Applications of Fluorescence Correlation Spectroscopy: Polydispersity Measurements

Area of Science:

• Analytical Chemistry
• Physical Chemistry
• Biophysics

Background:

• Determining particle and molecular polydispersity in solution is crucial for understanding material properties.
• Traditional methods like photon correlation spectroscopy (PCS) have limitations, especially for small particles and dilute solutions.

Purpose of the Study:

• To develop and validate a histogram-based method for assessing polydispersity using fluorescence correlation spectroscopy (FCS) data.
• To compare the effectiveness of FCS with existing techniques like PCS.

Main Methods:

• Application of the histogram method to fluorescence correlation spectroscopy (FCS) data.
• Utilizing imposed regularization and constraint conditions to address the ill-posed nature of polydispersity determination.
• Testing the method on simulated and real FCS data.

Main Results:

• The developed histogram method successfully determines polydispersity from FCS data.
• FCS demonstrates comparable efficiency to PCS for polydispersity determination.
• FCS shows superior sensitivity for particles <50 nm and enhanced selectivity in dilute solutions.

Conclusions:

• Fluorescence correlation spectroscopy (FCS) is a viable and effective technique for determining particle and molecular polydispersity.
• FCS offers significant advantages in sensitivity and selectivity for small particles and dilute systems.
• The findings support the utility of FCS in fields like environmental chemistry.