Determination of amines in air and water using derivatization combined with solid-phase microextraction

Solid-phase microextraction (SPME) is a simple, fast, economic and solvent-free sample preparation technique. The selectivity and sensitivity of this technique for the determination of amines in gaseous and aqueous matrices can be significantly improved by coupling derivatization with SPME during sampling. Derivatization has advantages in enhancing coating-gas and coating-water partition coefficients for amines, thus improving SPME extraction efficiency and method sensitivity. For air analysis, 4-nitrophenyl trifluoroacetate effectively derivatized volatile and polar amines into less polar amides in the gaseous phase, with limits of detection (LODs) at the low pg/ml level when gas chromatography-flame ionization detection (GC-FID) was used. For aqueous sample analysis, pentafluorobenzylaldehyde was utilized to convert polar primary amines into their less polar imines directly in aqueous solutions. Derivatization-SPME provided LODs at low ng/ml to pg/ml levels with GC-FID. Compared to direct SPME, derivatization-SPME lowered LODs by two-three orders of magnitude for the analysis of amines in air and aqueous solutions.