AUTOMATED INSTRUMENT FOR ABSORPTION-CORRECTED MOLECULAR FLUORESCENCE MEASUREMENTS BY THE CELL SHIFT METHOD

A spectrofluorimeter is described in which a dedicated microcomputer is used to shift the fluorescence sample cell so that the effective pathlengths for excitation and emission are changed. From fluorescence intensities measured at three cell positions, the absorption-free fluorescence intensity of the sample is calculated. The microcomputer also integrates the fluorescence and reference signals, scans the monochromators, and transmits the acquired data to a minicomputer for data reduction and permanent storage. The effectiveness of the instrument is demonstrated in an example where 0. 1 ppm aluminum is determined with oxine in the presence of 5. 0 ppm iron.