超声辅助浊点萃取-原子荧光光谱法测定水中痕量汞

Determination of Trace Mercury in Water by Atomic Fluorescence Spectrometry with Ultrasonic Assisted Cloud Point Extraction

为了适应水中痕量汞的分析要求,降低汞的检出限,采用硫代米蚩酮为络合剂,以非离子型表面活性剂Triton X-114为萃取剂,将水样中的痕量汞富集于表面活性剂相,建立了一种超声辅助浊点萃取预富集联合原子荧光光谱法测定水样中痕量汞的方法。在原子荧光光谱测定前,加入磷酸三丁酯作为消泡剂,用盐酸溶液(5%)定容,富集倍数可以达到10倍。优化萃取体系pH值、络合剂用量、萃取剂用量、超声平衡条件等浊点萃取的条件,在最优条件下,方法的检出限为0.003μg/L,相对标准偏差为4.2%~8.6%,加标回收率为85.0%~106%。结果表明,超声辅助浊点萃取-原子荧光光谱法能够适用于对地表水、自来水等清洁水样中痕量汞的分析,且具有更低的检出限、良好的准确度和精密度,能够适应于更高的样品分析要求。

In order to meet the analysis requirements of trace mercury in water and reduce the detection limit of mercury,a simple,rapid,and efficient sample pretreatment technique of ultrasonic-assisted cloud point extraction combined with atomic fluorescence spectrometry was developed for the determination of trace mercury in water samples.In this study,Thio-Michler′s ketone(TMK)was used as the complexing agent and Triton X-114 was used as an extractant to enrich trace mercury in the surfactant phase.Before the atomic fluorescence spectrometry test,tributyl phosphate was added as defoamer and 5%HCl solution was used for constant volume,the enrichment factor reaches 10.Under the optimal extraction conditions,such as pH,the amount of complexing agent,extractant and ultrasonic equilibrium,the detection limit of this method is 0.003μg/L,the relative standard deviation is 4.2%—8.6%,and the standard recovery is 85.0%—106%.The results show that ultrasonic-assisted cloud point extraction-atomic fluorescence spectroscopy method can be applied to the analysis of trace mercury in clean water samples such as surface water and tap water,with lower detection limit,good accuracy,and precision,which can meet the requirements of higher for sample analysis.