涡旋辅助分散液液微萃取分光光度法测定饮用水中的亚硝酸根

Determination of nitrite in drinking water by vortex-assisted dispersive liquid-liquid microextraction combined with spectrophotometry

目的建立涡旋辅助分散液液微萃取分光光度法检测饮用水中亚硝酸根的含量。方法在酸性条件下,亚硝酸根与对硝基苯胺和二苯胺反应生成红色偶氮化合物,通过测定红色偶氮化合物间接测定亚硝酸根的含量,以分光光度法检测,外标法定量。确定萃取剂种类,利用正交试验对萃取剂的用量、酸浓度和涡旋时间进行优化。结果在浓度10~200μg/L范围内线性关系良好(r^2=0.9912),检出限为2.0μg/L,富集倍数为14。加标回收率为87.3%~106.3%,相对标准偏差0.8%~4.4%。结论该方法具有简单、快速、灵敏度高、准确性好,适用于饮用水中亚硝酸根的日常监测。

Objective To establish a method for determination of nitrite in drinking water by vortex-assisted dispersive liquid-liquid microextraction (VA-DLLME). Methods Under acidic conditions, nitrite reacts with p-nitroaniline and diphenylamined to form red azo compound. Indirect determination of nitrite content by red azo compound was detected by spectrophotometry and quantified by external standard method. The type of extractant was determined, and the amount of extractant, acid concentration and vortex time were optimized by orthogonal test. Results The linear relationship was good in the range of 10?200 μg/L (r^2 =0.9912), the detection limit was 2.0 μg/L, and the enrichment factor was 14. The recoveries of spiked standards were 87.3%?106.3%, and the relative standard deviations were 0.8%?4.4%. Conclusion This method is simple, rapid, sensitive and accurate, which is suitable for the daily monitoring of nitrite in drinking water.