3.1.6. Validation of the method
The proposed procedure was applied to the determination of
mercury in
five certified reference materials. Unfortunately, nut
reference samples were not available and thus, Coal Fly Ash-NIST
SRM 1633b, Fucus-IAEA 140 and three samples of Rice Flour NIES-
10 (a, b, c) were employed. The comparison between the certified
values of Hg and results found are in good agreement, as it can be
seen in Table 6. The expanded uncertainty of difference between
result found and certified value (UD) showed no significant
differences at 95% confidence level. In the case of rice samples, the
only one for which a reference value was available, data found by
us was of the same order as that reported