Chemical Forums
Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: payata on April 16, 2019, 08:40:19 AM
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Hey Guys!
I have a problem with task below, hope you can navigate/ help me with it ???
In a 100 mL measuring flask 30 µL of butan-1-ol is placed by pipetting, The flask is filled to the mark with technical grade acetone,
The solution is analysed once and the following areas are found:
Area of
propan-2-ol 854
Area of
butan-1-ol 405
Calculate the concentration (v/v%) of propan-2-ol in the sample, Show the calculations:
What I did until now, I deviated Area of sample / Area of Internal standard (which is butan-1-ol, 0,03% v/v), I know that concentration I should find by drawing standard curve, but how if concentration is not given?
So formula should looks like that: c= (Area of sample/Area of IS - intercept)/slope . but, how to calculate concetration to draw std curve? ???
Thank you in advance!
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The only thing you can do it to assume signal to be directly proportional to the surface area.
This is equivalent to assuming at C=0 Area=0 - this way you have two points to build your curve on.
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I'm not quite sure if assumec=0, please look below
the answer is given c= (854/405+0,0116)/35,529 = 0,0597%
this is what the Lecturer gave to us ??? and I really do not how he got intercept, and slope for that, plus concentration
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There is no way to derive the formula used from the numbers given, so either you are missing something (earlier part of the lecture, page in a book, whatever), or you were given incomplete data.
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All class got same as I, so I think I will write to Lecturer and confirm :D
Thank you for reply!