What is the Normal Pump Pressure Reading for Each Column?
Purpose
This article outlines the nominal pressures for different columns as well as some common causes for a higher/lower observed pressure.
Solution
Please note there are many variables that can change the pressure such as tubing length, temperature, solvent composition, and precolumn. There is some back pressure expected even without a column due to frictional forces in the tubing. Below is a guideline of the expected pressure range under normal conditions using mobile phase.
- PP-ODS for DA and 5HT – 7.5 to 10 MPa
- AC-GEL for ACh – 4.5 to 6 MPa
- CA-5ODS for NE and E – 8.5 to 11 MPa
- GU-GEL for Glutamate – 5 to 7 MPa
- SC-5ODS for Monoamines – 6 to 9 MPa
- SC-3ODS for Monoamines – 9 to 13 MPa.
- AC-GEL for Acetylcholine- 4-6 MPa
- CAX for NE, DA, 5-HT- 7 to 9 MPa
- NOPAK (ENO-20) for Nitrite and Nitrate-1.2-1.8 MPa
Please also note that these values are just for reference. If the displayed pressure is outside of the range above, it’s not necessarily a cause for concern as long as the pressure reading is stable.
Higher pressure:
Possible causes
- Time to repack the precolumn.
- Time to wash/replace the separation column.
- Clogging in the tubing/connection fittings.
Lower pressure
Possible causes
- Flow problem. Check the measured flow rate compared to the set value.
- Check all connecting tubing for leaks.
- Air bubbles trapped in the pump (recommend purging).