以亲水性阴离子交换柱IonPac AS16为分析柱,以NaOH、乙腈和水的混合溶液为淋洗液,采用电导检测法测定了环境水样中的痕量高氯酸盐.通过添加有机改进剂有效地解决了4-氯苯磺酸和高氯酸盐共淋洗的问题.实验考察了4种有机溶剂对高氯酸盐和4-氯苯磺酸保留时间的影响,最终选定乙腈作为有机改进剂.为了提高方法的灵敏度,以AG19为浓缩柱对样品进行在线预浓缩.采用预浓缩技术可使方法的检出限低至0.1μg/L.在0.2~200μg/L线性范围内线性相关系数为0.9989,将0.5μg/L高氯酸盐溶液连续进样测定11次,所得峰面积的相对标准偏差(RSD)为4.2%.将该方法应用于环境水样的测定,加标回收率为93%~113%.
An improved ion chromatography(IC) method was developed to determine trace level perchlorate in environmental water samples by using hydroxide selective column IonPac AS16. Perchorate was separated with NaOH eluent added organic modifier. To eliminate the coelution of perchlorate and 4-chlorobenzene sulfonate(4-CBS), organic solvents as the modifier was added into the eluent. The effects of four kinds of organic solvents on the retention time of perehlorate and 4-CBS were studied, and acetonitrile was selected. To improve the method sensitivity, the concentrator column( AG19 ) was used to concentrate perchlorate online in this work. With the adoption of preconcentration technique, the sensitivity of this method was improved obviously and the method detection limit(MDL) is 0. 1μg/L. The linear range is 0. 2-200μg/L with a linear correlation coefficient of 0. 9989, and the relative standard deviation(RSD) of peak area for the eleven successive injections of 0. 5 μg/L perchlorate is 4. 2%. The method was applied to the determination of perchlorate in some real environmental water samples and the spiked recoveries were in the range of 93%-113%.