Development Development of a third-generation biosensor to determine sterigmatocystin mycotoxin: A nearly warning system to detect aflatox a third-generation biosensor to determine sterigmatocystin mycotoxin: A nearly warning system to detect aflatoxin B1

DÍAZ NIETO, C. H.; GRANERO, A. M.; GARCÍA, D.; NESCI, A.; BARROS, G.; ZON, M.A.; FERNANDEZ, H.

TALANTA

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2018 vol. 194 p. 253 - 258

0039-9140

A third-generation enzymatic biosensor was developed to quantify sterigmatocystin (STEH). It was based on aglassy carbon electrode modifed with a composite of the soybean peroxidase enzyme (SPE) and chemicallyreduced graphene oxide. The optimal conditions to construct the biosensor were obtained through an experimental design based on the response surfaces methodology. The experiments were performed in 0.1 mol L−1phosphate buffer solution, pH 5. Amperometric measurements were carried out at − 0.09 V vs Ag/AgCl(3 mol L−1 NaCl). The biosensor showed a lineal response in the concentration range from 6.9 × 10−9 to5.0 × 10−7 mol L−1. The limit of detection was 2.3 × 10−9 mol L−1 for a signal: noise ratio of 3: 1. Values of theapparent Michaellis-Menten constant, KM app, obtained by using both Lineweaver-Burk and Eadi-Hofstee methodswere (1.5 ± 0.2) × 10−6 and (1.2 ± 0.2) × 10−6 mol L−1, respectively. STEH was analyzed in corn samplesspiked with STEH, with an average recovery of 96.5%. The biosensor was also used to determine STEH in cornsamples inoculated with the Aspergillus flavus fungus, which is an aflatoxins producer. Considering that STEH is aprecursor of aflatoxin B1 (AFB1) in its biological transformation, its decrease over time was related to theproduction of AFB1. The STEH concentration determined using the biosensor was in very good agreement withthat determined by HPLC