Gin is one of the most consumed distilled alcoholic spirits
worldwide,
with more than 400 million liters sold every year. It is most often
produced through redistillation of agricultural ethanol in the presence
of botanicals, most notably juniper berries, which give gin its characteristic
flavor. Due to its natural ingredients, gin is a complex mixture of
hundreds of volatile and nonvolatile chemical constituents. In this
work, ultrahigh-resolution Fourier transform ion cyclotron resonance
(FT-ICR) mass spectrometry was used for the compositional analysis
of 16 commercially produced gins. Two complementary ionization methods,
namely, electrospray ionization (ESI) and atmospheric-pressure photoionization
(APPI), were employed to cover a wider compositional space. Each gin
provided unique chemical fingerprints by ESI and APPI, which allowed
semiquantitative analysis of 135 tentatively identified compounds,
including terpene hydrocarbons, terpenoids, phenolics, fatty acids,
aldehydes, and esters. Most of these compounds have not been previously
reported in gins. While chemical fingerprints were rather similar
between most products, some products contained unique compounds due
to their special natural ingredients or the production methods applied.
For instance, a barrel-matured gin contained a high content of syringaldehyde
and sinapaldehyde, which are typical phenolic aldehydes originated
from oak wood. In addition, the relative abundance of vanillin, vanillic
acid, gallic acid, coniferyl aldehyde, and syringaldehyde was clearly
higher than in the other gin samples. Ultrahigh-resolution FT-ICR
MS serves as a powerful tool for direct chemical fingerprinting of
gin or any other distilled spirit, which can be used for rapid product
quality screening, product optimization, or possible counterfeit product
discovery.