Anionic functionalized gold nanoparticle continuous full filling separations: importance of sample concentration.

Area of Science:

• Analytical Chemistry
• Nanotechnology
• Separation Science

Background:

• Electrically driven separations utilizing nanoparticles offer enhanced detection and separation capabilities.
• However, achieving reproducible results in these systems can be challenging due to various factors.

Purpose of the Study:

• To investigate and address sources of inconsistency in nanoparticle-enhanced capillary electrophoresis (CE) separations.
• To characterize anionic functionalized gold nanoparticles (AuNPs) and their impact on small molecule separations in CE.

Main Methods:

• Anionic functionalized gold nanospheres (AuNPs) were prepared using different self-assembled monolayers (SAMs).
• AuNPs were characterized using dynamic light scattering, extinction spectroscopy, zeta potential, and X-ray photoelectron spectroscopy.
• AuNPs were incorporated into continuous full filling capillary electrophoresis separations with varying small molecule concentrations.

Main Results:

• AuNP stability in the capillary improved with increased ligand packing density.
• Low AuNP concentrations (0-2 nM) had minimal impact on analyte migration times, but higher concentrations led to aggregation and inconsistencies.
• Analyte peak areas were significantly affected by decreasing analyte concentration, attributed to sample enrichment and electrostatic interactions.

Conclusions:

• Ligand packing density and AuNP concentration are critical parameters for reproducible CE separations.
• Understanding nanoparticle aggregation and electrostatic interactions is essential for optimizing nanoparticle-assisted CE.
• These findings guide the development of more reliable nanoparticle-enhanced analytical techniques.