Chemical Forums
Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: Orcio_87 on March 19, 2022, 10:25:46 AM
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I have two mixtures, both of them contains compound "x" and compound "y" but - I do not know how much of "x" and how much of "y" these mixtures cointain.
Also - I measured properties of these mixtures.
Problem is....
Properties of first compund "x" is unknown (and I do not have it), but - I have pure (100 %) compound "y"...
Can I use it somehow to determine composition of both mixtures ?
Like...
Mixture 1. has measured value 2000
Mixture 2. has measured value 1000
Pure compound "y" has value 100, so mixture contains a % of x and b % of y, and second mixture c % of "x" and d % of "y" ?
I am not sure.. is it problem with my mathematics or is it just a problem with too many unknown variables ?
(I dont want to waste the time for something that cannot be solved)
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Assuming linearity of the response you can try standard addition method.
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This seems similar in some ways to a question I posed previously in which I asked about methods for estimation of purity for a compound where a reference standard is not available https://www.chemicalforums.com/index.php?topic=110887.0 (https://www.chemicalforums.com/index.php?topic=110887.0)
In my case, a chance conversation with a colleague led me to considering qNMR as a possible option for dealing with this kind of situation. From what I understand, with qNMR there is no requirement for a reference standard (which suits your purposes as well as mine) and the technique can be carried out using a suitable internal standard with pretty high levels of accuracy and precision, apparently without the response factor and matrix effect issues that are present with many other techniques.
NMR is a bit of a dark art as far as I'm concerned which is why it didn't spring to mind initially, but will try to let you know if it works for me when/if I ever get my samples to actually give it a try, but might be worth consideration if you are set up for NMR...