https://doi.org/10.1351/goldbook.08014
Mass (amount of substance or number of entities) of a specified component divided by the mass (amount of substance or number of entities, respectively) of the system.
Notes:
- Purity is usually related to a major component. The other components are termed "impurities".
- The quantity, component, and system must be specified.
- The numerical quantity value of purity is often expressed as per cent or per mille.
- Purity can be estimated as \(1 - \sum_{j=1}^{j=N} f_{j}\), where \(f_{j}\) denotes fractions of the same type (mass fraction, amount of substance fraction or number fraction) of all other components \(j = 1, \dots, N\). If the contributions are expressed as mass fractions, this estimation is sometimes termed "mass balance".