How can I extend the shelf life of the IEX Cation Test Standard (186006870) after it has been reconstituted? - WKB92902

ENVIRONMENT

• Ion exchange chromatography (IEX)
• IEX Cation Test Standard
• Protein-Pak Hi Res IEX Columns

ANSWER

Reconstitute, filter through a 0.22-µm sterile filter into a sterile vial, and store the sterile vial at 4 °C. 

ADDITIONAL INFORMATION

Filtering with a sterile filter into a sterile vial minimizes bacterial growth in the reconstituted standard. The presence of bacterial proteases in the reconstituted standard can be lowered though sterile filtration and storage. Storing at 4 °C also helps slow microbial growth in the standard. Use a sterile syringe when withdrawing standard, so microbial growth is not introduced, and then place it into an autosampler vial for testing.

Another option is to add 0.1% sodium azide to solubilized proteins; this inhibits microbe growth. Store at 4 °C.

Freezing of reconstituted standard has not been evaluated by Waters. Repeated freeze-thaw cycles may cause proteins to precipitate out of solution.

Protein-Pak Hi Res Ion-Exchange (IEX) Columns and Standards Care & Use Manual