[Demelerlab] Fatemeh's report draft

[Borries Demeler]

Fatemeh,
AUC doesn't measure molar mass directly, it measures sedimentation (s) and
diffusion coefficients (D), as well as partial concentration.

If the partial specific volume (PSV) is known, we can convert s and D into
molar mass, but we don't know what it is. It could potentially be measured
by doing a density matching experiment in different concentrations of D2O.
Alternatively, we can skip this and you can make an educated guess and see
what kind of distribution would be obtained with certain PSV guesses.

The conversion is: MW = sRT/[D(1-PSV*rho)] where R is the universal gas
constant and T the temperature in kelvin. Rho is the density of the solvent
(water at 20C).

Given that only the hyperbranched sample actually sedimented, we can
proceed with that one. Also, you can use the UltraScan software to access
your data in our LIMS database and simulate various scenarios of PSV and
check out what molar mass distributions could be obtained with your PSV
guess combined with your data. We can help you get set up with UltraScan.
Also, Minh and Bao already know how to set it up.

Let us know how you want to proceed.

Regards, -Borries



On Thu, Oct 5, 2023 at 4:13 PM Fatemeh Mehrad <mehradnia20 at gmail.com> wrote:

>
> Hi Dr. Borries,
>
> Thank you so much for sending the results. Sorry for my late reply, I was
> on annual leave. Could you please let me know how I can calculate the Mw
> from these results? it is mentioned  that apparently we need information to
> be able to calculate the average MW?
>
> Thanks,
> Fatemeh
>
> On Thu, Sep 28, 2023 at 12:43 PM Borries Demeler <demeler at gmail.com>
> wrote:
>
>> Hi Fatemeh and Walid,
>> attached is the report I briefly discussed with Walid today. Sophia ran
>> all of the samples and was able to get a very good analysis done on the HP4
>> sample. it looks like only the HP4 sample actually sedimented. It looks
>> quite heterogeneous, a small amount of the sample appears to be quite
>> large, up to 100 S.
>> Please let us know if you have any questions that you would like to
>> discuss via Zoom. I have uploaded the results to the "Supplemental Files"
>> folder on your LIMS account.
>>
>> Regards, -Borries
>>
>>
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