Directory: 01 Fronting Peak
file name: 01_reconstitution_solvent

Note: There was no problems with mobile phase or needle wash or any method changes.

Symptom #

This is from marijuana metabolite. The normal presentation is on the right, the fronting peaks on the left. The peaks are all the same for three MRM. We don't use a guard column.

Investigation, Troubleshooting Tool and Root Cause #

Investigation and Tools used:

1. Q: Check the Maintenance Log.
   A: There were 850 injections and we normally change it at 2500. So it doesn’t really look like column degradation.
2. Q: Is sample overloaded?
   A: The right volume was injected.
3. Q: Check the system suitability tests results.
   A: They like normal.
4. It makes us suspicious of the sample itself.

Root Cause: Samples were reconstituted with 100% acetonitrile.

Reference:
MSACL: LC-MSMS Troubleshooting 101: Tips and Tricks for Getting Started : PART 1

MSACL: The Basics of LC-MSMS Troubleshooting: Tools, Strategy, Cases

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