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ISO 13914-2013 pdf free download
ISO 13914-2013 pdf free download.Soil quality — Determination of dioxins and furans and dioxin-like polychiorinated biphenyls by gas chromatography with high-resolution mass selective detection (GC/HRMS)
Qualité du so! — Determination des dioxines etfuranes comme biphényls polychiorés par chromatographie en phase gazeuse avec spectrométrie de masse a haute resolution (CG/SMHR).
Samples should be stored in suitable containers with an appropriate closure material such as polytetrafluoroethylene (PTFE). Samples to be frozen can be stored in aluminium containers precleaned by heating to 450 °C for a minimum of 4 h or by rinsing with a non-chlorinated solvent.
Samples should be kept cold (<8 °C) and in the dark. The sample pretreatment should take place within 3 d of sampling. Alternatively, samples can be frozen (-18 °C) directly after sampling and kept frozen before sample pretreatment.
7.2 Sample pretreatment
Drying and homogenization should be carried out according to ISO 14507, if not otherwise specified. Store the ground material in a desiccator or a tightly closed glass container.
8 Extraction and clean-up
In this International Standard, the minimum requirements for extraction and clean-up to be met are described as well as examples of operation. The analyst can use any of the procedures given below and in Annex C or any suitable alternative procedures.
The determination of PCDDs/PCDFs Is based on quantification by the isotope dilution technique using GC/IIRMS. 13C12-labelled 2,3,7,8-chlorine substituted PCDD/PCDFs congeners are added at different stages of the whole method. Losses during extraction and clean-up can be detected and compensated by using these added congeners as internal standards for quantification together with recovery standards which are added just before the GC/HRMS analysis. However, due to possible differences in the binding and adsorption characteristics between the native PCDDs/PCDFs and the 13C12-labelled congeners, which are added during analysis, complete substantiation of the extraction efficiency and compensation of losses during clean-up is not ensured. Therefore, in addition, the applied methods shall be validated thoroughly. Examples of well-proven extraction and clean-up methods are given in Annex C.
The main purpose of the clean-up procedure of the raw sample extract is the removal of sample matrix components, which can overload the separation method, disturb the quantification, or otherwise severely impact the performance of the identification and quantification method and to separate dioxin-like PCB from PCDD/F. Furthermore, an enrichment of the analytes in the final sample extract is achieved. Extraction procedures are usually based on Soxhlet extraction of the <2 mm fraction of the dry and ground or sieved solid sample. Sample clean-up is usually carried out by multi-column liquid chromatographic techniques using different adsorbents.
In principle, any clean-up method can be used which recovers the analytes in sufficient quantities. Furthermore, the final sample extract shall not affect adversely the performance of the analytical system or the quantification step.ISO 13914-2013 pdf free download.
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