Blinking-Based Identification of Single Dye Molecules in Ink.

Area of Science:

• Analytical Chemistry
• Heritage Science
• Materials Science

Background:

• Identifying fluorescent dyes in cultural heritage is difficult due to fading, sample scarcity, and complexity.
• Existing methods like surface-enhanced Raman scattering (SERS) can be invasive or lack single-molecule sensitivity.

Purpose of the Study:

• To develop a minimally invasive, ultrasensitive method for identifying single fluorescent dye molecules.
• To provide exclusive identification of structurally similar rhodamine dyes in inks.

Main Methods:

• Utilized widefield fluorescence microscopy and blinking analysis to detect intrinsic fluorescence intermittency.
• Applied change point detection and multinomial logistic regression to define identification factors.
• Validated results with bulk surface-enhanced Raman scattering (SERS) measurements.

Main Results:

• Successfully identified single rhodamine dye molecules based on their unique blinking patterns.
• Developed four quantitative determination factors for exclusive identification of three rhodamine dyes.
• Confirmed the presence of rhodamine B in commercial ballpoint ink samples.

Conclusions:

• Blinking-based dye identification offers single-molecule sensitivity and exclusive results without plasmonic substrates.
• This method is a powerful, minimally invasive tool for characterizing artists' materials.
• Opens new avenues for conservation and heritage science research.