High-speed, low-pressure gas chromatography–mass spectrometry for essential oil analysis

Analysis of parsley and fennel essential oils was performed by using low-pressure gas chromatography–mass spectrometry (GC–MS). The low-pressure instrument configuration was achieved by fitting a GC–MS instrument with a 530 μm I.D. capillary column and an appropriate capillary restrictor at the inlet of the column. Comparison of the performance of the low-pressure GC–MS setup was made with fast GC–MS using a narrow-bore capillary column. By comparing the two approaches side-by-side the benefits of low-pressure GC–MS for characterisation of moderately complex essential oils comprising less than 50 detectable components can be fully appreciated. Although efficiency is sacrificed, the improved sample capacity of the 530 μm I.D. column leads to higher peak intensities and in-turn better mass spectral library matching thus providing highly satisfactory results.