https://doi.org/10.1351/goldbook.E02070
For a mixture of \(\left(+\right)\)- and \(\left(-\right)\)-enantiomers, with composition given as the @[email protected] or @[email protected] fractions \(F_{\left(\!+\!\right)}\) and \(F_{\left(\!-\!\right)}\) (where \(F_{\left(\!+\!\right)}\,+\,F_{\left(\!-\!\right)}=1\)) the @[email protected] excess is defined as \(|F_{\left(\!+\!\right)} - F_{\left(\!-\!\right)}|\) (and the percent enantiomer excess by \(100\ |F_{\left(\!+\!\right)} - F_{\left(\!-\!\right)}|\)). Frequently this term is abbreviated as \(\text{e.e.}\)
See:
optical purity
Source:
PAC, 1996, 68, 2193. (Basic terminology of stereochemistry (IUPAC Recommendations 1996)) on page 2207 [Terms] [Paper]