Why isn't residual standard deviation used in FQY analysis?

I've been measuring relative fluorescence quantum yield (hereafter FQY) for a photosensitive pigment. Most analytical articles and standard operating procedures (SOPs) I've read suggest taking the average of multiple FQY measurements (at least 3) before calculating the standard deviation, which seems good; however, wouldn't comparing residual standard deviations (RSDs) of the linear regression of fluorescence intensity versus the absorbance of the dye standard (e.g. rhodamine B) and dye sample (e.g. hypericin) provide thorougher validation of the calibration fits and thus FQY? In other words, since the relative FQY is calculated from the slopes of these plots, can I glean more information by comparing the RSD of the plots and SD of the FQY?




You do need to account for the absorbance of each sample otherwise the yield will be hugely inaccurate, then take the average etc. Normally you would try to make each solution of the same concentration but you could do what you suggest provided you are sure that no aggregation etc. of the molecule is present.


To get relative yield (other than just a number proportional to a voltage from your detector) you also need to measure the fluorescence of a known standard molecule, and at the same wavelength because detection sensitivity will vary with wavelength.


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