液相色谱-冷原子荧光光谱法测定土壤中的烷基汞

Determination of alkyl mercury in soil by interface technique coupled liquid chromatography with cold atomic fluorescence spectrometry

建立了液相色谱-冷原子荧光光谱法测定土壤中的烷基汞(甲基汞、乙基汞)的方法。本文对实验分析条件进行了优化,并比较了不同浓度溶剂对土壤中烷基汞的提取效率。样品中的烷基汞经提取液提取,L-半胱氨酸-乙酸铵反萃取后,被流动相带入色谱柱中依次进行洗脱,洗脱后的烷基汞在紫外消解下被氧化为无机汞,然后在酸性条件下,硼氢化钾将离子态汞还原为汞蒸汽,最后由原子荧光光谱仪进行检测。在优化条件下,测定的RSD(n=6)均在5.3%以内;方法检出限甲基汞为0.013μg/g,乙基汞为0.025μg/g;加标回收率甲基汞为97%-103%,乙基汞为77%-91%。本方法操作简单,杂质干扰少,方法准确、可靠,具有很高的灵敏度。适用于土壤中甲基汞、乙基汞残留量的分析。

A method based on liquid chromatography on line coupled with cold atomic fluorescence spectrometry for alkyl mercury(methyl mercury,ethyl mercury)in soil was proposed.In this paper,the experimental analysis conditions are optimized,and the extraction efficiencies of alkyl mercury from soil with different solvent concentrations were compared.Alkyl mercury was extracted and reextracted by L-gystein and ammonium acetate from experimental sample,and flow in the column is eluted in turn.After elution,alkyl mercury is oxidized to inorganic mercury under UV digestion,And under acidic conditions,potassium borohydride reduces ionic mercury to mercury vapor.Finally,atomic fluorescence spectrometer was used for detection.In optimization conditions,the relative standard was less than 5.3%;methods the limit of methyl mercury was 0.013μg/g and the ethyl mercury was 0.025μg/g,the methyl mercury standard recovery was between 97%and 103%,the ethyl mercury standard recovery was between 77%and 91%.This method has the advantages of simple operation,less interference from impurities,accuracy,reliability and high sensitivity.It is suitable for the analysis of methyl mercury and ethyl mercury residues in soil.