Metals digestion acid concentration

[DSRM]

Somebody please enlighten me here:

I was reading the EPA Methods for metals digestion. (I run an AA
furnace.) Now, the method says to take your sample (say, 50 ml) and add
3 ml of conc HNO3... and then another 3 ml of conc HNO3... and then a
little more... "so that the final dilution contains 0.5% (v/v) HNO3."

That's over 6 ml of acid. What would the final volume need to be to
have 0.5% (v/v) HNO3? Wouldn't that be something like 1L? Am I missing
something?

Thanks.

[Farooq W]

msalguod@yahoo.com wrote:

[DSRM]

Oh, okay. I thought the 3+3 ml would simply concentrate further instead
of evaporating, since it doesn't go dry.

Thank you for the explanation.

[Farooq W]

msalguod@yahoo.com wrote:

[waterpollutionlaboratory@]

I generally use a 200 ml sample an 10 mls of acid an that works fine.

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