Chromatographic System Based on Amorphous Silicon Photodiodes

In this work, we present a novel thin layer chromatography system based on fluorescence detection by means of a linear array of amorphous silicon photodiodes. The photodiodes are optically coupled to a thin layer chromatography plate to monitor, in real-time, the separation of the components of a mixture during the chromatographic run. We designed a horizontal development chamber with UV transparent window and integrated eluent tank. The resulting system is extremely compact and ensures fast analysis using only small amounts of eluent. With our system, we analyzed different mixtures of fluorescent inks and other molecules such as fluorescein. Real-time data of sensors located in different position are used to detect the composition of the mixture. The various components can be determined from the time of the transit of the different species in front of the sensors. Furthermore, from the measured data it is possible to extract additional information as the transport properties of the stationary phase or the velocity profile along the run for each component of the mixture.