title: Impact of urine matrix and isolation procedure on retention behaviour of basic drugs in thin-layer chromatography.
abstract: The influence of three different isolation procedures, namely liquid-liquid extraction, Extrelut column extraction and XAD-2 column extraction, and of the urine matrix on the standardised Rf values and variability of Rf values of some selected basic drugs was investigated. It appears that the liquid-liquid extraction may give a significant deviation of standardised Rf values in respect of pure drugs, which is dependent on the TLC system. For all three isolation procedures, the search window for substance identification by means of data collection based on standardised Rf values of pure drugs should be slightly wider after extraction than when using pure drugs. The TLC system cyclohexane-toluene-diethylamine (75:15:10, v/v/v) showed the best accuracy and precision of Rf values.
authors.affiliation: Department of Analytical Chemistry and Toxicology, University Centre of Pharmacy, State University, A. Deusinglaan 2, 9713 AW Groningen, The Netherlands.
authors.forename: J P
authors.initials: JP
authors.lastname: Franke
authors.forename: R A
authors.initials: RA
authors.lastname: De Zeeuw
authors.forename: J
authors.initials: J
authors.lastname: Wijsbeek