SepSolve Analytical has produced an application note demonstrating the high performance of a flow-modulated GC×GC–TOF MS system, coupled with sample preparation by solid-phase micro-extraction (SPME), for the separation and identification of trace volatiles in three brands of whisky.
Introduction
Over 1000 compounds from a wide range of chemical classes are known to contribute to the aroma of whisky, and these include alcohols, phenolics, fatty acids, esters, lactones, aldehydes and nitrogen-containing compounds. It is important to be able to confidently identify these volatiles, for quality control and authentication purposes, as well as in the engineering of new aromas.
Comprehensive two-dimensional gas chromatography coupled with time-of flight mass spectrometry (GC×GC–TOF MS) is ideal for the analysis of such complex samples, because the enhanced separation capacity allows analysts to screen the entire composition in a single analysis, with confident identification of compounds that would ordinarily co-elute.
Method
This application uses the INSIGHT™ reverse-fill/flush device from SepSolve to investigate the application of flow-modulated GC×GC–TOF MS. This allows separation of volatiles ranging from C1 to C40 (and above), the flexibility to change the loop volume in method optimisation, and additional options including heart-cutting, backflushing, and splitting for simultaneous detection.
Conclusion
This study has illustrated the power of flow-modulated GC×GC to provide simple, robust and affordable separation of complex aroma profiles. Confident identification through reference-quality TOF MS spectra enables comprehensive characterisation of samples, while ChromSpace software is shown to further
enhance analyses, by speeding up data navigation and providing another level of information through global deconvolution.
