DETERMINATION OF TRACE ANILINE IN WATER BY A SPECTROPHOTOMETRIC METHOD AFTER PRECONCENTRATION ON AN ORGANIC SOLVENT-SOLUBLE MEMBRANE-FILTER

Based on collecting trace aniline on a membrane filter and dissolving the filter in an organic solvent, a simple and rapid preconcentration technique has been proposed for its spectrophotometric determination i n water samples. In 0.1M of hydrochloric acid medium, aniline diazotiz es with nitrous acid, which is then coupled with N-(1-naphthyl)-ethyle nediamine at the same acidity. The ate-dye formed is collected on a 0. 45 mu m nitrocellulose filler at pH 5.0 of acetate buffer solution in the presence of surfactant tetradecylpyridinium chloride. The dye with the filter is dissolved in a small volume of 2-methoxyethanol acidifi ed with hydrochloric acid, and the absorbance of the resulting solutio n is measured at 560 nm against a reagent blank. Detection limits bett er than 1.0 mu g . L(-1) of C6H5NH2 can be achieved. The components no rmally present in water do not interfere when a masking agent solution is added. The proposed method has been applied to the analysis of wat er samples from several sources. The recoveries of the aniline added t o the samples are quantitative, and results found are satisfactory.