Document the following:
1) screen shots of normal LC pressure traces
2) screen shots of normal baseline
3) normal composite extracted ion chromatogram (XIC) overlays with a fixed Y scale for all MRMs in a low calibrator with good chromatography. This documents normal retention times (Rt), peak shapes, resolution and relative heights.
4) As a baseline for future reference record the MS/MS response on more than one occasion from post-column infusion of pure standards in methanol. photographs of the MS/MS ion source and the cone, curtain plate or skimmer (differs by vendor - the first heated MS/MS surface encountered by volatilized samples) when clean.
Reference: AACC: Troubleshooting Liquid Chromatography-Tandem Mass Spectrometry in the Clinical Laboratory
Maintenance calendar:
Daily system checks:
Record MS/MS vacuum pressures, verify in range
Record # of injections on columns & guard columns, change as indicated
Run SST & record results, compare to action limits
Record LC pressure during a System Suitability Test (SST), compare to action limits
Check LC for leaks
Periodic Checks (daily, weekly, monthly, as needed):
Clean cones (curtain plate, skimmer, skimmer plate)
Check MS/MS resolution, calibration & response with infusion of a standard, compare to action limits
Perform mass resolution & mass calibration following service or with frequency per vendor recommendations
Best Practices:
- Run a System Suitability Test.
Protocol
1. 3-5 injections of pure standard(s) in injection matrix (and internal standards if desired)
2. Record mean and %CV of Rt, peak area (peak height, peak width)
3. Compare means & %CVs to action limits - Wash columns and leave LC system in 100% organic solvent (e.g. acetonitrile) with no acid, no buffer.
Reference: AACC: Troubleshooting Liquid Chromatography-Tandem Mass Spectrometry in the Clinical Laboratory
Records with dashboard