Each laboratory practical is different, and so will require different preparation and different aspects to be recorded. Similarly, lab book entries are somewhat personal, since what you need to do, to be fully prepared for an experiment, will likely differ from what someone else needs to do. For these reasons, it is impossible to give a comprehensive and exhaustive guide to what every lab book entry should be. Furthermore, different institutions (e.g. laboratories, universities, companies) have different requirements for what needs to be recorded in a lab book. However, the following aspects are widely recognised as good general practice for any lab book entry.

• Your lab book entry should include the date.

• The work should be appropriately titled, e.g.: “Synthesis of trans-Methyl 3-nitrocinnamate”.

• You should be consistent in writing style when planning your work. Since the lab work has not yet happened, you can write in future tense; present tense is also acceptable. For example: “We will be synthesising trans-Methyl 3-nitrocinnamate by the following method...”.

• When planning your work, you should include enough detail to help you work safely and efficiently in the lab. Clearly, more experienced workers, when conducting procedures that they are very familiar with, may write plans which are briefer in nature than those which a more inexperienced chemist would write.

• Acknowledging hazards, and outlining the precautions you will take to control the hazards, is an important part of planning your work.

• You should be consistent in your writing style when recording your labwork. Since you are supposed to record what happened, soon after it happened, the past tense is appropriate, e.g.: “The resultant clear liquid was transferred to a 100 cm3 conical flask...”.

• You should record observations as you make them, then any interpretation separately. For example, if you were conducting a test for reducing sugars with Benedict’s reagent, you should record the colour that you observe in the test (the observation), not that the test was positive or negative (the interpretation). This reduces the potential for errors in your work.

• You should record data clearly. If you make an error, or if something is hard to read in your lab book, you should correct it/rewrite it as soon as you can.

• There should be clear cross-references to any data/information that is collected as part of the practical work, but that is not present in the lab book itself (e.g. spreadsheets, bundles of spectra).

These general aspects are applicable to all lab book entries. Additionally, we can (somewhat simplistically) categorise the majority of lab activities as either synthetic activities, or measurement activities; many laboratory experiments include both types of activity.

Lab book entries for synthetic activities should, in addition to the general aspects described above, include:

• a clear diagram of the reaction, showing structures of reactants and products, showing reagents, conditions and stoichiometry.

• a “reagent table”, with entries for each reagent. Standard data for inclusion are:

  • number of molar equivalents

  • number of millimoles (the typical scale of reactions in Teaching Labs)

  • molecular mass

  • mass

  • density

  • volume

Some of these data will be given in the script, others you will need to calculate or look up. Online MSDS data, from a reliable source, is a good way to find some of this information; you can also use a chemical handbook or databook such as the CRC Handbook of Chemistry and Physics, or Lange’s Handbook of Chemistry. These sources will also give you more data on the compounds, for example, melting point, boiling point, solubility etc.

• details of calculations you did, if required, to complete the reagent table.

• a calculation of the theoretical yield, if appropriate.

• a description of any compound you have synthesised, and yield calculations, if appropriate.

• any characterisation data for compounds you have synthesised.

Lab book entries for measurement activities should, in addition to the general aspects described above, include:

• clearly laid out tables and graphs, if appropriate.

• you must show the primary data you recorded i.e. the measurements you made in the lab.

• it may be appropriate to paste in a printout of a spreadsheet, or a graph.

• guidance on drawing up tables and graphs can be found in the Style Guide (Google Doc).

• instrumental output such as spectra, chromatograms etc.

• details of any instruments that you use, which may include important settings. For example, you may collect HPLC chromatograms of some samples; the nature of the HPLC column, the composition of the mobile phase, and the detector frequency are all important parameters to record.

• details of any calculations you perform, and conclusions you reach.