Alternative sample-introduction technique to avoid breakthrough in gradient-elution liquid chromatography of polymers

Area of Science:

• Chromatography
• Polymer Science
• Analytical Chemistry

Background:

• Gradient-elution liquid chromatography (GELC) is vital for synthetic polymer characterization.
• Breakthrough phenomena in GELC can compromise chromatogram accuracy.
• Existing methods to prevent breakthrough are often impractical or impossible for certain polymers.

Purpose of the Study:

• To develop and validate a new strategy to prevent breakthrough in GELC.
• To improve the characterization of synthetic polymers using GELC.
• To address limitations of traditional breakthrough prevention methods.

Main Methods:

• Implementing a post-autosampler mobile phase mixing technique for GELC.
• Utilizing comprehensive two-dimensional GELC × size-exclusion chromatography (GELC×SEC).
• Analyzing a model mixture of poly(methyl methacrylate) standards with varying molecular weights.

Main Results:

• Successfully avoided breakthrough phenomena in GELC by mixing the mobile phase after the autosampler.
• Demonstrated the effectiveness of the method using a GELC×SEC system.
• The strategy is applicable to substances with strong retention dependence on mobile-phase composition, particularly large molecules.

Conclusions:

• The post-autosampler mobile phase mixing strategy effectively prevents breakthrough in GELC.
• This method offers a significant advancement for polymer characterization and other applications involving large molecules.
• While effective for retained substances, unretained or barely retained compounds may still experience peak broadening.