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PEG contamination observed on Mass Spectrometer with ACQUITY or nanoACQUITY front end - WKB15751

Article number: 15751


  • PEG contaminant ions observed - easily identified by repeating 44 Da difference between masses


  • ACQUITY (Classic, H-Class, or I-Class) with Mass Spectrometer
  • nanoACQUITY or M-Class with Mass Spectrometer


  • Washing bottles/glassware with soap
  • Allowing the UPLC solvents or sinkers to touch the gloves when replacing solvents


For M-Class and nanoACQUITY, use the following protocol:

  1. Remove the column and replace it with a union, or for a nanoACQUITY or M-Class, plumb a waste line to port 6 of the inject valve.
  2. Put A and B lines from the LC into the alcohol mix, which is 25/25/25/25 water/isopropyl alcohol/methanol/acetonitrile and 0.2% formic acid.
  3. Flush the system by priming for five minutes, and then pumping for at least two hours at a flow rate that gives at least 6000 psi pressure.
  4. Change the solvent to IPA and perform the same procedure as in steps 2 and 3.
  5. Prime and flush with fresh LC/MS-grade or Milli-Q water. 
  6. Put on fresh solvents that are used for the LC. If the solvent bottles were not cleaned for a while, use the alcohol mix to clean out the bottles. Rinse well with fresh solvent. 
  7. Attach the column - preferably a new one.
  8. Prime and flush the water using the fresh solvents and condition the column.
  9. Connect LC to MS and inspect for PEG contamination. 

For an ACQUITY (H-Class or I-Class), use the following cleaning procedure



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