BOULDER, Colo., Jan. 22 U.S. scientists have developed a simple, miniaturized technique for rapidly separating minute samples of proteins, amino acids and other chemical mixtures.The low-cost prototype device created by National Institute of Standards and Technology researchers can run up to eight separations simultaneously in a space about the size of a quarter.Conventional electrophoresis instruments separate mixtures of electrically charged species by injecting a discrete sample of the mixture at one end of a chemical racetrack, such as a capillary tube filled with a buffer solution. High voltage is applied between the sample and the other end of the track. Depending on size, charge and chemical mobility, the individual components of the mixture move down the track at different rates, gradually separating into individual bands. The new NIST technique works by opposing movement of the mixture's components with a stream of buffering solution. Only the most mobile components can move against the highest buffer flow but as that flow is reduced, lesser mobility components begin to move.A sensor placed over the channel detects each new component as it arrives,The research appears in the journal Analytical Chemistry.Copyright 2007 by UPI
