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Thermo Fisher Scientific

Preparation of Mobile Phase Solvents


How do I prepare the mobile phase solvents for the unit?


  • LX-2
  • LX-4
  • TLX-1
  • TLX-2
  • TLX-4


  1. Use LC/MS-grade solvents or better.
  2. Prepare fresh aqueous mobile phases daily (weekly as a minimum) in clean bottles. Do not refill or top off standing bottles.
  3. Make aqueous mobile phases in quantities that will be used daily.
  4. Do not use a thermoplastic sealing film, such as Parafilm™, as a mobile phase reservoir cover.
  5. Use an appropriate bottle cap that accommodates the solvent lines.

NOTE: If caps are not available, use aluminum foil to secure the solvent lines in the bottle and protect the solvent from dust. Ensure that the mobile phase line with attached solvent filter reaches the bottom of its intended reservoir.

  1. Wherever possible, include 2% acetonitrile or 0.1% formic acid in aqueous mobile phases to inhibit microbial growth.
  2. Do not use any mobile phases that have visible particulates or appear foggy.
  3.  Before each batch, vigorously swirl the mobile phase bottles and look for particulates that might be floating or moving in the liquid.
  4. Check the fluid lines and filters for particulates or slime. If you find particulates or foggy mobile phases, replace the bottles.
  5. Replace the solvent filters and purge the lines fully with new, clean, LC/MS-grade mobile phase.