Sensitive fluorimetric method for the determination of aniline by using tetra-substituted amino aluminium phthalocyanine

This is the first report of the determination of aniline with tetra-substituted amino aluminium phthalocyanine (TAAlPc) by a fluorimetric method. In KBr-HCl solution, nitrite ion diazotizes TAAlPc, thus, the fluorescence of TAAlPc is dramatically quenched. However, there is less quenching in the presence of aniline and the recovery in fluorescence intensity is linear with the concentration of aniline. Based on this, a novel method has been developed for the determination of aniline in aqueous solutions. Under the optimal conditions, the calibration graph for aniline is from 5 to 300 ng ml⁻¹ with a 3σ limit of detection of 1.8 ng ml⁻¹. The relative standard deviation for nine replicate measurements of 100 ng ml⁻¹ aniline is 1.7%. The method was applied to the analysis of water samples with satisfactory results.