Determination and Identification of Primary Aliphatic Amines Using 4-(1H-Phenanthro[9,10-d]Imidazol-2-yl)Benzoic Acid as Novel Pre-Column Labeling Reagent by LC with Fluorescence Detection and Atmospheric Pressure Chemical Ionization Mass Spectroscopy

摘要

4-(1H-Phenanthro[9,10-d]imidazol-2-yl)benzoic acid (PIBA), a new amine-reactive fluorescent probe was synthesized and used as a pre-column derivatizing reagent for the determination of aliphatic amines from environmetal water samples. Derivatization was successfully carried out by a condensation reaction using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride as the dehydrant. Studies on derivatization conditions indicated that the condensation reaction proceeded rapidly and smoothly in the presence of pyridine. Amines were labeled with PIBA to give the corresponding sensitively fluorescent derivatives with an excitation maximum at lambda (ex) 260 nm and an emission maximum at lambda (em) 445 nm. Identification of derivatives was carried out by online APCI-MS-MS and showed an intense protonated molecular ion corresponding m/z [M + H](+) in the positive ion mode. Excellent linear responses were observed with coefficients of > 0.9996. Detection limits were 6.7-27 fmol (at a signal-to-noise ratio of 3). The mean intra- and inter-assay precision for all amine levels were < 2.79 and 3.85%, respectively. The established method for the determination of aliphatic amines from real water was satisfactory.