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Hydrodynamic relaxation in flow field-flow fractionation using both split and frit inlets
M K Liu1, P S Williams, M N Myers
1Department of Chemistry, University of Utah, Salt Lake City 84112.
Analytical Chemistry
|October 1, 1991
Summary
Field-flow fractionation (FFF) can avoid stop-flow injection using split flow or frit inlet injection. While theoretically minimizing band broadening, experimental results show slightly larger broadening than predicted.
Area of Science:
- Analytical Chemistry
- Separation Science
Background:
- Field-flow fractionation (FFF) is a powerful separation technique.
- The stop-flow injection procedure can be cumbersome and time-consuming.
- Hydrodynamic relaxation is crucial for efficient FFF separations.
Purpose of the Study:
- To investigate two alternative methods for hydrodynamic relaxation in FFF: split flow injection and frit inlet injection.
- To theoretically analyze band broadening during hydrodynamic relaxation.
- To experimentally validate the performance of these methods using flow/steric FFF.
Main Methods:
- Theoretical analysis of band broadening during hydrodynamic relaxation.
- Experimental implementation of split flow and frit inlet injection in FFF.
- Application to latex standards using flow/steric FFF.
Main Results:
- Both split flow and frit inlet injection successfully achieve hydrodynamic relaxation, eliminating the need for stop-flow.
- Theoretical analysis indicates negligible band broadening when sample inlet flow is low relative to total flow.
- Experimental results confirm the expected trends but show slightly greater band broadening than predicted.
Conclusions:
- Split flow and frit inlet injection are viable alternatives to stop-flow injection in FFF.
- Optimization of sample inlet flow rate is important for minimizing band broadening.
- Further investigation is needed to fully understand the discrepancy between theoretical predictions and experimental observations of band broadening.