Determination of resin acid composition in rosin samples using cyclodextrin-modified capillary electrophoresis

Rosins are used in a wide variety of industries in varnishes, adhesives, drug coatings, etc. In this project a novel capillary electrophoresis method was developed to investigate the resin acid composition of rosins. The acids were separated and the concentrations of individual acids present in gum rosin samples determined in order to investigate any links between the presence and concentration of these acids and the tendency of rosins to crystallize. The capillary electrophoresis method successfully separated nine resin acids in various rosin samples where previously they could not all be separated. Calibration curves were created to determine acid concentration. Abietic, dehydroabietic, neoabietic, pimaric, isopimaric, levopimaric, sandaracopimaric, palustric, and 7-oxo-dehydroabietic acids were separated using a 20 mM tris buffer at pH 9 containing 15% methanol 5 mM (2-hydroxypropyl)-γ-cyclodextrin 10 mM sulfobutylether-β-cyclodextrin. Their concentrations in a crystallizing and a noncrystallizing rosin sample were determined.