荧光熄灭法测定痕量亚硝酸根离子研究

Study on determination of trace nitrite by fluorimetric quenching method

研究了在酸性介质中，NO2^-与酸性品红发生重氮化反应，致使酸性品红的荧光强度随NO2^-加入量增加而明显降低的现象，建立了荧光熄灭法测定痕量NO2^-新方法。方法的线性范围为0．02-0．32μg,／mL，线性回归方程△F=37．9＋1040．0c（μg／mL），相关系数r=0．9991，检出限为8．2ng／mL。本方法具有灵敏度高、选择性好、操作简便、快速的特点，用本方法测定自来水、珠江水等水样中的痕量NO2^-，结果满意。

A new fluorimetric quenching method for determination of trace nitrite has been developed in this paper. The method is based on the diazo-reaction between nitrite ion and fuchsin acid in a hydrochloric acid medium. The linear range of determination for NO2^- is 0.02 - 0.32 μg/mL with a detection limit of 8.2 ng/ mL.The regression equation and correlation coefficient are △F = 37.9 ＋ 1 040.0c （μg/mL）, and r = 0.999 1, respectively. This method has some advantages such as high sensitivity and selectiv- ity, easy and prompt operation. It is applied to determine trace NO2^- in water with satisfactory results.