Samples causing instrument contamination
Samples that contain metals that sublimate easily (high vapor pressure metals)
If a large quantity of metal is sublimated, it will be deposited on the QMS analysis tube, vacuum gauges and view port, creating a risk of impaired performance or failure.
The metal is also deposited on the inner walls and parts inside the chamber.
This contaminates the surfaces in the chamber and increases outgassing.
If this occurs, cleaning of the chamber interior and/or replacement of parts will be required.
Particular attention is required for Zn and Mg, which have a high vapor pressure and sublime at low temperatures.
Examples of metals with high vapor pressures: Zn, Mg, Pb, In, Mn, Ga, Ag, Sn, Al, Cu, etc.
Samples containing halogens
When components containing halogens (particularly fluorine) are desorbed, the halogens tend to remain in the main chamber and detector.
Samples containing organic compounds
Heating a large amount of an organic compound above the decomposition temperature induces thermal decomposition.
The decomposition products become scattered and contaminate the inside of the main chamber and detector.
Baking and cleaning of the main chamber is required, as well as parts replacement.
Samples that emit large quantities of gas
Even for substances that do not contaminate the instrument, if the sample being measured releases a large amount of gas, exceeding the rated pressure of the turbo molecular pump or QMS, this can cause malfunction of the turbo molecular pump or QMS.
A pre-measurement is recommended for samples that may cause contamination.
・Slower temperature increase rate. (About 10 ℃ per minute)
・Use Bar mode or Scan mode.
・Reduce the amount of sample as much as possible.
・ If components like those described above are detected, do not raise the temperature any further.