FIA-spectrophotometric determination of nitrazepam by oxidation with a solid-phase reactor and coupling with 2,2'-dihydroxybiphenyl reagent

Abstract

A new reverse flow injection system combined with a solid-phase reactor containing PbO₂ was suggested for spectrophotometric determination of nitrazepam in pharmaceutical tablets. Nitrazepam was  measured by coupling with a new reagent (2,2'-dihydroxybiphenyl) oxidized by forced through the reactor containing PbO₂ immobilized in a polymeric matrix. The absorbance of the resultant blue colored product was measured at 635 nm, and the calibration graph for nitrazepam was linear in the 10 to 300 µg/mLconcentration range with RSD of less than 2.5% (n = 38) and a sample throughput of 40 h^-1. The influence of the variables of flow system and solid-phase reactor such as composition, size of particles and length of the reactor, were studied. The proposed method was applied for determining nitrazepam in two commercial tablets without any interferences.

KEY WORDS: Reverse flow injection, Nitrazepam, PbO₂ reactor, Oxidative coupling

Bull. Chem. Soc. Ethiop. 2019, 33(1), 183-190

DOI: https://dx.doi.org/10.4314/bcse.v33i1.18