Advantage of liquid chromatography with high‐resolution mass spectrometry for the detection of the small and polar molecules trifluoroacetic acid and sulfamic acid

Abstract

This study addresses the selectivity of liquid chromatography with tandem mass spectrometry for the analysis of the polar analytes trifluoroacetic acid and sulfamic acid in water samples. Such analytes often lack sufficient retention in standard reversed-phase liquid chromatography and rarely produce mass spectrometry transition products of high diagnostic evidence by collision-induced dissociation. The chromatography based on an extra-dense bonding liquid chromatography column for trifluoroacetic acid and on hydrophilic interaction chromatography for sulfamic acid. This enabled sufficient retention of more than twice the void volume for both analytes. Liquid chromatography coupled to low-resolution mass spectrometry was compared with high-resolution mass spectrometry. The limits of quantification for direct injection analysis were determined to <0.05 μg/L for trifluoroacetic acid and <0.5 μg/L for sulfamic acid. Correction of matrix effects either by internal standards or the standard addition is strongly recommended as matrix effects may vary strongly. The concentrations determined for trifluoroacetic acid and sulfamic acid for real samples were comparable between low and high-resolution mass spectrometry. However, low-resolution mass spectrometry does not fulfill the identification criteria of the analytes following the European Commission council directive 96/23/EC or the SANTE/11945/2015. Since low-resolution mass spectrometry for these analytes may result in false-positive findings, such findings may be controlled by high-resolution mass spectrometry.