The effect of sample mass was also evaluated. Table 4 presents
recovery values for extractions of Hg applied for different sample
masses using 30% (v v−1) HCl under sonication for 5 min.
As mass increases, a decrease in recovery efficiency of mercury
occurs. Although a mass of 100 mg showed satisfactory effect in the
recovery of mercury, increase in standard deviation was verified.
Due to the mineral complexity of the matrix, the sample treatment
process may suffer higher analytical variations when a reduced
mass of sample is employed. In this case, it was considered to employ
amass value of 150mg as most favorable because standard deviation
values were lower.