Differential gel permeation chromatography

A new technique called Differential Gel Permeation Chromatography (DGPC), i n which a reference solution is used as eluent and the solution to be analy zed as the injected solution, is proposed. It can detect minute differences between the reference solution and the analyzed solution. A null signal in dicates that the reference solution and the analyzed solution are identical and a nonzero signal reflects the detailed differences between the referen ce and the analyzed solution. Two examples, concentration identification of five ethanol solutions and br and identification of three lubricant oils, are given to show the applicati on of the DGPC method. The potential application of the DGPC method to the identification of counterfeit products is also discussed.