Seal Information
Due to the precise tolerances needed to provide a seal that will give you a seal life
equal to or better than the HPLC manufacturers' seals, we source the seals from various
companies that can produce the quality needed on a consistent basis. In the HPLC market
there are about six or so companies that are used to produce all of the seals that go into
HPLC pumping systems. We cannot always purchase the seals from the same companies the OEMs
use because they make agreements to keep competition from getting the exact same seal they
sell from the same company they use. In those cases we go to another manufacturer and have
the seals made.
Black Plunger Seals
This seal is made of PTFE with a carbon fill. The carbon is inert and adds to the
stiffness of the PTFE for longer seal life. This seal is a very good general purpose seal
for any solvent. Failure mode is due to shedding of small seal particles.
Gold Plunger Seals
This seal is made of UHMWPE (Ultra High Molecular Weight Polyethylene) with a fill that
gives it the gold appearance. This material is being used by more and more manufacturers
in their HPLC instruments. The seal provides good seal life and does not shed particles
like that of other seals. The Gold seal is inert to all common HPLC solvent mixes.
Super Plunger Seals
This seal is made of UHMWPE (Ultra High Molecular Weight Polyethylene). The material
used in this seal is more rigid and does not shed the small particles like other seals.
The seal can have potentially longer life if it is used with a new sapphire plunger. If
the plunger is slightly worn and you do not have the ability to replace it, one of the
other plunger seals is going to be the best choice. This material is inert to all HPLC
solvents and aqueous buffer formulations.
Blue Plunger Seals
This seal is made of Teflon® with a blue inert inorganic filler. This seal is good in
all solvents at all temperatures for which Waters® instruments are capable. Failure mode
is the extrusion of a Teflon® sleeve into the plunger head cavity.
Red Plunger Seals
This seal is made of Rulon® LD with a certain percentage glass fill and was the
standard Waters® M6KA plunger seal for nearly twenty years. It is inert in most solvents
but is not good with acetonitrile. Failure mode is shedding of small translucent fibers
with eventual leaking.
