Chromatography Forum

Hi! For a week or so our 6495C have weird behavior. After tuning, which pass great, in jus a few hours responses for ions falls approx. 10 times, and even faster decreases when there is changing methods between runs (after pesticides in food, doing ochratoxin A, then returning to pesticides.) Then, it somehow regenerates overnight, sometimes, but it always running good just after tuning. From the service, they had idea about quads drivers, but it was in good shape, I think they concluded that, so they abandoned everything about hardware. About that, I must mention that they did PM with a lot of hardware preventively changed, and cleaned optics and quads, it was barely month ago, about in January. So we are now in magical loop, it runs good for a short time, then it goes crazy, and after tuning the loop goes again. Anyone have ideas about what happening?

I don't know if you already solved the issue? Our Agilent 6460 had very similar symptoms. When tuning, everything was fine, afterwards, the responses were like a rollercoaster. The quad drives were replaced, they even cleaned the first quadrupole rods and changed the x->y orientation. There was no improvement. Still inconsistent results. In the end, it came out it was the ion source that was the culprit. Two things affected the nebulizer performance:
- the yellow plastic ring around the nebulizer assembly was cracked and leaking nitrogen,
- the electrospray nebulizer locking screw on top of the AJS ESI was not tightened enough, so it has a little play, probably also leaking nitrogen

When both issues were resolved, the responses were a lot more consistent.