An improved reagent for determination of aliphatic amines with fluorescence and online atmospheric chemical ionization-mass spectrometry identification.

An improved reagent named 2-[2-(dibenzocarbazole)-ethoxy] ethyl chloroformate (DBCEC-Cl) for the determination of aliphatic amines by high-performance liquid chromatography (HPLC) with fluorescence detection and post-column online atmospheric chemical ionization-mass spectrometry (APCI-MS) identification has been developed. DBCEC-Cl could easily and quickly label aliphatic amines. Derivatives were stable enough to be efficiently analyzed by HPLC and showed an intense protonated molecular ion corresponding m/z [M+H](+) under APCI-MS in positive-ion mode. The ratios for fluorescence responses were I(DBCEC-amine)/I(BCEC-amine)=1.02-1.60; I(DBCEC-amine)/I(BCEOC-amine)=1.30-2.57; and I(DBCEC-amine)/I(FMOC-amine)=2.20-4.12 (here, I was relative fluorescence intensity). The ratios for MS responses were IC(DBCEC-amine)/IC(BCEC-amine)=4.16-29.31 and IC(DBCEC-amine)/IC(BCEOC-amine)=1.23-2.47 (Here, IC: APCI-MS ion current intensity). Detection limits calculated from 0.0244 pmol injection, at a signal-to-noise ratio of 3, were 0.3-3.0 fmol. The relative standard deviations for within-day determination (n=6) were 0.045-0.081% for retention time and 0.86-1.03% for peak area for the tested aliphatic amines. The mean intra- and inter-assay precision for all amine levels were <3.64% and 4.67%, respectively. The mean recoveries ranged from 96.9% to 104.7% with their standard deviations in the range of 1.80-2.70 (RSDs%). Excellent linear responses were observed with coefficients of >0.9991.