第八屆生物物理新知研討會

The 8th Symposium on Recent Advances in Biophysics
I12
Determination of Biological Small Molecules Using Novel Electrospray LC-MS Techniques: Mixed Mode Chromatography and Chemometrics
Shau-Chun Wang
Department of Chemistry, National Chung Cheng University
Electrospray ionization mass spectrometry has been a popular method of choice to determine ultra-trace endogenous level small molecules in biological fluids for example serum, plasma, or blood. Because of matrix complexity, ancillary techniques such as reverse-phase liquid chromatography are used to prepare “clean” samples. The retention capability of reverse-phase chromatography is not adequately effective to provide required sample purity for highly polar compounds epinephrine and norepinephrine. These compounds are usually co-eluted with matrix within short retention times. Their chromatographic peaks appear in the fluctuated background regimes. Therefore the LC-MS detection of highly polar compounds is problematic. To solve this problem, typically chromatography methods are used. The manual operation of hyphen-columns is tedious. Automatic column-switching techniques are effective but increase the LC system complexity. We investigated two alternative approaches: mixed mode LC-MS and chemometrics. The ion-exchange properties of mixed-mode columns enhance their retention capabilities for highly polar compounds while the organic mobile phase is used to remain the eluents’ electrospray compatibility. Chemometrics techniques, cross correlation and background subtraction, effectively recover small chromatographic peaks from background-fluctuated chromatograms. We compare our findings with the determination results using conventional multi-dimensional chromatography methods.