Troubleshooting Carry-Over in the LC-MS Analysis of Biomolecules: The Case of Neuropeptide Y.

We describe systematic troubleshooting of the carry-over of neuropeptide Y (NPY) in LC-MS analysis. The objective was to remove candidate parts of the LC-MS system that are responsible for carry over one-by-one. The findings indicate that the carry-over of NPY occurs on the column, particularly in 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.