The mean value for five determinations by the AAS
method was 461.6 ppm for V and 109.1 ppm for Ni, with
an r.s.d. of 3.3% and 4.6% respectively. The values
reported for the same number of determinations by
WDXRF were 453.8 ppm and 112.3 ppm, with an r.s.d. of
3.6% and 3.7% respectively. If the WDXRF method is
considered as the reference, the relative errors in
determinations by the AAS method are then 1.7% for V
and 2.9% for Ni