Mercury Speciation Determination in Fish and Soil Samples Based on Low Pressure LC-AFS Combined with Rapid Sample Pretreatment / 分析化学

ABSTRACT

The build-in low-pressure monolithic column combined with hydride generation atomic fluorescence spectrometry ( HG-AFS ) was employed for speciation analysis of fish meat. The sample pretreatment and separation approach could be accomplished within 30 min. The proper amount of fish sample was weighed and smashed into puree. The extraction solution composed of 10% HCl, 1% thiourea, and 0. 15% KCl was added before loaded into the automatic temperature controlled vertex system with 2000 r/min. The sample solution was separated through Merck monolithic column, with 3% ( V/V) acetonitrile, 30 mmol/L amonium acetate and 0. 03%(V/V) 2-mercaptoethanol (2-ME) as the eluent. The after-column eluent was digested by novel UV digestion device with pipeline sintered into the lamp, and then detected by hydrid-generation AFS. The rapid LC separation enabled fast mercury speciation of fish sample within 10 min. The different UV lamp digestion effects, eluent components, carrier gas, shield gas, lamp current, as well as PMT working power was optimized. Under the optimal conditions, the robust system achieved detection limits (DL) of 0. 15 μg/L and 0. 14 μg/L for methylmercury and HgⅡ, respectively. The RSD (n=7) was less than 5%, the linear correlation coefficient was 0 . 999 , and the matrix spiked recovery was in the range of 85%-110% for Hg speciation. This method was used for the determination of Hg speciation in fish and soil samples, and was proofed to be a reliable, easy approach for daily inspection.