Amperometric Biosensor Based on Tyrosinase Immobilized on to a Carbon Black Paste Electrode for Phenol Determination in Olive Oil

Abstract

A novel biosensor based on the immobilization of commercially available tyrosinase onto carbon black paste electrode was developed. This device showed significantly reduced noise compared to enzymatic sensors based on traditional graphite paste electrodes. Using catechol as the substrate, the response was linear in the range 0.013 to 150 µmol L⁻¹ with a detection limit of 6 nmol L⁻¹(based on three times the S/N ratio). Peroxidase and laccase biosensors were also prepared. The responses of these three enzymatic biosensors to twenty different phenolic compounds were investigated, taking into account their molecular structure and their specific enzyme activity relationship. In addition, another sensor was reported based on semipurified tyrosinase. There was a good statistical correlation between the results obtained with tyrosinase biosensor and Folin-Ciocalteu spectrophotometric methods for phenol determination in olive oils.

Keywords:

• Carbon black paste electrode
• Folin-Ciocalteu
• Olive oil
• Phenols
• Tyrosinase biosensor

Notes

Note: Phenol (Phe), benzoic acid (BA), catechol (Cat), resorcinol (Res), 4-hydroxyphenyl acetic acid (HPAA), tyrosol (Tyrl), 3.4-hydroxybenzoic acid (HBA), hydroquinone (HQ), p-coumaric acid (CoA), tyramine (Tyrm), tyrosine (Tyr), ferulic acid (FA), caffeic acid (CA), L-epinephrine (Epin), dopamine (DA), DL-3.4 dihydroxyphenylalanine (DOPA), hydroxytyrosol (Htyrl), epicatechin (Epic), chlorogenic acid (ChA), and rosmarinic acid (RA).

CPE-Tyr-Inc: Biosensor made with incorporated lyophilized Tyr.

CPE-Tyr: Carbon paste electrode made with graphite + Tyr immobilized on the electrode surface.

CBPE-Tyr: Carbon paste electrode made with carbon black + Tyr immobilized on the electrode surface.

Note: ^a Response to catechol substrate; ^b Response to phenol substrate; ^c Response to Cafeic acid substrate; n₁: Number of measurement; n₂: Number of Electrode; Aucoll: Gold colloidal particle; ^x Response time in (t ₉₀ ); ^y response time in (t ₉₅ ); CBPE: Carbon black paste electrode; CPE: Carbon paste electrode; GCE: Glassy carbon electrode; PPy-MWCNT: polypyrrole–Multiwalled carbon nanotube; EPD: Etylene propylene diene; CNi: carbon-coated nickel; PPO: Polyphenol oxidase (tyrosinase); PANI: polyaniline film; PVA: poly(vinyl alcohol); and GA: Glutaraldehyde.

CBPE-SP-Tyr: Biosensor made with carbon black and semi-purified (SP) Tyrosinase extracted in our laboratory, CPE-SP-Tyr: Biosensor made with graphite and semi-purified (SP) Tyrosinase extracted in our laboratory.