Poster Presentations
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Dr.
Ilker Polatoglu, Assist Prof., Celal Bayar University
Phenolic compounds are common organic contaminants. They are known to cause ecologically undesirable effects and they have adverse impacts on human health [1]. Therefore the detection of phenol is very significant. In general these compounds can be detected by traditional techniques (spectrophotometric and chromatographic) having lots of disadvantage. For that reason new alternative enzymatic biosensor designs are being developed for the detection of phenolic compounds [2]. Immobilization of the enzyme to the appropriate support strongly affects the performance of enzymatic biosensor. As a potential support for enzyme immobilization chitosan are becoming the focus of researchers because of excellent biocompatibility, non-toxicity and film forming ability [3].
In this study a simple method was designed for covalent attachment of tyrosinase on chitosan biocomposite film and a sensitive amperometric sensor for the detection of phenolic compound. Catechol as a phenolic compound was used as substrate to monitor sensor signal (the electrochemical oxidation of H2O2 produced from enzymatic reaction of catechol and tyosinase) as follows [4].
catechol + tyrosinase (O2) ?o-quinone + H2O2 (1)
H2O2 ? O2 + 2H+ + 2e- (2)
All electrochemical measurements were performed with three electrode system (PGSTAT 128N) including working electrode: tyrosinase–chitosan modified glassy corban electrode, reference electrode: Ag/AgCl electrode, auxiliary electrode: platinum wire.
A Well attachment of the enzyme to the chitosan support was achieved as understood from the FTIR and SEM characterizations. According to the washing experiment 30 min is sufficient to remove the nonimmobilized enzyme from the electrode surface. The optimum pH was found as 6.86. Hydrodynamic voltammetric studies (operated at the potential between -0.6 and 0.6 V, 50mV potential step in 0.1 mM catechol) showed that, a working potential of 0.5V (selected for the future amperometric measurements) is the best one depending on the difference between the background current and oxidation current of current of H2O2. the oxidation peak of 0.5 V was also observed from the CV measurement. Electrochemical sensing characteristics for the developed sensor will be given by evaluating the further amperometric detection by using 0.5 V potential.
Dr.
Ilker Polatoglu, Assist Prof., Celal Bayar University
Amperometric Detection of Phenolic Compound Using Tyrosinase Biosensor
Phenolic compounds are common organic contaminants. They are known to cause ecologically undesirable effects and they have adverse impacts on human health [1]. Therefore the detection of phenol is very significant. In general these compounds can be detected by traditional techniques (spectrophotometric and chromatographic) having lots of disadvantage. For that reason new alternative enzymatic biosensor designs are being developed for the detection of phenolic compounds [2]. Immobilization of the enzyme to the appropriate support strongly affects the performance of enzymatic biosensor. As a potential support for enzyme immobilization chitosan are becoming the focus of researchers because of excellent biocompatibility, non-toxicity and film forming ability [3].
In this study a simple method was designed for covalent attachment of tyrosinase on chitosan biocomposite film and a sensitive amperometric sensor for the detection of phenolic compound. Catechol as a phenolic compound was used as substrate to monitor sensor signal (the electrochemical oxidation of H2O2 produced from enzymatic reaction of catechol and tyosinase) as follows [4].
catechol + tyrosinase (O2) ?o-quinone + H2O2 (1)
H2O2 ? O2 + 2H+ + 2e- (2)
All electrochemical measurements were performed with three electrode system (PGSTAT 128N) including working electrode: tyrosinase–chitosan modified glassy corban electrode, reference electrode: Ag/AgCl electrode, auxiliary electrode: platinum wire.
A Well attachment of the enzyme to the chitosan support was achieved as understood from the FTIR and SEM characterizations. According to the washing experiment 30 min is sufficient to remove the nonimmobilized enzyme from the electrode surface. The optimum pH was found as 6.86. Hydrodynamic voltammetric studies (operated at the potential between -0.6 and 0.6 V, 50mV potential step in 0.1 mM catechol) showed that, a working potential of 0.5V (selected for the future amperometric measurements) is the best one depending on the difference between the background current and oxidation current of current of H2O2. the oxidation peak of 0.5 V was also observed from the CV measurement. Electrochemical sensing characteristics for the developed sensor will be given by evaluating the further amperometric detection by using 0.5 V potential.
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