Differential Pulse-Adsorptive Cathodic Stripping Voltammetric Determination of Sulfadiazine Drug in Pharmaceutical Formulations and Drug Residue in Wastewater at a Hanging Mercury Dropping Electrode

An adsorptive differential pulse cathodic stripping voltammetry method has been developed for determining the presence of sulfadiazine drugs. The method is based upon the adsorptive collection of the drug on a hanging mercury dropping electrode at −1.0 V versus Ag/AgCl reference electrode. Factors affecting the stripping performance such as, pH, accumulation time and potential, sweep rate were critically studied. The optimum conditions were achieved in a Britton–Robinson buffer of pH 5–6. At the optimal conditions, the cathodic stripping current of the drug at −1.0 V versus concentrations was linear in the concentration range 3.7×10-9\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${3.7 \times 10^{-9}}$$\end{document} –1.0×10-7molL-1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${1.0 \times 10^{-7}\;{\rm mol L}^{-1}}$$\end{document}. The lower limit of detection and quantification of the drug were 1.1×10-9\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${1.1 \times 10^{-9}}$$\end{document} and 3.7×10-9molL-1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${3.7 \times 10^{-9} {\rm mol L}^{-1}}$$\end{document}, respectively. The method was successfully applied for the determination of industrial wastewater, pure form (98.2±3.1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${98.2 \pm 3.1}$$\end{document} %) and drug formulations (98.3±2.9\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${98.3 \pm 2.9}$$\end{document} %). The method was validated by comparison with the standard HPLC and the reported methods. The method offers a simple system, coupled with good reproducibility, accuracy, ruggedness, and cost-effectiveness.