Characterization of non-solvent precipitated starch using asymmetrical flow field-flow fractionation coupled with multiple detectors

Flow field-flow fractionation coupled with multidetector: A robust approach for the separation and characterization of resistant starch

The unique properties of resistant starch (RS) have made it applicable in the formulation of a broad range of functional foods. The physicochemical properties of RS play a crucial role in its applications. Recently, flow field-flow fractionation (FlFFF) has attracted increasing interest in the separation and characterization of different categories of RS. In this review, an overview of the theory behind FlFFF is introduced, and the controllable factors, including FlFFF channel design, sample separation conditions, and the choice of detector, are discussed in detail. Furthermore, the applications of FlFFF for the separation and characterization of RS at both the granule and molecule levels are critically reviewed. The aim of this review is to equip readers with a fundamental understanding of the theoretical principle of FlFFF and to highlight the potential for expanding the application of RS through the valuable insights gained from FlFFF coupled with multidetector analysis.

Separation and size characterization of zinc oxide nanoparticles in environmental waters using asymmetrical flow field-flow fractionation

There are few studies on separation and size characterization of zinc oxide nanoparticles (ZnO-NPs), which have wide applications in several science and technology areas, in the environment. In this work, we report a method for the separation and size characterization of ZnO-NPs by asymmetrical flow field-flow fractionation (AF4) coupled to UV-vis detector. Experimental conditions such as composition of the carrier solution, focus time, crossflow, detector flow rate and injection volume were systematically studied in terms of NPs separation, recovery, and repeatability. Size characterization was achieved using polystyrene nanoparticles as a size standard and a mixture of < 35 nm (NP-A) and < 100 nm (NP-B) ZnO-NPs were separated and size characterized posterior preconcentration using ultracentrifugation. The method was also employed to characterize the size of homemade ZnO-NPs, and the results were in concordance with dynamic light scattering (DLS) analysis and thus, the method can be used as an alternate method. Upon application on environmental water samples, the two ZnO-NPs, NP-A and NP-B, have been separated and size characterized. The estimated hydrodynamic sizes of the NP-A and NP-B were found to be in the range of 83-97 nm and 188-202 nm, respectively, with good precision (RSD, <11%), suggesting that the current method can satisfactorily separate and generate information about sizes of the NPs in samples with a complex matrix. Therefore, the developed technique can be used as a baseline to investigate size related environmental processes of the NPs in environmental water samples.