二维离子色谱法测定精己二酸中痕量硝酸根离子

摘要

Two-dimensional ion chromatography method was developed for the determination of trace nitrate ion in pure adipic acid.Ion excluding column IonPac ICE-AS1 was used in the first dimension to separate the trace nitrate from adipic acid using deionized water as the mobile phase,nitrate ion separated was enriched in the pre-concentration column IonPac TAC-ULP1 at the same time.By using a gradient of potassium hydroxide made from the eluent generator cartridge as the eluent,the nitrate ion was eluted from the pre-concentration column into the second-dimension which using IonPac AS 17-C as analytical column,and detected by suppressed conductivity detector.The mass concentration of nitrate ion in pure adipic acid was linear with peak areas in the range of 2.0-50.0 μ g/L with r2 was more than 0.999,the detection limit was 0.10 p g/L,the relative standard deviation of determination results was less than 1.5％(n=7) and the recovery was 98.0％-105.0％.This method has the advantages of easy operation,high sensitivity,high accuracy and good selectivity,It can accurately determine the content of trace nitrate ion in pure adipic acid.%建立二维离子色谱法测定精己二酸中痕量硝酸根离子含量的方法.第一维采用去离子水作为流动相,经过IonPac ICE-AS1色谱柱将精己二酸中的硝酸根离子和己二酸进行预分离,分离出来的硝酸根富集于IonPac TACULP1浓缩柱上.以淋洗液发生器产生的不同质量浓度的氢氧化钾溶液作为淋洗液,将富集柱上的硝酸根淋洗下来,经第二维IonPac AS 17-C色谱柱进行分离,以抑制型电导检测器测定硝酸根离子的含量.精己二酸中硝酸根离子的质量浓度在2.0～50.0μg/L范围内与其色谱峰面积呈良好线性,线性相关系数r2＞ 0.999,检出限为0.10 μg/L,测定结果的相对标准偏差小于1.5％(n=7),加标回收率为98.0％～105.0％.该方法操作简单,灵敏度、准确度高,选择性好,能够准确测定精己二酸中痕量硝酸根离子的含量.