Chromogenic Reagent System for Complexation of Nitrobenzene and its Application to Real Sample

Abstract

A new sensitive analytical method for the determination of nitrobenzene is proposed. In this method, nitrobenzene is reduced in presence of Zn dust in acidic medium. The reduced nitrobenzene is then oxidized and subsequently coupled with phloroglucinol in alkaline medium. The red-purple color dye formed, shows an absorbance maxima at 450 nm. The reagent blank shows negligible absorbance in similar conditions. The color system obeyed Beer’s law in the range of 120 to 480 µg (12 to 48 mg L^-1) nitrobenzene in 10 mL of final volume. Molar Absorptivity and Sandell’S Sensitivity were found to be 2.1x10³ L mol^-1 cm^-1 and 0.06 cm respectively. The Standard Deviation and Relative Standard Deviation were found to be ±0.003 and 1.41% respectively. Various reaction parameters like time, temperature, alkalinity and reagent concentration etc. also studied and have been optimized for the complete color reaction. To assess the applicability of the method, it has been applied successfully for the analysis of nitrobenzene in polluted water, vegetables and grains.