Determination of Nitrate in Polluted Water with New Coupling Reagent Hydroxamic Acids : A Rapid and High Potential Reagent for Trace Determination of Nitrate in Polluted Water

Abstract

A rapid, stable and direct visible spectrophotometric method, based on the quantitative nitration of hydroxamic acids in concentrated sulphuric acid, is described for determination of nitrate in water samples from different sites of Bhopal. The nitration product was extracted in n-hexane and yellow complex formed was determined at 462 nm, 458 nm and 450 nm for N-PBHA, N-PClPBHA and N-PClPCHA, respectively. The calibration graph was linear over the range of 0.0001965-0.002751, 0.001965-0.03931 and 0.001965-0.02554 µg/25 ml for N-PBHA, N-PClPBHA and N-PClPCHA, respectively. The molar absorptivities were found to be 3.81x10⁶, 2.65x10⁵ and 4.11x10⁵ L mol^-1 cm^-1 for the above three hdroxamic acids. The accuracy of method did not depend on nitrate contents.

Key words: Nitrate, Hydroxamic acid, Water, Spectrophotometry, Potential.