Rapid and Direct Determination of Methanol in Alcoholic Beverages by Ion Mobility Spectrometry

This work introduces a new method for direct detection of methanol in alcoholic beverages, using ion mobility spectrometry (IMS), headspace sampling (HS), and Tenax adsorbent preseparation (HS-Tenax-IMS). An ionization method based on the dopant gases was employed to overcome the overlapping of the reactant ions with the methanol peak. Six different ketones dopants were tested, and 2-heptanone was selected as the optimal variant. Tenax-GR column was used for both HS and as a preseparation method of methanol and ethanol prior to IMS detection. The optimum sampling time of 15 min was achieved, and analysis time was less than 1 min. The linear range for detection of methanol in solution was from 0.08% to 1.0%, corresponding to 630-7900 mg/L (R² = 0.996). The obtained limit of quantification (LOQ) of 630 mg/L and limit of detection (LOD) of 210 mg/L are sufficient for efficient methanol detection in the food industry.