Vibol Sok

AMPEROMETRIC ENZYME-BASED DETECTION OF AGRICULTURALPESTICIDES ON NOVEL CARBON NANO-ONION COMPOSITES

There is currently a strong concern on the use of pesticides in agriculture and their possible side effects. This makes the development of sensitive and robust detection systems an important step in this direction. On the other hand, carbon nano-onions are very attractive and promising materials with defined structures and remarkable electrochemical properties that have been scarcely studied in biosensing. The overall objective of this thesis is to study the interaction of different pesticides with peroxidase and tyrosinase with the aim to develop biosensors for pesticide detection based on CNO-modified electrodes. To achieve this general objective, the following aspects have been focused on: 1) the inhibition of peroxidase and tyrosinase activities by three of the most used pesticides (2,4-D, 2,4,5-T and glyphosate), 2) the use of oxidized CNOs as supports for the immobilization of enzymes and a study of the activity and stability of the immobilized enzymes, 3) the development of electrochemical biosensors for pesticide detection based on the prepared CNO-enzyme modified electrodes. This thesis is thus a contribution to a rapidly growing field related with the development of new classes of carbon nano-onion based nanomaterials that aims at expanding their current applications in the construction of novel detection systems with improved performances.

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