Chromatography Forum

Hi there,
Did Gel permermeation Chromatography on Polystyrene in a lab session, the results have been given to us as an excel sheet with collumn headings "Retention Time, Reponse, MW, LogMW"

We need to find Mp, Mw, Mn, Mz, Mz+1 and PD. I have figured out that Mp is at the crest of the peak, but i have no clue what to do to find Mn, Mw, Mz and Mz+1.
then PD = Mn / Mw (or the other way around)

Thanks. (btw, report due in 6 hours so not sdure if ill get a response in time)

ok, i understand a little bit more now.

Mn = (Sum(Mi x ni)) / (Sum(ni))

Mw = (Sum(Mi^2 x ni))/(Sum(ni))

but what do i use for ni? The values in the response collumn?

Ni is the number of molecules having a particular molecular weight.

Try this link for help:

http://pslc.ws/mactest/average.htm

Hi,
I understand how ni is number of moleculesrepresenting each mass, but what i dont know is how to get n from the data i have. All i have is the 'response' of each Molecular Weight in millivolts?

my demonstarator gave me some hints.

In the results, there is another collumn titled "Norm Ht", and he said that this is related to ni.
The relationship/equation is not in my text book, lec notes. Looking round on net but no luck so far