For comparison with the SPME technique, water samples
were also extracted using SPE with a Porapak Rdx Sep-Pak
cartridge (500 mg) (Waters, Mississauga, Ont.) as described
in the USEPA SW-846 method 3535A [9]. The cartridge was
previously conditioned with 15mL of acetonitrile followed
by 30mL of deionized water as recommended by the manufacturer.
The aqueous sample (500 mL) was passed through
the cartridge at a rate of 10 mL/min. After letting the cartridge
dry under reduced pressure, potentially adsorbed contaminants
were eluted with 5mL of acetonitrile, and the sample
was diluted with 5mL of deionizedwater, before HPLC analysis.