On-line size-exclusion chromatography/electrospray ionisation mass spectrometry of aquatic humic and fulvic acids

Isolated aquatic humic and fulvic acids were analysed with on-line size exc lusion chromatography/ electrospray ionisation mass spectrometry (SEC/ESI-M S). An eluent composition which enabled electrospray ionisation was identif ied. The SEC separation improved interpretability of mass spectra and may o pen up new possibilities for molecular weight determination of humic substa nces. a linear dose-response relationship over a factor of 20 was obtained and the limit of detection was 50ng/uL for humic and fulvic acids, Spectral changes due to different ionisation conditions (pH and cone voltage) were investigated. A natural water sample from a Swedish lake was analysed, Copy right (C) 2000 John Wiley & Sons, Ltd.