The microdetermination of chloride, sulphate, phosphate and nitrite by reflectance spectrometry

Quantitative spot tests with a reflectance spectrometer have been developed for chloride (10-320 p.p.m.), sulphate (10-120 p.p.m.), phosphate (2-30 and 10-180 p.p.m.) and nitrite (1-35 and 10-100 p.p.m.). There are few interferences with these tests, and their effects can be overcome by standard techniques except for the interference from phosphate when it is present in the sulphate test, in large concentrations.