Discriminating among acid-, base-, and salt-based electrolytes using a single microfluidic channel

摘要

The information obtained by monitoring the adsorption progress rates of ionic species in a liquid-filled microfluidic channel is used for their identification. The adsorption rates of three different analytes, HC1, KOH, and K.C1, in a pure water-filled channel of microscale diameter are experimentally investigated by recording the temporal variation of the channel conductance. The electrolytes examined belong to the "acid", "base", and "salt" categories, respectively. Different temporal profiles are obtained for the electrical conductance of the channel. Each temporal profile was defined as a high dimensional vector which was mapped into a two dimensional feature space for categorization. It is shown that the extracted information from a conductance variation profile facilitates discrimination among HC1, KOH, and K.C1 solutions in distilled water regardless of their concentrations. The single channel device fabricated based on the presented concept is a low cost and disposable device which can be used for discrimination between "acid", "base", and "salt" electrolytes. The device can be utilized in electronic tongue applications.