I calculated relative quantum yields for two of my compounds by plotting Max emission intensity vs concentration. The standard I used was fluorescein, which was recommended by my PI. The plots are linear with R2 values above 0.990, and I calculated quantum yields of 0.016 and 0.0018 for the two compounds (excitations were placed at 370 and 398 nm. for these compounds, respectively). The concentrations used were below 20 uM and were mostly clear solutions.

Do I need redo these plots using absorbance in placed of concentration? I now know that inner-filter effects occur with more concentrated samples, quenching fluorescence intensity. However, my plots still display a linear relationship.