Phthalates and Nonylphenols in Roskilde Fjord

4.2 Extraction of water samples.The water samples and their sampling bottles was treated as entities,since there may be a significant adsorption to the glass walls. Hence, itwas not allowed to divide the samples, or to take subsamples. Afterthawing at room temperature, the volume of water present in the samplingbottle was measured. A volume of 0.1 ml extraction spike solutioncontaining 0.1 µg of three deuterium labelled phthalates (Table 5) wasadded, the bottle was shaken and left for 15 min to equilibrate the extractionspikes with the water and the glass surfaces. The sample was extractedby shaking 5 min with 100 ml CH 2 Cl 2 after addition of 2 ml 5MHCl. When the phases were separated, a sub-extract of 50 ml was taken,concentrated to near dryness by evaporation and the remanence dissolvedin 0.1 ml syringe spike solution (Table 6) containing 0.1 µg D 4 -DnOP.4.3 Extraction of sediment samplesAfter thawing at laboratory temperature the samples were air-dried for 48hours on filter paper. About 5 g of dried sample was weighed accuratelyinto a 250 ml wide-necked Pyrex bottle. A volume of 0.1 ml extractionspike solution (Table 5) was added, distributed in the sample by shakingand left for 15 min to equilibrate the extraction spikes with the sampleand the glass surfaces, and allow the ethanol in the spike solution toevaporate. A volume of 100 ml dichloromethane was added, and the bottlewas closed by a screw-lid covered by aluminium-foil. The sample wasextracted at laboratory temperature by shaking for 4 hours in a shakingapparatus (Heidolph Unimax 2010 at 200 shakes/min). When the phaseswere separated, a sub-extract of 10 ml was concentrated by carefulevaporation under N 2 , and the remanence re-dissolved in a volume of 1ml syringe spike solution, Table 6.The extracts were analysed directly by high-resolution GC/MS withoutfurther clean up. If necessary, the samples were diluted appropriatelywith syringe spike solution.All sediment samples were extracted and analysed in duplicates.4.4 BlanksEvery day empty laboratory glassware was extracted for determination ofthe blank values, i.e. one blank for about every 10 samples. Care wastaken to treat the blanks in any way as samples, using same batches ofsolvents, glassware etc. The blanks were subtracted from the results onan amount per sample basis for each analytical series.20