新型离子液体预富集-石墨炉原子吸收法测定透析液中超痕量铅

设计合成了新型室温离子液体—1-丁基-3-三甲基硅烷咪唑六氟磷酸，并用于透析液中超痕量铅的预富集。从双硫腙作为螯合剂使透析液(1 000 mL或更大体积)中存在的铅(Ⅱ)形成中性的铅-双硫腙配合物，摒弃传统的有机萃取剂—四氯化碳，代以1-丁基-3-三甲基硅烷咪唑六氟磷酸为绿色萃取剂来萃取铅配合物。收集含有配合物的下层离子液体相，加入硝酸分解铅配合物从而使铅(Ⅱ)进入水相，其水溶液中的铅含量直接用石墨炉原子吸收法测定。实验表明此富集体系明显优于传统有机溶剂四氯化碳和经典离子液体1-丁基-3-甲基咪唑六氟磷酸萃取体，铅的一次萃取率和富集倍数分别在99%和200以上。预富集结合石墨炉原子吸收法应用于透析液中超痕量铅的测定，结果令人满意。

Novel Ionic Liquid as Solvent for Preconcentration of Trace Lead in Dialysis Fluids and Its Determination by Graphite Furnace Atomic Absorption Spectrometry

A novel room temperature ionic liquid 1-butyl-3-trimethylsilylimidazolium hexafluorophosphate was designed and synthesized, and was applied to the preconcentration of ultra trace lead in a relatively large volume of dialysis fluids (such as 1 000 mL or bigger). In the present work, dithizone was employed as chelator to form a neutral lead- dithizone complex, and the ionic liquid 1-butyl-3-trimethylsilylimidazolium hexafluorophosphate was used to displace CCl4 as solvent for liquid/liquid extraction of lead complex. The ionic liquid was collected and the lead (II) was back-extracted into aqueous solution by adding nitric acid solution, and the above solution was directly applied to determine lead in the dialysis fluids by graphite furnace atomic absorption spectrometry. Experiments indicated that the proposed extraction system is superior over other systems in which organic solvent such as CCl4 or classical room temperature ionic liquid1-butyl-3-methylimidazolium hexafluorophosphate was selected as extraction medium, and its extraction efficiency of once extraction and enrichment factor of lead was more than 99% and 200 times, respectively. The preconcentration combined with graphite furnace atomic absorption spectrometry has been applied to the determination of trace lead in dialysis fluid samples with satisfactory results.