离子色谱同时分离测定三氟甲烷磺酸根,氟硼酸根及常见无机阴离子

Simultaneous Determination of Trifluoromethanesulfonate, Tetrafluoroborate and Common Inorganic Anions by Ion Chromatography

建立了离子色谱-直接电导检测同时测定三氟甲烷磺酸根,氟硼酸根及常见无机阴离子(F-,Cl-,Br-,NO3-,SO24-)的方法。实验采用Shim-pack IC-A3阴离子交换色谱柱,分别选用对羟基苯甲酸-三(羟甲基)氨基甲烷-硼酸,邻苯二甲酸-三(羟甲基)氨基甲烷,邻苯二甲酸氢钾为淋洗液,考察了淋洗液种类,浓度及色谱柱温度对分离测定三氟甲烷磺酸根,氟硼酸根及常见无机阴离子的影响。最佳色谱条件为:以1.2mmol/L邻苯二甲酸氢钾为淋洗液,柱温30℃,流速1.0mL/min。在此条件下,可同时基线分离7种阴离子,且色谱峰形对称。所测阴离子的检出限(S/N=3)为0.02～1.88mg/L,保留时间和峰面积的相对标准偏差(n=5)分别小于0.17%和2.05%。应用本方法测定离子液体中三氟甲烷磺酸根,氟硼酸根及常见无机阴离子,加标回收率在97.0%～102.8%之间。本方法简单,准确,可靠,具有较好的实用性。

A method was developed for the determination of trifluoromethanesulfonate,tetrafluoroborate and common inorganic anions by ion chromatography with direct conductivity detection. Chromatographic separation was performed on a Shim-pack IC-A3 anion exchange column using p-hydroxybenzoic acid ＋ tris （ hydroxymethyl） -aminomethane ＋ boric acid,phthalic acid ＋ tris （ hydroxymethyl） -aminomethane,and potassium biphthalate as eluent,respectively. The effects of the types of eluent,eluent concentration and column temperature on separation and retention of the anions were investigated. The optimized chromatographic conditions for the determination of the anions were as follows： 1. 2 mmol/L potassium biphthalate as eluent, column temperature of 30 ℃ and flow rate of 1. 0 mL/min. Under these conditions,the anions were in baseline separation. Moreover,the symmetry of peaks was better. Detection limit （ S/N = 3） for the anions was in range of 0. 02 1. 88 mg/L. The relative standard deviations （ RSD） of the chromatographic retention time and peak areas for the anions were not more than 0. 17% and 2. 05% （ n = 5） ,respectively. The method has been applied to the determination of trifluoroacetate,tetrafluoroborate and common anions in ionic liquids. The recoveries of the anions after spiking were from 97. 0 % to 102. 8 % . The method is simple,accurate, reliable and practical.