液液萃取/液相色谱/原子荧光光谱法测定水中有机汞

Determination of Organomercury in Water by LLE-HPLC-AFS

建立了水中有机汞(甲基汞、乙基汞、苯基汞)的液液萃取/反萃取/液相色谱/原子荧光光谱测定方法。水样经二氯甲烷萃取后,经半胱氨酸-乙酸铵溶液反萃取,采用高效液相色谱-原子荧光光谱联用法检测水中甲基汞、乙基汞和苯基汞。甲基汞和乙基汞标准曲线线性范围为1~100μg/L,苯基汞线性范围为5~100μg/L,3种有机汞校准曲线相关系数均不小于0.999 7。甲基汞、乙基汞和苯基汞的方法检出限分别为0.20、0.40和1.00 ng/L,实际样品加标回收率范围为69.5%~91.0%,相对标准偏差(RSD)范围为6.2%~13.5%。该方法操作简便、成本低、准确可靠、检出限低,适用于水样中甲基汞、乙基汞和苯基汞的测定。

A method based on liquid-liquid extraction( LLE)/back extraction/high performance liquid chromatography( HPLC)/atomic fluorescence spectroscopy( AFS) was developed for the determination of organomercury( methyl mercury/ethyl mercury/phenyl mercury) in water. The extraction of the water sample was performed on LLE using dichloromethane. The dichloromethane was then extracted by cysteine-ammonium acetate solution. Methyl mercury,ethyl mercury and phenyl mercury in water were determined by HPLC-AFS. The results showed that good linearities were observed in the ranges of 1-100 μg/L( methyl mercury and ethyl mercury) and 5-100 μg/L( phenyl mercury) with the correlation coefficient ≥0. 999 7. The method detection limit( MDL) of methyl mercury/ethyl mercury/phenyl mercury was 0. 20 ng/L,0. 40 ng/L and 1. 00 ng/L respectively. The recoveries were between69. 5%-91. 0%. The relative standard diviation( RSD,n = 6) was 6. 2%-13. 5%. The method is simple,low-cost,accurate and reliable with low detection limit and suitable for the determination of methyl mercury/ethyl mercury/phenyl mercury in water.