Gao Wei, Yu Hong, Ma Yajie
College of Chemistry and Chemical Engineering, Harbin Normal University, Harbin 150025, China.
Se Pu. 2010 Jun;28(6):556-60. doi: 10.3724/sp.j.1123.2010.00556.
Determination of five imidazolium ionic liquid cations by ion-pair chromatography was carried out using ultraviolet-visible spectrophotometry (UV/VIS) detection. Chromatographic separations were performed on a ZORBAX Eclipse XDB-C18 column with 1-heptanesulfonic acid sodium (adjusted by citric acid to pH 4.0) + acetonitrile as eluent. The effects of ion-pair reagents, acetonitrile concentration and column temperature on retention of the cations were investigated. The retention factor of imidazolium cation on column was increased with the increase of the concentration of 1-heptanesulfonic acid sodium. With the increase of the concentration of acetonitrile, the retention time of imidazolium cation was obviously shortened and the peak shape was improved. Under the optimum conditions, detection limits (S/N = 3) for the cations were 0.05-0.30 mg/L. Relative standard deviations (RSDs) for peak areas were less than 0.1%. The method has been successfully applied to the determination of two ionic liquids by chemically synthesized in laboratory with the recoveries of the cations of 98.6%-102.1% after spiking.
采用紫外可见分光光度法（UV/VIS）检测，通过离子对色谱法测定了5种咪唑鎓离子液体阳离子。在ZORBAX Eclipse XDB-C18柱上进行色谱分离，以1-庚烷磺酸钠（用柠檬酸调节至pH 4.0）+乙腈为洗脱剂。研究了离子对试剂、乙腈浓度和柱温对阳离子保留的影响。咪唑鎓阳离子在柱上的保留因子随1-庚烷磺酸钠浓度的增加而增大。随着乙腈浓度的增加，咪唑鎓阳离子的保留时间明显缩短，峰形得到改善。在最佳条件下，阳离子的检测限（S/N = 3）为0.05 - 0.30 mg/L。峰面积的相对标准偏差（RSDs）小于0.1%。该方法已成功应用于实验室化学合成的两种离子液体的测定，加标后阳离子的回收率为98.6% - 102.1%。
