Abstract
We describe systematic troubleshooting of the carry-over of neuropeptide Y (NPY) in LC-MS analysis. We aimed to remove candidate parts of the LC-MS system responsible for carry over one-by-one. We show that the carry-over of NPY occurs on the column, in particular at the guard column and at the consumable seals of the sample-needle and high-pressure valves. The methodology demonstrates that it is possible to troubleshoot carry-over in an LC-MS system in a systematic and logical manner.
