In this thesis, the efficiency and operational aspects of 2 extraction methods, microextraction by packed sorbent (MEPS) and solid-phase microextraction (SPME), were compared by their performance in quantifying chlorpromazine (CPZ) concentration of rat plasma samples. The extracts were then be analyzed by GCMS. Unfortunately, the GCMS instrument had a technical dysfunction before the final experiments could be performed. Despite that, it is shown that although it required a more complicated method development, SPME has better accuracy when analyzing the CPZ content of the samples than MEPS. However, the study still needs further investigation for strengthening the findings