Voltammetric determination of weak bases based on oxidation of α-tocopherol in an unbuffered solution

• Published in: Journal of electroanalytical chemistry (Lausanne, Switzerland) Switzerland), 2003-10, Vol.557, p.91-97
• Main Authors: Taguchi, Junichi, Ohtsuki, Sanae, Kusu, Fumiyo
• Format: Article
• Language: English
• Subjects: Analysis; Biological and medical sciences; Determination of base; General pharmacology; Lidocaine; Medical sciences; Oxidation; Pharmacology. Drug treatments; Voltammetry; α-Tocopherol
• ISSN: 1572-6657; 1873-2569
• DOI: 10.1016/S0022-0728(03)00351-6

Linear sweep voltammetry of weak bases with α-tocopherol was investigated at a plastic formed carbon electrode in methanol. A weak base present in an α-tocopherol solution gave rise to a new peak (oxidation prepeak) resulting from the oxidation of α-tocopherol at a potential more negative than that of α-tocopherol. With an increase in p K b of the base, the half-peak potential of the oxidation prepeak was found to shift to a less negative potential. The prepeak height was noted to depend linearly on the concentration of base compound up to a certain value, the same as that for α-tocopherol in the electrolyte. The electrode oxidation reaction was shown to occur in accordance with a prepeak current controlled by diffusion of weak base to the electrode surface in unbuffered solution. A new voltammetric determination of such weak bases as aniline, clotrimazole, cimetidine, disopyramide, lidocaine, medazepam, metoclopamide, and N, N-diethylaniline was developed.