Spectrophotometric Determination of Sulfathiazole Using 2,4 –dinitrophenylhydrazine as Coupling Reagent


A rapid, sensitive and selective spectrophotometric method was developed fordetermination of sulfathiazole (STHZ) in aqueous solution. The method is based on theoxidative coupling reaction with 2,4-dinitrophenylhydrazine (2,4-DNPH) in a basic medium(pH 10.9) in the presence of potassium periodate to produce an intense orange colour, solublein water , stable product and absorbs at 492 nm. Beer's law was in the linear range 2.0-28.0μg/ml of sulfathiazole, the molar absorptivity, Sandellʼs sensitivity index and detection limitwere 1.1437 ×104 liter. mol-1.cm-1,0.0223 μg.cm-2 and 0.1274 μg/ml respectively. The RSDvalue was 0.75 - 1.12 % depending on the concentration. This method was appliedsuccessfully to the determination of sulfathiazole veterinary injection liquid solution (bioprime) with average recovery of not less than 100.38 %