Abstract
Facile and highly sensitive spectrophotometric methods have been developed and adapted for rapid determination of nitrite. The methods are based on a diazotization of either dapsone or metoclopramide, followed by coupling with benzoylacetone in basic medium to give coloured azo dyes with lambda(max) of 437 and 411 nm, respectively. The molar absorptivity and Sandell's sensitivity were found to be 4.31 X 10(4) l mol(-1)cm(-1) and 1.07 x 10(-3) mu g cm(-2) for dapsone-benzoylacetone, while that for metoclopramide-benzoylacetone were found to be 3.18 x 10(4) l mol(-1) cm(-1) and 1.45 x 10(-3) mu g cm(-2). No significant interferences caused by various cations and anions. The proposed methods were successfully applied to the determination of nitrite in various water and soil samples. A proposal of the reactions pathways is also presented.