Planar electrochromatography using an electrospun polymer nanofiber layer.

Area of Science:

• Analytical Chemistry
• Chromatography
• Materials Science

Background:

• Traditional chromatography methods often face limitations in speed and selectivity.
• Electrospun polymer nanofibers present a novel material for chromatographic stationary phases.
• Planar electrochromatography (PEC) is an emerging technique with potential for rapid separations.

Purpose of the Study:

• To investigate the application of electrospun polymer nanofiber stationary phases in planar electrochromatography (PEC).
• To evaluate the performance of polyacrylonitrile nanofiber ultra-thin-layer chromatography (UTLC) plates for rapid analyte separations.
• To study the effects of various parameters on analyte migration and band broadening in the PEC system.

Main Methods:

• Utilized polyacrylonitrile (PAN) nanofiber ultra-thin-layer chromatography (UTLC) plates for planar electrochromatography (PEC).
• Employed a ternary mobile phase for separations, optimizing buffer concentration, pH, organic modifier ratio, and development time.
• Analyzed band broadening as a function of distance and investigated the impact of nanofiber alignment on separation performance.

Main Results:

• Achieved rapid separations on PAN nanofiber UTLC plates in 1-2 minutes.
• Observed a minimum plate height as low as 11 μm, with band broadening initially decreasing and then plateauing.
• Demonstrated that nanofiber alignment increased migration rate but larger spot sizes occurred with near-complete alignment.
• Showcased PEC's unique selectivity and >4 times faster analysis over 15 mm compared to UTLC.
• Reported a two-dimensional separation using UTLC and PEC in 11 minutes on a 40 × 40 mm plate, yielding a significant increase in separation number (70-77).

Conclusions:

• Electrospun polymer nanofibers are highly effective stationary phases for planar electrochromatography (PEC), enabling rapid and efficient separations.
• Tunable stationary phase thickness allows optimization for different separation complexities, with thinner layers favoring speed and thicker layers handling complex mixtures.
• PEC offers distinct advantages over UTLC, including enhanced selectivity and significantly reduced analysis times, making it suitable for high-throughput analytical applications.