because of we have no further idea I now try it here.
Since a few days I have a ghost peak in my method. It's the same with 2 different LC Systems and 3 different columns.
Further I opened new bottles for each eluent compound and buffer salts (even used no salt).
The longer I flush with starting condition (15%B, organic) the higher the Peak gets so I suggest that ist a Problem with eluent A (92% buffer).
We use this Methode without any problems for years.
What else can be the cause?
Thanx indeed for any idea
What happens if you do an injection with no vial number?
When is the last time you did a PM?
If you take the line from the pump to the column do you still see this ghost peak? If not I would replace the rotor seal, needle and seat.
What do you use for solvents? And for flushing your system?