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−	+	<div class="contentLayout" data-atlassian-layout="{"name":"pagelayout-two-simple","columns":["",""]}"> <div class="columnLayout twoColumns"> <div class="cell "> <div class="innerCell"> <p>EN 1528-1:1996 Fatty food – Determination of pesticides and polychlorinated biphenyls (PCBs) – Part 1: General</p> <p>EN 1528-2:1996 Fatty food – Determination of pesticides and polychlorinated biphenyls (PCBs) – Part 2: Extraction of fat, pesticides and PCBs, and determination of fat content</p> <p>EN 1528-3:1996 Fatty food – Determination of pesticides and polychlorinated biphenyls (PCBs) – Part 3: Clean-up methods</p> <p>EN 1528-4:1996 Fatty food – Determination of pesticides and polychlorinated biphenyls (PCBs) – Part 4: Determination, confirmatory tests, miscellaneous</p> <p> </p> <p><strong><em>Other methods available</em></strong></p> <p> </p> <p>ISO 8260:2008 – Milk and milk products – Determination of organochlorine pesticides and polychlorobiphenyls – Method using capillary gas-liquid chromatography with electron-capture detection</p> <p> </p> <p>US EPA Method 1668B: Chlorinated biphenyl congeners in water, soil, sediment, biosolids and tissue by HRGC/HRMS – determination of dioxin-like and non-dioxin like PCBs in fish tissue.</p> <p> </p> <p> </p> <p><strong><em>Alternative methods from literature</em></strong></p> <p> </p> <p>-          <em>Baeyens et al. PCBs and PCDD/Fs in fish and fish products and their impact on the human body burden in Belgium. Arch. Environ. Contam. Toxicol. 2007, 52, 563-571.</em></p> <p>Method for the chemical analysis of the non-dioxin like PCBs (28, 52, 101, 118, 138, 153, 180) is based on the normalized CEN method EN 1528-1:1996.</p> <p>The following key steps can be identified:</p> <p> </p> <p>-          Homogenization of the food sample;</p> <p>-          Extraction of fat with a mixture of hexane/acetone (1:1) in presence of 25 g anhydrous Na<sub>2</sub>SO<sub>4</sub>. An ASE extraction was performed;</p> <p>-          Removal of acetone with aqueous Na<sub>2</sub>SO<sub>4</sub> solution (2 %)</p> <p>-          Addition of <sup>13</sup>C-internal standards, i.e. isotopically labelled non-dioxin like PCBs</p> <p>-          Purification of fat (0.4 g) on silica acid column (6 g of silica/H<sub>2</sub>SO<sub>4</sub> 60/40, 1 g of Al<sub>2</sub>O<sub>3</sub>, 10 % water and 0.5 g of anhydrous Na<sub>2</sub>SO<sub>4</sub>).</p> <p>-          Elution of the PCBs of interest with hexane</p> <p>-          Measurement of the non-dioxin like PCB congeners on an Ion Trap in MS/MS mode.</p> <p>-          Quantification of the PCBs based on <sup>13</sup>C-PCB/<sup>12</sup>C-PCB ratios (isotopic dilution) using a 5-point linear calibration.</p> <p> </p> <p>-          <em>Pirard, C., Focant, J.-F., De Pauw, E. An improved clean-up strategy for simultaneous analysis of polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF), and polychlorinated biphenyls (PCB) in fatty food samples. Anal. Bioanal. Chem. 2002, 372, 373-381.</em></p> <p> </p> <p>The dioxin-like mono-ortho PCBs are analysed together with the non-dioxin like PCBs.</p> <p>The following key steps can be identified in the analytical method:</p> <p> </p> <p>-          Sample preparation for high-fat content food samples</p> <ul> <li>Homogenization of the samples</li> <li>Freezing of the samples under liquid nitrogen</li> <li>Freeze-drying of the samples</li> <li>Fat extraction by means of Pressurized Liquid Extraction (PLE) <ul> <li>Hexane as solvent</li></ul></li> <li>Drying of fat extracts over Na<sub>2</sub>SO<sub>4</sub></li> <li>Determination of the lipid content by gravimetric analysis</li></ul> <p>-          Clean-up of the fat extract</p> <ul> <li>Use of an open chromatographic multi-layer glass column freshly packed with: <ul> <li>6 g of acid silica</li> <li>1 g of deactivated alumina</li> <li>0.5 g Na<sub>2</sub>SO<sub>4</sub></li></ul></li> <li>Dilution of the fat extract (0.5 g) with 2 mL hexane</li> <li>Elution of the column with 20 mL of hexane</li> <li>Evaporation of the solution containing PCBs</li> <li>Addition of dodecane as keeper</li></ul> <p>-          Analysis by GC-MS/MS</p></div></div> <div class="cell "> <div class="innerCell"> <p> </p></div></div></div></div>

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