No abstract

No abstract

Measurements of fluorescence depolarisation are reported for perylsne in dodecyl-and hexadecyltrimethylammonium bromide micelles. The activation energies for perylene rotation, respectively 36 and 35 kJ mol-l in spherical micelles, are within experimental error identical to the activation energies for pyrene excimer formation. The implications of this are discussed in terms of twodimensional diffusion, and, within this model, coefficients of lateral diffusion calculated.The energy transfer contribution to fluorescence depolarisation is measured for peryleiie in hexadecyl-trimethylammonium bromide ; from this the average separation Y of perylene molecules in niicelles containing two perylene molecules is calculated as 2.2 < Y < 4.0 nm, a result which confirms the absence of solubilisate aggregation for these systems. Depolarisation results onperylene in high concentration dodecyl-trimethylammonium bromide solutions indicate that as cationic micelles become rod-like the microviscosity activation energy decreases significantly.Results are also reported on the fluorescence depolarisation of j3-(9-n-hexadecyl-lO-anthryl) acetic acid in hexadecyl-trimethylammonium bromide micelles.

Abstract— The photo‐oxidation by O2(1Δg) of individual lipid components in egg yolk lecithin is examined as a function of time. The rate of oxidation is correlated with the degree of unsaturation in the fatty‐acid chains.

The standard techniques for the analysis of Scotch whisky are non-specific. Methods are described for the determination of individual higher alcohols, esters, aldehydes and phenol using gas chromatography, for polyphenolic extractives and the products of ethanolysis of wood lignin using thin-layer chromatography, and for total acids, esters, aldehydes, tannins, phenols and sugars using volumetric and colorimetric methods.