Question

It the two methods of measuring molecular weight that can produce full molecular weight distributions? For each of these techniques, describe the major limitations of the technique?

Size exclusion chromatography and Mass Spectrometry those are the methods describe the major limitations of the techniques ????

Answer 1

Size-exclusion chromatography (SEC), is a chromatographic method in which molecules in solution are separated by their size, and in some cases molecular weight. It is generally useful for large molecules or macromolecular complexes such as proteins and polymers.

It is not much useful for non-polymeric molecules. in SEC, mass is not measured so much as the hydrodynamic volume of the polymer molecules, that is, how much space a particular polymer molecule takes up when it is in solution. However, the approximate molecular weight can be calculated from SEC data .

Mass spectrophotometry is much advanced technique. Mass spectrometry can find find molecular weight, it can also detect hetero atoms and can help to the great extent to find structure of an unknown compound. MALDI mass spectrometry can provide accurate molecular weight and molecular weight distribution.

Size exclusion chromatography (SEC) is one of the most used analytical methods in chemistry to determine the molecular weight distribution of macromolecules, including natural and synthetic polymers.