混合酸消解变化对土壤和沉积物中痕量硒分析影响

基于各3种采集环境样本、国家标准物质的土壤和沉积物,以当前环境监测行业常用的3种消解方法,探讨20种混合酸系统条件在消解条件变化中对复杂样本硒元素测定的影响。确定了最佳土壤和沉积物消解的组合为王水系统(盐酸∶硝酸∶氢氟酸∶过氧化氢∶高氯酸=3∶1∶1∶1∶1),各消解法的处理结果部分(n=5)∶水浴法消解时间仅需0.5h,总处理时间2h,准确度回收率达101%~104%,精密度RSD为1.95%~2.20%;电热板法总处理时间较长(7.5h),回收率106%,RSD偏高为8.46%,不推荐使用;微波法处理的总时间亦长达7.0h,回收率93.8%,但精密度亦偏高为8.24%,因此采用水浴法应用于环境样本的测定。该优化消解方法已直接应用于环境中农业、建筑用土和管道淤泥沉积物的3种样品类型前处理,利用同一优化条件即可快速对应土壤和沉积物性质样品,单次可批量处理72~84个样本,解决高通量样品痕量硒测定需求,提供环境污染监测和检测行业一参考依据。

Effect of Mixed Acid Digestion on Trace Selenium Analysis in Soil and Sediment

Based on the three kinds of soil and sediment samples collected in the environmental,and the national standard materials,the influence of 20 kinds of mixed acid system conditions on the determination of selenium in complex samples under the changes of digestion conditions was discussed through three kinds of digestion methods commonly used in current environmental monitoring industry.The optimal combination of soil and sediment digestion was determined as Aqua regia system: hydrochloric acid: nitric acid: hydrofluoric acid: hydrogen peroxide: perchloric acid = 3∶ 1∶ 1∶ 1∶ 1,and the results of each digestion methods were as follows(n = 5) : the digestion time of water bath was only 0.5 h,the total processing time was 2 h,the accuracy recovery was 101%~104% and the precision RSD was 1.95%~2.20%.The total processing time of electric hot plate digestion was longer(7.5 h),the recovery was 106% and the RSD was higher(8.46%),which was not recommended.The total processing time of microwave digestion was 7.0 h,the recovery was 93.8%,but the precision was also relatively higher(8.24%),so the water bath digestion was used in the determination of environmental samples.The optimized digestion method has been directly applied to the pretreatment of three types of samples which are agricultural,construction soil and pipeline sludge sediment samples in the environment.By using the same optimized conditions, the soil and sediment samples can be quickly corresponding.72~84 samples can be processed in batches at one time,which can meet the demand of high-throughput sample trace selenium determination and provide a reference for environmental pollution monitoring and detection industry.