Photometric Determination of Ammonia Nitrogen in Plant Sample by Its Color Reaction with Trichloroisocyanuric Acid and Salicylic Acid

Ammonia nitrogen in plant sample was determined photometrically by its color reaction with trichloroisocyanuric acid (TCCA) and salicylic acid (SA). In an alkaline medium, nitrogen in from of NH+4-ion was oxidized by TCCA and reacted with SA to give a blue colored complex, having its absorption maximum at 660 nm and in apparent molar absorptivity of 9.78×104L·mol-1·cm-1. Beer′s law was kept within 6.0 mg·L-1 of ammonia nitrogen. In analyzing plant samples by the proposed method, the results obtained were in consistency with the results found by elemental analysis.