Comparison of fluorescence correlation spectrometry with the ordinary fluorescence optical configuration with flow cytometry as a tool for micrometer-level size determination.

As a tool for micrometer-level size determination, fluorescence correlation spectroscopy (FCS), performed based on our previous report, was compared to flow cytometry (FCM). For this purpose, standard fluorescent beads were subjected to both methods. And hence, it was found that our FCS is a useful method with satisfactory precision for size determinations of individual particles at micrometer size levels, while providing the average size for a mixture of two kinds of particles with different sizes.