BS EN 12766-1 pdf free download
BS EN 12766-1 pdf free download.Methods of test for petroleum and its products.
4 Principle
A sample preparation (clean up) procedure is used to remove most of the impurities likely to interfere with the determination. The clean up procedure is chosen according to the type of sample. The PCB congeners are determined by gas chromatography using a high efficiency narrow-bore capillary column, an electron capture detector and an internal standard.
The PCI3 congeners are separated into single or small groups of overlapping congeners. Single congeners and unresolved groups are identified using a standard test mixture prepared from Aroclors4) and the gas chrornatogram shown in annex A.1. Experimental relative retention times (ERRTs [clause 11]) are calculated. Calibration and quantification of the identified peaks are achieved using individual congeners and an internal standard.
NOTE 1 PCB congener 138 cannot be separated on the specified (IC column (6.3) from congener 163. Overlaps of 25 – 35 % can be
analysed in technical mixtures. The concentration of congener 138 determined by this method includes concentration of congener 163
evaluated by using the response factor of congener 138.
NOTE 2 It should be verified that congener 101 is completely resolved from congener 84 on the column (6.3) used in this method.
5 Reagents and materials
Use only reagents of recognized analytical grade and water conforming to grade 3 of EN ISO 3696.
5.1 General provisions
All reagents and materials including those for clean up (clause 8 and annex H) shall he free from PUll contamination and compounds interfering in the ECD.
Where preparations of solutions etc. are expressed volumetrically, such preparations may alternatively he conducted gravimetrically.
6 Apparatus
6.1 General provisions
All parts of the apparatus coming into contact with the sample, especially the packed columns for the liquid chrornatographic clean up, shall he free from PCB and interliring compounds. The glassware shall he cleaned with solvent
(5.2.1).
The apparatus shall be usual laboratory apparatus and glassware, together with the following:
6.2 Gas chromatograph
High resolution, with accurately reproducible oven temperature control, capable, when used with the appropriate column and conditions, of resolving the test mixture (5.4.6) at least as well as shown in figure A.1 (at least 90 peaks to be observed) and of’ reproducing the experimental relative retention time (ERRT to within ±0,0015.
The injector shall be either an on-column injector, or a splitlsplitlcss injector.
NOTE 1 When a split/splitless injector is used it is necessary to operate it in the splitless mode (9.2).
The gas chromatograph shall be equipped with ECD and gas supply systems as specified in the manufacturer’s manuals.
NOii 2 1’he IiCD requires type approval in accordance with the national Regulations on Radiation Protection.
8 Clean-up procedure
8.1 In general, the relatively simple procedure given in 8.2 to 8.4 and illustrated by figure 2 shall be used before GC analysis of the sample solution. If this clean-up is unsatisfactory the alternative clean-up procedure given in annex 13.1 can be used. Additional clean-up steps are given in annex B.2 to B.5.
NOTE I A clean-up of the prepared sample solution is necessary to avoid contamination of the GC-system and to remove compounds which interfere with the determination of PCB congeners. For complex sample compositions like waste oils, there is no general clean-up procedure available for all possible interfering compounds.
NOTE 2 llalogenated aromatic compounds like tetrachlorobenzyltoluenes are not removed by the clean-up procedures given in this standard. Interferences as reported in annex E (figure E. 1) can result.
To determine the recovery of specified PCB congeners, submit solutions of standards in solvent (5.2.1) to the clean-up procedure and compare the results obtained with those obtained with similar solutions not submitted to the clean-up procedure. The calculated recovery of specified PCB congeners shall be greater than 95 % at a level of 1 ig/g each.BS EN 12766-1 pdf download.
