DSC Q Series Getting Started Guide
58
•
Gently dissolve the contaminants with the swab, starting at the outside of the silver housing within the
sample chamber and working inwards toward the Tzero thermocouple. Repeat the process until the
contaminants have been removed. Do not rub hard with the swab, especially at the Tzero thermocouple.
•
Dry the interior of the cell with a clean dry swab.
•
Heat the cell to 200°C in Nitrogen at approximately 50 ml/min, and hold for 5 minutes to remove all traces
of solvent.
•
Verify by running an empty baseline run. Always store all available Diagnostic Signals when running
verification baseline runs. If the anomalies are gone, the baseline shape or slope is not acceptable, than Tzero
calibration may be necessary. If the anomalies are still there, but are less evident, repeat the above steps and
re-verify the baseline.
•
If you are unable to remove the anomalies using the above procedure, then you will need to perform
additional cell cleaning by heating the cell to a high temperature in an oxidizing atmosphere. This procedure
should only be done as a last resort.
•
Begin by connecting the air purge (See also: Connecting Purge Gas Lines), and then follow the steps below
depending on which cooler is installed.
NOTE: Cleaning of the cell is performed with the lids off to prevent the lid gas exit tube from
becoming plugged by condensing off-gases. If your instrument is equipped with an autolid
mechanism you will need to open the cell manually at the start of the method. You can open
the cell by selecting
LID
on the Control Menu touch screen or by selecting
Lids/Open
from the
Control menu.
Burning Off Contamination in a DSC Cell with a FACS Installed
•
Begin cleaning by heating the cell with an air purge to 50°C above the highest operating temperature or
600°C, whichever is lower, without pans. Use a heating rate of 20°C per minute. The Ramp test can be used
for this method. Volatile contaminants can be removed at lower temperatures; decomposed contaminants
must be oxidized above 550°C.
•
After cool-down, lightly brush out the cell with a small fiberglass brush (included in the DSC accessory kit).
Then remove the residue from the cell using clean compressed air.
•
Run a baseline (empty cell). If there is an improvement relative to the baseline before “burn off” but the
baseline is still unacceptable, repeat the procedure above.
