Li 670.783 by 5900 ICP-OES

We recently got a 5900 ICP-OES I have noticed that Li 670.783 has better recovery for the middle standards in my curve when viewed in radial mode than it does when viewed in SVDV.  The middle standards (20, 10, 5 ppm) are recovering about 115% in SVDV and about 95% in radial mode.  I noticed when I set up two methods for only Li and Lu (my ISTD) with the exact same conditions except for the viewing mode.  I am hoping to achieve a Li range  from somewhere around 0.01 to 50 ppm, for which I would need to analyze the 670 line.  I would like to know why the 670 line seems to work better radially and if there is anything I can do to improve the recoveries in SVDV so that I don't have to increase the analysis time by using multiple viewing modes.  My matrix is 2% Nitric and 2% Hydrochloric.

I am not sure this is related, but I have not been able to get K to pass the wavelength calibration in radial mode.  It works in Axial mode though so that is the mode I used.

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  • I would try it without weighted fit and without forcing through the blank because you are calibrating up to 50ppm. I'm sorry but I cannot be more specific on how the DSC works for SVDV mode in this forum. Consult your local applications engineer support person or sales person.

  • I would also check what viewing height you are using in radial mode and change the viewing height in your SVDV condition to that same viewing height

  • Thanks.  It worked great without weighted fit.

  • Do you know why the wavelength calibration is failing for K in radial mode?  I am using the Agilent Wavelength Calibration Solution that came with the instrument.  I have also tried using a single analyte K solution with the same concentration.  Is this indicative of any problems with my instrument?

    Which viewing mode should I perform the wavelength calibration in?  I am using SVDV for analysis.

    Thanks.

  • Although you have an SVDV instrument, you can perform the wavelength calibration in either axial or radial mode. If it is passing in axial mode, I don't think there is anything wrong with your instrument. I would recommend the following: perform a dark current with the plasma off. Then turn on the plasma and let it warm up for 20 minutes. Then perform a wavelength calibration in axial mode, then in radial. If it is still failing for K in radial mode, you could try cleaning the radial pre-optic window and using the default sample intro system: Seaspray nebulizer and double-pass spray chamber. 

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