The Laboratory Notebook

The Laboratory Notebook

– A laboratory notebook is needed to record measurements and observations concerning an analysis.

– The book should be permanently bound with consecutively numbered pages (if necessary, the pages should be hand-numbered before any entries are made).

– Most notebooks have more than ample room, so there is no need to crowd entries.

– The first few pages should be saved for a table of contents that is updated as entries are made.

Maintaining a Laboratory Notebook

(1) Record all data and observations directly into the notebook in ink.

– Neatness is desirable, but you should not achieve neatness by transcribing data from a sheet of paper to the notebook or from one notebook to another.

– The risk of misplacing—or incorrectly transcribing—crucial data and thereby ruining an experiment is unacceptable.

(2) Supply each entry or series of entries with a heading or label.

– A series of weighing data for a set of empty crucibles, for example, should carry the heading “empty crucible mass” (or something similar), and the mass of each crucible should be identified by the same number or letter used to label the crucible.

(3) Date each page of the notebook as it is used.

(4) Never attempt to erase or obliterate an incorrect entry.

– Instead, cross it out with a single horizontal line and locate the correct entry as nearby as possible.

– Do not write over incorrect numbers.

– With time, it may become impossible to distinguish the correct entry from the incorrect one.

(5) Never remove a page from the notebook.

– Draw diagonal lines across any page that is to be disregarded.

– Provide a brief rationale for disregarding the page.

Notebook Format

– The instructor should be consulted concerning the format to be used in keeping the laboratory notebook.

– In one convention, data and observations are recorded on consecutive pages as they occur.

– The completed analysis is then summarized on the next available page spread (that is, left- and right-facing pages).

– As shown in the following Figure:

 – The first of these two facing pages should contain the following entries:

(1) The title of the experiment (The Gravimetric Determination of Chloride).

(2) A brief statement of the principles on which the analysis is based.

(3) A complete summary of the weighing, volumetric, and/or instrument response data needed to calculate the results.

(4) A report of the best value for the set and a statement of its precision.

– The second page should contain the following items:

(1) Equations for the principal reactions in the analysis.

(2) An equation showing how the results were calculated.

(3) A summary of observations that appear to bear on the validity of a particular result or the analysis as a whole.

– Any such entry must have been originally recorded in the notebook at the time the observation was made.

Reference: Fundamentals of analytical chemistry / Douglas A. Skoog, Donald M. West, F. James Holler, Stanley R. Crouch. (ninth edition) , 2014 . USA