Q3. (a) Explain the principle of Size Exclusion Chromatography (SEC).
(b) Two polymers of molar mass 21,000 are injected simultaneously in an SEC system. One has Mark-Houwink-Sakurada parameters of K = 2.1 × 10–5 dL.g–1 and α = 0.672, while the other has values of K = 11.4 × 10–5 dL.g–1 and α = 0.716.
(i) Will they elute at the same time? If not, which polymer will elute first?
(ii) If elution time is proportional to the logarithm of the hydrodynamic volume, approximately how much later (as a fraction of the time taken for the first polymer to appear) will the second polymer elute?
Dear student
A)The principle of size exclusion chromatography is the separation of mixtures based upon the molecular size ( basically , hydrodynamic volume ) of the components . Separation is achieved by the differential exclusion or inclusion of solutes as they pass through stationary phase consisting of heteroporous crosslinked polymeric gel or beads. The process is based upon different permeation rates of each solute molecule into the interior of gel particles .
Large molecules are completely excluded from the pores that pass through space in between gel particles or matrix and come first in effluent .Small molecules are distributed in between the mobile phase of in and outside the molecular seive and the these molecules pass through the column at slower rate.
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Q3. (a) Explain the principle of Size Exclusion Chromatography (SEC). (b) Two polymers of molar mass 21,000 are injected...
(b) Two polymers of molar mass 21,000 are injected simultaneously in an SEC system. One has Mark-Houwink-Sakurada parameters of K = 2.1 × 10–5 dL.g–1 and α = 0.672, while the other has values of K = 11.4 × 10–5 dL.g–1 and α = 0.716. (i) Will they elute at the same time? If not, which polymer will elute first? (ii) If elution time is proportional to the logarithm of the hydrodynamic volume, approximately how much later (as a fraction...