How to Remove and Inspect the ICP-MS Torch, Bonnet, and Platinum Shield Plate

Answer

This Information Applies To: Agilent ICP-MS systems (7700/7800/7850/7900/8800/8900)

Issue

The torch, bonnet, and shield plate must be removed and inspected during routine maintenance, and when troubleshooting plasma ignition problems. Faults with the torch, bonnet, or shield plate can cause plasma ignition problems. If the plasma will not light, remove these components, inspect, and replace any damaged parts before trying the parafilm test. 

Items Required

• Standard Torch, quartz, 2.5 mm id - not suitable for samples containing hydrofluoric acid. (p/n G3280-80053)
  see the Agilent Spectroscopy Supplies Catalog if you use a nonstandard torch
• Bonnet (p/n G1833-65421)
• Platinum Shield Plate (p/n G1833-65419)

Steps to Follow

Warning: The torch remains hot after the plasma is turned off. Do not touch the torch box for 10 minutes after turning off the plasma to let them cool.

1. With the ICP-MS in Standby mode, open the ICP-MS small cover (Figure 1).
   

   
   
   Figure 1. ICP-MS small cover open
   
   

2. Release the torch box clip, and remove the torch box cover (Figure 2).
   

   
   
   Figure 2. Torch box cover removal
   
   

3. Remove the clamp that connects the torch to the transfer tube (Figure 3).
   

   
   
   Figure 3. Torch and transfer tube clamp removal
   
   

4. Loosen the thumbscrew located on the bottom of the spray chamber block, and slide the spray chamber block to the left to separate the transfer tube from the torch (Figure 4). 
   

   
   
   Figure 4. Spray chamber block thumb screw loosened and spray chamber slid to the left
   
   

5. Loosen the plasma and auxiliary gas connections and disconnect from the torch (Figure 5).
   

   
   
   Figure 5. Removal of plasma and auxiliary gas lines from the torch
   
   

6. Unlock the torch stand clip and remove the torch from the torch stand, taking care that the bonnet is removed along with the torch (Figure 6). 
   

   
   
   Figure 6. Removal of torch, bonnet, and platinum shield plate
   
   

7. Take apart and inspect the torch, shield plate, and bonnet (Figure 7). 
   

   
   
   Figure 7. Disassembly and inspection of torch components
   
   

8. Check the torch:
   
   • Replace if cracked, chipped, or deformed by high temperatures.
   • Perform maintenance if deposits have formed in the central torch tube.
9. Check the bonnet:
   • Replace if fractured, cracked, or chipped.
10. Check the shield plate:
    • Replace if extensive corrosion is visible.
    • Replace if deformed or scorched by high temperatures.
    • Replace if torn.
    • See Figure 8 for pictures of damaged platinum shield plates.

Figure 8. Damaged platinum shield plates
1. Shield plate torn in half, 2. Scorch marks

Tips: For additional torch maintenance and plasma ignition troubleshooting, see the folloing articles: How to Clean the ICP-MS Torch ICP-MS Parafilm Test for Plasma Ignition Problems

Learn how to effectively maintain your Agilent ICP-MS System:  Agilent 7800/7850/7900 ICP-MS with MassHunter Agilent 8900 Triple Quadrupole ICP-MS with MassHunter e-learning courses available from Agilent education