Sample preparation in the analysis of cardiovascular drugs and their metabolites from biological matrixes with liquid chromatography–mass spectrometry

The literature part of the thesis focused on reviewing published LC–MS/MS methods for cardiovascular drugs in biological matrices. Emphasis was given to the used sample preparation procedures and usability in different types of analyses, and their effects to the performances of the whole methods. Published methods for cardiovascular drugs in biological matrixes from the last decade were reviewed and presented. Insight into the challenges biological matrixes present was given, as well as a short overview of cardiovascular drugs. Plasma and urine were the most common sample matrixes, but some methods have also been published for serum and whole blood, and one even for fat tissue. Development and basic principles of liquid chromatography and mass spectrometry were presented, focusing on high and ultra-high performance liquid chromatography (HPLC and UHPLC) and triple quadrupole tandem mass spectrometry (QqQ–MS), as these seemed to be prevalent industry standard. Of sample preparation techniques, protein precipitation, direct dilution, liquid–liquid extraction (LLE), solid-phase extraction (SPE) and turbulent flow chromatography (TFC) were covered, with additions of some miniaturized versions. Some newer miniaturized online techniques have successfully been utilized for cardiovascular drug analysis, and their popularity will likely increase as the hardware in laboratories gets more and more modern. Advances in sample preparation techniques were relatively mild during the decade covered in this review, despite the significant proportion cardiovascular drugs hold in used medications. Newly published methods were either quantitative for a handful of analytes, or qualitative screenings for several analytes, some of which are cardiovascular drugs. Plasma and urine samples were used almost exclusively. In addition to the literary review, an experimental study was done at THL, where a LC–MS/MS method was successfully developed and validated during 2018–2019. The method has been used since 2019 as the primary qualitative method in cause–of–death investigations for 55 cardiovascular drugs analysed from post-mortem whole blood samples. In light of the done review, this method is exceptionally comprehensive regarding included analytes, and could potentially be at least partially automated with suitable instrument