AN AMPEROMETRIC TYROSINASE INHIBITION-BASED BIOSENSOR FOR THE DETERMINATION OF SULFITE IN NATURAL WATERS

Abstract

A tyrosinase-based amperometric biosensor for the determination of sulfite in natural waters is reported based on the inhibitory effect of the analyte on the biocatalytic activity of tyrosinase. Titanium dioxide sol modified with gold nanoparticles, multi-walled carbon nanotubes, and Nafion were used for entrapment of the enzyme. The analytical characteristics of the biosensor were evaluated with respect of sensitivity, limit of detection, repeatability, and reproducibility. The biosensor demonstrated a linear range up to 5.10 μM, a high sensitivity of 0.75 μA/μM, and a low limit of detection, 0.08 μM. Possible matrix effects were examined for ions usually found in water samples. The biosensor was successfully used for the determination of sulfite in spiked spring and surface water.

Keywords:

• biosensor
• gold nanoparticles
• multi-walled carbon nanotubes
• sulfite
• tyrosinase inhibition

ACKNOWLEDGMENTS

We kindly acknowledge Dr. Jarosław Wilamowski for his valuable contribution in experimental part of work.

Notes

*Mean value of two determinations.