A simple and fast flow injection amperometry for the determination of methimazole in pharmaceutical preparations using an unmodified boron-doped diamond electrode

Fast and simple voltammetric sensing of avanafil in the pharmaceutical formulation by using unmodified boron-doped diamond electrode

Background and purpose

Erectile dysfunction is a common issue among adult males involving difficulty in maintaining an erection, and it is often treated with fast-acting, low-side-effect drugs like avanafil (AVN), among other phosphodiesterase-5 inhibitors. Hence, developing fast, simple, and sensitive methods to detect AVN is crucial.

Experimental approach

This study conducts an electroanalytical inquiry and provides a new voltammetric method for accurately analyzing AVN utilizing a boron-doped diamond (BDD) electrode without any modifications.

Key results

In the Britton-Robinson buffer (BR, 0.04 mol L-1, pH 4.0), cyclic voltammetry showed a clearly defined and irreversible anodic peak at around +1.44 V relative to Ag/AgCl. The pH of the solution was shown to have an impact on the voltammetric signals of the oxidation peaks. A good linear response for AVN quantification was achieved using square-wave voltammetry. This was done in a 0.04 mol L-1 BR (pH 4.0) solution at a potential of +1.33 V (vs. Ag/AgCl). The method exhibited a wide dynamic range of 0.5 to 30.0 μg mL-1 (1.0 to 62 μmol L-1) and a low limit of detection of 0.14 μg mL-1 (0.29 μmol L-1). The method proposed demonstrated suitability for determining AVN content in pharmaceutical formulations. The accuracy of the approach was demonstrated by comparing the results obtained using the developed method with those achieved using the UV-Vis spectrometry method.

Conclusion

Our method simplifies the analytical process by eliminating the need for electrode modification, reducing both time and resource requirements while enhancing overall feasibility.

An electrochemical sensing platform based on a modified carbon paste electrode with graphene/Co3O4 nanocomposite for sensitive propranolol determination

A simple and sensitive method for the determination of propranolol using a modified carbon paste electrode with graphene/Co3O4 nanocomposite was presented. The electrochemical measurements of propranolol are studied using differential pulse voltammetry, cyclic voltammetry and chronoamperometry. The graphene/Co3O4 nanocomposite exhibits excellent catalytic activity towards the electrochemical oxidation of propranolol in phosphate buffer solution of pH 7.0. The graphene/Co3O4 nanocomposite facilitates the determination of propranolol in the concentration range 1.0-300.0 μM and a detection limit and sensitivity of 0.3 μM. and 0.1275 μA/μM were achieved.

Voltammetric determination of hydrochlorothiazide at a modified carbon paste electrode with polypyrrole nanotubes

In this paper, the electrochemical behavior of hydrochlorothiazide (HCTZ) is described using carbon paste electrodes modified with polypyrrole nanotubes (PPy-NTs/CPEs) at pH value 7. Experiments revealed that the presence of HCTZ greatly impacts the electrochemical behavior of modified CPEs. The synthesized PPy-NTs were utilized as a sensing material for the electrochemical detection of HCTZ and were investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry. The key experiment conditions, including supporting electrolyte and electrolyte pH, were studied and optimized. Under optimized conditions, the prepared sensor displayed the linear relationships for the concentrations of HCTZ from 5.0 to 400.0 μM (R2 = 0.9984). The detection limit of the PPy-NTs/CPEs sensor was found to be 1.5 μM using the DPV method. The PPy-NTs is highly selective, stable and sensitive for the determination of HCT. Therefore, we believe the newly prepared PPy-NTs material can be useful for different electrochemical applications.