低压液相色谱-原子荧光快速测定鱼肉和土壤样品中汞形态

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

使用最新的低压液相整体柱与原子荧光联用及控温混旋提取技术,建立了鱼肉样品中汞形态分析的快速前处理及测定的方法。称取适量鱼肉样品,打成泥状,加入提取液（10%HCl,1%硫脲,和0.15%KCl）,置于恒温混旋仪上,2000 r/min混旋提取,整个前处理和分析过程在30 min内可完成。样品的提取液先经过分离,然后经形态管内紫外消解,使用氢化物发生原子荧光的方法检测,得到各形态组分。本方法采用Merck整体柱分离,通过流速梯度淋洗将色谱分离和检测时间缩短到10 min之内。对流动相的配比和组分进行优化,确定了流动相的组成为3%（V/V）乙腈,30 mmol/L乙酸铵和0.03%（V/V）2-巯基乙醇。在样品分离后,选用灯内紫外消解方式,再进行检测,获得更高的检测灵敏度。本方法得到甲基汞和无机汞的检出限（DL）分别为0.15和0.14μg/L；相对标准偏差（RSD）〈5%；线性相关系数（R）〉0.999；用本方法检出了实际鱼肉和土壤样品中的汞形态,加标回收率在85%~110%之间。本方法快速、简单、准确可靠,可用于鱼肉样品中的汞形态的日常检测。

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.