3.1.5. Analytical figures of merit
The proposed method for mercury determination by pyrolysis
of previous defatted samples is appropriated for the tree nuts. To
evaluate the reliability of the method a series of recovery
experiments were performed by spiking mercury standard
solutions to solid samples in different concentrations (2.5–
10mg kg1 of Hg). The levels of concentration, the mass of sample
introduced in the system and the results are summarized in
Table 5. As shown in the table, recovery values varied between 94
and 101%, indicating the absence of matrix interferences during
sample measurement. The repeatability of the methodology was
evaluated by making six independent analyses of a nut containing
1.2mg kg1 Hg. The results found provided a relative standard
deviation (RSD) of 14% and additionally, the coefficient of
variation for 3 independent determinations of each sample
varied between 2.0 and 14%.