CYCLOHEXYLAMINE ADDITIVES FOR ENHANCED PEPTIDE SEPARATIONS IN REVERSED-PHASE LIQUID-CHROMATOGRAPHY

While the choice of stationary phase, organic modifier, and gradient s trength can have significant effects on biomolecule separations, mobil e phase additives can also have a significant effect on the chromatogr aphic selectivity, recovery, efficiency and resolution. Given the impo rtance of stationary phase coverage, the beneficial, silanol-masking p roperties of amines, and the potential for selectivity modification th rough ion-pair interactions, cyclohexylamine was examined as a mobile phase additive and compared with triethylamine and trifluoroacetic aci d. Greatly improved separation was possible when cyclohexylamine was u sed as compared with phosphate buffer, and cyclohexylamine did not req uire purification before use, while triethylamine required distillatio n before 'clean' chromatograms were obtained. (C) 1977 by John Wiley & Sons, Ltd.