Development of magnetic split-flow thin fractionation for continuous particle separation

Split-flow thin (SPLITT) fractionation is designed for preparative separation of macromolecules, colloids, and particles with throughputs typically in the gram(s) or less per hour range depending on the applied field. Magnetic separation using permanent magnets is fast, simple, highly selective, and economical. Magnetic SPLITT fractionation (SF) is a newly developed family of SF techniques for separating magnetically susceptible particles. Particles with different degrees of magnetic susceptibility can be separated into two fractions by adjusting perpendicularly applied magnetic forces and flow rates at inlets and outlets. The preparative applications of magnetic SF using various magnetically susceptible particles and mixtures were studied. Throughputs at various channel dimensions, sample concentrations, magnetic field strengths, and channel flow rates were examined. The minimum difference in magnetic susceptibility required for complete separation was about 3 x 10(-6) cgs. Sample recoveries were higher than 94%. Continuous particle separations using magnetic SF were successful over 8 h. The throughput of magnetic SF was approximately 3 g/h using our experimental setup. The throughput can be scaled up by using longer channel lengths, broader channel breadths, and stronger magnetic fields. This technique has shown good potential for becoming useful in separating magnetically susceptible colloids, and particles. (C) 2003 Elsevier B.V. All rights reserved.