ssDNA degradation along capillary electrophoresis process using a Tris buffer.

Area of Science:

• Analytical Chemistry
• Biochemistry

Background:

• Tris-Acetate buffer is standard for single-stranded DNA (ssDNA) selection and characterization via capillary electrophoresis (CE).
• High voltage in CE causes water electrolysis, altering pH and generating Tris derivatives.

Purpose of the Study:

• To investigate the electrochemical modification of Tris buffer during CE.
• To identify the cause of ssDNA degradation observed during CE experiments.
• To propose an alternative buffer system for improved ssDNA analysis.

Main Methods:

• Capillary electrophoresis (CE) was used to analyze ssDNA.
• Electrochemical reactions in Tris buffer were studied.
• ssDNA degradation was monitored over multiple injections.
• A sodium phosphate buffer was tested as an alternative.

Main Results:

• Tris buffer undergoes electrochemical modification in running vials during CE.
• Electrically generated species in Tris buffer degrade ssDNA, even with clean separation buffer.
• Oligonucleotides were completely degraded after repeated injections.
• Metal ion composition in buffer vials changed during the process.

Conclusions:

• Electrochemical reactions in Tris buffer pose a significant challenge for CE-based ssDNA analysis.
• The degradation of ssDNA is caused by electrochemically synthesized species from Tris buffer.
• Sodium phosphate buffer is an electrochemically inactive alternative, preventing ssDNA degradation.