Electrochemical immunosensor modified with carbon nanofibers coupled to a paper platform for the determination of gliadins in food samplesElectronic supplementary information (ESI) available. See DOI: 10.1039/c9ay00255c

The gluten-free diet is a unique, effective treatment for different conditions related to gluten consumption. Therefore, it is crucial the availability of new methodologies for the sensitive and specific determination of gluten content in food samples. Herein, a screen printed electrode modified with carbon nanofibers coupled to a paper immunoaffinity platform was reported for the determination of gliadin in foods samples. The paper microzone covalently functionalized with specific anti-gliadin antibodies was placed on the modified electrode surface for the electrochemical determination of gliadin. The surface of the electrode modified with carbon nanofibers was characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV), which showed the improved sensitivity of the modified surface. The developed device was evaluated using different flour samples obtaining a favorable response. The calculated limit of detection for the device in analyzed samples was 0.005 mg kg−1and for the enzyme-linked immunosorbent assay was 1.5 mg kg−1. The coefficient of variation (CV) for the determination of 20 μg kg−1of gliadin was 4.11%. The disposable electrochemical sensor developed, represents an easy-to-use and low-cost strategy for the determination of gliadin in food samples.