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What are the solvent recommendations for the ACQUITY H-Class washes (seal wash, wash solvent, purge solvent)? - WKB14943

Article number: 14943



Seal Wash:

  • The seal wash system must never run dry, particularly during separations that use a polar mobile phase.
  •  Isopropyl alcohol or mixtures of methanol and water, like 20% methanol/water, are effective seal wash solvents for THF solvent mixtures.
  •  For reversed-phase applications, use aqueous seal wash solutions with a weak organic component (for example, 1:9 methanol/water).
  •  Do not use 100% organic seal wash solutions.


Wash Solvent (needle wash):

  • Avoid buffered wash solvents.
  • The wash solvent must be strong enough to dissolve any remaining sample, and the wash duration must be long enough to remove residue from the system.
  • HFIP should never be used in wash solvents.


Purge Solvent:

  • Do not use concentrations of THF or hexane greater than 10% as purge solvent.
  • Typical organic sample diluents such as dimethylsolfoxide (DMSO) and dimethylformamide (DMF) are supported.
  • Waters recommends a purge solvent of 90/10 water/methanol whenever possible.



  • Do not leave buffers stored in the system.
  • Flush all flow paths, including the needle wash, with plenty of non-buffered solvent before shutting down the system.
  • For extended shutdown periods (longer than 24 hours), use 10% to 20% methanol in water.
  • When using a buffered wash solvent, prime it for a minimum of 30 seconds.
  • Use of buffers can cause salt buildup on the needle and wash port, which can require periodic cleaning.

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