Christoph Johann

Field-flow fractionation (FFF) coupled to light scattering is a powerful method to separate and characterize nanoparticles, proteins, and polymers from a few nanometres to a few micrometres. The technique is one of the few that can cover the full size range of nanomaterials and provide high-resolution size distributions and additional characterization. New developments in FFF enhance performance and productivity.

Flow-field flow fractionation (flow-FFF) offers highly versatile separations for the analysis of complex fluids, covering a size range of macromolecules and particles from 1 nm to 10,000 nm. However, flow-FFF is often perceived as a difficult technique to learn because of the multiple parameters available for adjustment. Recent advances in software for simulating flow-FFF overcome this obstacle, enabling the virtual optimization of flow-FFF methods and opening up the power of flow-FFF separations to non-experts. An added benefit is the ability to easily analyze particle size distributions by elution time from first principles.

The fate and modification of nanoparticles in real life matrices can be investigated by the combination of field-flow fractionation (FFF) with inductively coupled plasma mass spectrometry (ICP–MS). This article explains more.

The functional principles of AF4 and HF5 are discussed.

Recent development of the instrumentation for asymmetric flow field flow fractionation (FFF) brings new possibilities for the characterization of synthetic and natural polymers with several advantages over traditionally used size exclusion chromatography (SEC). The main difference of asymmetric flow FFF compared to SEC is that the polymer separation takes place in an entirely empty channel, which eliminates undesirable SEC effects such as shearing degradation of polymers with ultra high molar mass, anchoring of branched macromolecules in SEC column packing, and enthalpic interactions of polymer molecules with a stationary phase.

Asymmetric flow field flow fractionation is a type of field flow fractionation (FFF) separation technique. FFF has been co-existing with size exclusion chromatography (SEC) for several decades.

One of the biggest problems facing researchers involved in pharmacogenomics is analysing the recombinant proteins of interest to monitor if they are in a folded state. This article describes a rapid and economical method using asymmetric flow field-flow fractionation combined with multi-angle light scattering (AF4–MALS) to characterize refolded proteins, which overcomes some of the disadvantages associated with other techniques.