Asymmetrical flow field-flow fractionation coupled to multiangle laser light scattering detector: optimization of crossflow rate, carrier characteristics, and injected mass in alginate separation.

The coupling of the flow field-flow fractionation (FlFFF) to differential refractive index (DRI) and multiangle laser light scattering (LS) detectors is a powerful tool for characterizing charged polysaccharides such as alginate. However, the correct interpretation of the experimental results and extrapolation of meaningful molecular parameters by using an analytical tool with such a level of complexity requires improvement of the knowledge of the alginate behavior in the channel and careful optimization of the operating conditions. Therefore, the influence of the critical operating parameters, such as crossflow rate, carrier composition and concentration, and sample load, on the alginate retention was carefully evaluated.

Cell sorting by one gravity SPLITT fractionation.

The need for innovative separative techniques suitable for the fractionation of biomaterials prompted this investigation into the performance of the gravitational split-flow thin channel (G-SPLITT) system as a cell sorter. The rigorous mathematical description of the separation mechanism allows achievement of fast separation of several million myeloma cells from healthy splenocytes using flow conditions calculated from theory. Separation in G-SPLITT is based on differences in sedimentation rate.

Influence of ionic strength, sample size, and flow conditions on the retention behavior of pullulan in flow field-flow fractionation.

Polymer molecular parameters such as hydrodynamic size are expected to be invariant regardless of the technique used to measure them, and to vary only, to some extent, with the solvent power and the polymer structure and properties as predicted from polymer chemistry. The hydrodynamic size of five pullulan standards derived from FlFFF in solutions of different ionic strength appears to correlate well to molecular mass as expected for neutral polymers for all fractions except that of lower mass. The correlation also holds for large amounts of injected sample even though with a slope which increases with rising polymer load.

Flow field-flow fractionation and characterization of ionic and neutral polysaccharides of vegetable and microbial origin.

The flow field-flow fractionation (FlFFF) analysis of a variety of neutral as well as ionic polysaccharides from plants and micro-organisms shows the generally broad distribution in molecular size of these polymers. This result is also obtained on a commercial sample of pullulan whose size distribution appears much wider than that of any of five standard fractions of the same polymer. Clear evidence of some physico-chemical properties of the polysaccharides is given by the study of the effect of the carrier ionic strength on salep, oxidized salep and konjac, carboxymethylcellulose and hyaluronic acid.