雪冰中痕量高氯酸盐的在线富集方法

On-line preconcentration of trace level perchlorate in snow and ice

利用一维离子色谱建立了高氯酸盐的在线富集方法,以期为建立定量检测南极雪冰中痕量高氯酸盐的离子色谱-串联质谱法奠定基础.选用高容量、强亲水性的IonPac AS20阴离子交换柱进行分离,以淋洗液自动发生器在线产生的KOH作为淋洗液,等梯度淋洗.考虑到南极雪冰样品量十分有限,选定5 mL为富集体积,对应的富集时间为10 min.高氯酸盐质量浓度在0.5—50μg.L-1范围内,方法具有良好的线性(相关系数为0.9995),检出限(以S/N=3计)为0.05μg.L-1.将浓度为0.5μg.L-1的标准溶液连续11次富集进样,所得峰面积的相对标准偏差(RSD)为4.7%.以人工配制的仅含有高氯酸盐的溶液实施了加标回收实验,回收率在85%—108%之间.

A simple on-line preconcentration method of perchlorate with ion chromatography is presented,which provides the necessary basis for the determination of trace level perchlorate in Antarctic snow and ice samples by the ion chromatography-electrospray tandem mass spectrometry(IC-ESI-MS-MS).Perchlorate is separated using an IonPac AS20 anion exchange column with high capacity and hydroxide selective,and isogradient potassium hydroxide eluent generated by the automated eluent generator.Due to the limited amount of Antarctic snow and ice samples,injection volume is set to be 5 mL with accumulative time of 10 minutes.The method is linear over the range of 0.5—50 μg · L-1 perchlorate,with linear correlation coefficient of 0.9995.The detection limit for perchlorate is 0.05 μg · L-1.And the relative standard deviation(RSD) of peak area for the eleven successive injections of 0.5 μg · L-1 perchlorate is 4.7%.The simulative water samples containing only perchlorate are used to carry out the recovery test,and results show that the spiked recoveries are in the range of 85%—108%.