We have applied the Ion Mobility Spectrometry (IMS) technique to detect the β-methyl-γoctalactone (Whisky Lactone-WL) vapours in the air and as well WL vapours originating from the oak wood samples. The IMS with Atmospheric Pressure Chemical Ionisation (APCI) based on Corona Discharge (CD) ion source, was operated in the positive polarity. IMS responds to WL with appearance of two peaks in the IMS spectrum, monomer with reduced ion mobility value K0=1.39 cm 2 V-1 s-1 and dimer K0=1.09 cm 2 V-1 s-1. Using Ion Mobility orthogonal acceleration Time of Flight mass spectrometer (IMS-oaTOF MS) techniques we have identified these peaks as protonated monomer M. H +. (H2O)0,1 and dimer M2. H + ions respectively. The limit of detection study resulted in LOD for WL of 50 ppbv. Detection of WL from oak wood samples of different "Quality Level" (QL) categories (categories 1 to 10), indicated strong correlation between the QL category number and the response of the IMS.

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