Portable detection system for ochratoxin A by real time chromatography and a-Si:H photodiodes

In this paper, we report on the design, fabrication and characterization of a low cost, portable detection system able to quantify, in a rapid and reliable way, the contamination level of Ochratoxin A (OTA) in wine and beer. The operating principle is the real time monitoring of the natural fluorescence of OTA molecules during a chromatographic run on a Thin Layer Chromatographic plate. The fluorescence is detected by an array of amorphous silicon photosensors whose photocurrents are directly proportional to the amount of OTA molecules present in the sample under analysis. By comparison with a reference sample the system is able to determine if the OTA contamination level is below or above the limit law for each food commodity. The system performances have been verified in real matrices analyzing several samples extracted from wines and beer obtaining a minimum detectable quantity of 0.2ng.