On-chip ultra-thin layer chromatography and surface enhanced Raman spectroscopy

Area of Science:

• Analytical Chemistry
• Materials Science
• Spectroscopy

Background:

• Developing integrated platforms for chemical mixture analysis is crucial.
• Surface-enhanced Raman spectroscopy (SERS) offers high sensitivity but can lack specificity.
• Ultra-thin layer chromatography (UTLC) provides separation capabilities but requires sensitive detection methods.

Purpose of the Study:

• To demonstrate the use of silver nanorod (AgNR) array substrates for combined on-chip UTLC and SERS.
• To evaluate the separation and detection performance of AgNR-based UTLC-SERS for chemical mixtures.
• To assess the improvement in detection specificity through UTLC-SERS coupling.

Main Methods:

• Fabrication of UTLC-SERS plates using AgNR arrays via oblique angle deposition.
• Separation of dye mixtures and melamine/Rhodamine 6G mixtures using UTLC on AgNR substrates.
• Spatially-resolved SERS spectral acquisition along the mobile phase development direction.
• Generation of chromatograms based on specific SERS peak intensities.

Main Results:

• AgNR substrates effectively separated components in tested chemical mixtures.
• Achieved low plate heights of 9.6 μm for dye separation.
• Demonstrated limits of detection in the range of 10(-5)-10(-6) M.
• UTLC-SERS coupling enhanced specificity by separating analytes from interfering background.

Conclusions:

• AgNR array substrates are viable for integrated on-chip UTLC-SERS analysis.
• The developed platform offers efficient separation and sensitive detection of chemical mixtures.
• This approach significantly improves the specificity of SERS-based chemical analysis.