A New Label-Free Impedimetric Affinity Sensor Based on Cholinesterases for Detection of Organophosphorous and Carbamic Pesticides in Food Samples: Impedimetric Versus Amperometric Detection
- 362 Downloads
Due to their increasing use in agriculture, the presence of pesticide residues in food and water currently represents one of the major issues for the food safety. Among the pesticides, organophosphate and carbamate species are the most used, and their toxicity is mainly due to their inhibitory effect on acetylcholinesterase (AChE). For this reason, a monoenzymatic acetylcholinesterase impedimetric biosensor was developed in order to sensitively detect carbamate and organophosphate compounds with a very fast response. The working principle of the AChE biosensor exploits the capability of carbamate and organophosphate pesticides to form a stable complex with the enzyme, which causes an impedimetric change. The impedimetric biosensor showed a linearity between 5 and 170 ppb for carbamates and 2.5–170 ppb for organophosphate compounds, with a reproducibility (RSD%) interelectrode equal to 4.8 and 3.1% for organophosphates and carbamates, respectively. Moreover, the common amperometric evaluation of AChE inhibition degree was correlated to the impedimetric changes of the electrode surface, showing a good correlation (R 2 = 0.99 for carbamates and R 2 = 0.98 for organophosphates) between the two methods. In contrast to amperometric evaluation that needs a response time of 20 min, impedimetric detection requires only 4 min. Finally, the impedimetric biosensor was used to measure carbaryl and dichlorvos spiked in different concentrations in tap water and lettuce samples, showing a recovery near to 100% for all concentrations and for both pesticides.
KeywordsPesticides Electrochemical impedance spectroscopy Affinity biosensors Acetylcholinesterase
- Albanese, D., Di Matteo, M., & Pilloton, R. (2012). Quantitative screening and resolution of carbamic and organoposphate pesticides mixture in extra virgin olive oil by acetylcholinesterase-choline oxidase sensor. J Environ Sci Eng A, 1, 68–77.Google Scholar
- Arduini, F., Ricci, F., Tuta, C. S., Moscone, D., Amine, A., & Palleschi, G. (2006). Detection of carbamic and organophosphorus pesticides in water samples using cholinesterase biosensor based on Prussian Blue modified screen printed electrode. Analytica Chimica Acta, 580, 155–162.CrossRefGoogle Scholar
- Vakurov, A., Simpson, C. E., Daly, C. L., Gibson, T. D., & Millner, P. A. (2004). Acetylcholinesterase-based biosensor electrodes for organophosphate pesticide detection: I. Modification of carbon surface for immobilization of acetylcholinesterase. Biosensors and Bioelectronics, 20(6), 1118–1125.Google Scholar