微波消解-原子荧光法测定土壤总砷的方法探究

Study on the Method of Determining Total Arsenic in Soil Using Microwave Digestion Atomic Fluorescence Spectrometry

采用微波消解-原子荧光法测定土壤中砷的含量,通过调整还原剂硼氢化钾-氢氧化钾的浓度及预还原剂硫脲-抗坏血酸浓度,确定在硼氢化钾质量分数2.0%、氢氧化钾质量分数0.4%,硫脲-抗坏血酸加入量为1.5m L条件下时,既能节约试剂,又可以满足试验要求:方法检出限为0.006 1 mg/kg,土壤标准样品GSS2、GSS3相对误差及相对标准偏差分别为-4.4%、-3.9%及3.1%、3.8%,其测定值也均满足不确定度要求。消解后的样品待测液在存放14 d的情况下,其测定值、精密度、准确度及加标回收率均不受影响。

The content of arsenic in soil was determined by microwave digestion atomic fluorescence method.By adjusting the concentration of reducing agent potassium hydride potassium hydroxide and the concentration of pre-reducing agent thiourea ascorbic acid,it was determined that when the mass fraction of potassium hydride was 2.0%,the mass fraction of potassium hydroxide was 0.4%,and the addition amount of thiourea ascorbic acid was 1.5mL,the reagent could be saved and the test requirements could be met:the detection limit of the method was 0.0061 mg/kg.The relative error and standard deviation of soil standard samples GSS2 and GSS3 are-4.4%,-3.9%,and 3.1%,3.8%,respectively,and their measured values also meet the uncertainty requirements.The measured value,precision,accuracy,and spiked recovery rate of the digested sample solution were not affected after being stored for 14 days.