Ultrasensitive Determination of Malathion Using Acetylcholinesterase Immobilized on Chitosan-Functionalized Magnetic Iron Nanoparticles

Author(s)

Marinho Rodrigues, Nubia Fernanda ^{[1, 2]} ; Neto, Sakae Yotsumoto ^[3] ; Silva Luz, Rita de Cassia ^[3] ; Damos, Flavio Santos ^[3] ; Yamanaka, Hideko ^{[1, 4]}

Affiliation

^[1] Sao Paulo State Univ UNESP, Dept Analyt Chem, BR-14800900 Araraquara, SP - Brazil

^[2] Fed Univ Maranhao UFMA, Dept Nat Sci, BR-65200000 Pinheiro, MA - Brazil

^[3] Fed Univ Maranhao UFMA, Dept Chem, BR-65080805 Sao Luis, MA - Brazil

^[4] UNESP, Natl Inst Alternat Technol Detect Toxicol Evaluat, POB 355, BR-14800900 Araraquara, SP - Brazil

• Document type: Journal article
• Source: BIOSENSORS-BASEL; v. 8, n. 1 MAR 2018.
• Web of Science Citations: 11

Abstract

A renewable, disposable, low cost, and sensitive sensor for the detection of organophosphorus pesticides was constructed by immobilizing the acetylcholinesterase enzyme (AChE), via glutaraldehyde, on magnetic iron nanoparticles (Fe3O4) previously synthesized and functionalized with chitosan (CS). The sensor was denoted AChE/CS/Fe3O4. The magnetic nanoparticles were characterized by Fourier transform infrared spectroscopy and transmission electron microscopy. Acetylthiocholine (ATCh) was incubated with AChE/CS/Fe3O4 and attached to a screen-printed electrode using a magnet. The oxidation of thiocholine (from ATCh hydrolysis) was monitored at an applied potential of +0.5 V vs. Ag/AgCl(KClsat) in 0.1 mol L-1 phosphate buffer solution (pH 7.5) as the supporting electrolyte. A mixture of the pesticide malathion and ATCh was investigated using the same procedure, and the results were compared and expressed as inhibition percentages. For determination of malathion, the proposed sensor presented a linear response in the range from 0.5 to 20 nmol L-1 (R = 0.9942). The limits of detection (LOD) and quantification (LOQ) were 0.3 and 0.8 nmol L-1, respectively. Real samples were also investigated, with recovery values of 96.0% and 108.3% obtained for tomato and pond water samples, respectively. The proposed sensor is a feasible option for malathion detection, offering a linear response, good sensitivity, and a low detection limit. (AU)

• FAPESP's process: 14/50945-4 - INCT 2014: National Institute for Alternative Technologies of Detection, Toxicological Evaluation and Removal of Micropollutants and Radioactivies
• Grantee: Maria Valnice Boldrin
• Support Opportunities: Research Projects - Thematic Grants