What is a normal pump pressure reading for each column?

  • 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

These values are just for reference.  Longer tubing causes higher pressure.

 

Higher pressure may indicate that it is time to replace the precolumn. However, the higher pressure is just one of the reasons to repack precolumn. Please check the precolumn quality by injecting standard samples without precolumns and directly to the separation column. If the removed precolumn was the factor of bad separtion, the separtion should be improved when the injection is made without the precolumn.   

 

Lower pressure normally indicates the pump is having a flow problem.  Please remove air from the pump. 

·         Check all connecting tubing for leaks

·         Purge the pump by attaching a 10cc syringe to the valve port and aspirate at least 3mL of mobile phase.  Insert the syringe then open the valve, aspirate the liquid and then twist valve closed before removing the syringe.  Pulse free mode should be off during this process.  Once the aspiration process is completed turn the pulse free mode back on and check the pressure levels.

·         If flow is still low an air bubble may be trapped within the pump, especially at the check valve.  To remove, attach the 10cc syringe as before twisting open the valve.  Then while aspirating, disconnect the clear tubing below the pump to allow a large air bubble to enter the pump.  This large air bubble will capture any smaller air bubbles present within the pump.  Then tighten the tubing and aspirate 3 more mL of mobile phase, including air.  Pulse free mode should be off during this process. Once the aspiration process is completed turn the pulse free mode back on and check the pressure levels.

 


D
Derek is the author of this solution article.

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