Acid degree value method

This suggests that an analytical method that measures total free fatty acids (e.g., acid degree value) may be a poor measure of the off-flavor potential of these fatty acids. 

Traditional chemical methods are currently used in the characterization of fatty acids neutralization values permit the calculation of the mean molecular weight and a series of values (for instance, iodine, thiocyanogen, and hydrogenation values) for determining the degree of unsaturation. A complete analysis of fatty acid mixtures would nevertheless require the qualitative and quantitative detection of all the fatty acids (Fontell et al., 1960). Such methods as crystallization of salts and bromine adduct formation have been used to some extent. Nowadays, less conventional methods have found wide... 

The classic chemical technique for measuring the degree of unsaturation in diene polymers is iodometry (iodine value) [102]. Kubo et al. [103] extensively measured the iodine value to determine the amount of residual double bonds present in the HNBR. However, this method exhibited significantly poorer precision as compared with IR and NMR spectroscopies [99-101]. Acid... 

The ease of N determination in PVN samples appears to be a function of the degree of polymerization. The nitrometer method gives consistent results, but are about 0.6% lower than the true values (Ref 6). Difficulty is experienced with high viscosity PVN. These products dissolve slowly in sulfuric acid, and give scattered results. Analytical methods based on titanous chloride,... 

In an early work by Mertz and Pettitt, an open system was devised, in which an extended variable, representing the extent of protonation, was used to couple the system to a chemical potential reservoir [67], This method was demonstrated in the simulation of the acid-base reaction of acetic acid with water [67], Recently, PHMD methods based on continuous protonation states have been developed, in which a set of continuous titration coordinates, A, bound between 0 and 1, is propagated simultaneously with the conformational degrees of freedom in explicit or continuum solvent MD simulations. In the acidostat method developed by Borjesson and Hiinenberger for explicit solvent simulations [13], A. is relaxed towards the equilibrium value via a first-order coupling scheme in analogy to Berendsen s thermostat [10]. However, the theoretical basis for the equilibrium condition used in the derivation seems unclear [3], A test using the pKa calculation for several small amines did not yield HH titration behavior [13],... 

Values found for the molecular weight of deoxyribonucleic acids also vary considerably, but probably lie between 1.0 X 106 and 4.4 X 106. Various difficulties encountered in making such measurements have been discussed by Jordan,244 and it is probable that more reliable information will be obtained only when the behavior of polyelectrolytes in general is better understood. Certain of the techniques used are useful in detecting differences between different nucleic-acid preparations, but the discrepancies between the values given by different methods of measurement appear to vary with the degree of polymerization.246... 

---