超声水浴-王水浸提-全自动测汞仪测定重度污染土壤中的总汞

Determination of Total Mercury in Heavily Contaminated Soils by Automatic Mercury Detector with Ultrasonic Water Bath-Aqua Regia Leaching

为准确测定重度污染土壤中的总汞含量,通过单因素实验考察王水用量、超声时间和超声温度对土壤中总汞测定的影响,得到最佳前处理方法,建立了以超声水浴辅助王水浸提,使用全自动测汞仪测定重度污染土壤中总汞含量的方法。确定了0.5 g土壤样品中加入5 mL的王水溶液,放入超声波清洗器中70℃水浴下超声提取70 min,使用超纯水定容至50 mL,直接进样测定的实验方法。结果表明,汞含量在0~20 ng线性良好,相关系数R=0.9995;汞含量在20~150 ng线性良好,相关系数R=0.9993。方法检出限为0.006 mg/kg,定量下限为0.024 mg/kg。通过对土壤样品及土壤加标样品的测定,回收率为90.4%~117%,相对标准偏差RSD为1.9%~3.3%(n=6),方法的精密度和准确度较高。超声水浴-王水浸提-全自动测汞仪用于测定重度污染土壤中的总汞,前处理简单,自动化程度较高,可快速、高效地用于重度污染土壤总汞测定工作。

In order to accurately determine the total mercury content in heavily contaminated soil,the effects of aqua regia dosage,ultrasonic time and ultrasonic temperature on the determination of total mercury in soil were investigated through one-way experiments to obtain the optimal pretreatment method,and a method was established for the determination of total mercury in heavily contaminated soil by using a fully automated mercury meter with the assistance of aqua regia leaching in an ultrasonic water bath.The experimental method was determined as follows:adding 5 mL of aqua regia solution to 0.5 g of soil sample,then placing the sample into an ultrasonic cleaner and extracting it under ultrasound for 70 min at 70℃in a water bath,subsequently,the sample was finalized to 50 mL with ultrapure water,and directly injected for determination.The results showed good linearity in the range of 0—20 ng with a correlation coefficient of R=0.9995,and good linearity in the range of 20—150 ng with a correlation coefficient of R=0.9993.The method limit of detection was 0.006 mg/kg and the lower limit of quantification was 0.024 mg/kg.The recoveries of the soil samples and soil spiked samples ranged from 90.4%to 117%with the relative standard deviations of 1.9%—3.3%(n=6),which indicated that the method has high precision and accuracy.Ultrasonic water bath-aqua regia leaching-fully automated mercury meter for the determination of total mercury in heavily contaminated soil,simple pre-treatment,high degree of automation,can be quickly and efficiently used for the determination of total mercury in heavily contaminated soil.