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Recent Advances and Potential Applications of Nanoemulsions in Food Stuffs: Industrial Perspectives
Published in Bhaskar Mazumder, Subhabrata Ray, Paulami Pal, Yashwant Pathak, Nanotechnology, 2019
Bankim Chandra Nandy, Pranab Jyoti Das, Sandipan Dasgupta
Field flow fractionation (FFF) is a flow-assisted process for the separation of analytes from macromolecules, such as proteins in the nanometer range to micrometer-sized particles. FFF separates particles based on their Stokes diameter (Dulog and Schauer, 1996; Jores et al., 2004). In this method, smaller particles are moved faster and elute earlier for parabolic flow. For cross flow with particles of the same volume and different shape, the isometric particles will be eluted first, before the asymmetric particles (Jores et al., 2004). The advantages of the FFF method over other methods are the reduction of sample carry-over and simple sterility issues. The separation times usually range from a few minutes to 30 minutes. The FFF has the disadvantage of being easily overloaded by higher concentrations of the compounds. Dilutions should be made in order to overcome this problem.
Field-Flow Fractionation
Published in Grinberg Nelu, Rodriguez Sonia, Ewing’s Analytical Instrumentation Handbook, Fourth Edition, 2019
Field-flow fractionation (FFF) is a family of instrumental techniques that separates and characterizes macromolecules, colloids, and particles (macromaterials) on an analytical scale (Colfen and Antonietti, 2000; Schimpf et al., 2000). As illustrated in Figure 27.1, the FFF channel has a ribbon-shaped geometry, typically with length 30–50 cm, breadth 1–3 cm, and thickness 0.005–0.025 cm. Because of the high aspect ratio between breadth and thickness, liquid that is pumped through the channel flows in a laminar fashion, with a velocity profile that varies across the thin (x) dimension. A field is applied external to the channel in order to force analyte into the slower flow streams near one wall. The resulting velocity of the analyte through the channel depends on its interaction with the field, and therefore, on physicochemical properties that govern that interaction. Those physicochemical properties vary with the nature of the applied field, but always include the size of the analyte, because size determines the ability of analyte to reach the faster moving flow streams away from the accumulation wall.
Use Of Field-Flow Fractionation Techniques To Characterize Aquatic Particles, Colloids, And Macromolecules
Published in Jacques Buffle, Herman P. van Leeuwen, Environmental Particles, 2018
Field-flow fractionation (FFF) is a set of liquid chromatography-like elution methods which have been used to achieve high resolution separation and sizing of a wide range of particulate, colloidal, and macromolecular materials.13–15 Environmental samples that have been studied to date include humic substances,15–17 clays (Murphy, unpublished results), bacteria (Sharma, unpublished results), suspended particulate matter,18–21 soils22 and sediments.23 The potential for FFF techniques to be applied to help understand complex environmental samples has scarcely been tapped, particularly when it is realized that they can be applied to samples ranging in size from molecules smaller than 1000 in relative M mass up to particles larger than 50 μm in diameter. This represents an enormous five orders of magnitude in size or perhaps 15 orders of magnitude in mass.
Microplastics and nanoplastics in the soil-plant nexus: Sources, uptake, and toxicity
Published in Critical Reviews in Environmental Science and Technology, 2023
Nisha Singh, Meshal M. Abdullah, Xingmao Ma, Virender K. Sharma
In general, approaches used in concentrating and identifying MPs/NPs from aquatic environments have been extended to soil sample pretreatment in order to remove interferences from organic and inorganic constituents. Extraction methods for analyzing MPs include visual sorting, drying, sieving, density separation, oil extraction, elutriation, pressurized fluid extraction, and electrostatic separation (Thomas et al., 2020). Visual sorting is accomplished by staining MPs with fluorescent dyes such as Nile red, Calcofluor white, and Evans blue. Field-flow fractionation, differential centrifugal sedimentation and size-exclusion chromatography are employed to separate MPs/NPs based on their size, shape, and density (Awet et al., 2018; Park & Park, 2021). However, the probability of co-elution of particles and interactions with column material can compromise the characterization of MPs/NPs.
Colloidal lead in drinking water: Formation, occurrence, and characterization
Published in Critical Reviews in Environmental Science and Technology, 2023
Javier A. Locsin, Kalli M. Hood, Evelyne Doré, Benjamin F. Trueman, Graham A. Gagnon
In environmental samples, colloids are mixed with larger particles, therefore the sample may need to be size fractionated. Common fractionation methods include membrane filtration, size exclusion chromatography (SEC), hydrodynamic chromatography (HDC), field flow fractionation (FFF), and ultracentrifugation (UC). Membranes are used to physically separate particles that are passing through a medium with fixed pore size to provide discrete size fractions (de Mora & Harrison, 1983). With membrane filtration, particles can be separated via micro (0.05–10 μm), ultra (0.001–0.05 μm), and nano filtration (0.0005–0.001 μm) (Singh & Hankins, 2016). However, size separation by filtration is prone to measurement variability: filter material, imperfections in filter construction, filtration technique, degree of particle agglomeration, adsorption onto the membrane, filter clogging, and water quality can impact analyte recovery, particle size distributions, and reproducibility (de Mora & Harrison, 1983; Doré et al., 2021; Lytle et al., 2020).
Engineered nanomaterials in the environment: Are they safe?
Published in Critical Reviews in Environmental Science and Technology, 2021
Jian Zhao, Meiqi Lin, Zhenyu Wang, Xuesong Cao, Baoshan Xing
The released NMs in the environment were first detected by transmission electron microscopy/energy dispersive X-ray analysis (TEM/EDX) and inductively coupled plasma-mass spectrometry (ICP-MS) (Kägi et al., 2008). Currently, electrothermal atomic absorption spectrometry (ET-AAS) (Li et al., 2016), asymmetric-flow field flow fractionation with inductively coupled plasma–mass spectrometry (AF4-ICP-MS) (Hoque et al., 2012), and especially, single particle inductively coupled plasma-mass spectrometry (sp-ICP-MS) (Loula et al., 2019; Peters et al., 2018; Wu et al., 2020; Xiao et al., 2019) have been developed for characterization and quantification of NMs in natural environments. Figure 3 summarized the MECs of NMs in surface water, and sediment based on the published data (Table S2).