The effectiveness of fluorometric scanning using a fiber optic to analyze substances adsorbed onto solid surfaces is described. The relative efficiencies of signal capture by different widths of monochromator slits were studied. The signal and signal-to-noise ratios were compared using monochromators or long-pass filters. Accuracy and precision of the measurements were compared with and without substraction of the background signal; the detection limits for fluorescein and several phenothiazine compounds were compared under different experimental conditions to explore the range of effectiveness of the system.