Detection of Fake Alcoholic Beverages Using Electrolyte-Free Nanogap Electrochemical Cells.

Because of the similarity of odor, appearance, and chemical structure of methanol and ethanol, measuring the low concentration of methanol in an alcoholic beverage is difficult to perform in a quick, quantitative, and repeatable fashion. However, it is important for people to monitor the content of methanol in a liquor because a high amount of methanol absorbed will result in blindness, coma, and death. In response to this need, we have developed electrolyte-free methanol electrolysis and ethanol electrolysis based on the nanogap electrochemical cells for the methanol and ethanol sensing. Upon applying a voltage, a high electric field across the nanogap cell enhances the solution ionization and the ion transport rate. Moreover, the nanoscale distance between the electrodes provides a shorter path for electrolysis to easily occur. The nanogap electrochemical cells not only make the direct electrolyte-free organic solvent electrolysis possible but also enhance the sensitivity of the chemical of interest in low-concentration solutions without the influence of the added electrolyte. The nanogap electrochemical cells have been demonstrated having high sensitivity to detect 0.15% methanol volume concentration in deionized water solutions without adding any electrolyte, and its ability for the fake alcoholic beverages' detection has successfully demonstrated.