01Identify a preparation rather than a generic category

Names such as water, saline or assay buffer can cover different products and locally prepared mixtures. The notebook needs enough detail to distinguish the actual liquid used from other liquids with a similar informal name.

William Outlaw’s Florida State University notebook guidance records supplier and lot information for reagents and links derived solutions to the notebook page for their parent stock. This is a useful historical teaching example of preparation traceability.William H. Outlaw Jr., Florida State University — How to Keep a Laboratory Notebook (opens in a new tab)

Apply that principle by connecting sample S18 to buffer preparation B6 and connecting B6 to its component records. An unexplained label such as “standard buffer” cannot perform the same job when several versions exist.

A purchased ready-made product and a laboratory preparation need different supporting records. The former may be identified through its product and lot documents; the latter also needs its local preparation history.

02Separate nominal composition from measured properties

The FSU teaching record distinguishes nominal solution descriptions from recorded quantities and includes a measured pH alongside the intended description. It illustrates why an intended value and an observation should occupy different fields.William H. Outlaw Jr., Florida State University — How to Keep a Laboratory Notebook (opens in a new tab)

These numbers are a documentation example, not a recommended buffer or acceptance range. Replacing the observation with the target would make the record look tidier while removing information.

Where a measurement is relevant, retain its method and conditions through the linked record. A number without those details may be difficult to compare with measurements made elsewhere.

03Describe the liquid after additions and transfers

The identity of the starting buffer does not automatically describe the final sample after other solutions are added. Keep links to additions that change the composition, including a stock solution’s accompanying solvent.

For instance, two samples may both start in B6 but receive different recorded volumes of a second solution. Calling both simply “B6 samples” would hide a difference relevant to their comparison.

Record whether stated concentrations refer to the stock, an intermediate mixture or the final experimental sample. The unit alone cannot identify which stage a value belongs to.

If a component or quantity was not recorded, state that gap. Reconstructing a plausible recipe later is a hypothesis about the preparation, not an original preparation record.

04Make the description useful to a later reader

A concise experimental record can name the final sample and point to a complete preparation entry. It need not repeat every reagent detail in every result file if the referenced information remains accessible.

Check whether a colleague could distinguish today’s preparation from last week’s version without asking its author. Version, date and parent-stock links often resolve ambiguities that a familiar buffer nickname cannot.

This documentation does not establish that a solvent is suitable for a particular peptide or assay. Suitability needs material-specific evidence and the laboratory’s method; a complete record simply makes the actual choice assessable.

The aim is to preserve what the sample contained at the relevant stage, including the limits of what was measured, rather than to turn a target formulation into an unsupported claim about the final material.