Combined Size Density Fractionation
Combined Size Density Fractionation - Related Videos
08:38
Combined Size and Density Fractionation of Soils for Investigations of Organo-Mineral Interactions
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Cited by 8 •
2019
Combined size and density fractionation (CSDF) is a method to physically separate soil into fractions differing in texture (particle size) and mineralogy (density). The purpose is to isolate fractions with different reactivities towards soil organic matter (SOM), in order to better understand organo-mineral interactions and SOM dynamics.
11:15
Nanosponge Tunability in Size and Crosslinking Density
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Cited by 1 •
2017
This article describes a process for tuning the size and crosslinking density of covalently crosslinked nanoparticles from linear polyesters containing pendant functionality. By tailoring synthesis parameters (polymer molecular weight, pendant functionality incorporation, and crosslinker equivalents), a desired nanoparticle size and crosslinking density can be achieved for drug delivery applications.
09:07
Electroconvulsive Seizures in Rats and Fractionation of Their Hippocampi to Examine Seizure-induced Changes in Postsynaptic Density Proteins
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Cited by 4 •
2017
Electroconvulsive seizure (ECS) is an experimental animal model of electroconvulsive therapy for severe depression. ECS globally stimulates activity in the hippocampus, leading to synaptogenesis and synaptic plasticity. Here, we describe methods for ECS induction in rats and for subcellular fractionation of their hippocampi to examine seizure-induced changes in synaptic proteins.
03:05
Gradient Centrifugation Based Purification of Nuclei: A Technique to Obtain Ultrapure Fraction of Intact Nuclei Using Density Gradient Centrifugation
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2023
In this video, we describe a simple and efficient protocol using gradient centrifugation to isolate single nuclei. Once isolated, these nuclei can be used for sequencing and genome analysis.
10:19
Cell Fractionation of U937 Cells by Isopycnic Density Gradient Purification
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Cited by 1 •
2021
This fractionation protocol will allow researchers to isolate cytoplasmic, nuclear, mitochondrial, and membrane proteins from mammalian cells. The latter two subcellular fractions are further purified via isopycnic density gradient.
FAQs
Size separation distinguishes particles by physical dimensions, while density separation further sorts particles according to buoyancy or settling behavior in a selected medium. Applying both characteristics creates fractions that are more physically uniform than fractions based on size or density alone. This combined resolution helps link particle properties with contaminant association, organic matter, mineral composition, or microplastic occurrence.
The selected medium provides the conditions that allow particles with different densities to behave differently during separation. Particles may respond through differences in buoyancy or settling behavior, so the medium directly influences how density-related fractions form. Consistent use of the medium is therefore important when comparing particle distributions among soil, sediment, or other particulate environmental samples.
Using only size may group together particles with substantially different densities, while density separation alone may leave particles with different dimensions in the same fraction. Combining both properties narrows the physical range within each group. The resulting fractions can support clearer comparisons of where particle-bound pollutants, organic matter, minerals, or microplastics occur within a complex sample.
The distribution of a substance across size and density fractions can indicate which physical particle compartments are associated with it. Comparing these patterns among samples helps researchers examine pollutant transport and persistence in relation to particle properties. It also supports assessment of potential ecological exposure by showing whether contaminants are concentrated in particular environmental fractions rather than distributed uniformly.
A typical workflow first applies a size-based separation, such as sieving, to divide the environmental sample into particle-size groups. Each resulting group can then undergo density-based separation in a selected medium, using differences in buoyancy or settling behavior. The separated fractions are collected as physically differentiated materials for subsequent characterization of contaminants, organic matter, minerals, or microplastics.
The approach is suited to complex particulate materials such as soil, sediment, and other environmental particle samples. Its value increases when a sample contains mixed physical components whose size and density may influence chemical association or environmental movement. Producing differentiated fractions makes it easier to compare composition and pollutant distribution across these heterogeneous materials.
Researchers can use the separated fractions to investigate how particle-bound contaminants, organic matter, minerals, and microplastics are distributed within environmental samples. The method also supports comparisons of transport, persistence, and ecological exposure across samples. In environmental studies, these outcomes connect measurable particle properties with the compartments in which pollutants or other materials are found.