Derivatization of amines in solid-phase extraction supports with 9-fluorenylmethyl chloroformate for liquid chromatography

A new method based on reaction in solid-phase extraction cartridges with 9-fluorenylmethyl chloroformate is described for improved derivatization of amines prior to liquid chromatography. The effects of the reaction conditions, the kinetics of the reaction and the kind of packing material on the derivatization have been evaluated. The reliability of the described approach has been tested by derivatizing propylamine, diethylamine, diethanolamine, glycine, glutamic acid, p-aminobenzoic acid and β-phenylethylamine. Reaction yields compared with those of the analogous solution derivatizations were in the 44–169% range, and satisfactory linearity was achieved at concentrations of the amine-FMOC derivatives in the 5–100 μg/ml interval. As an illustrative example of application to real samples, a procedure for the determination of β-phenylethylamine in urine (at 0.01–1.0 μg/ml levels) using C18 solid-phase extraction cartridges and spectrophotometric detection is described. Analyte responses after cleanup plus derivatization were (91 ± 5)%, the limit of detection being 0.1 ng/ml at 254 nm.