HT2800T_en_c.doc Page 254 of 275
Figure 212: Syringe with syringeID adapter containing the RFID tag
11.1 SPME mode
SPME (solid Phase extraction)
SPME is a solvent free technique that integrates sampling, extracting, concentrating and
injection of the sample in only one phase. The analytes are directly extracted and concentrated
in the extraction Fiber. The Fiber is fused silica with a small polymeric coating. The SPME Fiber
is directly immersed in the liquid sample or in the Headspace of the sample. The principal
advantage of this technique are the good analytical performance, simplicity and the low cost.
Desorpiton
After the sampling the Fiber is exposed and the analytes are desorbed thermally in the GC
injector.
Fiber Pre-Washing
Fiber washing after extraction (before desorption) by the immersion in a proper solution inside
the wash vial.
Post-Cleaning
Cleaning process after the desorption: the Fiber is exposed in the injector or inside the Fiber
Cleaning Device (available only in HT2850T).
Derivatization
During the derivatization the Fiber is exposed to substances that can modify the adsorbed
analytes to obtain better final analytical results.. The derivatization can cause a chemical
transformation of analytes in a form that is more suitable for the analysis. By derivatization it is
possible, for example, to increase volatility and/or decrease the polarity of some analytes and
thus increase the efficiency, selectivity and sensitivity of the analysis. This approach makes
possible the identification of substances difficult to be detected, highly reactive or thermally
unstable.
The derivatization can be carried out in two stages:
Post-extraction: After the extraction, the extracted compounds in this case are exposed to the
derivatizing agent in the vapour phase for a set time.
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