[stdacet]

The multielement standard for  heavy metals analysis (e.g. by ICP-oes) are available in ppm range that are diluted to make required concentrations.
Are the standards available commercially in ppb range ?

[Corribus]

For most major suppliers of ICP standards (e.g., SCP Science), you can request what you want and they'll make it for you (assuming there are no technical issues with your request) for an added fee. I don't know if there's a minimum concentration they will prepare; you'll just have to call and ask. But, why would you want to purchase a low concentration standard? Standard procedure is to buy concentrated solutions and dilute them as appropriate.

[stdacet]

But, why would you want to purchase a low concentration standard? Standard procedure is to buy concentrated solutions and dilute them as appropriate.

To reduce the uncertainty in the final solution. As first preparing the stock solution and then diluting it will add uncertainty at each step.

[Corribus]

True, but to do a standard curve you've got to do multiple concentrations, so unless you're buying each concentration separately (expensive) you're going to have to dilutions either way. Plus, as I recall more concentrated solutions retain their quality better over time.

Anyway, with good technique the error due to dilution is negligible - at least, it's far overshadowed by other sources of systematic error.

[Arkcon]

Like Corribus: said, I'm sure they'll make the ppb standards available, for a premium price, for say, validating a system.  And then you'll have some excess if you want to check someone's work.  But as a general rule, you'll want to rely on your own dilutions.

[stdacet]

Thanks for the replies,  I think its suitable to first perform by making dilutions and next try to reduce uncertainty.

[GCMASTER]

Multi Element standards are not available in concentration under 100 ppm, because of adsorption on vessel will reach unacceptable influence on accuracy of the standard.
Standards with concentrations under 100 ppm must be Daily prepared in Lab with Great care to prevent any contamination.

Good lack