Cleaning a Blocked Nebulizer in the Agilent ICP-OES System

Answer

This Information Applies To: Agilent ICP-OES Systems

Issue:

The glass concentric Seaspray nebulizer comes by default with the 5000 Series ICP-OES instruments. If running samples which contain high % total dissolved solids (TDS), it is important to first centrifuge or filter them through a 0.45 micron filter prior to running on the ICP-OES. If samples are not fully digested, concentric nebulizers can easily become blocked (partially or fully) by sample particles. Once you have performed the Nebulizer test, as detailed in ICP-OES: Checking for a Blocked Nebulizer, and have learned that your nebulizer may be blocked, this procedure details how to clean the nebulizer.

Steps to follow:

Before removing the nebulizer from the spray chamber, rinse with deionized water. Always wear appropriate safety equipment and follow all regulations for chemical use and disposal.

1. Turn off the plasma and peristaltic pump.

2. Remove the sample inlet line tubing (see Figure 1)

3.  Remove the gas inlet fitting from the nebulizer side arm (see Figure 1). Not all nebulizers are the same. Fittings will vary depending on the nebulizer.

   
   
   Figure 1. Nebulizer
   1. Sample inlet tubing, 2. Gas inlet fitting
   
   

   Caution: The concentric glass nebulizer is fragile and easily broken. Handle it with extreme care and ensure that the tip is protected from damage. Wear appropriate gloves and clothing.

    

4.  Unscrew the white knurled nut, or gently twist the nebulizer depending on the nebulizer and spray chamber used to remove it from the spray chamber, being careful not to touch the tip of the nebulizer. See Figure 2

   
   Figure 2. Spray Chamber 
   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 sample tubing
   

5. Using a syringe or nebulizer cleaning tool, push water, methanol or rinse solution through the nebulizer in the reverse direction to normal flow. Either push liquid through using the nebulizer cleaning tool or pull it through with a syringe by placing the tip of the nebulizer in the solution and applying a vacuum to the sample inlet end. Rinse with deionized water. 

6. If the blockage remains, push 25% detergent solution through the nebulizer with a nebulizer cleaning tool and then soak the nebulizer overnight. Rinse with deionized water.

   Warning: Nitric acid is very corrosive and can cause severe burns when it comes into contact with thebody. It is essential that appropriate protective clothing be worn at all times when handling acids. If acid contacts the body, wash off with copious amounts of water and seek medical attention immediately.

7. If the blockage is still present, soak the nebulizer overnight in concentrated nitric acid. Ensure that no air is trapped in the central capillary and that the nebulizer is completely submerged in the acid.
   Before placing the nebulizer in concentrated nitric acid, use a Pasteur pipette to gently fill the central capillary with acid through the sample inlet of the nebulizer.

8. Rinse well with water and allow to dry before use.

9. Reconnect the gas tubing and the sample tubing to the nebulizer.

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