IntelliQuant V7.5 - Difficulties with Na & K



I am using an Agilent 5100 ICP-OES with ICP-Expert V7.5. I am having some issues getting IntelliQuant to give me back a good estimate for Na, K and Mg but mainly Na.


I've recently updated the calibration just using Agilent Solution #1 only as this contains all the elements I'm interested in at 0, 10 and 100 mg/l in Axial and Radial. I used the diluent I'd normally prepare the samples in and the same instrument conditions I'd normally use to analyze my samples. The problem is when I select Axial or Radial View on IntelliQuant for Sodium particularly it shows as either not being present at all or displays a concentration 100's of times higher than what's actually present. Or displays no concentration for Na but displays a concentration for K even though there is only Na present. 


I'm going to guess that the presence of EIEs like Na, K, Ca is causing ionisation interference in the plasma which is giving crazy concentration values. For the radial parameters I used a 2 mm height when calibrating the IntelliQuant so maybe I should use a higher radial height?  Or maybe I missed something in the calibration process?


Also, is it possible to include IntelliQuant in your fully quantitative method validation? If anyone has any experience of that. 

  • A viewing height of 2mm is viewing very low in the plasma, where the temperature is hottest. Easily ionized elements like Na and K like the cooler part of the plasma, at a higher viewing height.. However, this part of the plasma is subject to ionization interferences, so it is important to optimize the viewing height. I would start with a viewing height of 8mm, and optimize  +/-2 or 3 mm from there. 


    I don't know of any customers who have used IntelliQuant as part of their method validation. With IntelliQuant in 7.5, you have many nice features to custom calibrate, look at different wavelengths, etc. but you cannot use FACT models to remove spectral interference, so I prefer to use the fully quantitative analysis for method validation.

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