离子液体双水相萃取-蒸气发生原子荧光法测定痕量镉  

Determination of Cadmium by Hydride Generation Atomic Fluorescence Spectrometry After Extraction with Ionic Liquid Two-aqueous Phase System

作　　者：陈明丽[1] 付海阔 孟皓[1] 王建华[1] 

机构地区：[1]东北大学分析科学研究中心,沈阳110819

出　　处：《分析化学》2010年第9期1299-1304,共6页Chinese Journal of Analytical Chemistry

基　　金：国家自然科学基金(No20805004);国家杰出青年科学基金(No20725517)资助项目

摘　　要：研究了离子液体1-异戊基-3-甲基咪唑溴代盐-K2HPO4-水双水相体系对镉-双硫腙络合物的萃取性能,建立了测定痕量镉的蒸气发生-原子荧光光谱法。经离子液体双水相萃取后,在离子液体相中的镉-双硫腙络合物经酸化后可直接与还原剂(NaBH4)混合进行蒸气发生反应,并经气液分离后将蒸气引入原子化器中进行原子荧光检测,离子液体的存在不影响蒸气发生过程。考察了双水相系统的组成以及相关实验条件对镉-双硫腙络合物萃取的影响。在最佳实验条件下,样品体积为1mL时,测定痕量镉的线性范围为0.25～5.0μg/L,检出限为0.07μg/L;相对标准偏差为3.4%(n=9,2.0μg/LCd2+)。用国家标准物质GBW08608(水中镉、铬、铜、镍、铅、锌成分分析标准物质)验证了方法的准确性,并对实际水样中的痕量镉进行了测定。A procedure for the determination of cadmium by hydride generation atomic fluorescence spectrometry was developed after the cadmium-dithizone complex was extracted by using a two-aqueous phase system formed by ionic liquid 1-isopentyl-3-methylimidazolium bromide and K2HPO4.The cadmium-dithizone complex extracted in the ionic liquid-rich upper phase was acidified with hydrochloric acid and mixed with NaBH4 to facilitate the hydride generation process.The hydride was separated from the reaction mixture in a gas-liquid separator by purging with an argon flow,which was afterwards directed into the atomizer of the atomic fluorescence spectrometer for quantification.A thorough scrutiny has been made to optimize the experimental parameters,including the two-aqueous phase system itself.By using a sample volume of 1 mL,a linear calibration graph was obtained in the range of 0.25 -5.0 μg/L,along with a detection limit（3σ） of 0.07 μg/L and a precision of 3.4%（n = 9,2.0 μg/L Cd2 ＋）.The procedure was demonstrated by analyzing cadmium content in a certified reference material（GBW08608） and real water samples.

关 键 词：离子液体双水相 萃取 蒸气发生-原子荧光 镉 

分 类 号：O614.242[理学—无机化学] X832[理学—化学]