Stepwise Elution of Hop Resin Constituents from QAE Sephadex A-25 Ion-Exchange Resin. Gail B. Nickerson and Sam T. Likens. J. Am. Soc. Brew. Chem. 36:0023, 1978.

A method was developed for the chromatographic separation of hop constituents by stepwise elution. A column of QAE Sephadex A-25 acetate was used with different concentrations of acetic acid in 80% methanol:water (v/v). The separated constituents included the β-acids, α-acids, humulinic acids, iso-α-acids, and hulupones. Results obtained were comparable to those from gradient elution in accuracy and precision. Resolution was improved, particularly for the separation of β-acids from the less acidic unidentified substances. Stepwise elution eliminates the need for automated gradient elution equipment.

Keywords: α-acids, β-acids, Hulupones, Humulinic acids, Iso-α-acids.