ICP-OES:  Checking for a Blocked Nebulizer

Document created by tharville Employee on Oct 21, 2020Last modified by tharville Employee on Nov 3, 2020
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Agilent Support Insights


This Information Applies To: All Agilent ICP-OES instruments



Blocked nebulizers are the source of many instrument performance issues including loss of sensitivity and poor precision, especially when running organics, high solids, or high salt concentration solutions.  The glass concentric Seaspray nebulizer comes by default with the 5000 Series ICP-OES instruments. If running samples that contain high % total dissolved solids (TDS), it is important to first centrifuge or filter them through a 0.45 micron filter prior to running them on the ICP-OES. If samples are not fully digested, concentric nebulizers can easily become blocked (partially or fully) by sample particles. The Nebulizer Test helps you to verify nebulizer performance. Run this test if you notice no mist in the spray chamber or have low sensitivity during analysis, or high % RSD's on your replicates. Visually examining the nebulizer may reveal a blockage, but this is not the most effective way to determine whether the nebulizer is partially or fully blocked. Once you have performed the Nebulizer test, as detailed below, and have learned that your nebulizer may be blocked, follow the procedure on How to Clean a Blocked Nebulizer.


Before you start:

  1. Turn on the external exhaust and then the ICP-OES.
  2. Open ICP Expert software.
  3. Install the nebulizer, spray chamber, and torch and ensure the gas supply is connected and turned on.

For a good reference point, perform this test when the nebulizer is new and compare the results when testing for blockages.


Steps to follow:

   1. Click Instrument on the toolbar.

   2. Click Dashboard.

   3. Select the appropriate nebulizer from the 'Nebulizer Select' drop-down menu. Select 'Other' if your nebulizer is not available in the list.

   4. Click Start to run the test.

   5. Once the test is finished, click the Status tab and then Tests to view the results.


What to do if the Back Pressure Test Fails

High Back Pressure

This is often caused by a blocked nebulizer or torch injector tube.

  • Replace the nebulizer with a brand new one (preferably) or clean one
  • Clean the nebulizer
  • Check and clean if necessary the torch injector tube


Low Back Pressure

This is often caused by the nebulizer leaking, the internal capillary of the nebulizer is cracked or broken, or the nebulizer is not connected properly.

  • Check the connections and reinstall the nebulizer


Learn more on how to effectively troubleshoot your ICP-OES:

ICPOES-5110-1270e - Agilent 5110 ICP-OES Maintenance and Troubleshooting e-Learning course on Agilent University 



Keywords: ICP-OES nebulizer, clogged nebulizer, nebulizer blockage, 700 Series ICP-OES, 5000 Series ICP-OES, Seaspray