Yavuz Yardım

This article reports on the development of an electroanalytical method for the quantitative determination of the selective estrogen receptor modulator raloxifene (RLX) using voltammetry at a pretreated boron-doped diamond (BDD) electrode. RLX exhibited irreversible cyclic voltammetric (CV) behavior in 0.04 mol L-1 Britton?Robinson (BR) supporting electrolyte at pH 2, generating two anodic oxidation peaks at approximately 0.79 V (PA1) and 1.46 V (PA2). Scan rate analysis revealed that both adsorption and diffusion mechanisms govern RLX transport to the electrode surface. Consequently, incorporating a preconcentration (deposition) step was hypothesized to enhance analytical sensitivity. Optimal deposition parameters, along with supporting electrolyte pH and square-wave voltammetry (SWV) modulation settings, were systematically optimized. Quantitative analysis was based on the first anodic peak (PA1) in 0.04 mol L-1 BR buffer at pH 2, exhibiting a linear dynamic range from 0.025 to 5.0 ?g mL-1 (from 4.9?10-8 to 9.9?10-6 mol L-1) and a detection limit of 0.0073 ?g mL-1 (1.4?10?? mol L-1). The method?s applicability was validated by successfully quantifying RLX in pharmaceutical formulations.

In this work, the voltammetric sensing of nifuroxazide (NFX) was assessed utilizing a boron-doped diamond (BDD) electrode that underwent electrochemical pretreatment, enhancing its surface activity. Cyclic voltammograms of NFX revealed well-defined, single, and irreversible peaks at 0.94 V (vs. Ag/AgCl) in a 0.04 M Britton- Robinson (BR) buffer solution at pH 6.0. The oxidation peaks of NFX were found to be pH-dependent across a range from 2.0 to 12.0. Introducing a cationc surfactant (CTAB; cetyltrimethylammonium bromide) into the selected electrolyte increased the anodic peak currents of NFX. Under optimized conditions, a linear relationship was established for NFX quantification in 0.04 M solution of BR buffer (pH 6.0) containing 2×10-4 M CTAB at +1.02 V (vs. Ag/AgCl). The linear range spanned from 0.05 to 2.0 μg mL-1 (1.8×10-7 – 7.2×10-6 M), with a detection limit of 0.013 μg mL-1 (4.7×10-8 M). The NFX concentration in the drug formulation was successfully quantized using this method.

This research paper presents an electroanalytical investigation using the voltammetric method to quantify indacaterol maleate (IND) employing an unmodified boron-doped diamond (BDD) electrode. IND exhibited a distinct, irreversible oxidation peak at approximately 1.06 V (vs. Ag/AgCl) in a 0.1 mol L-1 phosphate buffer solution (PBS) with a pH of 2.5, as demonstrated by cyclic voltammetry (CV). A hypothetical mechanism for the electro-oxidation of IND, based on data gathered from CV investigations, was suggested. The square wave-adsorptive stripping voltammetric technique achieved acceptable linearity in PBS (pH 2.5) at approximately 0.90 V. The methodology demonstrated linearity within the concentration range of 1.0 to 30.0 ?g mL-1 (equivalent to 1.97?10-6?5.89?10-5 mol L-1) and yielded a limit of detection (LOD) of 0.22 ?g mL-1 (equivalent to 4.33?10-7 mol L-1). The proposed method?s applicability was assessed through the sensing of IND in drug formulations.

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.

This study presents an electroanalytical approach to measure the catechol-O-methyltransferase (COMT) inhibitor tolcapone (TOL) using a boron-doped diamond (BDD) electrode. The application of cyclic voltammetry (CV) technique revealed that TOL exhibited a distinct, diffusion-controlled, irreversible anodic peak at a potential of approximately +0.71 V (vs. Ag/AgCl) in a 0.1 mol L–1 phosphate buffer solution (PBS) with a pH of 2.5. The oxidation of TOL is highly dependent on the pH and supporting electrolytes. Based on the data obtained from the pH investigation, a proposed mechanism for the electro-oxidation of TOL is suggested. Using the square wave voltammetry (SWV) technique, a satisfactory linear relationship was observed at approximately +0.66 V in a 0.1 mol L–1 phosphate buffer solution (PBS) with a pH of 2.5. The presented method exhibited linearity within the concentration range between 1.0–50.0 μg mL–1 (3.7 × 10–6–1.8 × 10–4 mol L–1), with a limit of detection (LOD) of 0.29 μg mL–1 (1.1 × 10–6 mol L–1). The BDD electrode demonstrated good selectivity against inorganic ions and filler materials interference. Finally, the suitability of the developed approach was assessed by measuring TOL in tablet formulations, resulting in favorable recoveries ranging from 103.4% to 106.2%.