固相微萃取-原子荧光测定鱼样品中痕量甲基汞

Determination of trace methyl-mercury in fish samples by solid-phase micro-extraction atomic fluorescence spectrometry

研制了一种用HF处理石英纤维表面的萃取纤维和一次性微量注射器组成的固相微萃取装置，研究了用甲基聚硅氧烷作为萃取头涂层对氢化甲基汞的萃取，得到的最佳条件是：在室温条件下，缓冲液的pH值为5、萃取时间为lh、NaCl的用量为2g、洗脱时间为50min、KBH4质量浓度为60g／L。在上述优化条件下，甲基汞的萃取率可以达到70％，检出限为0.17ng。测定了鱼样品中甲基汞，所测鱼虾中甲基汞的质量分数为12．4～53．4ng／g，加标回收率为87．6％～112．8％。

A solid-phase micro-extraction （SPME） apparatus by a silica fiber pretreated with HF and a micro-injector was set up, and extraetion eondition of methyl-mereury with a siliea fiber eoated with poly-methyl-siloxane was studied. The optimum eonditions are as follows： pH 5, extraetion time 1 h, salt 2 g, washing time 50 min, and density of kBH4 60 g/L. Under the optimized eonditions, the extraetion effieieney of methyl-mereury ean reaeh 70% , and the deteetion limit is 0. 174 ng. The method has been applied to fish sample sueeessfully, the density of methyl-mereury in samples is 12.4- 53.4 ng/g, and reeoveries are from 87.6% to 112.8%.