超声辅助-邻菲罗啉/离子液体微萃取分离Cr(Ⅲ)和Cr(Ⅵ)

Separation of Cr(Ⅲ) and Cr(Ⅵ) by ultrasound-assisted phenanthroline/ionic liquid-based microextraction

以邻菲罗啉(C12H8N2)为螯合剂,1-己基-3-甲基咪唑六氟磷酸盐([C6M IM][PF6])为萃取剂,采用超声辅助-分散液液微萃取分离Cr(Ⅲ)和Cr(Ⅵ),结合电感耦合等离子体质谱法(ICP-MS)实现对铬元素形态分析。实验结果表明:邻菲罗啉浓度0. 3 mol/L、pH值为8、超声时间20 min、超声温度30℃时,Cr(Ⅲ)的萃取效果最好,Cr(Ⅵ)和Cr(Ⅲ)可以分离。通过ICPM S测定Cr(Ⅲ),由总铬减去Cr(Ⅲ)得到Cr(VI)含量。Cr(Ⅲ)浓度在0~80μg/L范围内呈现好的线性关系,检出限为0. 06μg/L,Cr(Ⅲ)的加标回收率在91. 5%~110. 2%之间,相对标准偏差(RSD)在1. 3%~4. 5%之间,表明结果可靠且符合环境水样中铬元素形态分析的要求。

The speciation of Cr (Ⅲ) and Cr (Ⅳ) were proposed by ultrasonic assisted dispersive liquid-liquid microextraction, using phenanthroline ( C12 H8 N2 ) as chelating agent and 1-hexyl-3- methylimidazolium hexafluorophosphate ([ C6 MIM ][ PF6 ]) as extractant coupled with inductively coupled plasma mass spectrometry ( ICP-MS). The results showed that Cr(Ⅲ) had the best extraction effect when the concentration of phenanthroline was 0. 3 mol/L, pH value was 8 , ultrasonic time was 20 min, and ultrasonic temperature was 30℃.Cr(Ⅳ) and Cr(Ⅲ)) could be separated. Cr(Ⅲ)was determined by ICP-MS. Cr(Ⅳ) was subtracted from total chromium to obtain Cr(Ⅳ) content. The concentration of Cr (Ⅲ) showed a good linear relationship in the range of 0 - 80μg/L with the detection limit of 0. 062 (μg/L, the spiked recoveries were between 91. 5% and 110. 2%, and the relative standard deviations were between 1. 3% and 4. 5%, indicating that these results were reliable and this method could meet the requirements of the chromium analysis in environmental water samples.