2.5.5. Extraction of fat
To remove the fat content, previously to the direct determina-
tion of Hg, about 3 g of samples was treated with 15 mL of a
solution of chloroform–methanol in the ratio 2:1 (v/v) according to
Table 1
Operation conditions for the direct Hg determination in tree nuts.
Sample weight
Sample boat drying
Drying temp/time
Ashing temp/time
Decomposition temp/time
Catalyst delay time
Gold trap temp/time
Measurement time
Oxygen
flow rate
50–150 mg
Nickel
200 C for 10 s
850 C for 180 s
650 C
180 s
850 C for 12 s
30 s
200 mL min1
Parameter Setting
M.J. Silva et al. / Analytica Chimica Acta 838 (2014) 13–19 15
the method of Vonderheide et al. [29]. The