BS 16167:2012 pdf download – Sludge, treated biowaste and soil — Determination of polychlorinated biphenyls (PCB) by gas chromatography with mass selective detection (GC-MS) and gas chromatography with electron-capture detection (GC-ECD)
7.6.1Preparation of calibration standard solutions of PCBs
Prepare individual concentrated primary standard solutions of about 0,4 mg/ml in n-heptane (7.2.2) byweighing approximately 10 mg of each of the calibration standards (7.5.2) to the nearest 0,1 mg anddissolving them in 25 ml of n-heptane.
Combine small quantities (2 ml to 10 ml) of these individual primary standard solutions into a mixed standardsolution of PCB.
NOTE Because of the dangerous nature of the substances to be used, commercally available – preferably cerified -standard solutions or mixed standard solutions are preferred.Avoid skin contact.
The working standard solutions shall be in the same solvent like the extract.
Store the primary and diluted standard solutions in a dark place at a temperature of (5±3)°℃.The solutionsare stable for at least one year, provided that evaporation of solvent is negligible.
Components present in mixed standard solutions should be completely separated by the gas chromatographiccolumns used.
7.6.2Preparation of internal standard solution
Prepare a concentrated primary internal standard solution,containing at least three different components(7.5.3), of about 0,4 mg/ml in n-heptane (7.2.2) by weighing approximately 10 mg of each of the choseninternal standards to the nearest 0,1 mg and dissolving them in 25 ml of n-heptane. Prepare from this asecondary internal solution with such a concentration that the added amount gives a peak with measurablepeak area or peak height in the chromatogram (at least 10 times the detection limit).
lf the two step procedure for GC-MS is used, make two different internal standard solutions, one containingthe non-labelled compounds. At least two unlabelled congeners shall be used in the first internal standardsolution and at least three labelled congeners in the second solution.
7.6.3 Preparation of injection standard solution
Prepare a concentrated primary injection standard solution，containing at least two different components(7.5.3), of about 0,4 mg/ml in n-heptane (7.2.2) by weighing approximately 10 mg of each of the choseninjection standards to the nearest 0,1 mg and dissolving them in 25 ml of n-heptane. Prepare from this asecondary internal solution which such a concentration that the added amount gives a peak with measurablepeak area or peak surface in the chromatogram (at least 10 times the detection limit).
8.1Extraction and clean-up proceduresUsual laboratory glassware.
All glassware and material that comes into contact with the sample or extract shall be thoroughly cleaned.
8.1.1 Sample bottles,made of glass, stainless steel or aluminium,with glass stopper or screw top andpolytetrafluoroethylene (PTFE) seal of appropriate volume.
Glass is not appropriate for sludge samples.
WARNING —For safety reasons, biologically active sludge samples shall not be stored in a sealedcontainer.
8.1.2 Shaking device, with horizontal movement (200 strokes to 300 strokes per min).
8.1.3 Water bath, adjustable up to 100 °C.
8.1.4 Separating funnels of appropriate volume.
8.1.5 Conical flasks of appropriate volume.
8.1.6 Soxhlet extraction apparatus, consisting of round bottom flask, e.g. 100 ml, Soxhlet extractors and Soxhlet thimbles, e.g. 27 mm × 100 mm, vertical condensers, e.g. 300 mm, heating device.
8.1.7 Concentrator, Kuderna Danish type.
Other evaporators, e.g. a rotary evaporator, may be used if found to be equally suitable.
8.1.8 Boiling chips, glass or porcelain beads.
8.1.9 Quartz wool or silanized glass wool.
WARNING — Working with quartz wool imposes a risk to health through the release of fine quartz particles. Inhalation of these should be prevented by using a fume cupboard and wearing a dust mask.
8.1.10 Calibrated test tubes, with a nominal capacity of 10 ml to 15 ml and ground glass stopper.
8.1.11 Chromatography tubes. Chromatography column of glass, 5 mm to 10 mm inside diameter, length e.g. 600 mm.
8.2 Gas chromatograph
Equipped with a capillary column, mass spectrometric detection (MS) or electron capture detector (ECD) based on 63 Ni.
NOTE Working with an encapsulated radioactive source as present in an ECD requires a licence according to the appropriate national regulations.