Anion-exchange chromatography–electrospray ionization mass spectrometry method development for the environmental analysis of aliphatic polyhydroxy carboxylic acids

For environmental analytical purposes, an anion-exchange chromatography–electrospray ionization MS method was developed enabling the identification and quantification of 18 aliphatic (poly)hydroxy (poly)carboxylic acids including sugar and uronic acids. The initially incomplete separation could be partially improved for specific analyte combinations adding borate, the zwitter ionic MES, or an alkylglycoside to the NaOH gradient supplied with the Dionex IonPac AS-11 HC column. Despite the incomplete separation, reproducible and sensitive identification and quantification is possible with MS detection in the selected ion-monitoring mode. Applying an internal standard for the compensation of the sensitivity drift of the detector, linear calibration functions were calculated for all analytes. Limits of detection spanned between 18 and 71 μg L−1 which could be further improved for some more hydrophobic analytes by post-column addition of MeOH.