Study of Retention Properties of Selected Tyrosine Metabolites under HPLC Conditions

Charles University Faculty od Pharmacy in Hradec Králové Department od Pharmaceutical Chemistry and Pharmaceutical Analysis Candidate: Michaela Gieslerová Supervisor: PharmDr. Petr Kastner, Ph.D. Title of thesis: Study of retention properties of selected tyrosine metabolites under HPLC conditions The aim of this diploma thesis was to study the retention properties of selected tyrosine metabolites under the high performance liquid chromatography using spectrofotometric (285 nm) and fluorimetric detection (emission 279 nm, excitation 320 nm). The total of eight analytes was examined - tyrosine, L-DOPA, dopamine, epinephrine, norepinephrine, homovanillic and vanillylmandelic acid. Firstly, we studied the effect of mobile phase composition, buffer concentration and pH for the separation of analytes. Analysis of selected analytes was performed using an KINETEX 5 μm EVO C18 column (150 mm x 3 mm, 5 μm; PHENOMENEX). The best separation showed the mobile phase methanol:100 mM acetic acid (pH adjusted with sodium hydroxide to 4,5); 5:95. Next, the effect of stationary phase for the separation of analytes was studies with the mobile phase described above. A total of 7 different columns were studied, namely stationary phases with modified silica gel C18 group, PFP group, combined stationary phase (C18 group..