[stdacet]

For heavy metals analysis in water samples, the sample is preserved with nitric acid to pH < 2. At the site, it might be impractical to first measure the sample volume and then add measured amount of nitric acid.

If in almost 500 ml of water sample, 1 ml of conc. nitric acid is used, will it be ok to consider the sample undiluted. Means, Is it accurate to not account for added nitric acid in final calculations.

[Hunter2]

I think its ok, because you have the systematic error in all samples. Also your blank should contain nitric then.

[stdacet]

Yes, blank will also contain nitric acid, but dilution will not be an issue in the case of blank.

Actually its difficult for me to add nitric acid preservative in measured quantity of collected water sample. I just want to be sure that it will not affect accuracy.

[Borek]

In the worst case your result will be off by 1/500 or 0.2%. How accurate is the analysis in general?

[stdacet]

98-99 %