水杨酸盐分光光度法测定空气中的氨

Determination of Ammonia in Air by Salicylate Spectrophtometry

[目的]探讨水杨酸盐分光光度法测定空气中氨的方法。[方法]用装有酸性溶液的大型气泡吸收管采集空气样品,以水杨酸盐为显色剂,采用722N型分光光度计,于波长690 nm处测定光密度比色定量。[结果]该方法的检出限为0.02μg/mL,日间精密度和日内精密度的相对标准偏差为0.5%-2.1%,样品加标回收率在96.0%-103.0%之间。标准参考物质的测定值在标准值范围内,测定结果与国标法（纳氏试剂分光光度法）比较,差异无统计学意义（P〉0.05）。[结论]空气中氨的水杨酸盐分光光度法操作简单,干扰少,具有良好的选择性和重现性,适合在基层推广应用。

[Objective] To develop an approach to determining ammonia in air by salicylate spectrophotometry.[Methods] To collect air samples by large air-bubble absorption tube containing acidic solution;apply salicylate as chromogenic reagent and use 722N spectrophotometer in 690 nm wave-length to measure absorbency;determine the quantities of ammonia in air samples by colorimetric analysis.[Results] The detection limit of this approach was 0.02 μg/mL;the relative standard deviations between inter-day precision and intra-day precision ranged between 0.5% to 2.1%;the spike recovery rates of samples ranged from 96.0% to 103.0%.The determined results of standard samples were within standard range.There were no significant differences between the results determined by salicylate spectrophotometry and GB method（Nessler＇s reagent method）（P〉 0.05）.[Conclusion] The approach to determining ammonia in air by salicylate spectrophotometry is easily operated and less interfered.Therefore,it can be easily selected and replicated at the grassroots level.