SIMULTANEOUS DETERMINATION OF SEROTONIN PRECURSORS - TRYPTOPHAN AND 5-HIDROXYTRYPTOPHAN - IN COFFEE

SIMULTANEOUS DETERMINATION OF SEROTONIN PRECURSORS - TRYPTOPHAN AND 5-HIDROXYTRYPTOPHAN - IN COFFEE. Epidemiological studies attributed positive effects in the central nervous system (CNS) to coffee. Among possible active constituents, serotonin, a neurotransmitter in the CNS, is present: but dietary sources do not cross the blood-brain barrier. Tryptophan and 5-hidroxytryptophan (5-HTP) are serotonin precursors and can affect brain concentrations. Art ion-pair-HPLC, post-column derivatization with o-phthalaldehyde and fluorimetric detection before and after hydrolysis with NaOH and extraction with methanol: water was developed for the simultaneous determination of these compounds. It was selective, sensitive (LOD = 0.3 and 0.2 mu g/mL), precise (91.3 and 94.2% recovery for tryptophan and 5-HTP. respectively), and linear from 0.3 to 40 mu g/mL for both compounds. It was applied to green and roasted arabica and robusta coffees.