How to clean RF coils?

Dear all,

we have not measured many samples, only some organic samples. Could someone please explain, what cause the RF coils change the color like this? Does it affect the plasma ignition? How to clean it properly? 

Is it correct, I take the coils off firstly, then scrub with alcohol. Maybe need aluminum oxide powder to polish it?

Does the cone need to be cleaned as well?

Thank you very much!

Best regards,

Sophia

Parents
  • Hello ,

    This is very common in organic applications due to the use of the oxygen/argon mixture. The copper goes oxide due to the presence of O2.

    In a given time, you will get some ignition problems and plasma stability, because the magnetic field that sustain the plasma will not be as efficient as with a new coil.

    You can clean the coil but it is a very delicate job, because you can deform it and misalign the coil relatively to the torch position. You can remove it using a wrench (chiller off) and do it outside the torch box. When reinstalling it, you have to be very careful not to deform the coil, and also to let it aligned. Use a spent torch to do the job when aligning it - so you avoid breaking a new one.

    To check if it is not touching the quartz tube, you can rip off a piece of paper and pass it through the coil and the outer tube. If it stucks, then adjust the coil. Another way to check the alignment is to use the camera of your smartphone on top of the outer tube, and see if the outer tube is centered to the coil.

    The RF coil is considered a spare part, so it is a good idea to have some in your lab.

    Don't worry about the cone - it will not clog as as an ICP-MS cone. But it is important to check the axial lens once in a while or when you start to get poor results.

    Best regards,
    Rodolfo

Reply
  • Hello ,

    This is very common in organic applications due to the use of the oxygen/argon mixture. The copper goes oxide due to the presence of O2.

    In a given time, you will get some ignition problems and plasma stability, because the magnetic field that sustain the plasma will not be as efficient as with a new coil.

    You can clean the coil but it is a very delicate job, because you can deform it and misalign the coil relatively to the torch position. You can remove it using a wrench (chiller off) and do it outside the torch box. When reinstalling it, you have to be very careful not to deform the coil, and also to let it aligned. Use a spent torch to do the job when aligning it - so you avoid breaking a new one.

    To check if it is not touching the quartz tube, you can rip off a piece of paper and pass it through the coil and the outer tube. If it stucks, then adjust the coil. Another way to check the alignment is to use the camera of your smartphone on top of the outer tube, and see if the outer tube is centered to the coil.

    The RF coil is considered a spare part, so it is a good idea to have some in your lab.

    Don't worry about the cone - it will not clog as as an ICP-MS cone. But it is important to check the axial lens once in a while or when you start to get poor results.

    Best regards,
    Rodolfo

Children
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