Reliability of Van den Dool retention indices in the analysis of essential oils

The aim of this study is to evaluate how extensive retention indices (RIs) can be identifying an essential oil component within a single laboratory. The essential oils of Matricaria chamomilla L., Tagetes lucida Cav., and Artemisia roxburghiana Wall, are investigated with different columns and under different analytical conditions. These oils are analyzed with a GC unit and columns coated with the same stationary phases (polysiloxane OV-1 and polyethylene glycol CW-20M) but different characteristics (producer and inner diameter) under different analytical conditions (temperature program and mobile phase conditions). The great number of data obtained are used to determine what parameters other than stationary phase influence RI reliability, the range of variation of RIs with different columns or under different operating conditions, and the validity of D-RI measurements.