Enantiomer fractions are preferred to enantiomer ratios for describing chiral signatures in environmental analysis

The enantiomer ratio (ER) is currently the standard descriptor of enantiomeric (chiral) signatures for environmental samples. In this paper, we argue for the adoption of the enantiomer fraction (EF) as the standard descriptor by showing drawbacks to the use of ER. The enantiomer fraction is superior because it provides a more meaningful representation of graphical data and is more easily employed in mathematical fate expressions. Several useful expressions are presented that allow EF to be used for tracking and apportioning chemical movement between environmental compartments and for investigating microbial degradation processes.