MeOH (Methanol),  450 mL

If all the other flow tests are fine, then yes, you probably have a clog in a line, but it is more than likely in the gas pressurizing line, not the liquid line. If the instrument has been idle for over a week, piperidine sitting in the lines can combine with carbon dioxide in the air and generate crystals, which can then clog up the line.  The best way to remove the crystals is to use a syringe to force methanol through the appropriate tubing to flush it clear (with the piperidine bottle removed from the instrument).

Find additional tips, troubleshooting help, and resources within our Protein Assays and Analysis Support Center.

Sample purity is critical. Serine, Glycine, and Alanine contaminate peaks are caused by dust and skin; therefore we strongly recommend you adhere to the following guidelines for sample preparation, especially for cLC and low level HT samples:
- Dedicate a low-traffic area in your lab for sample handling and preparation. This will make it easier to keep the area and your samples as clean as possible.
- Always wear non-powdered gloves.
- Thoroughly clean all work surfaces with straight methanol before preparing samples.
- Clean pipette tips and all other sample receptacles with a solution of 50% methanol in D.I water with 0.1% trifluoroacetic acid before use.
- Clean all forceps and other sample handling devices with neat or pure methanol, and then dry them before use.
- Do not wipe implements or pipette tips to dry them. Dry them with clean, dry compressed air, or allow them to air dry.