A fully automated system for dissolution rate analysis of potassium in slow release tablets is described. Aliquots are removed after 1, 2, and 4 hr from six samples, and potassium is analyzed in a flame photometer at 768 nm. A complete study of six samples takes 5.5 hr. The system may be run overnight. During the time intervals between the removal of aliquots, the system can be used for the determination of the total assay of tablets.