Quantification of Cr(VI)-Thymoquinone Complex Using Cyclic Voltammetry

Farah Kishwar; Khalid Mohammed Khan; Rubina Perween; Anila Anwar; Nasir Akhtar

doi:10.52763/PJSIR.PHYS.SCI.59.2.2016.76.82

Farah Kishwar Department of Chemistry, Federal Urdu University of Arts, Science and Technology, Gulshan-e-Iqbal Campus, Karachi-75300, Pakistan
Khalid Mohammed Khan H.E.J. Research Institute of Chemistry, International Centre for Chemical and Biological Sciences, University of Karachi, Karachi-75270, Pakistan
Rubina Perween Department of Chemistry, Federal Urdu University of Arts, Science and Technology, Gulshan-e-Iqbal Campus, Karachi-75300, Pakistan
Anila Anwar Department of Chemistry, Federal Urdu University of Arts, Science and Technology, Gulshan-e-Iqbal Campus, Karachi-75300, Pakistan
Nasir Akhtar Department of Chemistry, Federal Urdu University of Arts, Science and Technology, Gulshan-e-Iqbal Campus, Karachi-75300, Pakistan

DOI: https://doi.org/10.52763/PJSIR.PHYS.SCI.59.2.2016.76.82

Keywords: Cr(VI)-thymoquinone complex, quantitative studies, cyclic voltammetry

Abstract

Quantitative studies of Cr(VI)- thymoquinone complex have been performed by cyclic voltammetry. For this purpose glassy carbon, platinum and saturated calomel electrodes were used as working, auxiliary and reference electrodes, respectively. The effects of concentrations and metal-ligand ratios on Cr(VI)- thymoquinone complex were investigated. Effect of concentration was found to follow Randles-Sevcik equation. Calibration curve method with linear regression line confirms that cyclic voltammetry can be used for quantification of Cr(VI)-thymoquinone complex for pharmaceutical assay. Complete complex formation seems to occur at metal ligand ratio 1:1. Results indicate quasi-reversible electron transfer
mechanism. E° and diffusion coefficient of complex at different concentrations and metal ligand ratios were also calculated and found to be 0.244±0.01 V and 3.45´10-5 cm2s-1, respectively. The values of transfer coefficients, a and b, were found to be 0.716±0.02-1.231±0.01 and 0.814±0.01-0.906±0.01, respectively.