Polymer Characterization - American Chemical Society

considerably so that thermal F F F now is a powerful tool for the sep aration of ... (16) where μ is the electrophoretic mobility and Ε is the elect...
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14 Field-Flow Fractionation Promising Approach for the Separation and Characterization of Macromolecules

Downloaded by UNIV OF CALIFORNIA SAN DIEGO on January 31, 2017 | http://pubs.acs.org Publication Date: June 1, 1983 | doi: 10.1021/ba-1983-0203.ch014

J. C A L V I N G I D D I N G S , K A T H Y A. G R A F F , KARIN D . C A L D W E L L , and MARCUS N. MYERS University of Utah, Department of Chemistry, Salt Lake City, U T 84112

Field-flow

fractionation

(FFF) technology

to the characterization cules and particulate

and separation

is

of

applicable macromole-

species over an effective

weight range of 103—1018. Separations

molecular

take place in an

open flow channel over which a field is applied dicular

to the flow.

subtechniques, methacrylate, perature Other

by

utilizing field

applied

subtechniques

use

diameters, flexibility techniques,

respectively.

electrical,

to

flow.

sedimentamacromolecules

of and

from first

variety

charges, masses, and Stokes FFF

include

programming

minimal adverse effects due

and shear degradation,

ity in many cases to characterize calculation

FFF poly-

in a tem-

perpendicular

Advantages

high resolution,

in a

diffusion

due to the variety of fields

to surface interactions

to

polymethyl

polymers

to separate

to their electrical

perpen-

of the

applicable

thermal

tion, and cross-flow fields according

one

polytetrahydrofuran,

and polyethylene

gradient

FFF

FFF,

has been shown

styrene, polyisoprene, of solvents

Thermal

and abil-

macromolecules

by

principles.

F I E L D - F L O W F R A C T I O N A T I O N ( F F F ) is the g e n e r a l n a m e of a f a m i l y of separation t e c h n i q u e s that use f i e l d s or g r a d i e n t s that c a n interact w i t h solute m a c r o m o l e c u l e s to force t h e m d i f f e r e n t i a l l y i n t o t h e s l o w streamlines of a

flowing

fluid

(I). S e p a r a t i o n s take p l a c e i n t h i n , o p e n

channels of rectangular cross-section u n d e r conditions of flow.

A

field

laminar

i s a p p l i e d p e r p e n d i c u l a r l y t o t h e f a c e o f t h e c h a n n e l so

that solutes form n a r r o w layers against the c h a n n e l w a l l b a s e d o n their f i e l d - i n d u c e d v e l o c i t y a n d t h e c o u n t e r a c t i n g a b i l i t y to d i f f u s e a w a y f r o m t h e c h a n n e l w a l l (see F i g u r e 1). T h e r a t e o f e l u t i o n o f t h e l a y e r s i s 0065-2393/83/0203-0257$06.00/0 © 1983 A m e r i c a n C h e m i c a l Society

Craver; Polymer Characterization Advances in Chemistry; American Chemical Society: Washington, DC, 1983.

Craver; Polymer Characterization Advances in Chemistry; American Chemical Society: Washington, DC, 1983. Zone A

Parabolic flow profile

ZMUC

Zone ΒΟ

3&1

ο ο o.S

CROSS-FLOW VECTOR

DETAIL

/

Figure 1. Scheme of the relationship of FFF flow channel tails of flow profile and macromolecular

CHANNEL FLOW VECTORS

CHANNEL FLOW IN

F L O W PROFILE IN C H A N N E L

de­

CHANNEL FLOW OUT

to applied field (top) and approximate distribution (bottom).

FIELD

Downloaded by UNIV OF CALIFORNIA SAN DIEGO on January 31, 2017 | http://pubs.acs.org Publication Date: June 1, 1983 | doi: 10.1021/ba-1983-0203.ch014

δ 2

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