Choose a diluent
Sterile or bacteriostatic water is the most common laboratory diluent for peptides. Some peptides with poor aqueous solubility may require a small amount of a co-solvent first; consult the peptide's documentation before selecting a diluent.
Calculate your concentration
Concentration is mass divided by volume. Decide the volume of diluent you will add, then divide the peptide mass in the vial by that volume to get the concentration.
Example: a 10 mg vial reconstituted with 2 mL of diluent yields 5 mg/mL (10 mg ÷ 2 mL). Adding 1 mL instead yields 10 mg/mL. Choose a volume that gives a concentration convenient for your measurements.
Add the diluent gently
- Let a refrigerated vial come to room temperature before opening to limit condensation.
- Wipe the stopper with an alcohol swab and add diluent slowly, letting it run down the inside wall of the vial.
- Do not spray liquid directly onto the powder and do not shake — swirl gently and let the peptide dissolve on its own.
- If material remains undissolved, allow more time at room temperature rather than agitating vigorously.
Label and record
Record the lot number, diluent, volume added, resulting concentration, and date of reconstitution. Accurate records keep your results reproducible and make it easy to match material back to its certificate of analysis.