Analysis of low-molecular-mass inorganic and organic anions by ion chromatography-atmospheric pressure ionization mass spectrometry

Different nonvolatile mobile phases have been tested for the combination of ion-exchange chromatography combined with mass spectrometric detection of anions and organic acids. Buffer systems based on carbonate, sulfate, oxala te and citrate as the eluting species have been used. Among these, citrate proved to be the most versatile eluent allowing the separation of anions wi th absolute detection limits between 0.4 and 0.7 ng and of organic acids wi th detection limits between 0.4 and 4 ng in the non-suppressed mode. In the suppressed eluent mode iodate, bromate and chlorate could be separated usi ng sodium carbonate as the mobile phase resulting in detection limits of 50 pg. The method was applied to the analysis of water samples containing oxy halides originating from ozonization. Additionally, organic acids were sepa rated by chromatographic separation techniques like reversed-phase, ion-pai r or ion-exclusion chromatography and the compatibility with mass spectrome try was investigated with special respect to sensitivity of this detection mode. (C) 1999 Elsevier Science B.V. All rights reserved.