The instrument detection limits (LODs) and limits of quantification
(LOQs) were calculated statistically according to IUPAC as 3.84 and
10 times, respectively the standard deviation of the signal corresponding
to 10 blank solutions divided by the slope of the calibration
curve (Currie, 1999). The LOQs were also calculated, according
to the EURACHEM Guidance, as the lowest concentration of the
analytes for which the relative standard deviation (RSD) of the signal
is equal or less a fixed percentage (10% in our case).