Suggested Method for Nitrate Determination With 2.6‐Xylenol Reagent

Abstract

In Standard Methods, two methods are given for the determination of nitrate ions in water: the phenoldisulfonic acid method; and, the reduction method. In recent years, the use of brucine as a colorimetric reagent for nitrate has been reinvestigated and proposed for the determination of nitrate ions in water. The brucine method has the advantage over the standard methods in speed and simplicity. The brucine color system does not obey Beer's law, and, owing to variability of color development from one occasion to another, one must run a set of standards along with the sample. A new spectrophotometric method, employing 2,6‐xylenol as a reagent, is suggested for the determination of nitrate ions. Absorption measurements are made at 322‐324 mμ, Beer's law is obeyed in the concentration range of 0‐125 ppm nitrate, and precision, expressed as the coefficient of variation, averages about 1 per cent in this range. Direct determination of samples is possible and requires less than 10 minutes.