Some organic acids have stronger adsorptive property than fatty acid which makes trace analysis of such compounds difficult. Therefore, special care must be taken for such analysis. To prevent adsorption, these acids are first derivatized and highly polar stationary phases such as polyesters, are fairly used. Hydroxylic acids or dicarboxylic acids can be analyzed by using Unisole 30T as the stationary phase (Fig. 1). However, at low concentrations, quantitative results cannot be inferred due to the unsymmetrical peaks. By adding phosphoric acid to Unisole 10T, symmetrical peaks can be obtained for organic acids (Fig. 3).