新型离子液体作为溶剂萃取光度法测定环境水中超痕量钼

A novel ionic liquid as solvent for extraction spectrophotometric determination of ultra trace molybdenum in environmental water samples

离子液体是一种绿色溶剂,可替代易挥发的有机溶剂用于液/液萃取。在阳离子表面活性剂CTMAB存在下,Mo（Ⅵ）与9-（2-羟基-5-偶氮对甲苯）苯基荧光酮（MBASF）反应形成稳定的络合物,其最大吸收波长位于522 nm。在显色后的体系中加入离子液体-1-丁基-3-三甲基硅咪唑六氟磷酸盐（[C4tmsim][PF6]）,Mo-MBASF络合物被高效萃取进入离子液体相。由于离子液体在萃取前后均为透明液体,可直接用于光度法测定钼。在1000 mL水样中,0-4μg Mo（Ⅵ）符合比尔定律,络合物的表观摩尔吸光系数达1.2×10^7L.mol^-1.cm^-1。绝大多数离子可大量存在,方法具有高的灵敏度和选择性,已应用于环境水样中超痕量钼的测定。

Ionic liquid is a novel green solvent, it can be used as the novel solvents to displace the volatile organic solvent in solvent extraction. In the presence of cationic surfactant CTMAB, molybdenum（Ⅵ ） reacts with methybenzeneazosalicylfluorone（MBASF） to form a stable complex with maximum absorption wavelength at 522 nm. After added 1- butyl-3-trimethylsilylimidazolium hexafluorophosphate （ [ C4tmsim] [ PF6 ] ） ionic liquid into the system, Mo-MBASF complex was rapidly extracted into the ionic liquid phase from the aqueous solution. The ionic liquid can be directly used to determine molybdenum as the ionic liquid shows transparent state before and after the extraction. 0 - 4 μg of Mo/L was obeyed for Beer＇s law, apparent molar absorptivity of the complex is 1. 2 × 10^7 L·mol^-1, cm^-1. Most of ions studied can be tolerated in considerable amounts. The proposed method has very good sensitivity and selectivity, and it has been applied to determine ultra trace molybdenum in environmental water samples with satisfactory results.