Hydrophilic Fraction

The optimum water content of most cells is around 80%. Liquid water is absolutely necessary for the stability of the lipid membrane and the hydrophobic regions in proteins. The hydrophilic fractions of the nucleic acids and the proteins require liquid water for maintaining their three-dimensional structures and thus their functionality. 

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. 

Sulfur K-edge NEXAFS also detected significant differences between oxidation states in hydrophobic and hydrophilic organic matter (Hundal et al., 2000). Oxidized organic sulfur forms were dominant in the hydrophilic fraction, whereas reduced sulfur forms were dominant in the hydrophobic fraction. 

Provenzano, M. R., Gighotti, G., Cilenti, A., Erriquens, F., and Senesi, N. (2006). Spectroscopic and thermal investigation of hydrophobic and hydrophilic fractions of dissolved organic matter. Compost Sci. Util. 14(3), 191-200. 

Distribution of Hydrophobic and Hydrophilic Fractions of DOM Derived from Organic Wastes (% of Total DOM)... 

The hydrophobic/hydrophilic fractionation of organic carbon in ground-water is different than the fractionation of organic carbon in surface water. Table 3 shows that the amount of hydrophobic material in the groundwaters studied was less than 35%, and in surface waters the amount of hydrophobic... 

The lipophilic soft resin consists of a series of phloroglucinol derivatives known as a-ac-ids (humulone) and )3-acids (lupulone). Both a- and )3-acids are gradnally denatured during storage. The hard resin contains both a hydrophilic fraction (5-resin) and a lipophilic fraction (/ resin). 

Saleh et al. studied Suwannee River fulvic acids (SRFA) using stepwise RP-HPLC and PDA detection. They reported that the hydrophilic constituents represented about 40% fulvic acid and can be resolved into at least six peaks, while the hydrophobic constituents represented about 30% and can be resolved into 12 peaks. The retention and LfV-Vis spectra of the resolved peaks were characteristic of aliphatic organic acids in the hydrophilic fraction and of conjugated aliphatic ketones and phenols in the hydrophobic fraction. 

Firstly, taking into account the polarity and the hydrophobicity of dichloromethane, we may assume that dichloromethane does not interact with the surface hydroxyl groups. Hence, the 5 bet(CH2C12) surface area value should only correspond to the hydrophobic fraction of the silica surface. Hence, the Sbet(H20) value should only correspond to the hydrophilic fraction of the surface. 

The results of this study look very promising in particular, it now seems possible, by IGC, to readily determine the hydrophobic and hydrophilic fractions of silica surfaces. 

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