Electrochemical enzymatic fenitrothion sensor based on a tyrosinase/poly(2-hydroxybenzamide)-modified graphite electrode

• Published in: Analytical biochemistry 2018-07, Vol.553, p.15-23
• Main Authors: Alves, Maria de Fátima, Corrêa, Ricardo Augusto Moreira de Souza, da Cruz, Filipe Soares, Franco, Diego Leoni, Ferreira, Lucas Franco
• Format: Article
• Language: English
• Subjects: 2-hydroxybenzamide; Benzamides - chemistry; Biosensing Techniques - methods; Biosensor; Catechol; Electrochemical Techniques - methods; Electrodes; Electropolymerisation; Fenitrothion; Fenitrothion - analysis; Graphite - chemistry; Insecticides - analysis; Monophenol Monooxygenase - chemistry; Polymerization; Tyrosinase
• ISSN: 0003-2697; 1096-0309
• DOI: 10.1016/j.ab.2018.05.014

This paper reports the electrosynthesis and characterisation of a polymeric film derived from 2-hydroxybenzamide over a graphite electrode and its application as an enzymatic biosensor for the determination and quantification of the pesticide fenitrothion. The material was analysed by scanning electron microscopy and its electrochemical properties characterised by cyclic voltammetry and electrochemical impedance spectroscopy. The enzyme tyrosinase was immobilised over the modified electrode by the drop and dry technique. Catechol was determined by direct reduction of biocatalytically formed o-quinone by employing the flow injection analysis technique. The analytical characteristics of the proposed sensor were optimised as follows: phosphate buffer 0.050 M at pH 6.5, flow rate 5.0 mL min−1, sample injection volume 150 μL, catechol concentration 1.0 mM and maximum inhibition time by fenitrothion of 6 min. The biosensors showed a linear response to pesticide concentration from 0.018 to 3.60 μM. The limit of detection and limit of quantification were calculated as 4.70 nM and 15.9 nM (RSD