I am in the process of changing LC-MS columns from a 50mm X 2.1mmID, 3um RPC18 column to a cartridge system using slurry packed 20mm X 4.0mm ID, 3um C18 cartridges. Does anyone have any experience using these cartridges? I am curious about the resolution and retention of these new cartridges. I am told they have very good retention, reproducability and the same life as a normal C18, 50 X 2.1 column. The reason I would like to switch is that we use many columns and the cartridges are not only easier to use but also less expensive, however I do not want to loose my quality chromatography results. Any advise would be greatly appreciated. Thank you.