Chromatographic technique that involves continuous addition of sample to the column. With the result that only the least-sorbed compound, which moves at the fastest rate is obtained in a pure state. The second least-sorbed compound elutes with the first-eluting compound, the third least-sorbed compound with the first and second compound, etc., until the original sample is eluting at the column exit. Frontal analysis is seldom used and is mainly a preparative technique.