good day everyone,
i have a simple question, when studying the kinetics of an ATRP polymerization reaction, i take samples at fixed time intervals than precipitate and dry it before solubilizing in the eluent to inject in the SEC. at low monomer conversions, this strategy is time consuming and it's particularly difficult to precipitate short polymers. my question: is it possible to simply take a sample straight from the reaction, diluted in the eluent, filtrate and inject it ? can this do harm to the machine ?
other than the polymer, we'll have monomer residue, reaction solvent and catalyst.
thanks
Perhaps, but we need more information! What is the polymer? What is the monomer? What is the solvent? What is the SEC column and its packing particle size?
These particles may become clogged by not following the current procedure or the column's lifetime significantly shortened.
i think the column is PS-DVB, i need to check the particle size but i know we can go up to 10^6 Da ! the polymer is simply polystyrene, reaction solvents can be DMF, toluene or sulfolane.
actually, in every article i read, they take the sample directly from the reaction, it's then diluted in the eluent and injected, so i was wondering if i can just do like they do or not.
It depends! What else is in the mixture that is used to manufacture the polymer? Is it likely to kill the column?
Just in case, before you perform a direct injection, you should have a replacement column onhand.
PS-DVB is short for 'polystyrene divinyl benzene'. It is a generic column with a pore size of about 100 Angstroms, and is generally used for SEC. See link below;
https://www.phenomenex.com/Products/HPLCDetail/PolymerX/
so the ATRP reaction consists of : the monomer/polymer, the solvent, the complex ( ex. CuBr/PMDETA), all of which are perfectly soluble in the eluent (THF), to have enough polymer injected, i need to take like 10 ul, dilute it in 1 ml THF, and inject 50 ul of the diluted solution, this makes only 0.5 ul of the reaction mixture finally injected in the SEC, which is equipped of course with a pre-column.
A direct injection seems reasonable to me. PS-DVB is a 'robust' column with a very strong backbone.
However, THF has a tendency to 'swell' column particles. Check solvent compatibility (THF) of PS-DVB.
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