Agilent InfinityLab LC Series Diode Array Detectors User Manual
64
4
Preparing the Module
Solvent Information
There is still a number of known incompatibilities with chemicals such as
chloroform, methylene chloride, THF, DMSO, strong acids (nitric acid > 10 %,
sulfuric acid > 10 %, sulfonic acids, trichloroacetic acid), halogens or aqueous
halogen solutions, phenol and derivatives (cresols, salicylic acid, and so on).
When used above room temperature, PEEK is sensitive to bases and various
organic solvents, which can cause it to swell. Under such conditions, normal
PEEK capillaries are sensitive to high pressure. Therefore, Agilent uses stainless
steel cladded PEEK capillaries in bio-inert systems. The use of stainless steel
cladded PEEK capillaries keeps the flow path free of steel and ensures pressure
stability up to 600 bar. If in doubt, consult the available literature about the
chemical compatibility of PEEK.
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, 1290 Infinity II
pumps, the G7104C 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 with 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.
Tantalum (Ta)
Tantalum is inert to most common HPLC solvents and almost all acids except
fluoric acid and acids with free sulfur trioxide. It can be corroded by strong bases
(e.g. hydroxide solutions > 10 %, diethylamine). It is not recommended for the use
with fluoric acid and fluorides.
