BS/EN 16181-2018 pdf download.Soil, treated biowaste and sludge – Determination of polycyclic aromatic hydrocarbons (PAll) by gas chromatography (GC) and high performance liquid chromatography (HPLC).
3.4
Surrogate
PAH that Is unlikely to be present in samples added to the sample prior to analysis and used to correct
for losses of the PAl-I analytes during sample extraction or clean-up
4 Principle
Due to the multi matrix (horizontal) character of this European Standard, different procedures for different steps (modules) are allowed. Which modules should be used depends on the sample. A recommendation is given in this European Standard. Performance criteria are described and it is the responsibility of the laboratories applying this European Standard to show that these criteria are met. Using of spiking standards (internal standards) allows an overall check on the effIciency of a specific combination of modules for a specific sample. But it does not necessarily give the information upon the extensive extraction efficiency of the native PAH bonded to the matrix.
After pretreatment to reduce the moisture content and to increase the homogeneity (see 9.2), the test sample is extracted with a solvent.
The extract is concentrated and interfering compounds are removed by a clean-up method suitable for the specific matrix. The eluate is concentrated. For HPLC analysis, the concentrated eluate is taken up in an appropriate less volatile water miscible polar solvent and the non-polar cluate residue is removed.
The extract is analysed by GC-MS using a capillary column with a stationary phase of low polarity or by HPLC-UV-DAD/FLD with an appropriate reversed phase column.
PAH are identified and quantified with GC-MS by comparison of relative retention times and relative peak heights (or peak areas) with respect to internal standards added, and with HPLC by using the corresponding variables of the external standard solutions. The efficiency of the procedure depends on the composition of the matrix that is investigated.
5 Interferences
5.1 Interference with sampling and extraction
Use sampling containers of materials (preferably of steel, aluminium or glass) that do not change the sample during the contact time. Avoid plastics and other organic materials during sampling, sample storage or extraction. Keep the samples from direct sunlight and prolonged exposure to light.
During storage of the samples. losses of PAIl may occur due to adsorption on the walls of the containers. The extent of the losses depends on the storage time.
5.2 Interference with GC-MS
Substances that co-elute with the target PAH may Interfere with the determination. These interferences may lead to incomplete resolved signals and may, depending on their magnitude, affect accuracy and precision of the analytical results. Peak overlap does not allow an interpretation of the result. Unsymmetrical peaks and peaks broader than the corresponding peaks of the reference substance suggest interferences.
Chromatographic separation between dibenzo(a,hlanthracene and indenoll,2,3-cdjpyrene are mostly critical. Due to their molecular mass differences, quantification can be made by mass selective detection. When incomplete resolution is encountered, peak integration shall be checked and, if necessary, corrected.
A chrornatographic resolution of R> 0,8 is required for benzolbjfluoranthene, benzo[kjtluoranthene and benzo[ilfluoranthene (m/z = 252). If the criterion is not met for benzo[jlfluoranthene, the result shall be reported as the sum of the coeluted PAIl.
5.3 Interferences with the HPLC
Substances that show either fluorescence or quenching and co-elute with the PAl-Is to be determined may interfere with the determination. These Interferences may lead to Incompletely resolved signals and may. depending on their magnitude, affect accuracy and precision of the analytical results. Peak overlap does not allow an interpretation of the result. Asymmetrical peaks and peaks being broader than the corresponding peaks of the reference substance suggest interferences. This problem may arise for naphthalene and phenanthrene depending on the selectivity of the phases used.
Incomplete removal of the solvents used for sample extraction and clean-up may lead to poor reproducibility of the retention times and wider peaks or double peaks especially for the 2- and 3-ring PAIls. Extracts shall be diluted sufficiently with acetonitrile for the HPLC-analysis, otherwise the detection of naphthalene and 3-ring PAR can be interfered with by a broad toluene peak.
Usually perylene is incompletely resolved from benzo[b]fluoranthene, but by choosing a selective wavelength, the perylene peak can be suppressed.BS/EN 16181-2018 pdf download.