Long spike after injection

I am trying to perform a single cycle kinetics to evaluate an antibody against a toxin. The toxin is immobilized in a CM5 sensorchip by amine coupling. Everything could be right except by the fact that just after the sample injection there is a long spike that happens during a few seconds, which at the end prevents the calculation by Biacore software. I changed the buffer, I did desorb/sanitize and superclean, I prepared another sensorchip... Could anyone tell me what else I should do?

An example of a sensorgram:



Zoom in:

Hi,

What kind of Biacore do you use? This happens already several times? And why not at the last three injections? I think it is at the start of the injections. Did you check if there is no air in the tubes?

Kind regards

Arnoud

Hi, I am using Biacore T200.
Yes, it happens most but not all the runs. I thought it could be air bubbles, but this means I may have equipment problems...

Thank you

What you can check is the pumps, behind the door.
If you trigger a prime you can see if the pumps are fully filled while operating.
If they draw some air you know you need some servicing.

Arnoud

Hi!
I called GE service. They tightened the degasser connectors and advised me to perform "Flush system wash". I did it twice and the problem seems solved.
Thank you again!