环境样品中总汞测定方法的建立——吹扫-金柱捕集-(双柱)热脱附-冷原子荧光法

基于美国环境保护局(U.S.Environmental Protection Agency,USEPA)1631方法,自制双柱热脱附装置,以国产AF-610B型原子荧光仪为检测器,搭建吹扫-金柱捕集-(双柱)热脱附-冷原子荧光系统,用于测定环境样品中的总汞。对吹扫流速、吹扫时间和尾吹流速等实验参数进行了优化。双柱热脱附装置的脱附效率为99%—100%。在最优测定条件下,仪器检出限为5.0pg,海水测定的方法检出限为0.50ng/L,土壤、沉积物和红树样等固体样品测定的方法检出限为1.0ng/g。采用基底加标回收率法和参考样,验证了该系统的准确可靠性。结果表明,海水、土壤、沉积物和红树植物组织等样品的基底加标回收率均符合USEPA的限定范围,土壤参考样(ESS-4)和近海海洋沉积物参考样(GBW07314)的测定结果在参考值的可控范围内。该系统可满足环境样品中总汞测定的要求。

Determination of Total Mercury in Environmental Samples by Cold Vapor Atomic Fluorescence Spectrometry with Purge-Trap, Dual-Trap Amalgamation

Based on U. S. Environmental Protection Agency （USEPA） Method 1631,a detection system was established for the determination of total Hg in water, sediment, soil and biota samples with the devices of purge-trap, and cold vapor atomic fluorescence spectrometer （CVAFS）. The system equipped with a lab-made dual-trap thermal desorption set-up and an AF-610B CVAFS instrument. The parameters including flow rates of purging gas and tail gas, as well as the purging time, were optimized. The desorption efficiencies of the dual-trap thermal desorption were ranged from 99 % to 100 %. Under the optimized conditions,the instrumental detection limit was 5.0 pg,and the detection limits for seawater and solid sample （soil,sediment and plant sample） were 0. 50ng/L and 1.0ng/g,respectively. The recoveries of matrix pike samples were in the ranges regulated by USEPA Method 1631,and the results of soil certified reference material （CRM） （ESS-4） and sediment CRM （GBW07314） were within the 95 % confidence interval values.