Fractionation of organic acids

Wershaw, R. L., Llaguno, E. C., Leenheer, J. A., Sperline, R. R, and Song, Y. (1996b). Mechanism of formation of humus coatings on mineral surfaces. 2. Attenuated total reflectance spectra of hydrophobic and hydrophilic fractions of organic acids from compost leachate on alumina. Coll. Surf. A 108,199-211. 

A second fraction of organic acids was recovered from the water/methanol filtrate by adjusting the pH to 4.0 with hydrochloric acid followed by suction filtration. The precipitate was washed with water, dried in vacuo at 80° C and weighed (1.6 g, 14%). Ion Exchange Separation of Asphaltenes... 

Fractionation of organic acids by electrophoresis has also been studied by some workers and has been found very useful for separating some special acids. 

The chemical composition of the produced oil was analyzed by GC-MS. The samples were prepared by diluting the bio oil in methanol in a way that the fraction of organic oil was the same in each GC-vial. The products found in the oil were grouped as aldehydes, acids, alcohols, ketones, phenols, polyaromatics and others. The most interesting groups are shown in Table 4 and Table 5, arranged according to their retention time (RT). The procedure for the GC-MS analysis has been previously reported by the authors [4],... 

While in lab experiments or on-site the pH can be controlled, in an in situ application it will always decrease due to the formation of organic acids. This will effect shifts in the oxidation mechanism toward the direct oxidation pathway and in the chemical equilibrium of the soil. Furthermore, both ozone applications will result in changes in the soil chemical constituents, i. e. the cation exchange layer and the humic fraction. The consequences of these changes are still mostly unknown. A special lag-phase and a selection of bacteria in regrowth might be caused by the ozonation. 

Another strategy exploits the nucleic acids from diverse organisms where it is not necessary to isolate the bacteria themselves. This approach has particular benefits because only a small fraction of organisms in a particular habitat is culturable (Table 3.4). 

Is this a plausible premise In order to approach this question, we can assume that the mixture of organic compounds in carbonaceous meteorites such as the Murchison meteorite resembles components available on the early Earth through extraterrestrial infall. A series of organic acids represents the most abundant water-soluble fraction in carbonaceous meteorites [ 15,67,68]. Samples of the Murchison meteorite were extracted in an organic solvent commonly used to extract membrane lipids from biological sources [69,70]. When this material was allowed to interact with aqueous phases, one class of compounds with acidic properties was clearly capable of forming membrane-bounded vesicles (Fig. 7). 

Among the more oxidized compounds, oxalic acid has received significant attention (Martinez-Huitle et al. 2004, 2005 Ivandini et al. 2005) because often it constitutes the final product in the oxidative process of organics. It is generally selected as a model compound to represent the aliphatic fraction of organic substrate in the waste. 

Eisenbraun EW (1963) The separation and fractionation of lignosulfonic acids from spent sulfite liquor with tn-n-hexylamme m organic solvents Tappi 46.104-107 Felicetta VF, McCarthy JL (1957) Tappi 40.851-866 Forss KG, Pirhonen IMJ (1974) U S Patent No 3825526... 

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