The limit of detection, expressed as the concentration, \(c_{\rm{L}}\), or the quantity, \(q_{\rm{L}}\), is derived from the smallest measure, \(x_{\rm{L}}\), that can be detected with reasonable certainty for a given analytical procedure. The value of \(x_{\rm{L}}\) is given by the equation \[x_{\rm{L}}=\overline{x}_{\rm{bi}}+k\ s_{\rm{bi}}\] where \(\overline{x}_{\rm{bi}}\) is the mean of the blank measures, \(s_{\rm{bi}}\) is the standard deviation of the blank measures, and \(k\) is a numerical factor chosen according to the confidence level desired.