Cleaning The Glass Mixing Chamber - Thermo Scientific iCAP 7000 Series Manual

iCAP Customer Familiarisation Manual
10.5.5 Plugged capillary (fusible solids e.g. waxes)
Note: This procedure should be used when no passage remains through
the deposit.
Carefully heat the nebuliser in the region of the capillary obstruction. Simultaneously
(or intermittently) apply gentle gas pressure at the sample input tube.
Caution: Avoid overheating residues that may produce insoluble
pyrolysis products
Stop treatment when you have opened a passage through the blockage.
10.5.6 Firmly lodged particle in the capillary
Warning: This procedure places the nebuliser at substantial
Resort to this only when all other methods have failed.
Insert a fine fishing line, or (7-8 mil) piano wire into the capillary from the nozzle end
of the nebuliser. Gently push against the particle, in the direction of increasing
diameter, until it is dislodged. Avoid pushing hard enough to buckle the wire as this
can break the capillary. Remove the wire and back flush with compressed gas. Do
not attempt to insert the wire (or any other object) into the gas annulus.

10.6 Cleaning the glass mixing chamber

The glass mixing chambers need cleaning if an oily film is deposited on the chamber
walls as these deposits can cause the sample to bead and form large droplets on
the chamber walls. When these large droplets finally drip to the drain, a change in
back pressure causes a spike to the sample injection and elevates the RSDs.
The sample should drain smoothly from the sides of the chamber.
To clean the mixing chamber, wash it with soapy water. The mixing chamber does
not need drying before re-installation in the spectrometer. Keep in mind that this
causes a high blank for a while afterwards
To clean the torch of carbon deposits, place the torch in a muffle furnace and heat
to 750ºC. Open the door to admit air for a few seconds, then close the door and
allow the temperature to return to 750ºC. Repeat two or three times until the carbon
is burned off. Switch off the muffle furnace and allow it to cool down without
opening the door This will take several hours
The furnace will cool sufficiently slowly to prevent stress in the quartz. It is
recommended that at least 2 torches be rotated, so that you do not have to stop
work while waiting for the torch to be cleaned.
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