工作场所空气中氨的离子色谱测定方法

Determination of ammonia in the air of workplace by ion chromatography

目的 建立工作场所空气中氨的离子色谱测定方法。方法 工作场所空气中氨用甲烷磺酸吸收液采集,与甲烷磺酸反应生成铵盐后经阳离子色谱柱分离,用电导检测器检测,以保留时间定性,峰面积定量。结果 氨在0.32-30μg/ml范围内呈二次相关（r〉0.999）,最低检出限0.1μg/ml,定量下限0.32μg/ml,当采集7.5L标准条件下空气时最低定量浓度0.21mg/m3。甲烷磺酸吸收液对空气中氨的采样效率〉99%,采样相对标准偏差〈5%。结论 该法操作简单,采样效率高,干扰少,符合GBZ/T 210.4-2008要求,与纳氏试剂比色法相比几乎无污染,可作为工作场所空气中氨的标准测定方法。

Objective To develop an ion chromatography method for the determination of ammonia in workplace air. Meth- ods Ammonia in workplace air was collected through bubble absorption tubes, absorbed by methanesulfonic acid, and then con- verted to NH4 ＋. NH4 ＋ was separated by cation- exchange chromatography column and determined by electrical conductivity detector. The retention time and the peak area were used for qualitative and quantitative analysis respectively. Results When the concentration of ammonia ranged from 0.32 μg/ml to 30 μg/ml, it displayed a quadratic correlation （ r 〉0. 999）. The mini- mum detection limit was 0.1 μg/ml and the quantitation limit was 0.32 μg/ml. The minimum quantitation limit could reach 0.21 mg/m^3 when 7.5 L air sample could be collected under standard condition. The sampling efficiency with methanesulfonic acid as absorbing solution was above 99 %, and the relative standard deviation （RSD） was less than 5 %. Conclusions It is a simple, convenient, highly efficient and less interferential way to determinate the ammonia in workplace air by ion chromato- graphy described above. It meets the demands of GBZ/r 210,4 - 2008, produces less pollution than Nessler＇ s reagent colorime- try, and will be further developed into a standard determination method for ammonia in workplace air.