(2) The samples were comminuted, and 10 g of each sample was
then placed into 50 ml polyethylene tube. Samples were extracted
and cleaned up immediately after sampling using QuEChERS
methodology (Anastassiades et al., 2002). 15 ml of acetonitrile was
added into each tube. The samples were well shaken using a
vortex mixer at maximum speed. Afterwards, 6 g of anhydrous
magnesium sulfate and 1.5 g of sodium chloride were added, then
extracted by shaking vigorously on vortex for 5 m and centrifuged
for 10 m at 4,000 rpm. An aliquot of 4 ml was transferred from the
supernatant to a new clean 15 ml centrifuge tube containing 100
mg PSA and 600 mg anhydrous magnesium sulfate. The samples
were again vortexed for 3 m and then centrifuged for 10 m at 4,000
rpm. Sodium Chloride saturated solution (35%) was used for
washed and slated method. Peeled method was done by the use of
a sharp knife; the samples were taken through the whole samples
preparation mentioned above. In general, each sample was
conducted in three replicates