Overview

This guide outlines the correct conditioning and storage procedures for Controlled‑Flow and Zero‑Flow Capillaries used in capillary electrophoresis (CE). These capillaries are sensitive to strong bases and require appropriate handling to protect the internal polymer treatment responsible for their controlled‑flow characteristics. Conditioning includes polyimide removal, solvent rinses, and buffer equilibration before use. Between injections, shorter rinse cycles maintain reliability and performance.

For storage, a sequence of final rinses followed by purging with nitrogen or helium ensures long‑term stability and prevents contamination or drying artifacts that can affect reproducibility.

Conditioning Controlled and Zero‑Flow Capillaries

Capillary Conditioning Procedure

Important: Never use strong bases on these capillaries.

• Remove the capillary from its shipping or storage container carefully to avoid damage.
• Remove the protective polyimide coating using one of the below techniques:
  • 98% fuming sulfuric acid heated to 100°C (one drop is typically sufficient), or
  • The MICROSOLV Window Maker™, ensuring the capillary does not touch the glowing heating coils.
  • Always follow approved safety protocols when handling corrosive chemicals or heat sources.
• Rinse the capillary with a water/methanol solution (50:50 or 30:70 v/v) for 10 minutes.
• Rinse with CEwater™ for 10 minutes.
• Perform a final rinse with your run buffer for 10 minutes.
• Between injections, repeat a shortened version of the conditioning cycle:

1. 1 minute rinse with water/methanol solution
2. 2 minutes rinse with CEwater™
3. 2 minutes rinse with run buffer

Capillary Storage Procedure

1. Rinse the capillary with your run buffer for 25 minutes.
2. Rinse with CEwater™ for 15 minutes.
3. For extended storage, gently purge the capillary with nitrogen or helium under slight pressure.
4. If storing for an extended period, we recommend that N2 or helium should be blown, under slight pressure, through the capillary.