BS EN 15308-2008 pdf download.Characterization of waste — Determination of selected polychiorinated biphenyls (PCB) in solid waste by using capillary gas chromatography with electron capture or mass spectrometric detection.
NOTE 2 Using ECD, gas chromatographs equipped with two detectors and with facilities for connecting two capillary columns to the same injection system are very well suited for this analysis: with such apparatus the confirmatory analysis can be performed simultaneously.
6.3 Capillary columns
Comprising a non-polar stationary phase, e. g. 5 % phenyl-methyl silicone, coated onto a fused silica capillary column or an equivalent chemically bonded phase column. Use a chromatogram of a standard solution containing PCB-28 and PCB-31 (5.5.2.3) at equal concentrations run under identical conditions as samples for the determination of the resolution of the critical pair PCB-28/PC-B31 The resolution of this pair shall be better than 0,5. In general column lengths should be 25 m to 60 m, internal diameter 0,18 mm to 0.32 mm and film thickness 0,1 pm to 0.5 pm.
Using ECD-detection, a column coated with a moderate polar phase. e. g. CP-Sil 19, OV 1701 etc., shall be used to confirm the result obtained on the non-polar column. Confirmation analysis using a second column is not necessary in case the analytical result is much below any regulatory level.
7 Safety precautions
Anyone dealing with waste and sludge analysis has to be aware of the typical risks of that kind of material irrespective of the parameter to be determined. Waste and sludge samples may contain hazardous (e. g. toxic, reactive, flammable, infectious) substances, which can be liable to biological and/or chemical reaction. Consequently it is recommended that these samples should be handled with special care. The gases, which may be produced by microbiological or chemical activity, are potentially flammable and will pressunse sealed bottles. Bursting bottles are likely to result in hazardous shrapnel, dust and/or aerosol. National regulations should be followed with respect to all hazards associated with this method,
8 Interferences
Some organic chlorinated compounds (e. g. tetrachlorobenzyltoluenes, polychlorinated naphthaenes, polychloninated terphenyls. toxaphenes. also sulphur) give rise to interferences since their behaviour is very similar to that of PCB during sample clean-up and gas chromatographic separation. It is possible that several PCB congeners elute within one peak. On many capillary columns PCB-138 coelutes with PCB-160, PCB-163 and PCB-164. Hence PCB-138 concentration may represent the sum of those congeners (also in case of mass spectrometric detection) The same is true for PCB-101 and PCB-90. Typically the concentrations of the co-eluating congeners compared to those of the target congeners are low.
Presence of considerable amounts of mineral oil in the sample may interfere with the quantification of PCB in GC-MS analysis. In such cases. GC-ECD may be the preferred method or clean-up of the sample extract according to 11.3.8 using DMSO/n-hexane partitioning to remove the mineral oil from sample extract is recommended.
10.2 Drying
Depending on the nature of the sample material and the extraction solvent to be used a drying step might be needed. If it is necessary, air-dry the complete sample or dry it in a ventilated drying oven at 40 °C or in a freeze dryer. The drying time depends on the technique chosen and the nature of the sample.
For sludge, freeze-drying is strictly applied.
10.3 Particle size reduction
In order to achieve a homogeneous and representative test portion, one or more particle-size reduction steps might be needed. The choice of the technique depends on the nature of the sample and on the particle size needed. Typically, particle-size reduction is a multi-step operation that implies the use of a sequence of different techniques like crushing, cutting or grinding.
Grinding of samples which have a plastic or paste-like consistency requires embrittlement with liquid nitrogen and particle size reduction to less than 0.5 mm, e. g. by using an ultra-centrifugal mill.
NOTE In case of plastic materials (e. g. cable shredder) the material to be granulated is poured in portions Into liquid nitrogen and ground in a centrifugal mill (10 000 rounds/mm to 15 000 rounds/mm) cooled with liquid nitrogen It should be noted that the mill is constantly kept cool by addition of liquid nitrogen In short intervals. The plastic matenal should be failed into the mill constantly in small portions without causing any significant slowing down of the grinder.
11 Procedure
11.1 Blank
Perform a blank determination following the paragraphs of the procedure applied to samples (selected extraction and clean-up). Use the same amounts of reagents that are used for pre-treatment. extraction, clean up and analysis of samples. Analyse the blank immediately prior to analysis of the samples to demonstrate freedom from contamination.
11.2 Extraction
11.2.1 Extraction by shaking or sonification
Weigh a test portion of 10 g to 25 g to the nearest 0,1 g in a stoppered flask. Add a definite volume of the internal standard solution. lsotopically labelled internal standards may be added after extraction to an aliquot of the extract where appropriate. Typically the concentration of the individual internal standards in the final extract will be 0,1 pg/mI. Add 50 ml of acetone to the test sample, Extract by shaking thoroughly for 30 mm on a shaking device or by sonification. BS EN 15308-2008 pdf download.
BS EN 15308-2008 pdf download
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