This Information Applies To: Agilent 1100, 1200, 1260 LC Pumps
The following procedure allows the cleaning of residues from the pump's check valves, often caused by polymerization of aged Acetonitrile or Salt-based solutions, that may prevent the inlet and outlet valves from functioning correctly.
When inlet and/or outlet valve do not close correctly, the pump pressure will fluctuate. When monitoring the pressure trace, the user may see a sawtooth pattern (up and down) of various amplitude.
If the sonication of the valves does not solve the issue, please contact Agilent Technologies for further support.
Steps to follow:
- Switch off the pump at the main power switch.
- Open the doors of the module.
- Disconnect the Outlet valve.
The outlet valve is positioned above the pump head as depicted in figure 1.
1. Disconnect the Valve Capillary.
2. Unscrew the valve by turning counterclockwise, using a wrench.
Figure 1. Outlet Valve.
- Disconnect the Inlet Valve
The Inlet Valve is positioned below the pump head as shown in figure 2. It shows an Active inlet valve.
Figure 2. Active Inlet Valve.
The Inlet Valve can be either Passive or Active.
To disconnect the Active inlet valve, follow the steps below.
1. Disconnect the Valve Cable by pulling straight out of the connector. DO NOT twist and unscrew the valve cable from the connector as you will expose the electrical pins that can be damaged.
2. Disconnect the Solvent Inlet Tube.
3. Unscrew the valve using a 14 mm wrench.
4. Carefully remove the Cartridge from the Valve Body (see figure 3) being careful not to damage the edges as that help to form the seal.
Figure 3. Active Inlet Valve Cartridge.
The Passive Inlet Valve can be disconnected similarly to the Outlet one and will not need to be further disassembled before sonication.
- Sonicate Valves for 30 minutes
Place the Active Inlet Valve Cartridge/ Passive Inlet Valve and the Outlet Valve in Methanol or Isopropanol and sonicate them for 30 minutes. If it's suspected that salts may have precipitated in the valves, then use warm water instead of an organic solvent to sonicate. DO NOT sonicate the Active Inlet valve body as it will destroy the electronic components.
Then wash them out with water and re-assemble them on the pump head. Refer to your pump modules user manual for detailed instructions on reassembly.
After the valve sonication procedure
It is suggested to purge the pump with water at 60 degrees, keeping the purge valve open.
Wash the system with Isopropanol (excluding the column).
Finally equilibrate the system with your solvents before use.