Abstract
A simple, rapid, reliable and fully validated square wave adsorptive stripping voltammetric procedure has been developed for the determination of rifampicin drug in bulk form, capsules and human urine in acetate buffer pH 5.0 which shows electrochemical reduction at a new Dysprosium nanowires modified carbon paste electrode (DyNW/CPE). In this paper, the modified carbon paste electrode (DyNW/CPE) exhibiting an electrocatalytic response toward the oxidation of RIF is described. The shift of the E1/2 values of RIF to more negative potentials upon the increase of pH indicated the involvement of protons in the electrode reaction and that the proton-transfer reaction precedes the electrode process properly. Based on the interfacial adsorptive character of the drug onto the electrode, a validated direct square-wave adsorptive stripping voltammetric (SWAdSV) procedure has been described for the trace determination of the drug in pharmaceutical and real samples. The catalytic action of the DyNW/CPE is attributed to the formation of the porous construction and the increase of efficient surface of the electrode, due to the adulteration of DyNW with carbon powders. The optimized operational conditions were investigated. The proposed procedure is much simpler, fast, sensitive, and achieved much lower limits. The limit of detection (LOD) 5.0x10-10 M and limit of quantitation (LOQ) 8.0x10-10 M was achieved respectively in pharmaceutical formulation and spiked human urine.
Keywords: Dysprosium nanowire modified electrode, Rifampicin, Adsorptive square wave voltammetry
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