Spme Sampling Mode - Agilent Technologies Varian CP-8400 Operator's Manual

SPME Sampling Mode

SPME mode is designed for using the special Solid Phase Micro-
Extraction fibers and fiber holder.
Note that you can not select the SPME Sampling mode from the CP-
3800 keypad. In order to configure the system to use SPME you must
set a switch on the syringe sled to the correct position and install the
special SPME fiber holder block. This means of setting up the system to
use SPME was adopted to avoid unintentional damage to either SPME
hardware or syringes.
SPME mode actions are summarized below:
•
Warning: do not use the clean mode actions unless you have
experience with SPME or have very dirty samples with insoluble
materials that need to be removed. Indiscriminate use of
cleaning can introduce contaminants into your analytical run
and degrade your results.The number of pre-injection solvent clean
flushes specified in the method will be performed by dipping the fiber
into the solvent and waiting for each clean stroke the time specified
in the Adsorb Time for Cleaning. Once the cleaning strokes are
completed the tower will rotate over the waste station, the fiber
holder will descend and the fiber exposed for drying/desorbing
(desorbing requires a heated gas stream to be gently blown over the
fiber).
•
If Prep-Ahead is used, the Auto Sampler will begin the sampling
process at the set delay time after the Prep-Ahead timer has expired.
This allows you to sample for extended lengths of time without
adversely affecting the throughput of your system. The Prep-Ahead
timer starts after the Auto Sampler has finished all injections actions
for the current injection.
•
If Derivatization is specified, the fiber will next be introduced into the
Derivatizing Agent vial specified in the Derivatization page. The fiber
will penetrate into the Derivatizing agent vial the depth set for the
Solvent penetration depth on the main SPME parameters page. The
fiber will wait for the specified Adsorb time and then be withdrawn.
•
The SPME fiber holder will be positioned over the sample vial and
the number of agitation strokes requested will be performed.
Agitation is accomplished by moving the fiber into and out of the fiber
holder at between 1 and 2 times per second. It is common for this
action to pause a little longer sometimes relative to others. This non-
regular motion is expected and normal. Each time the fiber
descends into the sample, it will stay in the sample for the specified
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