目的 探讨连续流动注射仪测定水中氨氮浓度的可靠性和适用性。方法 利用流动注射分析技术实现在线分析, 根据贝特洛反应,氨与氯反应生成一氯胺后,再和水杨酸盐发生化学反应生成5-氨基水杨酸盐,5-氨基水杨酸盐被氧化后和自身偶合反应生成绿色的络合物,在波长660 nm下比色测定。结果 氨氮在0~1.00 mg/L时具有良好的线性关系,相关系数为0.9998;检出限为6.33 μg/L;平均相对标准偏差为<2％;加标回收率为96.2%~99.6%之间;有证标准物质测定均在定值范围内,相对误差<2％;采用纳氏比色法和连续流动注射法同时对20份水样测定,发现两种方法检测结果差异无统计学意义(t=0.988,P=0.336)。结论 流动注射仪测定水中氨氮的方法灵敏度高,准确度好,大大缩短了测定时间,尤其适合大批量水样分析。

Objective To explore the reliability and applicability of continuous flow injection analyzer for determination of ammonia nitrogen concentration in water. Methods Samples were analyzed automatically on line by flow injection analysis technology, and the test reaction was based on the improved Berthelot reaction, in which ammonia nitrogen in water was chlorinated to form monochloramine, and the monochloramine reacts with salicylate to form 5-amino salicylate. The green complex was produced through oxidation and oxidation coupling reaction, and was determined at the wavelength of 660nm. Results Under the experimental conditions, a mmonianitrogen has a good linear relationship between 0 and 1.00mg/L. The correlation coefficient was 0.9998 and the detection limit was 6.33μg/L.The mean relative standard deviation was <2％, and the recovery rate was 96.2%-99.6%.All the certified standard substances were measured within the specified range, and relative error was <2％. 20 water samples was measured simultaneously by flow injection analysis and Nessler's reagent colorimetric method, the results showed that there was no statistic difference between the two methods(t=0.988,P=0.336). Conclusion The method of measuring the ammonia nitrogen in water by flow injection analyzer was proved to be sensitive and accurate, which greatly reduces the measurement time, and is especially suitable for analysis of large-scale water samples.