Quantitative structure-retention relationships of phenolic compounds without Hammett's equations

Retention times of phenolic compounds in a given pH eluent in reversed-phase liquid chromatography were predicted from dissociation constants derived from atomic partial charges and log P-values calculated by a computational chemical method. The precision of the calculation of atomic partial charges by AM1 and PM3 methods of MOPAC(TM) was evaluated. The atomic partial charges obtained by AMI were the more acceptable. The atomic partial charges obtained from the hydrogen of the hydroxyl group included an ortho-effect, therefore an ortho-effect was added to the predicted pK(a) values. The precision of predicted retention factors obtained using predicted pK(a) values was similar to that using reference pK(a) values. (C) 2002 Elsevier Science B.V. All rights reserved.