Cleaning the 5000 Series ICP-OES Torch, Organic Matrices

This Information Applies To: Agilent 5000 Series ICP-OES (5100/5110/5800/5900)

Issue

The ICP-OES torch plasma ionizes the introduced gas or aerosol stream. In normal operating conditions, incomplete ionization occurs and material is deposited on the torch surface. Build up of deposits can create blockages, damage the torch or interact with the sample stream creating poor precision, accuracy, and memory effects.

ICP-OES overview

The ICP-OES sample introduction components are detailed in Figure 1.

Figure 1: ICP-OES sample introduction components

1. Torch loader handle 2. Torch 3.Torch clamp 4. Nebulizer gas connections 5. Spray chamber drain tubing 6. Spray chamber 7. Nebulizer 8. Nebulizer inlet tubing

Caution: The torch is fragile. Do not use cleaning wire or abrasives like brushes or a scourer to clean the torch. Avoid acid contact with the seal where the quartz meets the plastic base. Damage to the seals and torch body may occur.

Steps to follow

Removing the torch:

1. Turn off the plasma and allow instrument to cool.

   Caution: The torch and torch compartment become hot during instrument operation and remain so for some time after the plasma has been switched off. Allow the plasma compartment to cool before accessing the plasma compartment. Allow the torch to cool before touching the outer tube or attempting to dismantle the torch.

2. Disconnect the spray chamber (Figure 1).

3. Remove the torch from the instrument.

4. Disassemble fully demountable torches (Figure 2) and semi-demountable torches (Figure 3).

   

   Figure 2: Fully demountable torch

   

   Figure 3: Semi-demountable torch

5. Inspect the torch components for damage including holes or cracks in the plastic housing, seal or glass tubing, and the outer quartz tube becoming rough to touch. Discoloration of the plastic housing occurs with long-term exposure to acid and does not impact on performance. Replace as necessary.

Cleaning the torch:

Caution: Using the muffle furnace or portable handheld propane torch will heat the torch to high temperatures. Always wear appropriate Personal Protective Equipment.

1. Fully and semi-demountable torches: Place only the quartz ICP torch tubes in a muffle furnace at approximately 500^oC for one hour. Do not put plastic components in the muffle furnace. 
2. One piece torch and quartz components attached to plastic torch body
   1. Do not remove the torch adhesive cap on the one-piece torch that covers the seal between the quartz and the plastic.
   2. Wrap a wet cloth around the plastic components. 
   3. Use a hand-held propane torch to heat the quartz and remove deposits.
3. The outer tube and injector should be stood in a vertical position until they have cooled.

Rinsing the torch:

1. Hold the torch with the ball joint connector at the top and thoroughly rinse the outside, inside through ball joint connector, upper and lower gas ports.

2. Rinse the removable top seal on semi-demountable torches.

   

Drying the torch

1. Flush all torch components with laboratory grade compressed air or nitrogen. Flush the torch through the gas supply ports and the ball joint connector, then invert and flush through the open end of the quartz outer tube set. Do not insert the air/nitrogen nozzle inside the tube set. When flushing is not available, dry glass components in a drying oven and plastic components with a lint free cloth.

2. Ensure that all moisture is removed then re-assemble and refit the torch.

3. When not is use, store the torch in the original packaging or the ICP-OES Easy-fit torch storage rack (part number G8010-67000).

Additional checks

1. When refitting the torch, inspect for damage such as loose fitting of the quartz tubes in the plastic base, holes, or significant cracks. If any damage is found, replace the torch immediately.

2. Check for carry-over after refitting the torch to determine if the cleaning procedure has been sufficient. If carry-over is found, repeat the cleaning process.

3. Replace the torch when the outer surface of the quartz outer tube is rough to the touch, which indicates signs of wear, devitrification, or if there are any cracks visible.

Recommended maintenance: Agilent recommends daily inspection and weekly cleaning of the torch. Analysis of samples with complex matrices may require more frequent cleaning.

Learn how to effectively maintain you ICP-OES: ICPOES-5110-1270e - Agilent 5110 ICP-OES Maintenance and Troubleshooting e-learning course available from Agilent education