Under the influence of light New chromatographic tools for elucidating photodegradation mechanisms

In photodegradation a molecule is excited by light, which causes it to degrade. It happens everywhere around us, such as in cultural-heritage, food, and in water-treatment facilities. Studying photodegradation is complex and the current monitoring techniques focus on the degradation of the main component, instead of on the formation of degradation products. In this project, a new way of studying photodegradation was developed. A new light-exposure cell was developed, based on a liquid-core-waveguide principle. One way to use this cell is by coupling it to liquid chromatography (LC) or implement it in two-dimensional liquid chromatography (2DLC) as a type of modulator. To optimize the LC separations, retention modelling (RM) can be used, where the chromatographic behaviour is predicted from scanning experiments. In this work, RM was investigated for both LC and 2DLC, as was photodegradation with different (new) light-exposure cells. For RM, new applications in the field were described, after which guidelines for scanning-experiments were formulated. Moreover, RM was applied to stationary-phase-assisted modulation (SPAM), an active modulation technique, to facilitate its optimization in 2DLC. In the second part of the thesis, the new light cell was compared to other, more-established degradation techniques, after which it was implemented in multiple-heart-cut 2DLC. Another LC setup was designed to facilitate the elucidation of photodegradation mechanisms. The thesis ends with the development of an alternative light cell that is more compatible with comprehensive 2DLC.