Steroids have many important roles in the biological processes of the body which makes them important to analyse in biological matrices. However, a biological sample can present various challenges for the analysis, like a small analyte concentration. Thus, sensitive sample preparation methods and analytical techniques are required for steroid analysis.
The literature part of this thesis consists of a review of studies of sample preparation methods used for biological samples in the chromatography based analysis of steroids. Gas chromatography (GC) and liquid chromatography (LC) analysis often require laborious and time-consuming sample preparation steps. Since a run time of a chromatography based analysis is relatively short, the sample preparation step has become the bottleneck of the analysis. There is a need for less laborious sample preparation methods that will shorten the total analysis times and increase the sample throughput. It was found that traditional sample preparation techniques like liquid-liquid extraction (LLE) have remained prevalent in the steroid analysis studies. Alongside the traditional methods, previously less used sample preparation techniques have also gradually been introduced to the steroid analysis of biological samples. It was concluded that, despite the developments and advances in the steroid analysis methods, sample preparation is still a significant bottleneck of the analysis and thus still requires further development.
The experimental part studies a novel atmospheric pressure ionization technique called capillary photoionization (CPI), developed by the Division of Pharmaceutical Chemistry and Technology in the Faculty of Pharmacy at the University of Helsinki. The aim was to develop a new sensitive gas chromatographic-capillary photoionization-tandem mass spectrometric (GC-CPI-MS/MS) method for the analysis of steroids in biological samples. The results from the method validation showed the good chromatographic resolution, specificity, sensitivity and repeatability of the method. The method was successfully applied for the analysis of steroids in urine samples. However, the sample preparation procedure of the newly developed method was found to be rather labour-intensive and time-consuming. It was concluded that the sample preparation should be developed further to shorten the analysis times and decrease the amount of manual labour in the method.
