Sulphanilic acid (R015) is used along with α-Naphthylamine Solution to determinaton of nitrate reduction by bacterial strains.The nitrate reductase producing organisms reduce nitrate to nitrite which reacts with sulphanilic acid to form a diazonium salt. This salt reacts with a-naphthylamine to form a red coloured, water soluble azo dye which results in the visualization of pink-red colour. A distinct red colour formation within 1-2 minutes indicates reduction of nitrate to nitrite. Acinetobacter calcoaceticus ATCC 43498
Negative (No colour change); Enterobacter aerogenes ATCC 13048 Positive(Development of distinct red colour)