整体柱离子对色谱快速分析高氯酸盐

Fast Analysis of Perchlorate by Ion-pair Chromatography Using a Monolithic Column

研究了用硅胶整体柱和直接电导检测的离子对色谱快速分析高氯酸盐的方法。实验采用Chromolith Speed ROD RP-18e色谱柱，以氢氧化四丁铵（离子对试剂）＋邻苯二甲酸＋乙腈（有机改进剂）为淋洗液，讨论了离子对试剂浓度、有机改进剂浓度、pH、色谱柱温度和流速对ClO4^-保留时间的影响。确定最佳色谱条件为：0．25mmol／L氢氧化四丁铵＋0．18mmol／L邻苯二甲酸＋7％乙腈（pH5．5）作为淋洗液，柱温30℃，流速6．0mL／min。在此条件下，ClO4^-的保留时间在1min之内。其它常见阴离子（Cl^-、NO3^-、SO4^2-和I^-）不干扰测定。方法的检出限为1．56mg／L；工作曲线的线性范围是2．4～100mg／L；峰面积的相对标准偏差（RSD，n=5）为1．9％。将本方法应用于测定加标果汁和加标地下水中的ClO4^-，加标回收率分别为98．2％和97．6％。

Fast analysis of perchlorate was carried out by ion-pair chromatography using a silica-based monolithic column and direct conductivity detection. Chromatographic separation was performed on a Chromolith Speed ROD RP-18e （50 mm×4.6 mm） with tetrabutylammonium hydroxide （TBA-OH） ＋ phthalic acid ＋ acetonitrile as eluent. The effects of eluent concentration, eluent pH, column temperature and flow rate on retention time of perchlorate were investigated. The optimized chromatographic conditions for determination of perchlorate were as follows： 0. 25 mmol/L TBA-OH ＋ 0. 18 mmol/L phthalic acid ＋ 7% acetonitrile （ pH 5.5 ） as the eluent, column temperature 30 ℃ and flow rate 6.0 mL/min. Retention time of perchlorate is less than 1 min under the conditions. Common anions （ Cl^- , NO3^- , SO4^2- and I^- ） do not interfere with the determination. Detection limit （S/N = 3 ） for perchlorate was 1.56 mg/L. Calibration graph between the peak area and the concentration of prchlorate was linear in the range of 2.4 - 100 mg/L. Relative standard deviation （RSD） of chromatographic peak area was 1.9% （ n = 5 ）. The method was applied to the determination of perehlorate in juice and groundwater. Recoveries of perchlorate after spiking were 98.2% and 97. 6%, respectively.