Artifact generation and monitoring in the analysis of cholesterol oxide products: Ramifications of stability differences for artifact monitoring

This dissertation is comprised of four main parts each focusing on cholesterol oxide products (COPs) and their methodology with emphasis on artifact generation and monitoring. Cholesterol can undergo several types of oxidation and the resulting products are COPs. Analysis of COPs is difficult, complex and lengthy and further complicated by the generation of artifacts during analysis. Artifacts are defined as COPs generated during analysis from either cholesterol or other COPs. They can either not be inherently present in the sample or quantities present following analysis may be increased or decreased from what is originally present prior to analysis. Artifacts are perpetuated in the literature and complicate data analysis and compilation as well as method comparison and harmonization. The first chapter is a review of COPs in terms of artifact generation and monitoring. While numerous reviews of COPs exist with focuses on biological activities, presence in foods and analysis, this review is unique in its focus on artifact generation and monitoring. Chapter 2 is a comparison of stability during saponification conditions and discussion of the ramifications of stability differences in artifact monitoring. This chapter suggests the use of the least stable COP as a marker of artifact monitoring in lieu of the practical drawbacks of multiple labeled COPs or the inadequate use of cholesterol, labeled or unlabeled. Chapter 3 consists of a short term stability study of cholesterol and COPs in solution at three different temperatures. Chromatographic concepts are discussed and used to interpret data. The final chapter is a published letter to the editor addressing artifact generating methods used in a study published in "Diabetes Research and Clinical Practice". It represents the application of COPs and artifact generation knowledge to limit and acknowledge perpetuation of artifacts in the literature.