Whisky analysis by electrospray ionization-Fourier transform mass spectrometry

Electrospray ionization (ESI) coupled to ultra-high resolution and accuracy Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was employed for the direct analysis of whisky samples. No pre-separation or extraction steps were employed and, owing to the gentleness of ESI, characteristic profiles of polar constituents of authentic whiskies from five different brands were obtained, which greatly contrast to those of counterfeit samples. Owing to the accuracy of FT-ICR MS mass measurements, elemental composition of the main ions detected were also securely determined, and related to a series of carboxylic acids, phenols, saccharides, fat acids and sulfur or nitrogen constituents of whisky. The accurate mass measurements and the number of detected ions, together with the direct, no sample preparation procedure employed, make FT-ICR MS a highly reliable approach to fingerprint whisky and to control its quality, and to screen for aging, counterfeiting and adulteration at the molecular level.