用微波消解法测定日用化学品中砷时存在的问题及克服方法

针对现有文献方法中微波消解法测定砷时赶酸时间不确定、赶酸不完全等缺点,研究了尿素结合沸水浴加热消除微波消解液中亚硝酸根和挥发性氮氧化物的干扰,考察了微波消解液中剩余硝酸对测定的干扰情况.优化了微波消解-氢化物发生原子吸收法测定日用化学品中砷的条件.方法检出限为0.4 μg/L,定量下限为1.5 μg/L;样品加标测定的相对标准偏差为1.2％,回收率为91％～102％.

The Removal of Interference from Microwave Digestion Solution Used for the Determination of Arsenic in Daily Chemicals

In existing literature,there is no affirmatory time for evaporating excessive acid to microwave digestion solution of different samples.In this paper,a new method was developed.The interference from nitrite ion and volatile nitrogen oxides which were generated during digestion were quickly removed by adding urea and heating with boiling water.The interference from nitrate was studied.The conditions of determination of arsenic with hydride generation atomic absorption spectrometry were optimized.The detection limit was 0.4 μg/L and minimum quantitative detection limit was 1.5 μg/L,the relative standard deviation of standard addition method in sample was 1.2% and recoveries were from 98% to 102%.