BS EN 16143-2013 pdf download.Petroleum products Determination of content of Benzo(a)pyrene (BaP) and selected polycyclic aromatic hydrocarbons (PAH) in extender oils Procedure using double LC cleaning and GC/MS analysis.
Depending on chromatographic conditions (e.g. column length), it can happen that the different benzofluoranthene isomers co-elute. In these cases, determining the sum of the three isomers rather than reporting each isomer separately shouki be considered. Another alternative would be to use longer GCcolumns (60 m instead of 30 m). See B.2 for further advice on the peak overlap of the isomers.
Ferrules used shall not contain more than 40 % graphite (a suitable ferrule is made of 60 % polyimide and 40 % graphite) to decrease the risk that PAHs are absorbed.
6.3 Sample concentrator, typically a rotary evaporator or similar digital evaporator device.
7 Sampling and sample handling
7.1 General sampling procedure
Samples shall be taken according to EN ISO 31/u or EN ISO 31?1, as well as in accordance witn me requirements of national standards or reguLations for the sampling of the product under test.
If samples are not tested immediately, they shall be stored tightly sealed and in a cool and dark place.
It shall be secured that glassware is thoroughly cleaned and that all new materials that may come into contact with the sample are checked by blank analysis that they give no interference.
NOTE Interferences which can affect the results can occur due to contaminations from glassware, solvents and other matenals that can come into contact with the sample. Such interferences will forni an artefact or will increase the detector baseline. Interferences can also come from components in samples that co-elute with the specific PAHs of interest.
7.2 Preparation of a sample solution
Approximately 70 mg of the sample is introduced to the nearest 0,1 mg into a 5 ml volumetric flask (5.9) and dissolved in 2 ml n-pentane (5.1.3). Before the sample clean-up, the sample solution is spiked with internal standard. The concentration of internal standard shall be adjusted such that it is in the same range as the expected PAHs in the sample.
8.2 FIrst clean-up step using silica column
8.2.1 Preparation of the silica column
Before use, the silica gel (5.2.1) is deactivated over 24 h by stirring with 7 % (ni/rn) water which does not contain PAHs. Of the deactivated sihca, 5 g is mixed with n-pentane (5.1.3) and then transferred into a glass column (5.7.1). Vibrate or knock mildly on the column to ensure that the silica is evenly and sufficiently packed without voids.
8.2.2 Chromatography on silica column
Run 10 ml of n-pentane (5.1.3) throu9h the column and discard the eluted volume. Apply the sample just before the last free n-pentane is about to vanish from the silica surface. Apply the sample in portions with a suitable Pasteur pipette (5.6).
After the applied sample volume has vanished from the surface, apply an additional 2 ml portion of n-pentane to assure that whole sample is apped in the column. Just before the last n-pentane has vanished from the silica surface, apply 25 ml n-pentane in several portions. All volume eluted with n-pentane shall be discarded.
Apply 75 ml cyclohexane (5.1.2) in several portions and collect the eluted volume in a clean 100 ml volumetric flask. Concentrate the collected cyclohexane fraction using the sample concentrator (6.3) to less than 1 ml, ensuring that the temperature does not exceed 35 °C. If the second clean-up step is applied for quantitative results, this concentrate is to be submitted to further processing in the Sephadex clean-up step (8.3.2)
If the Sephadex clean-up step is not used, transfer the concentrate to a 1 ml volumetric flask, add the injection standard to it and adjust the sample solution volume to lml with Cyclohexane by filling up to the mark. This 1 ml sample is used to inject test portions for GC separation.
8.3 Second clean-up step using Sephadex-LH 20 column
8.3.1 Preparation of the Sephadex-LH2O column
Prepare a slurry of 5 g of dry Sephadex-LH2O (5.2.2) and propanol-2 (5.1.4), using a 3:1 (rnfm) proportion for the solvent/Sephadex mixture. Let the slurry stand overnight for deactivation.
Fill a glass column (5.7.2) with 5 g of the deactivated slurry and drain the column from any free propanol-2, then close the bottom valve.
When a fresh Sephadex-LH2O quality batch is used, it shall be tested with a solution of approximately 100 mg/I fluoranthene in propanol-2, so that it has an elution volume between 24 ml and 32 ml propanol-2 and that a straight level zone can be seen under UV-light (366 nm).BS EN 16143-2013 pdf download.
BS EN 16143-2013 pdf download
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