Voltammetric Determination of Ascorbic Acid in Pharmaceutical Formulations Using Modified Iodine-Coated Platinum Electrode

Abstract

Background: Despite the high reactivity of the platinum electrode, the iodine-coated platinum electrode shows obvious inertness toward adsorption and surface processes. For that, iodine-coated platinum electrodes accommodate themselves to interesting voltammetric applications. Objectives: This study reports using the modified iodine-coated polycrystalline platinum electrode as a voltammetric sensor for ascorbic acid determination in pharmaceutical formulations. Methods: The developed voltammetric method based on recording cyclic voltammograms of ascorbic acid at iodine-coated electrode The optimized experimental parameters for the determination of ascorbic acid were using 0.1 M KCl as a supporting electrolyte with a scan rate of 50mV/s. Results: The anodic peak related to ascorbic acid oxidation was centered at nearly 0.28V. An excellent and extended linear dependence of the oxidative peak current on the concentration of ascorbic acid was observed in the range 2.84x10-3 - 5.68 mM. The limit of detection (LOD) and limit of quantitation (LOQ) were 1.0 µM and 3.01 µM, respectively, attesting to the method’s sensitivity. The investigation for the effect of potential interference from multivitamin tablet ingredients (vitamins B1, B6, B12, folic acid, citric acid, sucrose, glucose, and zinc) indicated specific selectivity toward ascorbic acid and the absence of any electrochemical response toward these components. Recovery results in the range 98.93±2.78 - 99.98±5.20 for spiked standard ascorbic acid in pharmaceutical formulations further confirmed the potential applicability of the developed method for the determination of ascorbic acid in real samples. Conclusions: The developed method was successfully applied to the analysis of ascorbic acid (vitamin C), and the obtained results were in good agreement with the labeled values; besides, the statistical tests indicated no significant difference at p=0.05 with a 95% confidence level.

Different Aspects of the Voltammetric Detection of Vitamins: A Review

“…Cyclic voltammetry with iodine-coated Pt electrode in 0.1 M KCL solution has been successfully applied for the selective determination of ascorbic acid in multivitamin pharmaceutical products (B1, B6, B12, B9, and C). The oxidation peak of ascorbic acid has occurred at 0.28 V, while the detection limits have been quite low [ 128 ]. Pharmaceutical formulations and foods have been studied with a combination of cyclic voltammetry and differential pulse voltammetry, with a carbon paste electrode molded with multi-walled carbon nanotubes and graphite in acidic solution with pH = 2 [ 129 ].…”

Box–Behnken Design Based Development of UV-Reversed Phase High Performance Liquid Chromatographic Method for Determination of Ascorbic Acid in Tablet Formulations

“…Various other analytical methods, such as spectrophotometry [18][19][20][21][22][23], thin layer chromatography [24][25][26][27][28], capillary electrophoresis [29] and voltammetry [30], have been published for the determination of ascorbic acid in pharmaceutical formulations and biological fluids. UV-HPLC methods render more advantages over spectrophotometry, thin layer chromatography, capillary electrophoresis and voltammetry in terms of the multicomponent analysis of analytes (even more than two components), sensitivity, wide linear dynamic range, selectivity and specificity via separation.…”