Direct determination of nitrate in natural water by ultraviolet first derivative spectrophotometry

摘要

A simple and sensitive method for nitrate determination by ultraviolet first-derivative spectrophotometry was described. The method allows to avoid the use of sulfamic acid, routinely needed to eliminate nitrite interference, and does not require any treatment of samples except acidification. The method gives a linear calibration curve over the range 0.1-1.8 mg.L~(-1). NO 3 — N with a reproducibility (RSD) of 1.27 % and a limit of detection of 0.03 mg.L~(-1). NO 3-N. The method is applied to determine nitrate in the ground and surface water. The comparison of results with those obtained by a reference method shows a good agreement (r = 0.9998) adequate for accurate and rapid analysis of a large number of samples.