Separation and determination of fluorobenzoic acids using ion chromatography–electrospray mass spectrometry

A method for the trace analysis of fluorobenzoic acids (FBAs) via IC–MS based on solid-phase extraction (SPE) prior to isocratic anion exchange chromatography is described. Up to 23 different fluorobenzoic acids were enriched and determined simultaneously. Solid-phase extraction on hydrophilic–lipophilic-balanced reversed-phase cartridges containing a poly(divinylbenzene-co-N-vinylpyrrolidone) polymer allowed a 500-fold enrichment of the acids if 100 mL sample was used with recoveries between 28% and 98%. The method enables the determination of FBAs down to the range of 16–210 ng L−1, provides sample-preparation (pH-adjusting prior to SPE only) with no need of derivatization, uses low amounts of chemicals and is adaptable to larger or smaller sample volumes.