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QUI-1057
Page 44
Markes International Ltd
T:
+44 (0)1443 230935
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+44 (0)1443 231531
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www.markes.com
levered tube cover to seal it into position then press the stop icon (
) to return the carrier gas flow path
to normal standby status.
If the sample is being re-collected during an analysis, re-activate the ‘exchange split tube’ icon as soon as
the desorber returns to standby mode after trap desorption. Remove the re-collected sample using the
above procedure and cap it immediately. Insert another clean (SecureTD-Q) sorbent tube or the charcoal
split tube as required, and press the stop icon (
) to return to normal standby mode.
NOTE
: SecureTD-Q will not work for methods that are operated entirely splitless. Either an inlet or outlet
split or both are required.
As well as repeat analysis, SecureTD simplifies method development, provides a convenient method
validation tool and allows critical samples to be archived when required.
For further information on split re-collection for repeat analysis see TDTS 24.
3.6.6
Cold Trap conditioning
Before using for sample analysis, the cold trap must be cleaned/conditioned. If the cold trap contains no
molecular sieve or carbonised molecular sieve type sorbents, trap conditioning is most easily achieved
using the Trap Heat function on UNITY 2 (see Section 2.3.2.). As with tube conditioning it is essential to
check the maximum isothermal temperature of the sorbent in the trap and never to set the trap
temperature more than 10°C below this. In addition, use a split flow of at least 50 ml/min to ensure
efficient conditioning of the trap and to reduce the mass of contamination allowed to reach the analytical
column.
For cold traps containing molecular sieve sorbents refer to the relevant cold trap certificate and purge the
trap with sufficient quantity of helium prior to operating the Trap Heat Method.