A method was established for the separation and detection of imidazolium ionic liquid cations by ion chromatography cou-pled with ultraviolet detection. The separation of imidazolium cations and direct ultraviolet detection were carried out by using meth-anesulfonic acid/acetonitrile as mobile phase and carboxylic acid cation exchanger as stationary phase. The results indicated that, the retention process of imidazolium cations was exothermic,the retention of imidazolium cation homologue was consistent with car-bon number rules. The successful separation of 1-ethyl-3-methyl-imidazolium,1-propyl-3-methyl-imidazolium,1-butyl-3-methyl -imidazolium,1-amyl-3-methyl-imidazolium and 1-hexyl-3-methyl-imidazolium cations within 33 min was achieved under the condi-tions of the column temperature 45℃,at a flow rate of 1. 0 mL·min-1,using 5. 0 mmol·L-1methanesulfonic acid/acetonitrile (91/9,v/v)as mobile phase. The detection limits of the cations were 0. 09～0. 43 mg·L-1. The relative standard deviations were less than 1. 5%. The method has been applied to the determination of imidazolium ionic liquid samples synthesized in chemical la-boratory with the spiked recovery rates between 97. 0%and 100. 7%. The method is simple,sensitive,and has better practicability.%建立了用离子色谱-直接紫外检测法对咪唑离子液体阳离子进行分离测定的方法.以甲烷磺酸/乙腈为流动相,羧酸型阳离子交换剂为固定相,实现了咪唑阳离子的分离和直接紫外检测.结果表明,咪唑阳离子的保留是放热过程,其同系物保留符合碳数规律.在柱温45℃,流速1. 0 mL·min-1,以5. 0 mmol·L-1甲烷磺酸/乙腈(91/9,v/v)为流动相的检测条件下,1-乙基-3-甲基咪唑阳离子、1-丙基-3-甲基咪唑阳离子、1-丁基-3-甲基咪唑阳离子、1-戊基-3-甲基咪唑阳离子和1-己基-3-甲基咪唑阳离子在33 min内达到基线分离.检出限是0. 09～0. 43 mg·L-1,相对标准偏差不高于1. 5%.将以上这种方法应用于实验室合成的咪唑离子液体样品的分析,加标回收率可以达到97. 0% ～100. 7%.本方法简单、灵敏,具有较好实用性.
展开▼
