Lower sensitivity at the beginning of a sequence in LC-MS

I am using a LC-MSD iQ system, and not quite often but it sometime happens that I have lower sensitivity for one analyte at the beginning of a sequence, it can be for instance 10% or 20% less area than usual. During the sequence, from injection to injection, the area increases until the area is back to what I usually get for the concentration injected. Then, everything is back to normal from sequence to sequence. Like I said, it does not happen very often, but when it does, thes sequence is a fail. Any idea what can be happening and how to avoid this.

Was this helpful?