Chromatographic framework for coffee ring effect-driven separation of small molecules in surface enhanced Raman...

Area of Science:

• Analytical Chemistry
• Physical Chemistry
• Nanoscience

Background:

• The coffee ring effect (CRE) is well-understood for particle and macromolecule deposition.
• Theoretical aspects of CRE-driven separation for small molecules, especially analyte-surface interactions, remain underdeveloped.
• Coupling CRE with surface-enhanced Raman spectroscopy (SERS) offers expanded analytical applications.

Purpose of the Study:

• To develop a theoretical framework for CRE-driven separation of small molecules.
• To investigate analyte-surface interactions in CRE-based separations.
• To adapt conventional chromatographic theory for CRE-driven nanochromatography.

Main Methods:

• Developed a theoretical framework combining CRE and Extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theories.
• Utilized SERS analysis of arsenicals (DMA^V, DMMTA^V, DMDTA^V) on gold nanofilms (AuNF).
• Derived a modified van Deemter equation for CRE-driven separation.

Main Results:

• Successfully predicted travel distances of arsenicals based on their affinity to AuNF.
• Demonstrated the potential for separating unknown analytes using CRE-based SERS.
• Validated the adaptation of classic chromatographic theory to CRE-driven nanochromatography.

Conclusions:

• The developed theoretical framework accurately describes CRE-driven separation of small molecules.
• CRE-based SERS provides a viable method for nanochromatographic separation and analysis.
• This work bridges the gap in theoretical understanding of CRE for small molecule analysis.