700 Series won't optimize at RF power lower than 1.2 kW

Our 700 series ICP-OES won't keep the plasma running below a RF power of 1.2 kW. We would like to be able to optimize using the AutoMax feature over the full range of RF power to try and improve accuracy for some analytes. When selecting the range over which to optimize using AutoMax, any lower limit below 1.15 kW causes the plasma to shut off immediately as soon as the power goes below 1.2 kW during the instrument's optimization. Any suggestions are welcome.

  • Hi,

    important is that the torch is clean/new and that the sample intro parts are tighten/good connected  

    Maybe the optical fiber looker inside the plasma chamber is dirty. It’s difficult to see but in the upper right corner of the chamber is an optical fiber located. It could be cleaned carefully with an cotton tip dipped in some water. 

    if after these checks and steps still the plasma extinguish at low power the please contact the local Agilent support for help


  • Hello,

    The torch we are currently using is brand new. This is a problem we have had for several years, where we can't optimize the instrument using the AutoMax feature in ICP Expert II at lower RF power levels. The torch is changed regularly. 

    I believe I found the optical fiber in the plasma chamber. How would this affect the plasma's ability to stay on at lower RF power? Is there any literature about the role of the optical fiber in the ICP-OES system?

    Thank you.

  • The only role of the optical fiber is to look at the plasma if it's lit and still on. sometimes the optical fiber is a bit dirty and not enough lite is measured. Then the instrument is thinking that the plasma is off. If the plasma is running at lower power then the plasma brightness is lower. So if the plasma shuts off at low power could it be caused by low light measurement due to dirty optical fiber.  

Was this helpful?