Microfluidic devices for optical determination of ethanol concentration

A microfluidic device with integrated optical fibres has been used for the determination of the ethanol concentration in wines and beverages. Two cleaved optical fibres were placed face to face perpendicularly to the microfluidic channel with a gap comparable to the width of the channel. They are respectively connected to a light source and a spectrometer for the optical detection. Absorption spectra of a mixture of potassium dichromate plus sulphuric acid and diluted ethanol have been studied as a function of ethanol content, showing a linear dependence between the measured absorbance and the ethanol concentration. Then, several commercial potable spirits and wines have been used to demonstrate the applicability of the proposal microfluidic method. (C) 2008 Elsevier B.V. All rights reserved.