A sulfite biosensor fabricated using electrodeposited polytyramine: application to wine analysis

Abstract

The development of a sulfite biosensor based on the immobilization of sulfite oxidase (SOD) in electrodeposited polytyramine is described. Electropolymerization of polytyramine and simultaneous immobilization of SOD on platinized glassy carbon (GC/Pt) were performed in an aqueous solution of 0.1 M tyramine containing SOD. The sulfite biosensor constructed with five voltammetric sweep cycles showed a sensitive response to sulfite with a linear calibration curve in the concentration range 0.002-0.3 mM sulfite, slope 2.70 mA l mmol 21 , and detection limit 0.001 mM sulfite (S/N = 3). Deposited polytyramine enhanced the selectivity of the biosensor by eliminating direct oxidation of sulfite and other interfering agents at the electrode. The biosensor was applied for the determination of sulfite in various types of wine samples, and the results obtained are in agreement with those using an AOAC method.

Glucose Oxidase Entrapment in an Electropolymerized Poly(tyramine) Film with Sulfobutylether-β-Cyclodextrin on Platinum Nanoparticle Modified Boron-Doped Diamond Electrode

“…The CV profile obtained in 50 mM phosphate buffer, pH 7 revealed a continual current decrease with the number of deposition cycles (Figure 2A). Unlike the electropolymerization of tyramine in NaOH, [5][6][7][8] the film formed at pH 7 was not self-limiting and could be up to 1 µm, depending upon the deposition condition and the electrode surface. 20 As a phenol derivative, the electrooxidation of tyramine produced phenoxy radicals, which in turn reacted with a neighboring tyramine molecule to form a para-linked dimer.…”

“…The amino group is separated from the phenolic ring by two methylene groups; hence, only the phenol moiety is oxidized to perform the polymerization. [4][5][6][7][8][9] Increasing the number of deposition cycles, reflecting increasing film thickness, decreased the signal response of H 2 O 2 , whereas its permselectivity against AA and UA was significantly improved. Therefore, 30 deposition cycles were considered as the best compromise.…”

“…4 Indeed, poly(tyramine) (PTy) has considerable advantages over other electrodeposited polymers with respect to reproducibility and the ability to screen out interferences when used in complex samples. [5][6][7][8] With the amino group separated from the phenolic ring by two methylene groups, only the phenol moiety participates in polymerization. The electropolymerization of tyramine can be conducted under basic, [5][6][7][8] acidic, 9 or neutral pH with a controllable thickness.…”

The Development of Reproducible and Selective Uric Acid Biosensor by Using Electrodeposited Polytyramine as Matrix Polymer

“…3C). The results represent that the polytyramine film prevent direct oxidation of uric acid on the surface of electrode and allows the detection of the hydrogen peroxide to be preceded through the polytyramine membrane film [26]. Steady state currents from the oxidation of hydrogen peroxide that was produced from enzymatic catalytic reaction of uric acid were obtained within two minutes after injection of uric acid into electrochemical cell.…”

“…However, since it is known that uric acid is oxidized on platinized electrode, then it is compulsory to protect direct oxidation of uric acid on the electrode surface by using a thicker polytyramine membrane film. This strategy is also valuable to prevent the electrode from oxidation of other electroactive compounds in the electrode surface, but allowed the oxidation of hydrogen peroxide produced by the enzyme-catalyzed oxidation at the electrode [26]. Choosing a thicker membrane film with reasonable response sensitivity has to be compromised for the construction of uric acid biosensor.…”