9-Fluorenylmethyloxycarbonyl (FMOC) derivatives of catecholamines, including dopamine (DA; 3,4-dihydroxyphenethylamine), norepinephrine (NE; 2-amino-1-(3,4-dihydroxyphenyl)ethanol) and epinephrine (EPI; 1-phenyl-1-hydroxy-2-methylaminopropane) as well as 3, 4-dihydroxybenzylamine (DHBA) have been analyzed using high performance liquid chromatography coupled to fluorometric detection and atmospheric pressure chemical ionization mass spectrometry at low femtomole levels. Structures of the derivatives have also been characterized by liquid chromatography/atmospheric pressure chemical ionization mass spectrometry and electrospray/tandem mass spectrometry. Protonated molecules of FMOC-DA and FMOC-DHBA as well as [M + H - H(2)O](+) ions of FMOC-NE and FMOC-EPI appear in their conventional mass spectra, and abundant fragments characteristic of catecholamines dominated the spectra. Structurally diagnostic ions using several hundred femtomoles of the FMOC derivatives of catecholamine were observed. Collision-induced dissociation (CID) of electrospray-generated protonated molecules of FMOC-DA and FMOC-DHBA as well as [M + H - H(2)O](+) ions of FMOC-NE and FMOC-EPI produced diagnostic product ion spectra. Liquid chromatography/atmospheric pressure chemical ionization mass spectrometric analysis of the FMOC derivatives of catecholamines and DHBA should prove useful in the separation and characterization of these compounds from biological materials.