| A method was developed for the determination of tetrafluoroborate by ion-exclusion chromatography coupled with direct conductivity detection.Chromatographic separation was performed on a Shim-pack SCR-102H column.Influences of eluent and column temperature on retention time of tetrafluoroborate were investigated.The results indicated the retention time of tetrafluoroborate was increased with the increase of column temperature,and the retention process of tetrafluoroborate was endothermic.The optimal chromatographic conditions for determination of tetrafluoroborate were using 0.2 mmol/L p-toluenesulfonic acid as eluent with a column temperature of 40 ℃ and a flow rate of 1.0 mL/min.Under the optimal conditions,a good separation of tetrafluoroborate and common organic acids（such as,citric acid,malic acid,formic acid and acetic acid） was obtained.The retention time of tetrafluoroborate was 5.95 min.The determination were not interfered by the common inorganic anions（Cl-,Br-,NO-3,SO2-4）.The calibration curve was linear in the range of 3-100 mg/L with a detection limit（S/N=3） of 0.14 mg/L.The relative standard deviations（n=5） for retention time and peak area were 0.02% and 0.7%,respectively.The method was successfully applied in the determination of tetrafluoroborate in ionic liquids with spiked recoveries of 99%-102%.With the advantages of simplicity,accuracy and good repeatability,this method could be applied in the quality control analysis of relevant ionic liquids. |