Documentation and record keeping

What is worth recording

• Compound, supplier and batch number
• Certificate of Analysis for that batch
• Date received and storage conditions since
• Date and details of reconstitution: solvent, volume, resulting concentration
• Storage of the reconstituted material and how many times it was entered
• Which experiments used which preparation

Why batch matters to results

Where a result changes between experiments, batch is one of the first variables to check. Without a record linking each experiment to a batch, that check cannot be made and an ordinary batch-to-batch difference becomes an unexplained anomaly.

Reconstitution records

The concentration of a solution is a calculation, not an observation. Recording the inputs — mass assumed, volume added, net peptide content if known — means the calculation can be checked later. Recording only the answer means it cannot.