Development of New Spectrophotometric Method for Determination of Sulfamethoxazole Based on Diazo Coupling Reaction

Abstract

Sulfamethoxazole (SMX) was treated with sodium nitrite and hydrochloric acid for
diazotization reaction followed by coupling with chromotropic acid in alkaline
medium to form,an orange colored azo dye compound which exhibits maximum
absorption (λmax) at 513nm and the concentration of(SMX) was determined
spectrophotometrically. The optimum reaction conditions and other analytical
parameters were evaluated. In addition to classical univariate optimization, modified
simplex method (MSM) has been applied in optimization of the variables affecting the
color producing reaction.
Beer’s law obeyed in the concentration range of 0.5–20μg.mL-1 with molar
absorptivity of 3.1786×104L.mol-1.cm-1. The limit of detection was found to be
0.043μg.mL-1 and the Sandell's sensitivity value was 7.9681μg.cm-2. The proposed
method could be successfully applied to the determination of (SMX) in synthetic
sample and urine.