Separation of water-soluble N-2,4-dinitrophenylamino acids.

1. An account is given of the development of a rapid method for separating water-soluble N-2,4-dinitrophenylamino acids by liquid–liquid partition chromatography. 2. The mechanism of the chromatography is discussed. 3. The R values of a number of water-soluble and ether-soluble DNP derivatives are listed.