Doubly charge in High Zn matrix

In our current application in the ICP-MS 7900, we are analyzing zinc electrolyte solutions which contain various levels of Ge.

We run this application 24/4 with samples coming to us every 4 hours, about 100 samples every 24 hours.

We are only interested in the following elements  As, Cd,Co,Cu,Fe,Ga,Ge,Ni,Pb,Sb,Se,Sn,Te, and Tl.

We see a constant increase in our double charge as expected because our samples are high in Zn and various levels of Ge.

I know that Agilent recommends <2%  for doubly charge; we have seen this going up over time without affecting our QC (over 100%).


Is there a way that we can look at doubly charge from other mases that doesn’t require isotope 70? How high is too bad?

I think our system will have a higher than normal residual mass 70 as our matrix is very high Zn.

What study can you recommend for us to see how much doubly charge can we tolerate?

At which point our system have seen so much Zn that we need to look at replacing the octople?

For 24/7 applications, how often do you recommend to be tunning? We have a day/night shift on 4x4 rotation, and the current practice is to tune at the beginning of the shift.

Thanks for any help that can be provided

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