Acquity I-class continues to over pressure
I work with an Acquity Iclass BSM and SM that has been having an issue with over pressuring. My solution has been to backflush the needle and needle seal which frees the occlusion (I am able to see a pressure spike before it goes back to baseline), but the issue recurs after a small number of injections (20-30). The problem persists despite changing columns, needles and needle seals, mobile phases, pre-filtering mobile phases, and adding a frit before the isolator column. I'm ready to rule out the mobile phases as the culprit and am thinking it's got to be the extracts themselves or something with the FTN and seal port assembly. I'm working on finding ways to filter the extracts - any possible leads on the occlusion coming from the seal port itself? Ever heard of PP vial caps causing a blockage in the FTN?