Comparison of GC-MS and HPLC for the analysis of Allilum volatiles

Volatile sulfur compounds produced enzymatically from Allium species have been identified by combined gas chromatography-mass spectrometry (GC-MS) and the results obtained have been compared with those from HPLC-UV analysis (with a diode-array detection, DAD). Analysis of the same onion sample by successive SPME-GC-MS or by solvent extraction then GCMS enabled us to identify the true onion volatiles including lachrymatory factor and thiosulfinates. Conversely, for garlic samples HPLC analysis is more suitable because of the substantial degradation of allicin (the main thiosulfinate in garlic) during GC. An El mass spectrum of allicin obtained by GC-MS is reported for the first time.