Standardized GC–MS (EI) procedure for monitoring the detection and identification performance applied to herbal remedies

A procedure for monitoring the identification performance of GC–MS instrumentation as applied to herbal remedies was established, using eugenol (extracted from cloves) as a control compound. The following parameters were monitored: retention time (acceptable variability 0.5%); signal-to-noise ratio (at least 40% of the initial value); ion intensity ratio (acceptable variability 20%); and identity search result (reverse match, with minimum match value of 850 for quadrupole instruments and 800 for ion trap instrument). Other candidates for control compounds (pulegone, caffeine, and methoxsalen) as well as other parameters (relative retention time, second ion intensity ratio, peak area, and direct match) did not give any additional information concerning variability, observed trends, and sensitivity.