Determination of nitrite and nitrate in some horticultural and meat products and in samples of soil

This study of quantitative determination of nitrite and nitrate contents is based on spectrophotometric measurement of the red colour formed when sulphanilic acid is diazotised by the nitrite to be determined and coupled to 1-naphthylamine-7-sulphonic acid (Cleve's acid 1-7). Nitrate is first reduced to nitrite in a cadmium reducing column. Good results have been obtained with some horticultural and meat products and samples of soil.