Mesoporous immunosensor applied to zearalenone determination in Amaranthus cruentus seeds

REGIART, MATÍAS; FERNÁNDEZ, ODIL; VICARIO, ANA; VILLARROEL-ROCHA, JHONNY; SAPAG, KARIM; MESSINA, GERMÁN A.; RABA, JULIO; BERTOLINO, FRANCO A.

MICROCHEMICAL JOURNAL

ELSEVIER SCIENCE BV

Año: 2018

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 Fe2O3in 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