In-line coupling SPE and CE for DNA preconcentration and separation

Area of Science:

• Analytical Chemistry
• Biochemistry

Background:

• Capillary electrophoresis (CE) is a powerful separation technique.
• DNA analysis often requires high sensitivity and preconcentration steps.
• Solid-phase extraction (SPE) can be used for sample preconcentration.

Purpose of the Study:

• To develop an in-line solid-phase extraction coupled with capillary electrophoresis (SPE-CE) method for DNA analysis.
• To improve the sensitivity and preconcentration efficiency for DNA fragments.

Main Methods:

• An amino silica monolith was prepared in situ within a fused-silica capillary.
• The in-line SPE-CE method involved optimizing sieving matrix introduction, elution solvent composition, and elution time.
• Twenty millimolar ammonium hydroxide was used for DNA desorption, and linear poly(N-isopropylacrylamide) served as the separation matrix.

Main Results:

• The developed SPE-CE method achieved limits of detection of 0.065-0.123 ng/mL for DNA fragments ranging from 100-2000 bp.
• Preconcentration factors exceeding 100 times were obtained compared to conventional CE.
• The method demonstrated applicability by analyzing plasmid DNA from Escherichia coli crude lysate.

Conclusions:

• The in-line SPE-CE method offers a highly sensitive and efficient approach for DNA analysis.
• This technique significantly enhances preconcentration capabilities for DNA fragments.
• The method is suitable for analyzing DNA in complex biological samples.