OLEYL ALCOHOL: PURITY TESTING BY REVERSE PHASE HPLC WITH EVAPORATIVE LIGHT SCATTERING DETECTION V. Ioffe, M. Kaadan, A. Rosenberger Analytical Development, Global Innovative R&D, Teva Pharmaceutical Industries, Ltd., Israel RP HPLC method for testing Oleyl alcohol, especially for the precise quantitation of the most critical impurity – its trans-isomer (Elaidyl alcohol) has been developed. The method comprises a polymeric RP chromatographic column with medium-chain modifier, free of influence of residual silanols, and a completely volatile mobile phase, comprising three solvents (water, acetonitrile and methanol). Optimization of the mobile phase composition to achieve baseline separation between cis- and trans-isomers, especially when the minor component is eluted after the major one, is discussed in terms of mechanism of RP chromatographic separation. Evaporative light scattering detection (ELSD) is used for the compounds, which do not bear any chromophore. Issues of quantitation are discussed for the detection methods having non-linear correlation of concentration and response (peak area). Organized and Produced: http://www.isranalytica.org.il P.O.B 4034 Ness-Ziona 70400 Tel.+972-8-940-9085, Fax. .+972-8-940-9086 Site: www.BioForum.org.il E-mail: BioForum@bezeqint.net