Ma$netic separations in chemistry and biochemistrY Have you ever really thought about all the energy forms you might use? The authors have

W begin with three observations: . Methods for separating chemicals, materials, and objects are a critical part of chemical technology' . Magnetic interactions can achieve separations that are impossible or impractical to achieve l',)' other techniques. . Magnetic separations are inf reqtrently used in chemistry. How is it that chemistry, which has cheerfully exploited separations based on almost every type of physical interaction, has managed to neglect magnetic interactions almost entirel.v? This question has tu'o answers: First, magnetic separatiotts ilre applicable to a smaller set of chemical problems than the more comlnon methocls. In general, magnetic separations are restricted t0 separations of particlut fto- (or i1) suspension, and are 'ot applica6le to separations of moleatles from (in) solution. They are not particularly useful in svstems containing only organic ipecies. Second, chemists are too unfamiliar with magnetic separation to recognize promising areas of application. In this article we direct ottrselves to the problem of unfamiliarity. We summarize the physical principles underlying the tu'o major techniques for separations based on magnetic interactiotls, outline representative problems in which these techniques have been sttccessftrlly used, and