Determination of PCBs in Marine Sediment Using Pressurised Liquid Extraction-Gas Chromatography-Isotope Dilution Mass Spectrometry -Method Validation

The aim of this work was to develop and apply pressurized liquid extraction combined with GC-MS for more efficient determination ofPCBs in sediment samples. The proposed method was applied to the unknown marine sediment sample. The presented study was performed in the frames of the interlaboratory test organized by the Comite Consultatif pour la Quantite de Matiere (CCQM-K25). Validation parameters (selectivity, linearity, LOD, LOQ, range, repeatability, intermediate precision, trueness) of the developed procedure were calculated. Full uncertainty budget was calculated according to the Guide to the Expression of Uncertainty in Measurement [1]. Detection limits were below 0.65 ng g -1 PCB, while repeatability and intermediate precision (coefficient of variation) were below 4.2% and 5.6%, respectively. The expanded uncertainties were below 8.4% (coverage factor k = 2). Trueness was confirmed by comparing the obtained values with the mean value estimated in the CCQM-K25 test, similarly as in recovery study, and was in the range 96-103%. in Measurement [1]. Wyznaczone granice wykrywalnosci byly ponizej 0,65 ng g -1 PCB, podczas gdy wartosci powtarzalnosci i precyzji pośredniej (obliczone jako wartosci wspolczynnikowzmienności) byly ponizej odpowiednio 4,2% i 5,6%. Wartosci rozszerzonej niepewnosci nie przekraczaly wartosci 8,4% (dla wspolczynnika rozszerzenia k = 2). Poprawnośc wyznaczono poprzez porownanie otrzymanych wartosci z wartosciami srednimi z wynikow otrzymanych w trakcie testu CCQM-K25; jej wartosc (odzysk) miescila sie w przedziale 96-103%.