Recording capillary electrophoresis

Introduction to Electrodes

• Electrode Basics

  • Positive and negative electrodes are often a source of confusion.

  • Anode: Positively charged, attracts anions (negatively charged ions).

  • Cathode: Typically on the right-hand side of the detector, attracts cations (positively charged ions).

Electrical Double Layer

• Understanding Movement in the Capillary

  • Upon turning on the voltage, a reset occurs resulting in the movement of protons toward the cathode.

  • Protons are positively charged and are attracted to the negatively charged anode.

  • This movement of charge creates buffer flow towards the cathode.

Generation of EOS (Electroosmotic Flow)

• Applying Voltage and EOS

  • When voltage is applied, EOS is generated.

  • Uncharged species will migrate towards the middle, while cations will be drawn towards the cathode.

  • This explains the observed separation as components move at different rates within the flow.

Chromatogram and Separation Efficiency

• Separation Mechanisms

  • Important to understand how different charged and uncharged particles behave under electric fields.

  • Graph plots show time signal from the detector reminiscent of chromatograms, helping visualize retention and separation.