This study retrospectively analyzes the daily results of relative response factors (RRFs) of polycyclic aromatic hydrocarbons detected by gas chromatography–mass spectrometry (GC-MS). Although instrumental routine maintenance can enhance the reliability of measurement, there is no quantitative study to investigate the effects of glass liner contamination, manifold temperature drop, and column degradation on deteriorating sensitivities and stabilities of RRFs. This study demonstrates that by removing the contribution of outliners to the background level, great reductions of RRFs were achieved. Although several factors potentially undermined the analyzer’s confidence on data reliability, there were no significant differences on the relative sensitivities of RRFs.
