Hardware manual

4-72 Agilent 7500 Series ICP-MS Hardware Manual
4Maintenance
Check the Orifice
Retaining the correct shape and size of each orifice is critical for accurate
analysis results. Ensure that the orifice diameter and the orifice shape of both
the sampling cone and the skimmer cone have not changed. Use a
10x- magnifying lens to check the cone orifice. If the sampling cone's orifice is
larger than 1.0 millimeters, replace the cone. If the skimmer orifice is larger
than 0.4 millimeters, replace the cone.
It is necessary that the orifice shape of the sampling cone and the skimmer
cone is perfectly round. If it is deformed, replace the cone.
Refitting the Cones
This procedure assumes the torch box assembly is in its maintenance position
and the instrument is in Standby mode. Refer to the previous section,
“Removing the Cones” for more information.
NOTE
Discoloration or build up of impurities on the periphery of the sampling cone has no
influence on the analysis.
CAUTION
• The tip part has great influence on analytical results. Handle with care and do not
deform the tip.
• The tips of the sampling cone and the skimmer cone are easily deformed. Be careful
when handling them.
NOTE
The platinum skimmer cone should only be used with the brass skimmer base. This allows
the cone to operate at a lower temperature than with the standard stainless steel skimmer
base, extending the life of the cone. When fitting the brass skimmer base, transfer the
extraction lenses from the stainless steel base. For removing and refitting the skimmer
base and the extraction lens, refer to “Removing the Extraction Lenses” and “Refitting the
Extraction Lenses” in the section entitled 'Maintaining the Lenses'.
The nickel skimmer cone works better at higher temperatures and should always be used
with the stainless steel base.