Characteristics deterioration after cone cleaning


The problems emerged after cone cleaning (Ni sampler with Cu base and Ni skimmer). We cleaned them with wet cotton swab and sonicated in pure water about 5 minutes in different beakers. Because the Citranox solution is not available for us right now, for the next step we cleaned cones with 2% HNO3 and sonicated again for 3 minutes, as Hardware Maintenance Manual recommended.

After this a high signal of Cu occurred in all measured solutions. With time the signal decreased. However, after more than three hours of measurements the signal didn`t drop to previously registered background levels and comprised 173 cps (He mode, general purpose plasma).

Th second problem was that we obtained high Oxide ratio, and it continued to increase (3%, 8% and 20%).

Please, give us some advice.

Thank you in advance!

  • Hi Volodymyr,

    hope your are well.

    I hope you just forgot to mention, that you used different beakers for the HNO3 step as well. Otherwise this will cause such prolems!

    I would check the obvious thing.

    1. Are the cones mechanically OK ? Sampler as a 1mm opening, Skimmer approx. 0.4mm

    Are is the shape round?

    2. is the graphite sealing behind the Sample Cone OK?

    3. Has the Skimmer turned to a green colour? If so, you should contact Agilent.

  • Thank you for your reply!

    Of course, we treated them separately in all cleaning steps.

    1. As we can see, the shape and size of orifices is OK.

    2. Graphite sealing is intact.

    3. Except the greenish ring around skimmer base which can be seen at a certain angle (3rd photo) the color of cone is kind of brown.

  • Hi,

    visibly the cones look ok. But as always, you can only tell if the cones are good, by comparing them with new ones. If you have to order a new Sampler, I always would choose the  Ni-Plated Sampler Cone. It has a much better chemical resistance, is easier to clean and only costs a bit more than the copper version. 

    I would recommend another cleaning. Sonicate in 1% Nitric acid for 10min. Then 2 times sonicate for 10min in ultra pure water.

    Strange is the high oxide ratio, which could be caused by a damaged cone.

    If you have a interference on 173m it could be GdO (157+16) which would reflect the high oxide ratios.

    Are your vacuum readings the same as before the cleaning? Maybe the skimmer is not tightened correctly (do not use any force, just hand tight with the skimmer tool)

    By the way, what is your Matrix? 


  • Hello, Chris!

    Thank you for advice.

    Did I understand right that you recommend sonication in 1% Nitric acid? Isn`t it too harsh for the cones?

    Our vacuum readings are the same, we check every time when carry out some maintenance.

    Also, the oxygen indicator on our gas filter has started changing color from green to brown. May that be the cause of high oxides?

    Our matrix is pharmaceuticals. Some of them were just diluted (for example infusion solutions), some were acid digested in microwave.

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