In this paper the results of a systematic liquid chromatographic investigat
ion are described to characterise water-soluble organic compounds in fog. A
diode array detector is used to record the UV spectrum of the components d
uring separation and a mass spectrometer is applied to obtain information o
n the ion masses of the constituents. The combination of UV acid mass spect
ra reveal that the organic carbon content of fog water is distributed among
a great number of acidic compounds which have polar functional groups and
polyconjugated systems absorbing up to 500 nm. Due to the complexity of the
organic fraction in fog water an unresolved hump of ions was recorded by t
he mass spectrometer From m/z = 100-600 the most intense peaks being detect
ed around m/z = 200-250. Tannin and fulvic acid were also examined under th
e same conditions. In terms of complexity and ion distribution the mass spe
ctrum of the organic fraction was similar to that of a fulvic acid referenc
e material rather than to that of tannin. (C) 2001 Elsevier Science Ltd, Al
l rights reserved.