4
Important Safeguards
Vessel Safeguards
• Only use vessels and vessel components purchased directly from CEM or through its authorized dealer
network.
• All vessel components must be dry prior to use
• Always condition new liners and plugs
• Do not batch old liners with new liners unless new liners have been conditioned with at least 3 runs using
the customer’s sample
• Ensure vessels are assembled properly
• Align tab on load disc in center notch of liner
• Look for vent hole through the frame
• Align liner properly on insulator disc at bottom – liner flush with tab
• Use torque block
• Invert sleeves after every run to extend lifetime and promote better sealing & even heating
• Slide liner into the end of the sleeve with most resistance felt if unsure which side was previously
used
• CEM recommends using a high temperature pen to mark sleeves for a visual reference.
• Try to group liners with similar sample history and usage
• Segregate liners for HNO
3
and non-HNO
3
applications
• Do not use a new liner with a set of liners that has been run consistently until the new liner has
been conditioned with that sample type
• Pull ones that run 20 ºC hotter than average and run them together
• Bake out liners and plugs to remove residual HNO
3
& NOx gases
• Use Bake Out procedure for iPrep vessels (210 °C for 6 hrs – overnight)
• Bake out liners if TempGuard
TM
is triggered
Microwave Safeguards
• Always use the TempGuard feature in the method
• Set the TempGuard limit at 30 °C > control temperature if control temperature is < 250 °C.
• Set the TempGuard limit at 20 °C > control temperature if control temperature is > 250 °C
• Limit TempGuard to 270 °C for digestion of organics with HNO
3
(primarily)
• Limit TempGuard to 300 °C for H
3
PO
4
/H
2
SO
4
(primarily) applications
• Limit control temperature of organics with HNO
3
to 250 °C
• Choose Sample Type in method with software version 1.45 or higher as follows:
• Standard = Any acid mixture other than HCl or HF dominant
• HCl = aqua regia or acid mixtures that are ≥ 75% HCl
• Always use the Max Power Monitor and set the alarm time for 10 minutes
• Maximum programmable temperature is 300 °C
• Maximum temperature varies per acid. See "Operating Parameters" for temperatures
• Maximum programmable Hold Time is 45 minutes
• If a run is stopped or paused for more than 30 seconds during the digestion, do not restart the method
with hot vessels
• Allow vessels to cool < 80 °C
• Vent vessels and reseal
• Restart method from the beginning
• Allow vessels to cool below 80 ºC before opening the microwave door.