numbers of carbon atoms, but sufficient separation cannot be obtained for the aliphatic open-chain and cyclic hydroxy acids that are also present in coffee. The author suggests that good separation is achieved by reversed-phase chromatography as has been used in this work. Nevertheless, low k values (Table 4) were obtained for some of the organic acids. When acetonitrile and methanol were tested as organic modifiers (at 1% concentration in mobile phase) the k values did not show significant differences. Further work took us to test a drop in pH value of the mobile phase to 1.8 which resulted in improved separation between malic and pyruvic acid peaks (Fig. 2). Retention times of all other peaks were almost the same (Table 5). This indicates that lower pH values could be essayed as long as the separation column is adequate to that in order to improve capacity factor and resolution