What it is
Bacteriostatic water is sterile water containing 0.9% benzyl alcohol. The benzyl alcohol is a preservative. It does not kill bacteria outright, but it stops them multiplying, which is what bacteriostatic means.
Bacteriostatic water and sterile water
The preservative is the whole difference. It is why a vial of bac water can be drawn from more than once, and why a peptide reconstituted with it keeps for longer.
Bacteriostatic water for peptides
Lyophilised peptides are supplied dry because dry is stable. Bac water is the usual choice for bringing one into solution. The method is in reconstituting a lyophilised vial, and the peptide calculator works out the concentration for the volume you add.
Do you need it for our peptides?
No. Everything in our range is supplied pre-mixed, already in solution. Bac water is only needed for lyophilised peptides from elsewhere. We list bacteriostatic water for laboratories that work with both, and it is coming soon.
Vial sizes and where to buy
Bacteriostatic water is most often supplied in 10ml and 30ml multi-use vials. Because a typical lyophilised vial takes between 1ml and 3ml, the smaller size is enough for most work, and a vial that is finished within the period the label allows is better than a larger one that is not. Where to buy bacteriostatic water in the UK covers what to look for on the label.
Storing it
Keep unopened vials at room temperature, away from light, and follow the label once opened. Write the date of first puncture on the vial. Discard it if the water is cloudy or the stopper is damaged.