Flow injection spectrophotometric determination of amoxicillin in pharmaceutical samples by coupling with diazotized p-nitroaniline

Abstract

A spectrophotometric method using flow injection analysis (FIA) is described for the determination of amoxicillin (AMX). Its detection limit, linearity and reproducibility were examined.The automated method is based on a coupling reaction between AMX and diazotized para-nitroaniline (DPNA) in alkaline medium to form an intense reddish-orange, water-soluble dye that is stable and has a maximum absorption at 478 nm.The calibration graph was linear over the concentration range of 0.5-100 μg.ml-1 with a detection limit of 0.104 μg.ml-1 and sample throughput of 60 h-1. The proposed method was successfully applied to the determination of AMX in injections and capsules.