罗丹明B衍生物可见吸收光度法测定水中NO2--N

Determination of nitrite-N in water by visible absorption spectrometry with rhodamine B derivative

目的:建立一种测定水中NO2--N的新型可见吸收光度法。方法:合成了一种在可见区无吸收的罗丹明B衍生物,其可与NO2--N发生特异反应,促使体系光学信号从"无色、无吸收"转变为"洋红色、强吸收",实现了对水中NO2--N的高灵敏检测。结果:在5.0×10-8~7.0×10-6 mol/L范围内,体系的吸光度与NO2--N浓度呈线性关系,回归方程为:A=0.002267+0.00952CNO2--N(×10-7 mol/L),相关系数r=0.9994,检出限为1.50×10-8 mol/L。对纯净水和井水进行加标回收测定,回收率为96.0%~105.0%,RSD均小于5.0%。结论:方法特异性好、灵敏度高,适合水中痕量NO2--N的分析要求。

To develop a visible absorption spectrometry for the determination of nitrite-N in water. Methods: A rhodamine B derivative without absorption in the visible region was synthesized. It can react with NO2--N specifically, which makes the optical signal of the system change from "no colour, no absorption" to "magenta, strong absorption", and realizes the highly sensitive detection of NO2--N in water. Results: Under the optimized condition, the absorbance of the system was linear with the concentration of nitrite-N in the range of 5.0×10-8~7.0×10-6 mol/L. The linear regression equation was A= 0.002267+0.00952 CNO2--N(×10-7 mol/L) with a correlation coefficient of 0.9994. The detection limit was 1.50×10-8 mol/L. The recoveries ranged from 96.0%~105.0% and RSDs were less than 5.0% for the determination of well water and pure water. Conclusion: The developed method is specific and sensitive. It is suitable for the quantitative determination of trace nitrite-N in water.