Question

Describe SEC and how molecular weights can be determined from SEC:
a. How are the columns set up?

b. What does a graph look like?

c. How do you determine weight for SEC spectra?

Answer 1

a. SEC or Size Exclution Chromatography is a type of HPLC technique which separates molecule based on their size and geometry as is sounded from its name itself.SEC is of tyo types,

• one is GEL PERMEATION chromatography where mobile phase is organic solvent and the column is packed with a hydrophobic material
• other is GEL FILTRATION chromatography where mobile phase is aqueous solvent and column is packed with a hydrophilic material for separation.

​In SEC a column of gel particles is in equilibrium with with mobile phase for the molecules to be separated.

b. Curve with smaller slopes are packed (in column) with packing materials having small pores.

c.