Phthalates and Nonylphenols in Roskilde Fjord

chemical explanation for this may be that the phthalates contaminatingthe bottle is extracted more efficient in an empty bottle, which brings thesolvent (dichloromethane) in closer contact with the glass surfaces thanin a water filled bottle. For this reason is has previously been attemptedto use distilled water or tap water in the blanks. However, it was not possibleto obtain water with sufficiently low phthalate concentrations.(Vikelsøe et al. 1998), hence the use of distilled-water blanks was abandoned.No significant deviations from linearity were found as mentioned in AppendixA, which describes the performance experiment further.244.8 Performance test of sediment methodThe analytical method for sediment is essentially the same as the soilmethod described by Vikelsøe et al. 1999. The performance of the sedimentmethod was evaluated by a similar repeated standard addition experimentas that for water, carried out on a sediment sample from themiddle of Roskilde Vig. A test standard solution in ethanol 10 timesstronger than that used for the water experiment was added to 5 g of wetsediment (about 3.5 g of dm) in volumes of 0, 150 and 300 µl, respectively.Table 10 Statistics of performance experiment for fjordsedimentStatistics, ng/g NP NPDE DBP DPP BBP DEHP DnOP DnNPBlankBlank mean 29 123 68 0 0 126 0 0sd 4 64 5 0 0 1 0 0CV% 15 52 7 u u 1 u uLevel 0Added ng/g 0 0 0 0 0 0 0 0Found mean 608 689 287 19 6 923 3 7sd 272 437 48 30 10 5 5 11CV% 45 63 17 160 173 1 173 173Level 500Added ng/g 525 3983 342 351 407 160 371 208Found mean 959 2581 531 385 334 865 389 297sd 255 533 149 69 34 109 81 71CV% 27 21 28 18 10 13 21 24Level 1000Added ng/g 1050 7966 685 702 814 320 742 417Found mean 1074 4209 781 803 663 1221 700 437sd 384 1242 188 298 114 234 47 61CV% 36 30 24 37 17 19 7 14Summary statisticsPooled sd 309 820 141 178 69 151 54 54Detection limits 272 439 48 30 10 43 5 11u = undefined