二维离子色谱法测定精己二酸中痕量硝酸根离子

Determination of Trace Nitrate in Pure Adipic Acid by 2D Ion Chromatography

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Ion Pac 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Ion Pac TAC–ULP1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Ion Pac AS17–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0.10μg/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。

Two–dimensional ion chromatography method was developed for the determination of trace nitrate ion inpure adipic acid.Ion excluding column IonPac ICE–AS1was used in the first dimension to separate the trace nitrate fromadipic acid using deionized water as the mobile phase,nitrate ion separated was enriched in the pre-concentration columnIonPac TAC–ULP1at the same time.By using a gradient of potassium hydroxide made from the eluent generator cartridgeas the eluent,the nitrate ion was eluted from the pre–concentration column into the second-dimension which using IonPacAS17–C as analytical column,and detected by suppressed conductivity detector.The mass concentration of nitrate ion inpure adipic acid was linear with peak areas in the range of2.0–50.0μg/L with r2was more than0.999,the detection limitwas0.10μg/L,the relative standard deviation of determination results was less than1.5%(n=7)and the recovery was98.0%–105.0%.This method has the advantages of easy operation,high sensitivity,high accuracy and good selectivity,Itcan accurately determine the content of trace nitrate ion in pure adipic acid.