Minimizing the effect of spurious photodetector currents in flash spectrofluorimetry

摘要

The vitiating effect on the fluorescence measuring signal of extraneous currents flowing through the fluorescence detection means in flash spectrofluorimetry is almost completely eliminated by integrating the output of the fluorescence measuring means for the duration of the signal period, which includes a flash duration, and again for an equal period occurring between flashes which therefore does not include a flash duration. The second integral is then subtracted from the first to obtain a fluorescence measuring signal substantially unaffected by extraneous currents, such as dark current, sample phosphorescence, etc. The invention is applicable to single- and double-channel operation. In the latter, in addition to the fluorescence measuring channel there is provided a fluorescence reference channel. This enables the fluorescence measuring signal and the fluorescence reference signal to be ratioed together, the effect of extraneous currents having first been eliminated in both.