A sensitive and extractive spectrophotometric method for determination of trace amount of nitrite in environmental and biological samples

Seema Singh, Jeena Harjit*, H.

Abstract

A rapid, simple, selective and sensitive method for the spectrophotometric determination of nitrite in water, soil and biological samples has been developed and optimum r eaction conditions along with other analytical para meters have been evaluated. Nitrite reacts with N-phenyl-b enzo-hydroxamic acid N-PBHA(I), N-p-chloro-phenyl-b enzo- hydroxamic acid N-PClPBHA(II) and N-p-chloro-phenyl -cinnamo-hydroxamic acid N-PClPCHA(III) in acidic medium to form pink color complex. The intensity of colour increases with substitution. At analytical wavelength the maximum absorption of the complexes were 522 nm, 51 7 nm and 506 nm, and beer’s law is obeyed over the concentration range of 0.0002664-0.002930 ppm, 0.00 02664 – 0.003729 ppm and 0.002664 - 0.01864 ppm, fo r N- PBHA, N-PClPBHA and N-PClPCHA, respectively. The mo lar absorptivities were found to be 3.55x10 5 , 2.65x10 5 and 5.62x10 5 L mol -1 cm -1 and the relative standard deviation 1.19%, 1.84% an d 1.28%, respectively with detection limit of 0.01998, 0.01998 and 0.1332 μ g/25 ml of ni trite for N-PBHA, N-PClPBHA and N-PClPCHA, respecti vely. The optimum reaction conditions such as pH, time an d solvent, etc for complete color reaction have bee n evaluated with all three hydroxamic acid complexes. The metho d has been successfully applied for determination o f nitrite in water, soil and biological samples