Workspace

• Clean surface: wipe with isopropyl alcohol before and after a session. Keep unrelated materials off the bench.
• Dedicated tools: syringes, pipettes, and tips for one material at a time. Cross-contamination between sequences is a common source of unexplained results.
• Lighting: vial and syringe markings must be readable.
• Sharps: a rigid, puncture-resistant container for needles and used syringes.
• Waste: liquid and solid laboratory waste per local rules.

Personal protective equipment

• Nitrile gloves, changed between samples.
• Safety glasses when reconstituting or handling concentrated solvents.
• A lab coat or dedicated garment so contaminants stay off street clothing.

Working with vials

1. Warm refrigerated or frozen vials to room temperature while still sealed. Opening a cold vial in humid air puts condensation inside.
2. Briefly centrifuge or tap so powder sits at the bottom before the stopper is opened.
3. Wipe the rubber stopper with isopropyl alcohol before piercing.
4. When adding solvent, run it down the vial wall rather than onto the cake, to limit splash and shear.
5. Swirl gently to dissolve. Do not vortex aggressively if the sequence is shear-sensitive.

Solvent choice and volumes belong in your laboratory SOP. This page does not specify reconstitution amounts.

Recordkeeping

A notebook — paper, electronic, or both — is the primary tool of reproducible work. For each reconstitution or use event, record:

• Date and time
• Product name, lot number, and supplier
• Mass on the vial label
• Solvent type and volume added
• Calculated concentration
• Storage location of the resulting solution
• Aliquots: count, volume, location
• Anomalies (cloudiness, undissolved material, unexpected color)

If it is not written down, it did not happen. Memory is not a data source.

Equipment and contamination control

• Calibrate pipettes on a documented schedule. Calibrate balances with certified weights when they are used to weigh material.
• Monitor freezers and refrigerators. A failed freezer is a destroyed-inventory event.
• Balance centrifuge rotors. An unbalanced rotor at high speed is a safety hazard.
• Open one vial at a time.
• Use fresh syringes and needles for each draw unless a protocol allows reuse in a single session.
• Never return withdrawn material to the original vial.
• Label aliquot tubes when they are filled.

Inventory

• Keep a running log of lots, locations, and quantities.
• First in, first out: older lots before newer ones.
• Note expected stability windows and flag lots near the end of that window.
• Where practical, retain one unused vial from a lot as a reference sample.

What not to do

• Do not mix sequences in one vial unless the experimental protocol requires it.
• Do not use material whose appearance has changed (color, clumping, unexpected residue) without investigating.
• Do not estimate small volumes by eye. Use a calibrated pipette or syringe.
• Do not work alone with unfamiliar materials without supervision.

Professional standard. Treat every vial as if a colleague must reproduce the work from the notes alone. Also see peptide storage.