limit of detection in analysis

The limit of detection, expressed as the concentration, $c L$ , or the quantity, $q L$ , is derived from the smallest measure, $x L$ , that can be detected with reasonable certainty for a given analytical procedure. The value of $x L$ is given by the equation

$x L = x ̄ bi + k s bi$

where $x ̄ bi$ is the mean of the blank measures, $s bi$ is the standard deviation of the blank measures, and $k$ is a numerical factor chosen according to the confidence level desired.

Source:

Orange Book, p. 5