User`s guide

Sampling Techniques
336
Table 28 GC Certified Standards on PerkinElmer Tubes
These analytical results were in agreement with the values calculated
from the charging data, indicating that adsorption and desorption
were quantitative.
Standards are available from the BCR (CRM 112). Samples of CRM
112 can be obtained from:
Community Bureau of Reference (BCR)
Rue de la Loi 200
B-1049 Brussels
BELGIUM
Direct Sampling for Thermal Desorption
Samples containing volatile or semi-volatile organics that cannot be
injected into a gas chromatograph without some form of sample
preparation, can often be analyzed directly using a thermal
desorption/gas chromatography system.
This section illustrates a range of sample types and the relevant
sampling techniques.
PTFE inserts (P/N L407-1596) can be used for lining stainless steel
tubes. You can conveniently discard PTFE inserts after analysis.
Place any required packing and glass wool plugs directly into the
insert and then slide the PTFE insert into the stainless steel tube.
NOTE: You must condition the stainless steel sample tube with the
PTFE insert installed in order to eliminate the solvents
from PTFE manufacturing process.
Compound Analytical Result Calculated Result
Benzene: (1.053 ± 0.014) 1.054 µg per tube
Toluene: (1.125 ± 0.015) µg per tube 1.123 µg per tube
m-Xylene: (1.043 ± 0.015) µg per tube 1.039 µg per tube