Mesoporous immunosensor applied to zearalenone determination in Amaranthus cruentus seeds

REGIART D. MATIAS; ODIL FERNÁNDEZ; ANA VICARIO; VILLARROEL ROCHA JHONNY; SAPAG KARIM; GERMÁN A. MESSINA; JULIO RABA; BERTOLINO A. FRANCO

MICROCHEMICAL JOURNAL

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2018 vol. 141 p. 388 - 394

0026-265X

We describe an electrochemical immunosensor for zearalenone (ZEA) determination in Amaranthus cruentus seeds by an enzyme immunoassay sandwich type. The device is based on a screen-printed carbon electrode (SPCE) modified with amino mesoporous silica (MCM-41) synthetized with Fe2O3 in situ. Mesoporous material enlarges the surface available for anti-ZEA antibodies immobilization. SPCE/MCM-41-Fe2O3 was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, and cyclic voltammetry. ZEA in the sample previously pretreated was recognized and captured by anti-ZEA on SPCE/MCM-41-Fe2O3.Then, the horseradish peroxidase (HRP)-conjugated anti-ZEA-antibody was added, and the substrate solution (H2O2+4-terbutylcatechol (4-TBC)) reacted with the HRP that catalyzed the oxidation of 4-TBC to 4-terbutylbenzoquinone (TBQ). Finally, the enzymatic product was detected at −100 mV, and the current was proportional to the ZEA present in the sample.The calibration plot exhibited a linear range from 1.88 to 45 ng mL−1, and the limit of detection was 0.57 ng mL−1 (r2=0.998). The coefficient of variation inter- and intra assay was below 6%. Our method achieved a good selectivity, stability and reproducibility for ZEA detection in A. cruentus seeds.