A naphthoquinone/SAM-mediated biosensor for olive oil polyphenol content

Food Chem. 2016 Oct 15:209:274-8. doi: 10.1016/j.foodchem.2016.04.073. Epub 2016 Apr 19.

Abstract

We report on the design of an amperometric tyrosinase-based biosensor using a self-assembled monolayer of ω-mercaptopropyl naphthoquinone on gold electrode as an electron mediator. Under optimal conditions (i.e. pH=7.4 and E=-0.35V vs. KCl), the chronoamperometric response of the naphthoquinone-modified bioelectrode to successive additions of phenol was evaluated. The biosensor exhibits sensitive bioelectrocatalytic response at a working potential of -0.35V vs. Ag/AgCl (sat.KCl), reaching the steady-state current within 40s after each addition of phenol solution with a range of 0-135μM and a limit of detection and quantification which are 0.019μM and 0.0633μM, respectively. The bioelectrode was used to determine the content in polyphenol in a local virgin olive oil.

Keywords: Chronoamperometry; Electroactive monolayer; Impedance spectroscopy; Naphthoquinone; Phenol; Tyrosinase; Virgin olive oil.

MeSH terms

  • Biosensing Techniques / methods*
  • Electrodes
  • Enzymes, Immobilized / chemistry*
  • Gold
  • Monophenol Monooxygenase / chemistry*
  • Naphthoquinones / chemistry*
  • Olive Oil / chemistry*
  • Olive Oil / standards
  • Polyphenols / analysis*

Substances

  • Enzymes, Immobilized
  • Naphthoquinones
  • Olive Oil
  • Polyphenols
  • Gold
  • Monophenol Monooxygenase