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Technical Tips

Choosing the Right Accessories When Using High Temperature GC Columns

A Technical Tip by Kory Kelly, GC Product Manager


Liners

  • Liners with wool act as a barrier for particulates and less volatile compounds.
  • Routinely changing liners will reduce activity from buildup of non-volatile compounds.
  • Liners without wool are recommended for very active compounds like pesticides.
  • Higher inlet temperatures mean greater expansion volumes for solvents. Make sure that the volume of your inlet liner matches your solvent expansion volume.

Inlet Base Seals

  • A stainless steel base seal can be used for inert samples like hydrocarbons.
  • A gold plated base seal should be used for reactive samples like pesticides.
  • Routinely changing base seals can decrease activity and help prevent ghost peaks.

Ferrules

  • Graphite ferrules are recommended for non-MS applications because of their high temperature limits (>400C).
  • Vespel ferrules are not recommended for high temperature analysis because they shrink above 360C.
  • Use of metal ferrules is recommended for MS use at high temperatures.
    • For 0.25mm ID columns – Phenomenex part number 073200
    • For 0.32mm ID columns – Phenomenex part number 173201

Septa

  • High temperature applications usually mean high inlet temperatures. Make sure that the septum is rated for your inlet temperature.
  • High temperatures may cause septa to wear faster. Routine maintenance of the inlet should include changing of the septum.
  • Thinner needles like on-column needles should be matched with GuideRight septa.

Guard Columns

  • When using a guard at high temperatures, make sure that the press-tight connection is secure.
  • The most important aspect of a good seal is a good column cut.
    • The column end should be square and smooth (like a straw).Any irregularities will cause leaks.
    • Columns are long. Repeat cutting until a good cut is achieved.
    • Lightly scoring the column usually creates a cleaner opening.