A simple, sensitive, and mild method for the determination of amines based on a condensation
reaction with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC HCl) as the
dehydrant with fluorescence detection has been developed. Amines were derivatized to their acid
amides with labeling reagent 4-s(1-methyl-1H-phenanthro[9,10-d]imidazole-2-) benzoic acid
(MPIBA). Studies on derivatization conditions indicated that the coupling reaction proceeded
rapidly and smoothly in acetonitrile to give the corresponding sensitively fluorescent derivatives
with a maximum excitation at kex 260 nm and a maximum emission at kem 446 nm. The labeled
derivatives exhibited high stability and were enough to be efficiently analyzed by high-performance
liquid chromatography. Identification of derivatives was carried out by online post-column mass
spectrometry (LC=APCI–MS=MS) and showed an intense protonated molecular ion corresponding
m=z [MH]þ under APCI in positive-ion mode. At the same time, the fluorescence properties of derivatives
in various solvents were investigated. The method, in conjunction with a gradient elution,
offered a baseline resolution of the common amine derivatives on a reversed-phase Eclipse XDB-C8
column. Liquid chromatography separation for the derivatized amines showed good reproducibility
with acetonitrile–water as mobile phase. Detection limits calculated from 90.00 pmol to 88 fmol
injection, at a signal-to-noise ratio of 3, were 10.5–53.4 fmol. Excellent linear responses were
observed with coefficients of >0.9996. The established method for the determination of aliphatic
amines from real wastewater was satisfactory.
Copyright # Taylor & Francis Group, LLC
ISSN: 1082-6076 print/1520-572X online
DOI: 10.1080/10826070903430308