Magnetic split-flow thin fractionation: new technique for separation of magnetically susceptible particles

Abstract

A magnetic split-flow thin (SPLITT) fractionation system has been constructed for the purpose of extending the capabilities of SPLITT fractionation to magnetically susceptible samples. Permanent magnets of anisotropic ferrite and Nd–Fe–B magnets were tested and used to build the magnetic field. SPLITT cells were assembled and tested for operation. The integrity and capabilities of the system were examined using silica particles, labeled silica particles and magnetic particles (Dynabeads). Particle mixtures with high and low magnetic susceptibilities were completely separated. Successful separation of particle mixtures was demonstrated using Dynabeads with glass beads, labeled silica particles with glass beads or polystyrene beads, and Dynabeads with labeled silica particles. Continuous fractionation of samples was tested for a period of 8 h using mixtures of labeled silica particles and glass beads. Fractionation was verified using magnets and light microscopy. The throughput was around 0.1 g/h with the present set-up. Sample recovery ranged from 97 to 99% with a mean of 99%. Guidelines for scaling up of this system are provided for future reference. Magnetic SPLITT fractionation shows good potential for becoming a valuable technique for separation of magnetically susceptible particles.