Dionex AXP/AXP-MS Manual
2.4.3 Filtration
Solvent filtration is good practice for the reliability of the Dionex
AXP/AXP-MS pump and other components in an HPLC system.
Solvents should always be filtered with a 0.5-micron filter prior to use.
This ensures that no particles interfere with the reliable operation of
the piston seals and check valves. Solvents in which buffers or other
salts readily precipitate out will need to be filtered more often. After
filtration, the solvents should be stored in a closed, particulate-free
bottle.
2.4.4 Solvents with Harmful Effects
Except for PEEK pump heads, all portions of the Dionex AXP/AXP-
MS pump that contact mobile phase are manufactured of type 316
stainless steel, ceramic, sapphire, or ruby. Some of these materials are
extremely sensitive to acids (including some Lewis acids) and acid
halides. Avoid using solvents that contain any hydrochloric acid.
Some solvents you should specifically avoid are:
Aqua Regia Hydrochloric Acid
Bromine Hydrofluoric Acid
Chlorine Anhydrous Hydrofluorsilicic Acid
Copper Chloride Hydrogen Peroxide
Ferric Chloride Iodine
Ferrous Chloride Mercuric Chloride
Freon 12 (wet)
Guanidine
Hydrobromic Acid
In addition, some users of HPLC systems have observed that
chloroform and carbon tetrachloride slowly decompose to liberate
hydrochloric acid, which, as noted above, attacks stainless steel. Do
not leave these solvents in the systems for a prolonged period.
You may also want to avoid ammonium hydroxide. Although
ammonium hydroxide will not harm the pump itself, it is likely to
damage the stator and rotor in injection valves.
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