停流式流动注射催化光度法测定水中痕量亚硝酸根的研究

Studies on Kinetic Spectrophotometric Determination of Trace NO^-_2 by Stopped-flow Injection Method

亚硝酸盐与人体健康密切相关,是水质分析的重要项目之一。目前测定亚硝酸根的方法以分光光度法为主,但其灵敏度低、选择性欠佳。催化动力学光度法是测定亚硝酸盐的灵敏方法,本文把近几年发展起来的停流式流动注射技术与催化动力学光度法有机地结合起来,建立了高灵敏度、高选择性、简便快速地测定亚硝酸根的新方法,该方法可自动停流、阻断反应,省去了普通催化法所需的终止反应复杂步骤,所以快速、准确、重现性好,测定下限为2.4×1O-10gNO2-/mL,除Br-、I-、SCN-外,大多数阳离子和阴离子不干扰NO2-的测定,用于水中NO2-的测定,结果较为满意。

Based on the catalytic effect of trace NO2- on the oxidation of Rhodamine B by potassium bromate, a new kinetic spectrophotometric method for the determination of NO2- has been developed with stopped-flow injection technique. Beer' s law is obeyed for NO2- in the range of 0, 24~9. 0 ng/ mL and the limit of detection is 2. 4×10-10 g/mL. The method has been applied to the determination of NOf in water and the sampling frequency is 60 samples/h with satisfactory results.