Of aquatic humic and fulvic acids

Persson, L., Alsberg,T., Kiss, G., and Odham, G. (2000). On-line size-exclusion chromatogra-phy/electrospray ionisation mass spectrometry of aquatic humic and fulvic acids. Rapid Commun. Mass Spectrom. 14, 286-292. 

In a detailed study on methylated permanganate-degradation products of aquatic humic and fulvic acids (originating from Black Lake, North Carolina, and Lake Drummont, Virginia) by means of gas chromatography/mass spectrometry, Liao et al. (1982) found methyl esters of benzenecarboxylic acids, furancarboxylic acids, aliphatic mono, di, and tribasic acids, and (car-boxyphenyl) glyoxylic acids (Table 3). The degradation products of fulvic and humic fractions from the two lakes were qualitatively similar, but dis-... 

A scheme devised by Thurman and Malcolm (1981) uses XAD-8 to concentrate and isolate aquatic humic substances. According to this scheme, the sample is first filtered through 0.45 /am silver-membrane filters and acidified. After concentration on XAD-8 resin, the humic acid fraction is precipitated at pH 1. Both humic acid and fulvic acid fractions are hydrogen saturated by passing the sample through a cation-exchange resin in the H-form. These fractions are then freeze-dried to yield low-ash samples of aquatic humic and fulvic acids. This extraction scheme is outlined in Table 7. These authors successfully isolated humic substances from a number of surface and groundwaters. Even samples with DOC values of 0.7 mg C/L could be proc-... 

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