Report on Global Monitoring Project Pesticide Research Laboratory ...

hexane and then, 6 g of activated florisil was poured into the column (Florisil 60-100 mesh from
FISCHER, activated overnight at 130C). A gentle shaking of the column was necessary to settle
the florisil inside the column. Two cm of sodium sulphate was then added on top. Hexane was
poured into the column and when the hexane reaches the top of the filling, the stopcock was
closed, a 250 mL round bottom flask was placed under the column and the evaporated sample
extract was transferred to the top of the column using a Pasteur pipette. As the sample passes
through the column, the sample container was rinsed with 3 x 2 mL portions of hexane (from a
premeasured 50 mL of hexane) and rinses were also transferred to the column. The remaining
hexane was poured into the reservoir of the column and the elution of fraction 1 was performed
at a steady drip of 3 mL/min. When the hexane reached the top of the filling, the stopcock was
turned off, the flask with fraction 1 was replaced with another 250 mL flask, the column was
eluted with 50 mL of 15% DCM/Hexane (v/v) and fraction 2 was collected. The procedure was
then repeated for fraction 3 using 150 mL of 60% DCM/Hexane (v/v). Each of the 3 fractions
was separately rotary-evaporated (after adding 5 mL of iso-octane – Optima grade) to 1.0 mL. 1
uL of the extract was analysed by a Agilent 6890 GC-MS (scan mode) fitted with a HP 5MS
column (0.25mm x 0.25 um x 30m), the appropriate reference standards and the Chem-Station
Software.
Analysis of Mirror Samples
Fish and Cow‟s Milk samples were collected and each one was splitted to two –A and B. Fish
sample A and Cow‟s Milk sample A were sent to Dr. Estaben‟s Laboratory in Spain. B-samples
were analyzed at he Pesticide Research Laboratory.
Mirror Samples:
Results for UNEP Mirror Samples
PCB
Congeners
Fish/(ng/kg) Cow’s
Milk/(ng/kg)
PCB18 38.5 nd
PCB17 17 nd
PCB31 110.8 nd