Amorphous Silicon Photosensors for Detection of Ochratoxin a in Wine

The presence of ochratoxin A (OTA) in different food commodities deserves great attention because of its toxic and carcinogenic effects on humans and animals. In this paper, we report on the detection of OTA both in standard solutions and in contaminated samples of red wine by using amorphous silicon photosensors. The method relies on the excitation by ultraviolet radiation of the toxin molecules and on the absorption of the toxin reemitted light by the photosensor. The device is a p-i-n stacked structure, whose electro-optical characteristics have been optimized in order to maximize the photosensor responsivity and the limit of detection. For standard solutions, we found minimum detected OTA amount to be equal to 0.1 ng, while for contaminated red wine samples the technique coupled with very simplified and rapid extraction procedures has allowed the detection of OTA at the 1-ppb level.