On-line electrochemistry-liquid chromatography with UV absorbance detection for elucidating the electrochemical oxidation mechanism of α-tocopherol in methanol
✍ Scribed by Zhang Tian-Yi; Zhu Shi-Min
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 341 KB
- Volume
- 309
- Category
- Article
- ISSN
- 0003-2670
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✦ Synopsis
Electrochemical studies of cY-tocopherol were carried out in methanol-acetate buffer solution. cu-Tocopherol displayed one anodic peak in a cyclic voltammogram. Two-electron transfer in the oxidation of a-tocopherol was demonstrated by coulometry. The on-line electrochemistry-liquid chromatography with UV absorbance detection method was developed to separate and detect the intermediates and products which were formed during the oxidation of cY-tocopherol. When the potential was controlled at + 0.8 V (vs. Pd), the intermediates 9-hydroxy-cy-tocopherone and 9-methoxy-cy-tocopherone were identified together with the ultimate cY-tocopherylquinone product. Intermediates and products formed in the chemical oxidation of (Y tocopherol by N-bromosuccinimide were also studied. The changes in the chromatographic peaks indicated a clear transformation of 9-hydroxy-cx-tocopherone into the quinone. The experimental results revealed that the intermediates and products generated in the electrochemical and chemical oxidation processes were essentially the same.