ISSN:
0173-0835
Keywords:
Capillary electrophoresis
;
Polymer solution
;
Retardation coefficient
;
Field strength
;
Band width
;
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Subjecting particles in the size range of 3 to 1085 nm radius (R) to capillary electrophoresis in buffered solution of entangled uncrosslinked polyacrylamide (Mr 5 × 106), it was found that particle size-dependent retardation (“molecular sieving”) becomes electric field- and particle size range-dependent once the particle size exceeds 15-20 nm in radius. The field strength dependence of the retardation coefficient [KR = d(log mobility)/d(polymer concentration] and the positive or negative sign of dKR/dR suggest the existence of two different mechanisms of molecular sieving depending on the particle size range: particles with diameters less than the screening length (or blob size) of the polymer network are thought to penetrate into the available spaces within a discontinuous polymer network; particles with diameters larger than the screening length (or blob size) of the polymer network are thought to undergo size-dependent retardation by exerting shear stress against polymer chains, and displacing them, so as to cause local deformations in a continuous polymer network. A limit in the separating capacity of molecular sieving, due to a sharp increase in the rate of band widening with polymer concentration, was found when the value of the retardation coefficient exceeded 60 (mL/g).
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/elps.1150170619
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