ICP-OES 725 ES

Hey there, i´m working with the ICP-OES 725-ES and i have to detect Ca,Mg,K in a 5% Nacl matrix. The icp won´t detect kalium correctly so i have to dilute the samples 1:2 (50%). But if i do it i don`t reache the limit of determination. I show the method in the picture below maybe anyone can tell me

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  • 5% NaCl solvent is hard matrix for ICP-OES. It could be made EIE and contamination.

    First step, We need to check dark current, wavelength calibration, torch alignment. it must be normal result.

    I recommend ASA( Argon saturation Accessory) and adjust torch height for good optimization position in condition tab.

    If from 0.1 to 1.0 ppm range is bad, it was no reason for detection limit about 0.25 ppm.

  • Good morning,

    if i measure in the 1%HNO³  the calibration works fine. I know that the NaCl-matrix is bad for the icp and i tell it so often to the chemist. In the upper Picture you can see a regular calibration that we use for water solutions.

    The torch alignment is good an the wave lenght calibration is from 167.019nm to 766.491nm. The dark current only show that is all fine but no value.

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