The sample MRR01 (year 2010)was employed to determine the best
analytical conditions for the US-assisted extraction of Hg applying a univariate
randomized planning and CV AAS was selected for Hg determination.
The Hg concentration in this sample (0.91±0.05 mg kg−1), which
was determined by the inter-laboratory program of ANDA (n=20),was
used as the 100% value for further recovery tests used to select the best
conditions for the US-assisted extraction of Hg. Table 3 presents recovery
values for extractions performed using different acid compositions. Sonication
time and mass sample were kept in 5 min and 150 mg, respectively,
based on previous studies reported for metal determination in
similar matrices