Synopsis
Dial in solvent selection, concentration math, and storage strategy so every aliquot performs exactly as designed.
Reconstitution is where many peptide experiments drift off course. Temperature swings, poor solvent choices, or hurried calculations can introduce variability before the first data point is captured. Treat the process like an experiment in itself.
Pick the right solvent
- Sterile water: Default for neutral, hydrophilic sequences used immediately.
- Bacteriostatic water: Adds benzyl alcohol for multi-dose vials.
- 0.6% acetic acid: Stabilizes peptides with basic residues.
- DMSO: Last resort for highly hydrophobic analogs—dilute downstream.
Execution checklist
- Sanitize the workspace and gloves; stage calibrated syringes.
- Warm solvent to room temperature to avoid shocking the cake.
- Drip solvent along the vial wall while rotating gently.
- Let stubborn powders rest for 5–10 minutes before swirling again.
- Visually inspect; any haze or particles means you should re-filter.
Concentration math example
Objective: 1 mg/mL solution from a 5 mg vial.
- Add 5 mL of bacteriostatic water.
- Every 0.1 mL equals 0.1 mg (100 μg).
- Log both the concentration and solvent lot number in your ELN.
Storage and aliquoting
- 2–8°C: Use within 7–14 days.
- -20°C: Up to 30 days; avoid multiple freeze-thaw events.
- Aliquot into sterile screw-top vials sized for single experiments.
Label every aliquot with concentration, solvent, date, and initials so nothing relies on memory.
Common mistakes to retire
- Using tap water or expired solvent.
- Shaking aggressively, which denatures fragile sequences.
- Leaving reconstituted solutions on the bench during setup.
Your peptide may only be a few milligrams, but the rigor you apply to reconstitution echoes throughout the entire study.
