Fluorescence Probe of 10-Phenyl-acridone-2-sulfonyl Chloride and Its Application for Determination of Free Aliphatic Amines in Environmental Samples by HPLC with Fluorescence Detection and APCI-MS

A simple and sensitive method for the determination of free aliphatic amines using 10-phenyl-acridone-2-sulfonyl chloride (PASC) as a labeling reagent by high-performance liquid chromatography with fluorescence detection and online mass spectrometry identification (HPLC-FLD-MS) has been developed. Derivatization conditions including reagent concentration, buffer pH, reaction time and temperature were optimized. PASC reacted with aliphatic amines at 50 A degrees C for 4 min in aqueous acetonitrile (ACN) in the presence of sodiumtetraborate-NaOH buffer (0.10 mol L-1, pH 9.0) to give high yields of PASC-amine derivatives. Derivatives exhibited intense fluorescence with an excitation maximum at lambda(ex) 265 nm and an emission maximum at lambda(em) 418 nm. The separation of derivatives was performed by a reversed-phase Hypersil BDS C8 column in combination with a gradient elution. The identification of derivatives was carried out by online post-column mass spectrometry with atmospheric pressure chemical ionization (APCI) source in positive-ion detection mode. Excellent linear responses were observed with the correlation coefficients of larger than 0.9997, and detection limits (at a signal-to-noise of 3:1) were from 3.0 to 24.3 fmol. Comparing with 10-ethyl-acridine-2-sulfonyl chloride (EASC), PASC exhibited more intense fluorescence and ultraviolet absorbance. The proposed method is sensitive and reproducible for the determination of aliphatic amines from water and soil samples.