Spectrophotometric determination of aniline in air and water via oxidative coupling using guaiacol

A sensitive spectrophotometric method is described for the submicrogram determination of aniline in water. The method involves the use of an oxidative coupling reaction for aniline and guaiacol using N-chlorosuccinimide as oxidizing agent in alkaline medium (pH 10 to 11). The blue-colored dye thus formed exhibits absorption maxima at 615 nm. Beer's law is valid up to 1 to 8 ppm of aniline in water. Molar absorptivity and Sandell's sensitivity are found to be 8.8 × 103 liters/mol/cm (±100) and 0.01 μg cm−2, respectively. The important parameters for complete color reaction have been optimized and applied for the analysis of aniline in polluted water. The method has been successfully applied for the determination of aniline in laboratory air after absorption in dilute hydrochloric acid.