ABSTRACT
The structural descriptors with the best potential for predicting the reversed-phase retention of xanthines and their derivatives on the new Chromolith RP-18e columns have been examined, as has the molecular mechanism of the separation. QSRR analysis was performed by simultaneous solution of a set of linear equations. The logarithms of the capacity factors were the dependent variables. Structural descriptors calculated by means of semi-empirical methods of quantum chemistry were chosen as independent variables.
ABSTRACT
Several thin-layer chromatographic (TLC) and high-performance liquid chromatographic (HPLC) systems for the determination of biogenic amine neurotransmitters, alkaloids, and the metabolites of these two groups of compounds are developed. The possibility of the interference of these compounds is investigated. In all the systems developed for neurotransmitters, the retention of alkaloids is examined and vice versa. In TLC because of different visualization procedures (a dyeing reagent for alkaloids and visible light for neurotransmitters), compounds of both the groups may be determined simultaneously without the risk of interference. In HPLC, similarly, the possibility of false diagnosis through simultaneously employing the fluorimetric and diode-array detectors can be excluded.
