[mike89]

hi all,
i need opinion on my result...what i suppose to do when my AAs result show "sample absorbance is greater than that of the highest standard"
I'm do adsorption in concentration at 5,10,15,20 and 25 ppm Ni & Pb  for 2 hours.
10, 15,20 and 25 ppm of Ni show a result as i mention above
but for Pb all sample were okay..
and my standard 0.1, 0.5, 1.0, 3.0 and 5.0 ppm for both metal...
what am i gonna do about this?
should i change my standard?
or my sample conc..if i do so..doesn't it make sense if it too low?
especially for ni...

Help me thx

[JGK]

Dilute the samples by an appropriate factor and repeat the analysis for Ni.

[mike89]

can u please explain a little bit... ???i mean an example..
am i need to reduce the ppm of nickel?
what about pb should i do the same? because i'm afraid it would be hard for me to do comparison later on...
i really appreciate if u could suggest something..thx

[JGK]

For correct quantitiative sample analysis the sample data produced should be within the range covered by your standards.

In your original post you stated the Pb samples were all OK, I assumed from this that your Pb samples gave results that were within the standard range.

However the Ni results were all higher than your standard range. So you can either prepare a higher range of Ni standards and run the new standards and the samples again or dilute your samples so that they fall within the range of your current Ni STDs and reanalyze them.

eg if your original analysis showed 25 ppm nickel, dilute (x10) and reanalyze, the result after dilution should now be ~2.5 ppm.