Abstract: The sample (20 µL) is injected into a 1 mM KMnO4 carrier stream (pH 1.5; 1.8 mL min-1) and the stream is subsequently mixed with 1 mM Rhodamine B (C. I. Basic Violet 10; 1.8 mL min-1) before measurement of chemiluminescence with use of the flow cell and detector system described previously (cf. Alwarthan and Townshend, Ibid., 1986, 185, 329). Calibration graphs are rectilinear for up to 40 µM-1-naphthol, 50 µM-4-amino-3-hydroxynaphthalene-1-sulfonic acid, 80 µM-2-naphthol, 100 µM-1-amino-2-naphthol hydrochloride and 120 µM-6-hydroxynaphthalene-2-sulfonic acid. For 50 µM-2-naphthol the coefficient of variation was 0.5% (n = 13). The limit of detection was 0.5 µM.