α-Naphthylamine Solution is used along with Sulphanilic acid (R015)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)