Plant tissue-based membrane biosensor for l-ascorbic acid

✍ Scribed by L. Macholán; B. Chmelíková

• Publisher: Elsevier Science
• Year: 1986
• Tongue: English
• Weight: 430 KB
• Volume: 185
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(86)80045-9

✦ Synopsis

Coupling of a slice of the mesocsrp of squash (Cucurbita pepo) or cucumber (Cucumis sativus) to a Clark-type oxygen electrode allows 0.02-0.57 mmol 1-l L-ascorbic acid to be determined amperometrically. The method is based on monitoring the decrease in the current of oxygen at an applied potential of -650 mV vs. Ag/AgCl; oxygen is consumed in the analyte oxidation catalyzed by ascorbate oxidase in the plant tissue. One tissue slice serves for 50-80 measurements at 30°C and pH 6. Spare slices can be stored for at least a year in aqueous 50% glycerol without substantial loss of enzyme activity. The biosensor is highly selective towards ascorbic acid with a response time of 70-90 s, the relative standard deviation being about 3%. Satisfactory results were obtained in the analysis of some fruit juices and vitamin tablets.