A New Approach for the Voltammetric Determination of Amoxicillin in the Dosage Form Using Azo Coupling Reaction with Sulphanilamide.

The novel method of amoxicillin (AM) determination has been developed using single‐sweep polarography. The proposed method is based on the obtaining of yellow coloured azo compound due to azo coupling reaction of previous diazotized sulphanilamide (SA) (in the medium of 0.6 M hydrochloric acid) with amoxicillin at pH=9.0 with the further reduction of the formed analytical form on a dropping mercury electrode. Voltammetric determination of amoxicillin is carried out due to the reduction peak of azo group of the obtained azo compound in the presence of 0.05 mol ⋅ L−1 Na2B4O7 as a background electrolyte at the potential Ecp2=−0.55 V and potential sweep rate of 2.5 V ⋅ s−1. The developed voltammetric method has two linear ranges of the determined concentrations (0.05–2.0) ⋅ 10−5 mol ⋅ L−1 and (0.2–1.0) ⋅ 10−4 mol ⋅ L−1 and the high sensitivity: LOD without the removing of unreacted sodium nitrite is 1.1 ⋅ 10−6 mol ⋅ L−1, and 7.2 ⋅ 10−7 mol ⋅ L−1, when NaNO2 excess is removed using urea. The developed voltammetric technique of AM determination has been approved during the analyses of tablets and oral suspension. [ABSTRACT FROM AUTHOR]