Dichloric Acid Reaction Paper

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All solvents are pesticide residue (PR) grade and were purchased from SDFCL Fine Che-Limited. Dichloromethane (DCM), acetone, hexane (HPLC grade), sodium chloride (AR grade) were procured from SDFCL Fine Che-Limited. Analytical standards of 4, 4, DDT and HCH were purchased from Sigma Aldrich Laborchemikalien GmbH. The standard solutions (1.0 μg/mL) of individual and the mixture of organochlorine pesticides were prepared in hexane. Millipore Milli-Q purified water was used throughout the experiment.
All the glassware was acid washed and cleansed with distilled water. 10 g NaCl was taken in separating funnel and dissolved NaCl in 1000 ml of water sample, kept separating funnel with stopcock on stand vertically and added 60 ml of DCM (dichloromethane)
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In 10 g dried sediment sample added 7 ml 0.2 M NH4Cl solution. A mixture of 100 ml hexane: acetone (1:1) was used as a solvent to extract pesticides with overnight shaking for 12 h on reciprocal or wrist action shaker at 180 rpm. The extract was carefully decanted through activated florisil column (2-3 cm), giving twice wash with25 ml hexane: acetone (1:1) to the sediments. The elute was then washed with 200 ml water and then again aqueous layer was extracted with 50 ml hexane. Finally the hexane layer was washed with 100 ml water and then evaporated to dryness with a vacuum rotary evaporator. The concentrated extract was then passed through a chromatographic column (30 cm x 10 mm i.d) containing 2 g florisil (lower) and 1 g sodium sulphate (upper) which is pre wetted with hexane: acetone (1:1). OCPs were eluted with 25 ml hexane: acetone (1:1).The solvent was evaporated using rotary evaporator and final volume was adjusted to 5 ml, which is used for GC analysis. All the sediments were analyzed for HCH and…show more content…
WHO classifies lindane as “Moderately Hazardous” pesticide. The USEPA (2005) has determinated that lindane does not contaminate drinking water in excess of the Agency’s level of concern8. In water, sediment and fish samples collected from Maleksaban lake (S-6), residual concentration of ∑HCH ranged from BDL-1122.42μg/l, BDL-1275.26 ng/g and BDL-689.74 ng/g respectively. In the case of Nikol Lake (S-7), residue of ∑HCH concentration ranged from BDL-119.65μg/l, BDL-224.35 ng/g and BDL-23.01 ng/g respectively. If we compare the residues of organochlorine pesticides (OCPs) between different sampling sites, the site-6 from Maleksabanlake has maximum concentration of these persistent compound 1263.96 ng/g in sediment whereas the level is 1106.01μg/l in water sample

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