The use of moment index displacement in analyzing fluorescence time‐decay data

Moment index displacement automatically corrects a number of significant nonrandom instrumental errors in fluorescence time‐decay measurements. Three‐component data, obtained by measuring the fluorescence decay of three different species mixed in the same solution, were used as a test sample. It was shown, as predicted by theory, that moment index displacement corrects three nonrandom instrumental errors: (1) the presence of scatter in the data; (2) time origin shifts between lamp and fluorescence data; and (3) lamp drift, or time‐dependent changes in the shape of the excitation curve. The data clearly show that the use of the method of moments with moment index displacement to analyze fluorescence decay data is not a curve‐fitting procedure. This procedure will accurately obtain decay parameters for multiple‐exponential decays from certain badly distorted data, yielding a calculated curve very different from the actual data.