Impact of biological matrix and isolation methods on detectability and interlaboratory variations of TLC Rf-values in systematic toxicological analysis.
The retention behavior of eight basic and neutral drugs, extracted from plasma, blood, and liver by five different methods (XAD-2, Extrelut, Elut-X, Elut-C18, chloroform) and developed in three chromatographic systems [MeOH, Me OH:BuOH:NaBr, CHCl3:MeOH (KOH)] was observed in parallel in two laboratories. The corrected Rf-values were compared with reference data from a data base with data for pure drugs. The biological matrix and/or the extraction severely lowered the precision and, to a lesser extent, the accuracy of the Rf-values as compared to pure drug data and to reference Rf-values. The intra- and interlaboratory variation was smallest in the MeOH system and largest in the CHCl3:MeOH (KOH) system. The observed irreproducibility is caused by the biological matrix (extraction has a large negative impact on the potentials of TLC in identification procedures). Precision and accuracy of extracted drugs were independent of the biological matrix and on the extraction method used.
D002626:Chemistry, Pharmaceutical; D002855:Chromatography, Thin Layer / Q000379:methods* / Q000592:standards; D064420:Drug-Related Side Effects and Adverse Reactions; D006801:Humans; D008099:Liver / Q000378:metabolism; D004364:Pharmaceutical Preparations / Q000097:blood / Q000302:isolation & purification
D004364:Pharmaceutical Preparations