Characterization of ethanol concentrations at ultraviolet wavelength region

Abstract

This paper presents the measurement of optical absorption spectrum for different
concentrations of ethanol at ultraviolet wavelength. Ethanol absorption spectrum was
measured using portable spectroscopy setup from Avantes. It consists of Balanced Deuterium
Halogen light source and spectrometer. The light source can deliver a continuous broad
spectrum ranging from 0.2 to 2.5 μm and the spectrometer has the detection range of
μm. Several mixtures of ethanol in de-ionized water were prepared with various
concentrations of 0%, 0.1%, 0.5%, 1.0%, 2.5%, 5%, 10%, 15%, 25%, 50% and 100 vol%.
The baseline of the absorption spectrum was being analyzed and corrected using MATLAB
software. From the results, the spectroscopy setup was successfully detecting ethanol
concentration from 2.5-100vol%. However, only concentration range from 2.5-50vol% has
shown 99% of fulfilment towards the Beer’s Lambert Law.

Keywords: ultraviolet wavelength; spectroscopy; optical absorption; ethanol absorption spectrum baseline; Beer's Lambert law