https://doi.org/10.1351/goldbook.08022
Smallest or largest measured quantity value, obtained by a given measurement procedure, which fulfils a requirement of fitness for purpose.
Notes:
- The quantity measured is usually a mass fraction or a concentration but can also be for example, a mass or an amount of substance.
- The requirement can, for example, be a standard deviation under repeatability conditions of measurement or a measurement uncertainty.
- The smallest and largest measured quantity values correspond to the lower limit of quantification (LLOQ) and the upper limit of quantification (ULOQ), respectively. The interval between the LLOQ and ULOQ is the working interval.
- If the LLOQ is estimated as a multiple of the standard deviation of measured values of a blank material (or one spiked with a small aliquot of the component) obtained under repeatability conditions of measurement, it is important to document the multiplication factor, which may be 5, 6, or 10, applied so that different values stated for the LLOQ can be compared.