bath of 60℃for 30 min was determined.The inductively coupled plasma mass spectrometer(ICP-MS)passed^(209)Bi as an internal standard and the instrument used KED mode to eliminate mass spectral interferences.The method of eliminating the memory effect by co-formulating the gold solution with the internal standard reagent,thus forming an in-line rinse,was proposed.The results showed that the linearity of mercury concentration was good in the range of 0 to 20μg/L with a correlation coefficient of R=0.99946.The method detection limit was 1.5μg/kg and the method quantification limit was 6μg/kg.Comparative analysis of the measured values with the certified values showed that the measured results were within the range of the certified values,indicating that the accuracy of the method was high.The RSDs ranged from 2.1%to 3.4%(n=6),indicating that the method had high precision and met the analytical requirements.The method of ultrasonic aqua regia leaching-ICP-MS for the determination of mercury in soil is easy to operate and universal,and the accuracy and precision meet the requirements of testing,which can be applied to the determination of mercury content in soil in large quantities.