Many organic compounds undergo changes under the influence of light. This might be beneficial in, for example, water purification, but undesirable when cultural-heritage objects fade or when food ingredients (e.g., vitamins) degrade. It is often challenging to establish a strong link between photodegradation products and their parent molecules due to the complexity of the sample. To allow effective study of light-induced degradation (LID), a low-volume exposure cell was created in which solutes are efficiently illuminated (especially at low concentrations) while simultaneously analysed by absorbance spectroscopy. The new LID cell encompasses a gas-permeable liquid-core waveguide (LCW) connected to a spectrograph allowing collection of spectral data in real-time. The aim of the current study was to evaluate the overall performance of the LID cell by assessing its transmission characteristics, the absolute photon flux achieved in the LCW, and its capacity to study solute degradation in presence of oxygen. The potential of the LID set-up for light-exposure studies was successfully demonstrated by monitoring the degradation of the dyes eosin Y and crystal violet.
Bibliographical noteFunding Information:
We thank the Precision Mechanics and Engineering group at the Vrije Universiteit Amsterdam, and Dick van Iperen in particular, for the close collaboration towards designing and building the LID cells. This work is part of the TooCOLD project (Toolbox for studying the Chemistry of Light-induced Degradation; project number 15506) carried out in the TTW Open Technology Programme and is (partly) financed by the Netherlands Research Council (NWO).
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