Fig. 3.

Calibration of relations between fluorophore concentration and fluorescent intensity. The relations between fluorophore concentrations and fluorescence intensities were determined using commercially prepared labeled microbeads applied to microscope slides in known volumes at multiple known concentrations. To accommodate the range of conditions employed during imaging, multiple exposure times were used as indicated in the legend. The data were fitted with the logistic equation, and the inverse forms of these calibration equations were used to convert fluorescent intensities into relative mass values for all images examined. The values shown represent averages for 3 measurements at each concentration-time combination.