A new technique for the determination of phosphorus by the molybdenum blue method

Abstract

A new technique is described in which KI is used as reducing agent. The liberated I is removed by the addition of sodium sulphite and the color matched by means of a photoelectric absorptiometer or a visual colorimeter. The color is stable and obeys Beer''s Law closely if a correction is made for the faint color present in the blank. The maximum amts. of various salts which may be present in the sample without affecting the result have been detd. The range of the method is 1-100 [mu]g P and where applicable it gives a higher degree of accuracy than existing methods.