2.2.3. Quantification limit
Quantification limit (QL) is a parameter of quantitative assays
for low levels of compounds in the sample. It indicates the lowest
analyte concentration in a sample that may be calculated with precision
and accuracy (ICH, 2005). QL was determined by the angular
coefficient (b) from the calibration curve and the standard deviation
(s) calculated from seven blank samples according to Eq. (2).