Test Films for the Determination of Aromatic Amines and Hydrazines in Aqueous Solutions

Conditions of the test determination of toxic aniline (I), N,N-dimethylaniline (II), N,N-diethylaniline (III), 2,2,4-trimethyl-1,2-dihydroquinoline (IV), 1,1-dimethylhydrazine (V), and phenylhydrazine (VI) as their 4,6-dinitrobenzofuroxan (I) and 5,7-dinitrobenzofurazan (II, III, IV, V, VI) derivatives in aqueous solutions were found. Visual and spectrophotometric measurement of the signal was used. The reagents were immobilized in nitrocellulose films. Optimal results of visual determination of color development in test films were obtained with reagents immobilized in nitrocellulose at their concentration of 5 mass % and pH of the test solution in the range 6.0–7.5. The spectrophotometric measurement of the signal of test films was performed at wavelengths of 500–560 nm for I, V, and VI and 610–620 nm for II, III, and IV. The detection limit for spectrophotometric measurement was 0.01, 0.18, 0.13, 0.15, 0.16, and 0.04 mg/L for I, II, III, IV, V, and VI, respectively. The analytical range of the toxicants was 0.05–6.0 mg/L. Test determination is possible in the presence of alkylamines, ammonia, phenols, carboxylic acids, and inorganic salts.