Quantitative analysis of pharmaceutically active peptides using on-capillary analyte preconcentration transient...

Area of Science:

• Analytical Chemistry
• Separation Science

Background:

• Quantitative analysis of low peptide concentrations presents significant challenges.
• Existing methods often lack sensitivity and require large sample volumes.

Purpose of the Study:

• To develop a rapid and sensitive capillary electrophoresis (CE) method for quantitative analysis of low peptide concentrations.
• To integrate an on-capillary adsorptive phase for analyte preconcentration.

Main Methods:

• Construction of a mechanically stable on-capillary adsorptive phase using commercially available extraction disks (poly(styrenedivinylbenzene) in Teflon).
• Optimization of elution volume, elution strength, sample application speed, ionic strength, and capacity.
• Utilizing low-wavelength UV detection for quantitative measurements.

Main Results:

• Achieved a 3-4 order of magnitude improvement in detection limits compared to traditional methods.
• Established a limit of detection of 20 pg for model peptides with a 20 microL injection.
• Demonstrated satisfactory reproducibility and linearity in the low nanogram range.
• Showed no influence of matrix salt concentrations, broadening sample applicability.

Conclusions:

• The developed preconcentration CE method offers a rapid, sensitive, and robust approach for analyzing low peptide concentrations.
• The use of readily available materials allows for quick construction of the preconcentrator.
• This technique is suitable for diverse sample matrices due to its insensitivity to salt concentrations.