The comparison of two hyphenated techniques, LC/MS and CE/MS, for bioanalytical challenges

Hyphenated techniques using mass spectrometry as a detection strategy have become some of the most powerful analytical methodologies for bioanalytical challenges. Particularly, high performance liquid chromatography with mass spectrometric detection (LC/MS) and gas chromatography with mass spectrometric detection (GC/MS) are techniques that have gained widespread acceptance while capillary electrophoresis with mass spectrometric detection (CE/MS) remains in its infancy. Even though CE/MS has the capability of achieving better separation efficiencies and requires very low sample volumes for analysis than LC/MS, it lacks both the robustness and low concentration limits of detection (LOD) with respect to LC/MS and thus remains a less accepted analytical method.; The purpose of this research was to construct a simple CE/MS interface and attempt to mitigate the LOD and robustness limitations that the technique suffers. After the CE/MS interface was constructed, experiments were performed involving several bioanalytical challenges to explore the utility of CE/MS and LC/MS. This also served as a means to compare the relative advantages and disadvantages of the two techniques in a side by side comparison.; The first study was the analysis of bupivacaine metabolites in rat urine using both LC/MS and CE/MS to obtain structural information about the different metabolites. From the CE/MS and LC/MS data, structural information about nine different metabolites was obtained. A comparison of the two techniques showed that LC/MS was able to detect metabolites below the LOD of CE/MS. However, it was demonstrated that CE/MS was more efficient in separating the analytes from the background matrix components.; The second study was to quantitate the biomarker, 8-hydroxy-2 '-deoxyguanosine, in urine using both CE/MS and LC/MS. Using tandem mass spectrometry and HPLC (LC/MS/MS), the quantitation of 8-OHdG in urine was possible. CE/MS was unable to detect 8-OHdG in urine due to insufficient LOD.; The last application consisted of using LC/MS for the fast development of HPLC methods. By combining LC/MS with DryLab 2000, it was possible to quickly develop HPLC methods on several samples. This is of particular interest to the pharmaceutical industry since the strategy reduces the amount of time and resources needed to develop HPLC methods.