F-Trap Pyrene Ox: A Reagent Peak-Free Fluorescence Derivatization Reagent for Amine Analysis

Abstract

This study introduces F-trap pyrene Ox, a reagent peak-free pre-column fluorescence derivatization reagent for sensitive analysis of amines and amino acids. By oxidizing the thioether moiety of previously reported F-trap pyrene to sulfone, we significantly enhanced reactivity toward amino groups, achieving complete derivatization in 10 min at 90 °C. The reagent incorporates a fluorophilic perfluoroalkyl tag that enables selective removal of excess unreacted reagent through fluorous solid-phase extraction (F-SPE) with 75 % aqueous acetonitrile as eluent, achieving >99.4 % removal rate while maintaining excellent recovery. Method validation for aliphatic amines demonstrated good linearity (r² > 0.995) over 50 fmol to 50 pmol, excellent precision (intra-day RSD ≤ 6.7 %), and detection limits 4-times lower than F-trap pyrene. Additionally, we developed an online column-switching F-SPE system that automates the removal process. The method successfully analyzed 13 aliphatic amines and 16 amino acids without interference from reagent peaks, offering significant advantages for sensitive analysis of biologically active amines in complex matrices.