离子液体超声萃取-液/液微量反萃取-GFAAS法测定地表水中痕量铊

Determination of Trace Thallium in Surface Water by GFAAS with Ionic Liquid Ultrasonic Extraction and Liquid/Liquid Micro-volume Back Extraction

在p H=5的盐酸羟胺介质中,地表水中的TI＋与螯合剂DCH-18-Crown-6配位后采用离子液体[Hmim][PF6]室温下进行超声萃取,离心分离后离子液体相用HNO3（2 mol/L）进行微量反萃取分离,水相辅以Pd（NO3）2和Mg（NO3）2混合基体改进剂进行GFAAS法测定。试验测试了p H、DCH-18-Crown-6浓度、超声萃取时间、[Hmim][PF6]的用量以及共存离子对萃取效率的影响。在最佳试验条件下,铊的质量浓度在0~50μg/L范围内线性良好,方法检出限可达0.03μg/L,加标回收率为98.0%~102%。试验表明该方法具备简单、快速、取样量小与检出限低等特点,可用于环境样品中痕量铊的分析。

Thallium （ I ） in surface water reacted with DCH-18-Crown-6 to form chelate compound in the presence of hydroxylamine hydrochloride at pH 5, The TI＋ complex was rapidly extracted into [Hmim][PF6] ionic liquid phase in ultrasonic bath. After centrifugation, ionic liquid phase was back extracted with HNO3 （2 mol/L） solution. The thallium in water phase was determined by GFAAS using Pd（NO3）2 and Mg（NO3）2 as mixture modifier. The effects ofpH, concentration of DCH-18-Crown-6, ultrasonic extraction time, [Hmim][PF6] dosage and coexisting ions on extraction efficiency were investigated. Under optimum condition, the calibration curve was linear in the range of 0-50/ag/L, the detection limit was 0.03 lag/L. Its recover ration was obtained by standard addition method ranged from 98.0 %-102 %. These results showed the method is simple, rapid, little sample quantity and low detection limit. This method can be used to determine trace thallium of environmental sample.