This Information Applies To: All Agilent LC pump modules with MCGV installed (quaternary pumps)
Shifting retention times: The composition of the mobile phase in liquid chromatography directly influences retention times. If any of the channels of the MCGV are partially or fully blocked, the gradient produced will be different from the analytical method.
Clogging of the MCGV may occur when the system is not rinsed properly or stored incorrectly.
If the following steps don’t solve the shifting retention time issue, the MCGV may be damaged or leaking and may not be working correctly. This might require a replacement of the MCGV assembly.
Steps to follow:
- Loosen the fitting connected to the inlet of the LC column and place this capillary into a suitable and safe waste collection vessel. Make sure that the vessel capacity is at least 2 L.
- Place a solvent bottle full of LC-grade water heated to 60 to 70 °C in the LC system solvent tray and place all four solvent lines into the heated water bottle.
- Open the purge valve and purge channel A at the maximum purge rate (5 mL/min for analytical scale systems) for 10 min with heated LC-grade water.
- Repeat the procedure in step 3 for channels B, C, and D.
- With the purge valve open, purge all the lines simultaneously (25% of each channel) at the maximum flow rate the pump hardware will allow for 30 min with heated LC-grade water.
- Close the purge valve, and continue pumping through all four channels at a flow rate of 1 or 2 mL/min for 30 min.
- Reconnect all fittings and reconnect your LC column.
- Equilibrate the LC system and ensure you have a stable detector baseline.
- To verify if a clogged MCGV was the source of the issue, analyse a known sample. If the issue remains, please contact your local Agilent service representative.
Learn how to effectively operate your Agilent Quaternary Pump:
Agilent InfinityLab LC Series 1260 Infinity II Isocratic and Quaternary Pumps user manual on Agilent.com