The use of the rotating disk electrode (RDE) for batch injection analysis (BIA) is illustrated. The technique involves injections of microliter samples into a large-volume blank solution, at a fixed location below the disk center. Transient response peaks-similar to those of flow injection analysis-are observed, reflecting the transport of the sample plug toward and away from the RDE. The effects of various experimental variables on the BIA/RDE operation are described. Injection rates of several thousand samples per hour can be achieved, with relative standard deviations of 1-3%, and detection limits at the micromolar (ng) level.