March 05, 2024, 08:54:26 AM
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Topic: Specific rotation  (Read 1135 times)

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Offline mquandt

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Specific rotation
« on: August 01, 2023, 11:02:57 AM »
Hi,

I am looking for advice on measuring specific rotation with a polarimeter.
I was measuring the specific rotation of a compound with a polarimeter and the values were going all over. I could not get a consistent number and by the end the standard deviation was very large. At one point the screen was flashing red.

I was wondering if anybody has measured specific rotation and observed a large fluctuation in readings?

Could this be caused by an impure sample? Or an optically impure sample?

Any advice or leads on where to read more about this event would be greatly appreciated.

Thank you!

Offline dejswa

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Re: Specific rotation
« Reply #1 on: October 27, 2023, 08:54:30 AM »
What sort of machine (polarimeter) do you have?

I have some questions re measuring specific polarization. Perhaps we can help each other with these questions. There is very little help on this subject that I've been exploring for some time.

I have a manual polarimeter, BTW.

I am looking for a database of *specific polarization constants* for compounds of known interest, btw.

Offline kriggy

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Re: Specific rotation
« Reply #2 on: November 01, 2023, 05:01:38 AM »
Yes I observed similar stuff.

The solution was to read the instument manual :D In this case it was required to let the instrument warm up for 60 minutes then when sample was inserted wait at least 10  minutes for the sample temperature to eq. then measure

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