Strong acids and bases can negatively affect certain types of tubing, fittings, and component materials.
- Polyetheretherketone (PEEK) can be degraded in strong mineral acids, such as nitric and sulfuric acids, especially in the presence of halogens and halogen-containing chemicals.
- Silica capillaries and their polyimide coatings start to degrade at pH 8 and greater.
- Stainless steel (SST) can be attacked by certain acids below pH 2.3, especially in the presence of halogens and halogen-containing chemicals and strong mineral acids like nitric and sulfuric acids. SST can also experience degradation when used with organic acids in organic solvents.
- Quartz flow cells can have degraded lifetimes in the presence of pH greater than 12.
- Polyimide used in the needle seat is stable in a pH range between 1 and 10 and in most organic solvents. It degrades in the presence of concentrated mineral acids like sulfuric acid and in the presence of glacial acetic acid. It is degraded by elevated basic conditions, especially in the presence of ammonia or ammonium salts or acetates.
- To maintain optimal performance, it is recommended that you periodically inspect and, if necessary, replace all relevant components. Additionally, when operating the Alliance iS Bio HPLC System above pH 10, ensure that you are using the optional high pH kit. For further assistance, contact Waters.
Solvents to avoid
