Utilizing an anionic surfactant aqueous media for voltammetric sensing of anti-cancer drug imiquimod in the pharmaceutical formulation and urine samples at the boron-doped diamond electrode surface

This work demonstrates an electroanalytical evaluation for voltammetric sensing of the anti-cancer drug imi-quimod (IMQ) at the boron-doped diamond electrode. By using cyclic voltammetric technique, IMQ demon-strated a well-defined, adsorption-controlled, irreversible anodic peak at approximately +1.56 V (vs Ag/AgCl) in 0.1 M H2SO4 solution. A possible mechanism for the electro-oxidation of IMQ was proposed based on the pH investigation data. The voltammetric signals of IMQ were improved by adding sodium dodecyl sulfate (SDS), an anionic surfactant, to the selected supporting electrolyte. By utilizing the square wave-adsorptive stripping voltammetric technique, acceptable linearity was obtained in 0.1 M H2SO4 solution with SDS at about +1.49 V (vs Ag/AgCl). The presented approach was linear in the concentration range of 0.005 and 1.0 & mu;g mL-1 (2.1 x 10-8-4.2 x 10-6 M), with a lower limit of detection of 0.0015 & mu;g mL-1 (6.2 x 10-9 M). Eventually, the proposed approach's applicability was investigated by sensing IMQ in pharmaceutical formulations and urine samples.