Affiliation:
1. Instituto de Química de San Luis (INQUISAL), Facultad de Química, Bioquímica y Farmacia (FQBF), Universidad Nacional de San Luis (UNSL), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), INQUISAL (UNSL—CONICET), Chacabuco 917, San Luis D5700BWS, Argentina
Abstract
Nowadays, mycotoxin contamination in cereals and wastewater exposes a safety hazard to consumer health. This work describes the design of a simple, low-cost, and sensitive origami microfluidic paper-based device using electrochemical detection for zearalenone determination. The microfluidic immunosensor was designed on a paper platform by a wax printing process. The graphitized carbon working electrode modified with carbon nanohorns-decorated nanoporous gold showed a higher surface area, sensitivity, and adequate analytical performance. Electrodes were characterized by scanning electron microscopy, energy-dispersive spectroscopy, and cyclic voltammetry. The determination of zearalenone was carried out through a competitive immunoassay using specific antibodies immobilized by a covalent bond on the electrode surface. In the presence of HRP-labeled enzyme conjugate, substrate, and catechol, zearalenone was detected employing the developed immunosensor by applying −0.1 V to the working electrode vs silver as a pseudo-reference electrode. A calibration curve with a linear range between 10 and 1000 µg Kg−1 (R2 = 0.998) was obtained, and the limit of detection and quantification for the electrochemical immunosensor were 4.40 and 14.90 µg Kg−1, respectively. The coefficient of variation for intra- and inter-day assays was less than 5%. The selectivity and specificity of the sensor were evaluated, comparing the response against zearalenone metabolites and other mycotoxins that could affect the corn samples. Therefore, origami is a promising approach for paper-based electrochemical microfluidic sensors coupled to smartphones as a rapid and portable tool for in situ mycotoxins detection in real samples.
Funder
Universidad Nacional de San Luis
Agencia Nacional de Promoción Científica y Tecnológica
Consejo Nacional de Investigaciones Científicas y Técnicas
Ministerio de Ciencia, Tecnología e Innovación, Argentina
Subject
Physical and Theoretical Chemistry,Analytical Chemistry
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