Limit of Quantitation
The lowest concentration at which the analyte can be measured with acceptable precision and accuracy.
Formula / equation
LOQ = 10σ_blank / m
Unit
Various
In depth
Set at ten standard deviations of the blank, the quantitation limit is roughly three times the detection limit. Between the two limits an analyte can be reported as detected but not reliably quantified, a distinction that matters greatly in regulatory reporting.
Examples in the real world
A method with an LOD of 0.3 ppb typically having an LOQ near 1 ppb.