Soluble organic matter fractionation

There are two main aims in applications of PTLC in organic geochemistry (1) assessment of the bulk group composition of soluble organic matter by its fractionation and (2) separation of a particular selected group of compounds with geochemical meaning. The important factor in technique selection should be the repeatability of... 

Column Chromatography in Soluble Organic Matter Fractionation... 

Radke et al. [28] described an automated medium-pressure liquid chromatograph, now commonly called the Kohnen-Willsch instrument. At present, the method is widely used to isolate different fractions of soluble organic matter (for instance, as described in Reference 29 to Reference 31). A combination of normal phase and reversed-phase liquid chromatography has been used by Garrigues et al. [32] to discriminate between different aromatic ring systems and degrees of methylamine in order to characterize thermal maturity of organic matter. 

Another variation of the preceding method is to apply HPLC to fractionate the cleaned-up aliphatic-aromatic fraction from flash colurim separation of soluble organic matter as it is performed in the Chevron laboratory, for example, as described in Reference 2. A Waters HPLC system equipped with a preparative Whatman Partisil 10 silica column (9.4 X 500 mm), a HPLC pump, and two detectors for separation monitoring (a UV and refractive index detector) are used, giving three fractions of aliphatic hydrocarbons, mono-, di-, and triaromatics and polar compounds. The hrst two fractions are eluted with hexane, whereas polar compounds are eluted with... 

FIGURE 15.1 Scheme showing PLC group fractionation of soluble organic matter into fractions of aliphatic hydrocarbons, aromatic compounds with application of urea clathra-tion, and methylation of carboxylic acids in polar fractions based on experimental data given in Reference 36 to Reference 52, Reference 77 to Reference 81, and Reference 88 to Reference 89. 

FIGURE 15.2 Group fractionation of soluble organic matter with application of argentation PLC based on Reference 61 and Reference 89 to Reference 93. 

Teranishi, K., K. Hamada, and H. Watanabe, Mutagenicity in Salmonella typhimurium Mutants of the Benzene-Soluble Organic Matter Derived from Airborne Particulate Matter and Its Five Fractions, Mutat. Res., 56, 273-280 (1978). 

Chemical oxidation reactions and radical-induced hydrophobic-to-hydrophilic aging processes tend to increase the water solubility of OAs and, therefore, are thought to enhance the activity of atmospheric OAs as cloud condensation nuclei (CCN). As discussed by Gysel et al. (2004), at 75-90% of relative humidity (RH) the inorganic fraction dominates the water uptake (59-80%). Nevertheless, under the same conditions of RH, between 20% and 40% of total particulate water is associated with water-soluble organic matter. More data concerning the multiphase aerosol and cloud processes, as well as the chemical reactivity of carbonaceous aerosol components, have been compiled in the reviews of Jacobson et al. (2000), Kanakidou et al. (2005), and Poschl (2005) (and references therein). 

Once in the soil environment organic contaminants may move in, or interact with, the soil atmosphere, soil water, mineral fractions and organic matter. Ultimately, however, the organic contaminants will either dissipate or persist (Fig. 4.27). Compounds persist if they are of low volatility, low solubility (Box 4.14) or have a molecular structure that resists degradation. Conversely, if compounds are highly volatile, highly soluble or are easily degraded, they will be... 

Povoledo, D. and Gerletti, M. (1963). Studies on the sedimentary, acid-soluble organic matter from Lake Maggiore (North Italy). I. Heterogeneity and chemical properties of a fraction precipitated by barium ions. Mem. 1st. Ital. Idrobiol. 17, 115-150. 

The first stage performs some bacteriological disinfection, eliminates the phosphates, the carbonate hardness and most colloids. The second stage removes a fraction of the soluble organic matter and yields water of constant physical quality and a fouling index of less than 3. The recycled water should nevertheless exhibit low salinity and regular characteristics for reliable treatment before RO, and this is not often achieved. 

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