A spot test for nitrates

Abstract

At a dilution of 1:200.000, and in the presence of excess sulfuric acid, as little as 0.2 μg nitrate ion forms a yellow color with chroniotropic acid. Interfering colors due to nitrites and oxidizing agents are eliminated by previous treatment of the test sample with sodium sulfite, sulfuric acid, and sulfamic acid. © 1957 Springer-Verlag.