Except for PEEK heads, all portions of this pump that contact mobile phase are manufactured of 316 SS, ceramic, sapphire, ruby, or fluoropolymers. Some of these materials are very sensitive to acids Including some Lewis acids) and acid halides. Avoid using solvents that include any amount of hydrochloric acid.
Some solvents to specifically avoid are:
Freon 12 (wet)
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 solvents in the system for a prolonged period.
It is also recommended 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