Conventional inner diameter short capillary columns: an approach to speeding up gas chromatographic analysis of medium complexity samples.

Short capillary columns (5 m) with 0.25 mm inner diameter (I.D.) are applied to the GC analysis of medium complexity samples (up to 30 components) with the aim of shortening analysis time. This approach is complementary to fast GC with narrow-bore columns and is based on compensating the lower efficiency of short columns with conventional I.D.'s (0.25-0.32 mm) by using a stationary phase selectivity suitable to separate the components of the sample under investigation, so that the required resolution power is achieved but, at the same time, the analysis time is shortened. The qualitative and quantitative effectiveness of this approach is demonstrated through the analysis of: essential oils with different compositions (chamomile and rosemary), low-volatility triterpenes in a plant extract (Maytenus aquifolium and M. ilicfolium), thermolabile pyrethrins in a Pyrethrum extract, and a mixture of pesticides applied to protect medicinal plant crops. In all examples, GC analysis was five to ten times faster than with conventional columns.