[Sev]

Does anyone know why Silver would be high following a blank in ICPMS (i.e. samples run immediately after the blank will have a slightly higher silver content).  There is no Ag+ in the blank, so it isn't a carryover issue.  Any ideas?
Thanks

[curiouscat]

Interesting problem.

How sure are we this is not a statistical artifact? How high is slightly high? If you do Blank-Sample-Sample-Sample-Blank-Sample-Sample-Sample is the trend reproducible?

What's the composition of your blank? Is this only for Ag? Other elements are not affected?

[Sev]

Hi, thanks for your reply.
The blank is a mix of H2O and a "diluent".  The diluent is an aqueous solution of EDTA, Triton X-100, NH4OH and a few internal standards (Ge, Y, Rh to name three). 
The diluent is also added to other (blood) samples, so that can't be the problem.
I'm pretty certain it isn't a statistical artifact.  I haven't observed the high Ag myself, but it's a well-known problem in the lab (since before I arrived).  No one can explain it however.  We think the aqueous "matrix" of the blank (as opposed to blood matrix) somehow mobilises Ag in the glassware (spray chamber), nebuliser, or pump tubing.  Not sure how it does this, or if said parts even contain Ag.  We normally avoid the issue by running blood Ag samples in the middle of a run (away from the blanks).
Sorry for the esoteric question - I'm just curious.  The problem only happens with Silver (AFAIK).

I'd love to run a few experiments (blank-sample-sample-blank), but don't have the time at the moment.  Maybe one day /:)

[curiouscat]

Sorry for the esoteric question - I'm just curious.  The problem only happens with Silver (AFAIK).

Not at all. I find it an interesting question. Especially since you are careful to provide relevant details.

[curiouscat]

Just on a whim can you try running H2O alone, sans diluent and then see if the next sample still gets high Ag?

Leaching is a possibility, but then I'd have expected Ag to show up in the blank itself too. Does it?

[MOTOBALL]

Having a nasty suspicious mind, I would suspect the presence of that well-known metal-chelator, EDTA.  However, you have to identify the source of the silver. Assume that you see Ag+ as the 1:1 doublet at m/z 108, 110 ?