Abstract: A manifold and a chemiluminescence detector for flow injection analysis of, e.g., morphine, are described. Morphine in a carrier stream of 0.1 M polyphosphoric acid (2.6 mL min-1) was oxidized by 0.6 mM KMnO4 to chemiluminescent pseudomorphine for detection by a sensitive photomultiplier tube. The detection limit for morphine was 0.7 pg. Sample throughput was 150 samples h-1. The coefficient of variation was 1.8% (n = 10). Structurally related opiates, e.g., normorphine and morphine N-oxide, behave in the same way.