Division 6.2 Pressurized sample: use the sampling method described in the sampling chapter, but with the following refinements:

After transferring a sample into a transfer bottle (5.3), further introduce into the transfer bottle a volume of chloroform (4.1) as internal standard equivalent to the presumed quantity of dichloromethane and/or 1,1,1-trichloroethane contained in the sample. Mix thoroughly. Rinse the dead volume of the valve with 0,5 ml of carbon tetrachloride (4.2). After drying, determine accurately the added mass of the internal standard by difference.

After filling the syringe with the sample, the nozzle of the syringe should be purged with nitrogen (4.6) so that no residue remains before injection into the chromatograph.

After each sample is taken, the surface of the valve and of the transfer piece should be rinsed several times with acetone (4.5) (using as required a hypodermic syringe) and then dried thoroughly with nitrogen (4.6).

For each analysis, take measurements using two different transfer bottles and five measurements per bottle.