94 Agilent 1260 Infinity DAD and MWD User Manual
4
Using the Detector
Solvent Information
PEEK
PEEK (Polyether-Ether Ketones) combines excellent properties regarding
biocompatibility, chemical resistance, mechanical and thermal stability. PEEK
is therefore the material of choice for UHPLC and biochemical
instrumentation.
It is stable in the specified pH range (for the Bio-inert LC system: pH 1 – 13,
see bio-inert module manuals for details), and inert to many common solvents.
There is still a number of known incompatibilities with chemicals such as
chloroform, methylene chloride, THF, DMSO, strong acids (nitric acid > 10 %,
sulphuric acid > 10 %, sulfonic acids, trichloroacetic acid), halogenes or
aequous halogene solutions, phenol and derivatives (cresols, salicylic acid
etc.).
Polyimide
Agilent uses semi-crystalline polyimide for rotor seals in valves and needle
seats in autosamplers. One supplier of polyimide is DuPont, which brands
polyimide as Vespel, which is also used by Agilent.
Polyimide is stable in a pH range between 1 and 10 and in most organic
solvents. It is incompatible with concentrated mineral acids (e.g. sulphuric
acid), glacial acetic acid, DMSO and THF. It is also degraded by nucleophilic
substances like ammonia (e.g. ammonium salts in basic conditions) or
acetates.
Polyethylene (PE)
Agilent uses UHMW (ultra-high molecular weight)-PE/PTFE blends for yellow
piston and wash seals, which are used in 1290 Infinity pumps and for normal
phase applications in 1260 Infinity pumps.
Polyethylene has a good stability for most common inorganic solvents
including acids and bases in a pH range of 1 to 12.5. It is compatible to many
organic solvents used in chromatographic systems like methanol, acetonitrile
and isopropanol. It has limited stability with aliphatic, aromatic and
halogenated hydrocarbons, THF, phenol and derivatives, concentrated acids
and bases. For normal phase applications, the maximum pressure should be
limited to 200 bar.
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