Blank sulphur standards

[Ben Buse]

Hi,

What are the best metals to use as blanks for sulphur,

It frequently seems to be present in metals at trace contents.

Also possible sources of surface contamination

[Probeman]

Hi,

What are the best metals to use as blanks for sulphur,

It frequently seems to be present in metals at trace contents.

Also possible sources of surface contamination

What is the target material(s) you have in mind for trace analysis of sulfur?   

Ideally you would want the blank material to be the same metal as the unknown but 99.999% pure. The problem is that when you see something like 99.999% pure in the Johnson-Matthey catalog there will be a little asterisk that says: "metals basis".  Which means they aren't counting S, P, Cl, etc., etc.

One time we started seeing trace (~100 to 200 PPM) Cl in some samples that shouldn't have been there. We eventually tracked it down to our old Edwards carbon coater which has recently under gone a maintenance and the engineer had replaced the foreline hose (between the backing pump and the diffussion pump) with non food grade PVC, which was outgassing Cl into the coating chamber!

If you can share what your target metals are, I might have some suggestions for you.

[sem-geologist]

Beware Co, Ga, Sb, Te, Cs, Ba as these have higher order lines overlapping. Zr has one of absorption edge at SKa position - it can produce false positive S in some cases. Some metals prefer to catch sulphure on its surface than oxygen. I.e. Au. I think Ti is quite safe to have no S in most cases.

[Ben Buse]

Thank you both, that's very helpful

[jon_wade]

NIST's electrolytic Fe is as good as it gets (you definitely have some Ben as I pinched a bit )