Kinetic Study of the Inhibitory Effects of Methyl Isothiocyanate on a Peroxidase-Modified Platinum Electrode in Non-Aqueous Media
- 1 August 1994
- journal article
- research article
- Published by Taylor & Francis in Analytical Letters
- Vol. 27 (11) , 2071-2081
- https://doi.org/10.1080/00032719408007235
Abstract
The pesticide, methyl isothiocyanate can be determined based on its inhibitory effects on an amperometric horseradish peroxidase-modified electrode, in non-aqueous media. The apparent inhibition constant, Ki', was evaluated using steady-state binding kinetics and was used as a measure of sensor efficiency. Ki' was found to be 0.27 mmol/1, 0.18 mmol/1 and 0.37 mmol/1 in acetonitrile, methanol and 2-butanol, respectively. A correlation was observed between Ki' values and some physical properties of the solvents such as polarity, kinematic viscosity and dielectric constant. A possible solvent-induced deviation of the biosensor from Michaelis-Menten kinetics was evaluated based on a comparism of Hill coefficients. The least deviation was observed in 2-butanol (Hill coefficient = 1.04), whereas the greatest deviation was in methanol (Hill coefficient = 3.19) which exhibited the highest sensor efficiency.Keywords
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