Analysis of catecholamines and related substances using porous graphitic carbon as separation media in liquid chromatography–tandem mass spectrometry

Capillary porous graphitic carbon (PGC) columns have been utilized for separation of several catecholamines and related compounds (i.e. l-tyrosine, l-DOPA, 3-O-methyl-DOPA, dopamine, 3,4-dihydroxy-phenyl-acetic acid (DOPAC), homovanillic acid, noradrenaline, vanillomandelic acid and adrenaline) on-line with electrospray ionization tandem mass spectrometry (ESI–MS/MS). The use of a mobile phase without ion-pairing agents and with high content of organic modifier facilitated the coupling to the selective and sensitive mass spectrometric detection. Minimum detectable sample concentration (MDC sample) for noradrenaline, dopamine and l-tyrosine in a standard solution was estimated to 3, 10 and 30 nM, respectively (3 S/N corresponds to MDQ for l-tyrosine of approximately 8×10−14 mol). The developed strategy was applied for analysis of brain tissue, i.e. a substantia nigra (ns) sample.