Kinetic Determination of Nitrite in Drinking Water by Fluorometry

Abstract

A method for the kinetic determination of nanogram amounts of nitrite based on its acceleration of the rate of bromination of pyridine-2-aldehyde 2-pyridylhydrazone in acidic medium has been developed. The reaction is followed by fluorometry while monitoring the formation of a fluorescent product using an excitation wavelength of 291nm and an emission wavelength of 432nm. The kinetic methods of the initial rate and induction period have been assessed regarding their analytical performance, the latter showing improved capabilities. This method has been applied to drinking water analysis, with a detection limit of 4.6ng/ml and recoveries of 92-105%. The relative standard deviation of the method is 2.4%. The major advantages of this method are simplicity, absence of a reagent blank, selectivity and sensitivity.