2.4. Figures of merit
Limits of detection (LOD) and limits of quantification (LOQ) by
ICP OES were calculated according to previous studies (Thomsen,
Roberts, & Burguess, 2000) and demonstrated in the following
equations:
SBR ¼ ISR IBlank=IBlank BEC ¼ CSR=SBR
where CSR is the concentration of the reference solution multielement;
SBR is the analytical signal/background signal; and ISR
and IBlank are the intensities of the reference solution and the intensity
of the blank signal, respectively.
LOD ¼ ð3 BEC RSDBlankÞ=100
LOQ ¼ ð10 BEC RSDBlankÞ=100
where RSDBlank is the standard deviation of the blank (n = 10). However,
LOD and LOQ by GF AAS were calculated using 10 measures of
the analytical blank, where LOD = 3 s/m and LOQ = 10 s/m,
where ‘s’ is the standard deviation of analytical measurements of
the blank and ‘m’ is the slope of the analytical calibration curve
(Harris, 2007). Limit of detection and limit of quantification values
are presented in Table 2.