School of Chemistry and Environmental Sciences, Henan Normal University, Henan Key Laboratory for Environmental Pollution Control, Key Laboratory for Yellow River and Huaihe River Water Environment and Pollution Control, Ministry of Education, Xinxiang 453007, China.
Talanta. 2010 Mar 15;80(5):1638-42. doi: 10.1016/j.talanta.2009.09.059. Epub 2009 Oct 4.
Hydrophobic ionic liquid could be dispersed into infinite droplets under driving of high temperature, and then they can aggregate as big droplets at low temperature. Based on this phenomenon a new liquid-phase microextraction for the pre-concentration of lead was developed. In this experiment, lead was transferred into its complex using dithizone as chelating agent, and then entered into the infinite ionic liquid drops at high temperature. After cooled with ice-water bath and centrifuged, lead complex was enriched in the ionic liquid droplets. Important parameters affected the extraction efficiency had been investigated including the pH of working solution, amount of chelating agent, volume of ionic liquid, extraction time, centrifugation time, and temperature, etc. The results showed that the usually coexisting ions containing in water samples had no obvious negative effect on the recovery of lead. The experimental results indicated that the proposed method had a good linearity (R=0.9951) from 10 ng mL(-1) to 200 ng mL(-1). The precision was 4.4% (RSD, n=6) and the detection limit was 9.5 ng mL(-1). This novel method was validated by determination of lead in four real environmental samples for the applicability and the results showed that the proposed method was excellent for the future use and the recoveries were in the range of 94.8-104.1%.
疏水性离子液体在高温的驱动下可以分散成无数的液滴，然后在低温下又可以聚集成为大液滴。基于这一现象，开发了一种新的用于铅的预浓缩的液相微萃取方法。在该实验中，铅被转移到其络合物中，使用二硫腙作为螯合剂，然后在高温下进入无限的离子液体滴中。用冰水浴冷却并离心后，铅络合物富集在离子液体液滴中。研究了影响萃取效率的重要参数，包括工作溶液的 pH 值、螯合剂用量、离子液体体积、萃取时间、离心时间和温度等。结果表明，水样中通常共存的离子对铅的回收率没有明显的负面影响。实验结果表明，该方法在 10ng/mL 至 200ng/mL 的范围内具有良好的线性关系（R=0.9951）。精密度为 4.4%（RSD，n=6），检测限为 9.5ng/mL。该方法通过对四种实际环境样品中铅的测定验证了其适用性，结果表明该方法具有很好的应用前景，回收率在 94.8-104.1%之间。
