N-甲基-2-吡咯烷酮有机试剂中微量阴离子杂质的分析

Determination of Anions in N-Methyl-2-pyrrolidinone by Ion Chromatography

高纯度的化学试剂是许多食品分析、制药分析、工业制造等行业中的关键性基础化工材料之一，其中微量杂质的分析是发展这类试剂产业的关键技术环节之一。建立了高纯度有机试剂中的3种阴离子的离子色谱定量分析方法，分别以5和20mmol／L NaOH为流动相，Ionpac AS11-HC阴离子通用分析柱进行分离，电导检测器检测，可以实现HPLC级甲醇样品中添加的Cl^-、SO4^2-和NO3^-的含量分析。该方法3种离子的线性范围在5—100μg／L之间，3种阴离子的最低检出浓度分别为2（Cl^-）、5（SO4^2-）和5μg／L（NO3^-），方法的回收率为93％-107％，相对标准偏差（RSD）为2．0％～3．5％。此外，我们还进一步考察了前处理方法中采用WAX固相萃取技术对色谱纯的N-甲基-2-吡咯烷酮试剂中的阴离子进行富集，可以实现该样品中上述3种阴离子的分析检测。

A method for the determination of three anions in ultra-pure organic reagents was established by ion chromatography（IC）. The separation was performed in an Ionpac AS 11-HC column protected by AGll-HC column, NaOH solutions were used as mobile phase. Conductivity detector was used to detect the anions. The linear ranges were among the range of 5 -100 μg/L,and the detection limits were 2 μg/L （ Cl^- ） ,5 μg/L （ SO4^2- ） and 5 μg/L （ NO3^- ）, respectively. The recoveries ranged from 93% to 107% and RSD was 2. 0% -3.5%. When the three anions were extracted by WAX SPE column, these anions can be successfully detected in N-methyl-2-pyrrolidinone （GC grade）.