title: Using magnetic levitation to distinguish atomic-level differences in chemical composition of polymers, and to monitor chemical reactions on solid supports.
abstract: This communication describes a density-based method that uses magnetic levitation for monitoring solid-supported reactions and for distinguishing differences in chemical composition of polymers. The method is simple, rapid, and inexpensive and is similar to thin-layer chromatography (TLC; for solution-phase chemistry) in its potential for monitoring reactions in solid-phase chemistry. The technique involves levitating a sample of beads (taken from a reaction mixture) in a cuvette containing a paramagnetic solution (e.g., GdCl(3) dissolved in H(2)O) positioned between two NdFeB magnets. The vertical position at which the beads levitate corresponds to the density of the beads and correlates with the progress of a chemical reaction on a solid support. The method is particularly useful for monitoring the kinetics of reactions occurring on polymer beads.
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Mirica
authors.forename: Scott T
authors.initials: ST
authors.lastname: Phillips
authors.forename: Sergey S
authors.initials: SS
authors.lastname: Shevkoplyas
authors.forename: George M
authors.initials: GM
authors.lastname: Whitesides
mesh_terms: D002621:Chemistry / Q000295:instrumentation / Q000379:methods*; D005682:Gadolinium / Q000737:chemistry; D007700:Kinetics; D008280:Magnetics / Q000379:methods*; D011108:Polymers / Q000032:analysis*
chemical_list: D011108:Polymers; D005682:Gadolinium; C038958:gadolinium chloride