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Simple and Fast Picomolar Detection of Ochratoxin A Using a Reusable Label Free Aptasensor Built with a Layer‐by‐layer Procedure
Author(s) -
Simão Estéfani P.,
CaoMilán Roberto,
CostaPedro Graciela,
De Melo Celso P.,
Cao Roberto,
Oliveira Maria D. L.,
Andrade Cesar A. S.
Publication year - 2017
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.201700290
Subject(s) - aptamer , detection limit , chemistry , chromatography , layer (electronics) , ultrafiltration (renal) , adsorption , ochratoxin a , food science , mycotoxin , genetics , organic chemistry , biology
A label free impedimetric aptasensor for simple, fast and reusable picomolar detections of Ochratoxin A (OTA) in grape juices was designed. Two main factors were observed to affect the accurate detections of the toxin: i‐lateral interactions between self‐assembled aptamers ii‐ adsorption of large molecules present in complex matrixes like grape juices. Lateral interactions between aptamers were minimized by constructing the aptasensor in a Layer‐by‐Layer procedure. The interferences associated to the unspecific and irreversible adsorption of large molecules present in grape juice, were reduced by submitting samples to ultrafiltration prior to analysis. With this protocol, a 0.12 pM limit of detection and 0.24 pM limit of quantification in spiked grape juices were achieved after only 5–7 mins of interaction with the samples. The presented aptasensor can be recovered after a simple immersion in hot water (90 °C) for ten minutes.