How to Perform a Siphoning Test for AKTA Chromatography Systems

Published on 10 January 2025 at 09:10

What is Siphoning and Why is it Important?

Siphoning occurs in a chromatography system due to the tubing flow path's configuration. It happens when the outlet point is positioned lower than the reservoir, creating a vertical distance that drives flow under gravitational pressure. In chromatography systems, another scenario can occur where one pump is active while the other is idle. This can lead to a phenomenon where the active pump creates a vacuum or low-pressure area that causes fluid to be drawn from the inlet line of the idle pump.

To counteract siphoning:

Pump flow restrictor valves are installed.
These valves remain closed under gravitational pressure and only open when the pump creates enough pressure to overcome it.

Importance:

Prevents flow when pumps are idle.
Avoids unwanted contamination between the A & B inlet lines.

When to Perform a Siphoning Test

Annually: It is best practice to perform the test at least once a year.
When Suspected Issues Arise: Indications of a faulty pump flow restrictor valve include:
- Increased intake from the reservoir.
- Inconsistent purification results.
- Unstable UV & Conductivity readings.

How to Perform the Siphoning Test

Performing the test is quick and straightforward, typically taking about 5 minutes. In addition to our step-by-step guide, we have created a short easy to follow video for your assistance.

Materials Required:

A container with DI water.
A suitably sized syringe to purge the system pumps.

1. Prepare the Setup:

Place a container filled with DI water on top of the instrument and Immerse inlets A1 and B1 into the container.

2. Prime the Pumps:

Prime both A and B pumps using a syringe.

3. Test the Pump Flow Restrictor Valves:

Disconnect an outlet tube from the flow restrictor valve (.e.g. 2A) at the system pressure monitor.
Observe for 1–2 minutes.
Repeat the process for the other outlet, e.g. 2B.
If a sample pump is installed, perform the test using the buffer inlet and disconnecting the sample pump flow restrictor valve (2S).

4. Results:

The presence of flow from either outlet while the pump is idle suggests a failure in the pump flow restrictor valve. Possible causes include:
- Blockage preventing valve closure.
- Defective seals.

Further investigation and potential valve replacement may be required.

Additional Notes:

The procedure is demonstrated on an AKTA Pure system but is applicable to any AKTA Chromatography system with a pump flow restrictor valve installed. There are variations between system models such as a single outlet from the pump flow restrictor valve as opposed to two. It is important to familiarise yourself with the system flow path before attempting this procedure.
Important: This test is specific to pump flow restrictor valves only. The system flow restrictor serves a different purpose and requires a separate procedure (refer to the relevant AKTA User Manual for details).