Asymmetric flow field flowmeterIt is an important branch of field current classification technology, mainly used for the separation, size analysis, and characterization of complex samples (especially large molecules, nanoparticles, colloids, etc.), and widely applied in materials science, biomedicine, environmental science, and other fields. Its core advantage lies in the absence of chromatographic stationary phase, which avoids the adsorption, degradation or damage of fixed relative samples, making it particularly suitable for the analysis of "fragile" or highly dispersed samples.

The separation process of this device relies on the synergistic effect of "transverse field force" and "longitudinal flow force", and achieves sample grading by size (or diffusion coefficient) by controlling the balance of the two forces. Resolve the analytical limitations of traditional separation techniques such as GPC for "fragile samples, large-sized samples, and complex systems".

　　Asymmetric flow field flowmeterPrecautions for use:

Sample pretreatment: It is necessary to remove large particle impurities from the sample (such as filtering through a 0.22 μ m filter membrane) to avoid blocking the semi permeable membrane or channel of AF4.

Mobile phase selection: It is necessary to ensure compatibility between the mobile phase and the sample (such as no precipitation, no interaction), while avoiding damage to the semi permeable membrane (such as selecting solvent resistant membranes for strong organic solvents).

Parameter optimization: The ratio of lateral flow to longitudinal flow directly affects the separation resolution and needs to be adjusted according to the sample size range (such as larger particles requiring higher lateral flow to enhance repulsion, and smaller particles requiring lower lateral flow to avoid excessive focusing).

Membrane selection: The molecular weight cut-off value (MWCO) of the semi permeable membrane should be matched with the sample (such as low MWCO membrane for analyzing small molecules and high MWCO membrane for analyzing large molecules) to avoid sample loss through the membrane.