Determination of perfluorocarboxylic acids in aqueous matrices by ion-pair solid-phase microextraction-in-port derivatization-gas chromatography-negative ion chemical ionization mass spectrometry.

A rapid, selective and simple analytical procedure using tetrabutylammonium as ion pair in conjunction with solid-phase microextraction followed by in-port derivatization-GC-negative ion chemical ionization mass spectrometry was developed. The procedure allows an accurate determination of perfluoroalkylcarboxylic acids in aqueous samples at ng L(-1) levels (i.e. method detection limit 20 ng L(-1) forperfluorodecanoic acid) improving previous GC methods in terms of analysis time and sensitivity. Ammonia as reagent gas in the negative ion chemical ionization mass spectrometry increased the sensitivity at least 3-fold compared to methane for perfluorocarboxylic acid butyl esters. The developed procedure was successfully applied to effluents from wastewater treatment plants (i.e. 0.05-8.2 microg L(-1)) and harbor seawaters.