Investigations of supercritical fluid chromatography, supercritical fluid extraction and capillary electrophoresis combined with mass spectrometry for the analysis of drugs of forensic interest

• Main Author: Jackson, P. J.
• Published: Swansea University 1993
• Subjects: 543.8
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637384

The major objective of these investigations was to develop a total assay for quantifying drugs of forensic interest in biological fluids that have presented problems with more conventional procedures. Supercritical fluid techniques in combination with mass spectrometry provided the main basis of the studies reported in this thesis. The practical aspects of the combination of supercritical fluid techniques with mass spectrometry was also investigated with a view to increasing sensitivity and specificity. Chapter 1 provides an overview of basic chromatographic techniques such as gas chromatography (GC) and high performance liquid chromatography (HPLC). The development of supercritical fluid chromatgraphy (SFC) and capillary zone electrophoresis (CZE) were discussed in greater depth. A method was developed for the separation of a number of beta-blockers using CZE. The basic theory of mass spectrometry was also reviewed together with an example of electrospray ionization of some small polar pharmaceutical compounds. The development of interfaces capable of coupling SFC systems to a mass spectrometer was also reviewed. Chapter 2 gives an overview of the beta-blockers which were used as test compounds during method development. Supercritical fluid separations of the beta-blockers using UV and mass spectrometric detection were compared. SFC/MS using the thermospray interface proved to be the most sensitive. The use of a triple quadrupole mass spectrometer was utilised to provide an increase in specificity needed when detecting trace amounts of drug in complex matrices. Chapter 3 gave an overview of some of the common problems with conventional sample preparation techniques and how supercritical fluid extraction (SFE) may be used to overcome them. On-line SFE/SFC/MS was developed for analysis of beta-blockers in horse and human blood fluids with quantitative results obtained from off-line SFE/HPLC/MS. Chapter 4 describes the use of double charge transfer (DCT) spectroscopy to gain information on ground and excited electronic states of doubly charged ions. The final chapter describes the instrumentation and experimental conditions used in these investigations.