Comparison of GC Techniques for Whiskey Analysis

This technical report presents a comparison of extraction, gas chromatography (GC) separation, and mass spectral detection techniques for the determination of 2-methylisoborneol (MIB) and geosmin in finished whiskey. These compounds are known to impart undesirable musty and earthy odors, which can significantly affect the sensory quality of whiskey, even at trace levels. The study evaluates various methods, including single-dimensional GC with selected ion monitoring (SIM) and triple quadrupole mass spectrometry (TQ) with multiple reaction monitoring (MRM), alongside a Selectable 1D/2D-Gas Chromatography-Mass Spectrometry (1D/2D-GC-MS) approach. The report discusses the limitations of traditional GC methods due to insufficient resolution and interferences from complex matrices. It details the experimental setup, including sample preparation and analysis conditions, and presents findings on linearity, detection limits, and reproducibility across different instruments. The results indicate that while the 1D/2D-GC-MS method improves analyte separation and quantitation accuracy, challenges remain in achieving reliable measurements due to matrix effects in whiskey samples.