Verapamil-Sensitive Electrodes: Main Factors Responsible for Analytical Performance and Use in Drug Analysis

• Published in: Journal of analytical chemistry (New York, N.Y.) N.Y.), 2022-12, Vol.77 (12), p.1586-1594
• Main Authors: Faisal A. Salih, Novakovskii, Andrei D., Egorov, Vladimir V.
• Format: Article
• Language: English
• Subjects: Analysis; Analytical Chemistry; Chemistry; Chemistry and Materials Science; Electrodes; Hydrogen-ion concentration; Mathematical analysis; Membranes; Plasticizers; Selectivity; Verapamil
• ISSN: 1061-9348; 1608-3199
• DOI: 10.1134/S1061934822120127

It has been established that the correct choice of the plasticizer and the measurement conditions makes it possible to achieve better analytical characteristics of verapamil-sensitive electrodes based on commercially available components in comparison with the best described in the literature. Particularly, the effect of pH on the verapamil-sensitive electrodes response was found to manifest itself in much more acidic media than might be expected from protolytic equilibrium and is due to the non-exchangeable extraction of verapamil into the membrane phase. The best parameters of selectivity, lower detection limit (4 × 10 −8  M), and potential reproducibility (0.15–0.22 mV) are achieved when using ortho-nitrophenyloctyl ether as a plasticizer and creating conditions that exclude non-exchangeable extraction of verapamil into the membrane. The proposed methods for the determination of verapamil in dosage forms are characterized by simplicity, rapidity, and high metrological characteristics.