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Handbook of Size Exclusion Chromatography and Related ...

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Table 2 Effects <strong>of</strong> Column Dimensions on Chromatographic Performance<br />

Column change Result Advantage Disadvantage<br />

Reduce length Run time<br />

reduction<br />

Reduce diameter Sensitivity<br />

increase<br />

Reduce column<br />

aspect ratio<br />

Reduce<br />

particle size<br />

Constant<br />

separation<br />

volume<br />

B<strong>and</strong><br />

broadening<br />

reduction<br />

Efficiency<br />

increase<br />

Increase flow rate Run time<br />

reduction<br />

Shorter runs with<br />

less solvent<br />

Less injected<br />

mass <strong>and</strong><br />

eluent<br />

needed<br />

Shorter run times<br />

with identical<br />

pore volume<br />

<strong>and</strong> similar<br />

resolution<br />

Increases<br />

resolution<br />

(most notable<br />

in oligomer<br />

region)<br />

Lower resolution<br />

Lower pore volume<br />

Time gain very<br />

limited<br />

Needs microbore<br />

instrumentation<br />

Lower resolution<br />

Lower pore volume<br />

Higher shear rates<br />

Polymer<br />

degradation<br />

Very limited time<br />

gain<br />

No solvent savings<br />

High backpressure<br />

High shear rates<br />

Polymer<br />

degradation<br />

Limited time gain<br />

Shorter runs High backpressure<br />

Shorter column<br />

lifetime<br />

Lower resolution<br />

High shear rates<br />

Polymer<br />

degradation<br />

3.1.1 Results <strong>of</strong> aConventional Column<br />

Figure3showsatypicalchromatogramforaconventionalSECexperimentusinga<br />

st<strong>and</strong>ard column <strong>of</strong> 30 cm length <strong>and</strong> 8 mm internal diameter (ID) at the usual flow<br />

rate <strong>of</strong> 1.0 mL/mm. All results from columns with different dimensions were<br />

compared to the performance <strong>of</strong> this experiment. The overall run time <strong>of</strong> this<br />

experiment was about 13 minutes. As expected, the seven polymer st<strong>and</strong>ards show<br />

© 2004 by Marcel Dekker, Inc.

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