2.3.2. Real sample pretreatment and analysis
Fish and sediment samples were collected from two different
sites of Musa Creek. Musa Creek is located in the northwest of
Persian Gulf (21◦30–31◦30N, 52◦48E), and has several subsidiary
Creeks. Among them, Jafar Creek marked as a polluted site and
Behad Creek chosen as a reference site where it is far from petrochemical
industries. Sampling was carried out in August 2010. The
fish samples (platycephalusindicus) were stored in a plastic bag
on ice and transported to the laboratory and were kept at
−20 ◦C
before being used. A part of the muscles was taken out quickly and
was dried in an oven at 70 ◦C for 48 h [43]. After grinding the dry
tissue, 0.5 g of each sample was digested with 5 mL of concentrated
HNO3 in a Teflon beaker for 4 h at 100 ◦C. Resulted mixture was filtered
into 100 mL Erlenmeyer flask and then diluted with double
distillated water up to 100 mL. Sediment samples were collected
from each under investigation site, using Peterson grab sampler and
stored in a plastic bag in ice and transported to the laboratory and
was kept at
−20 ◦C until analysis. 1.0 g of sediment was digested
with 6 mL of HCl (37%) and 2 mL of HNO3 (65%) in a microwave
digestion system. Digestion was carried out for 2 min at 250 W,
2 min at 0 W, 6 min at 250 W, 5 min at 400 W, 8 min at 550 W and
then venting for 8 min [44]. The residue resulted from digestion
was then diluted to 100 mL with deionized water.