工作场所空气中四乙基铅国家标准检测方法的前处理优化研究

Optimization of the pre-process for the national standard of detection method for tetraethyl lead in workplace air

目的 对测定工作场所空气中四乙基铅的溶剂解吸-微量酸消解石墨炉原子吸收分光光度法的前处理过程进行优化。方法 选择新的四乙基铅解吸试剂,调整消解时间,通过实验计算前处理优化后的工作场所空气中四乙基铅的检出限、加标回收率、相对标准偏差等,并与国家标准方法进行比较。结果 前处理过程中选择正己烷作为解吸剂,使用10μL浓硝酸消解60 min。前处理优化后,检出限为0.001 3μg/mL,实验平均加标回收率为98.3%,平均相对标准偏差为2.7%,符合实验室质量控制规范的相关要求。与国家标准方法比,浓硝酸用量少、实验空白低,回收率高。结论 改进后的方法操作更简便、试剂空白值低、结果重复性好、样品加标回收率高。

Objective To optimize the pretreatment process of the national standard method of solvent desorption-micro acid digestion graphite furnace atomic absorption spectrophotometry for the determination of tetraethyl lead in workplace air.Methods A new tetraethyl lead desorption reagent was used,and the digestion time was adjusted.The detection limit,recovery rate,and relative standard deviation of tetraethyl lead in workplace air after pretreatment optimization were calculated through experiments and compared with national standard methods.Results n-Hexane was selected as the desorption reagent in the pretreatment process,and 10μL concentrated nitric acid was used for digestion for 60 min.After pretreatment optimization,the detection limit was 0.0013μg/mL with an average recovery rate of 98.3%and an average relative standard deviation of 2.7%,which met the relevant requirements of laboratory quality control specifications.Compared with the national standard method,the optimized method used less concentrated nitric acid,had a lower experimental blank,and had a higher recovery rate.Conclusions The improved method was more convenient to operate,had a low reagent blank value,good result repeatability,and a high sample recovery rate.