Magnetic field programming in quadrupole magnetic field-flow fractionation

Magnetic field-flow fractionation (MgFFF) is a technique for the separation and characterization of magnetic nanoparticles. It is explained that the analysis of polydisperse samples requires a programmed decay of field and field gradient during sample elution. A procedure for achieving reproducible field decay with asymptotic approach to zero field using a quadrupole electromagnet is described. An example of an analysis of a polydisperse sample under programmed field decay is given.