Mass Spectrometric Identification of Aliphatic Amines Using 2-[2-(7H-dibenzo[a,g]-carbazol-7-yl)-ethoxy] Ethyl Chloroformate as Novel Fluorescence Labeling Reagent

On a reversed-phase Eclipse XDB C8 (150 mm × 4.6 mm, 5 μm) column, 12 aliphatic amine derivatives were derivatized using 2-[2-(7H-dibenzo[a,g] carbazol-7-yl)-ethoxy] ethyl chloroformate (DBCEC-Cl) as a new pre-column derivatization reagent. The complete baseline resolution was obtained in conjunction with a gradient elution with acetonitrile/H2O as mobile phase. Detection was carried out by the fluorescence and online post-column LC-MS. The maximum excitation and emission wavelengths were at λex = 300 nm and λem = 400 nm, respectively. Identification of aliphatic amine derivatives was carried out by the online post-column ion trap/mass spectrometry with atmospheric pressure chemical ionization in positive-ion detection mode (APCI-MS). A rapid, accurate method for the determination of free aliphatic amine extracted from soil was proposed. The established method exhibited excellent reproducibility and recovery. Excellent linear responses were observed with the correlation coefficients > 0.9991. The detection limits (at signal-to-noise of 3:1) were at the levels of 0.3–10.1 fmol.