Figure 3From: TargetSearch - a Bioconductor package for the efficient preprocessing of GC-MS metabolite profiling dataRetention index markers report. Retention time of the first four retention index markers in the standard mixture experiment. Samples and retention times are represented in the x and y-axis, respectively. Different days of measurement are indicated by numbers 2, 3 and 4. A so-called day effect is observed between days 2, and 3 and 4, manifested as a retention time shift.Back to article page