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New Whitepaper: Examining the Exciting Potential of Electrical Asymmetrical Flow Field-Flow Fractionation

This highly informative whitepaper describes the technique of Electrical Asymmetrical Flow Field-Flow Fractionation (EAF4) and shows examples of how it has been applied to real-world applications of separation and characterisation of nanoparticles, polymers and proteins.


In recent years the industrial applications of nanoparticles have been growing immensely. Medicine, healthcare, electronics, information technology, energy, and environmental remediation are a few examples among the major industries that nanoparticles help improve or revolutionize. The application of nanoparticles in medicine has produced solutions for disease prevention, clinical diagnosis, and therapy. Extensive research is being conducted in cancer treatment where nanoparticles are utilized as drug carriers. This allows researchers to find new therapeutics which, by delivering the drug directly to the cancerous cells, reduce the risk of damage to healthy tissue. Nanoparticle uptake by cells is highly size and surface-charge dependent. Therefore, size and charge characterization of nanoparticles is very important. Batch mode analytical techniques such as dynamic light scattering and electrophoretic light scattering are widely used to measure nanoparticle size and charge. Although they can provide rapid information, their use is mostly limited to monodisperse and homogeneous suspensions.


In addition to the need for characterization of engineered nanoparticles, another emerging application is analysis of nanoplastics. Typically formed by the weathering and breakdown of plastic materials in the environment, nanoplastics are challenging to separate and characterize by commonly used techniques such as dynamic light scattering or size exclusion chromatography.


Asymmetrical Flow Field-Flow Fractionation (AF4) is a high-resolution separation technique for characterization of nanoparticles, suitable for both monodisperse and polydisperse suspensions. In addition to the primary separation field (crossflow), an electrical field can also be applied across the separation channel in AF4 which shifts the elution time of charged species based on their charge polarity and magnitude.


In this whitepaper, the Electrical Asymmetrical Flow FFF (EAF4) system was utilized to separate and characterize:

• The electrophoretic mobility of silver nanoparticles with different surface coatings
• A nanoplastic (polystyrene) sample
• The electrophoretic mobility of the NIST mAb RM8671 


To obtain a copy of this informative whitepaper, please send an email to with ‘EAF4 WP10’ in the subject line.

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