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Please use this identifier to cite or link to this item: http://dspace.unimap.edu.my:80/xmlui/handle/123456789/2638

Title: Biosensor for antioxidant determination in herbal tea, Orthosiphon stamineus benth
Authors: Mohd Noor Ahmad
Kwan, Wei Yen
A.K.M. Shafiqul Islam
Zhari Ismail
Misni Surif
Keywords: Orthosiphon stamineus benth;Xanthine oxidase;Biosensors;Chitosan;Antioxidants;Herbal tea
Issue Date: 5-Dec-2007
Publisher: Gadjah Mada University
Series/Report no.: Proceedings of the 14th Regional Symposium on Chemical Engineering 2007
Abstract: An amperometric biosensor has been developed using xanthine oxidase (XO) enzyme as sensing materia] for the determination of antioxidant property of Orthosiphon stamineus benth (Cat whiskers) extracts. The enzyme was physically entrapped in modified chitosan membrane on carbon paste electrode. Experimental variables concerning the biosensor preparation such as the effect of enzyme amount, chitosan pH, pH of working buffer were optimized. The sensor showed linear response towards xanthine (poised at +600mV vs. Ag/AgCl) between 5.0 x 10ֿ7M to 43 x 10ֿ5M at pH 7.0 with detection limit of (S/N=3) of 1.5 x 10 ֿ7M. The biosensor reached 95% of it's steady-state current at about 6 seconds. The usefulness of the biosensor for the herbal extracts was demonstrated by determining percentage of inhibition of Orthosiphon stamineus extracts and compared with the method reported earlier by Tadataka Noro et al. using the uv-vis spectrophotometry.
Description: Organized by Chemical Engineering Department, Gadjah Mada University, 4th - 5th December 2007 at Yogyakarta, Indonesia.
URI: http://hdl.handle.net/123456789/2638
Appears in Collections:Conference Papers

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