建立了整体柱离子对色谱-紫外检测法梯度淋洗快速分离测定4种吡啶离子液体阳离子的方法.分离采用C18反相硅胶整体柱,以离子对试剂(用柠檬酸调节pH值)-乙腈为淋洗液,并采用多级梯度洗脱程序.实验考察了色谱柱、离子对试剂、乙腈浓度、色谱柱温度及流速对吡啶阳离子保留的影响,并讨论了其保留规律.咪唑阳离子的保留符合碳数规律.最佳色谱条件是:在流速3.0 mL/min,柱温30℃下,以1.0 mmol/L庚烷磺酸钠(pH 4.0)(A)+乙腈(B)为淋洗液进行梯度洗脱.淋洗梯度为0～2.0 min,10％ B;2.0～2.5 min,10％～15％ B;2.5～4.0 min,15％ B;4.0～4.5 min,15％～20％ B;4.5～10.0 min,20％B.在此条件下,4种吡啶阳离子可在7 min内基线分离.所测阳离子的检出限(S/N=3)为0.05～0.17 mg/L;峰面积的相对标准偏差(n=5)小于0.6％.将本方法用于实验室合成的离子液体样品和污水样品的分析,加标回收率在95.7％～99.0％之间.本方法准确、快速,具有较好的实用性.%A fast and gradient ion-pair chromatographic method was developed for the determination of four pyridinium ionic liquid cations using a reversed phase silica-based monolithic column and ultraviolet detection. Chromatographic separations were performed on a Chromolith Speed ROD RP-18e column with 1-heptanesulfonic acid sodium solution(pH 4. 0 adjusted by citric acid)+acetoni-trile as eluent and gradient elution. The effects of chromatographic column, eluent, flow rate and column temperature on retention and separation of the cations were investigated. The retention rules of pyridinium cations on the monolithic column were discussed. The retention of imidazolium cations accords with carbon number rule. The gradient elution procedure was optimized using 1. 0 mmol/L 1-heptanesulfonic acid sodium(pH 4. 0)+acetonitrile as eluent, and simultaneous separation of four pyridinium cations within 7 min was achieved under the optimum gradient conditions. Detection limits (S/N = 3) for the cations were 0. 05 -0. 17 mg/L. Relative standard deviations(n=5) for peak areas were less than 0. 6%. The method has been applied to analyze the ionic liquid synthesized by chemical laboratory and sewage water with spiked recoveries of 95. 7% -99. 0%. The method is accurate, reliable and rapid, and has better practicability.
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