Noninvasive monitoring of photocatalytic degradation of X‐ray contrast media using Raman spectrometry

Abstract

The photocatalytic degradation of the X-ray contrast agents iohexol and diatrizoate are monitored by in situ Raman spectrometry measurements in aqueous solution with a TiO 2 photocatalyst. Spectral features and changes are interpreted with the use of density functional theory calculations. While we observe similar results to those published previously, significant changes seen in the Raman spectrum allow us to better identify the mechanisms without the need for deductive approaches or complicated sample preparation. Diatrizoate spectra are consistent with hydroxyl radical attack leading to the loss of CO 2 . Iohexol is more difficult to interpret, representing a current challenge to the use of Raman spectrometry for real-time monitoring of photocatalytic degradation experiments. We explore internal standards that can be added to gauge overall degradation rates to some extent. Potential extensions of the work are described, particularly in terms of increased rate of data acquisition and more general application.

Recent advances in linear and nonlinear Raman spectroscopy. Part VIII

“…Potential extensions of the work are described, particularly in terms of an increased rate of data acquisition and more general application. [248] Schloesser et al evaluated a new method for Raman depolarization measurements including geometrical effects and polarization aberrations. The correction of the experimental measurement data for various effects resulted in depolarization ratios, which mostly differed by less than 5% from those obtained by quantumcalculations.…”

“…They explore internal standards that can be added to gauge overall degradation rates to some extent. Potential extensions of the work are described, particularly in terms of an increased rate of data acquisition and more general application . Schloesser et al .…”

Chemical Waste and Allied Products

“…Diatrizoate spectra are consistent with hydroxyl radical attack leading to the loss of CO 2 . Iohexol is more difficult to interpret, representing a current challenge to the use of Raman spectrometry for real-time monitoring of photocatalytic degradation experiments (Salkic et al, (2013). Reduction of frond size in water lentils and shoot length in higher plants suggested an additional plant growth-retarding mode of action of climbazole.…”

A Buoyant, Microstructured Polymer Substrate for Photocatalytic Degradation Applications

“…We [36,37] and others [38] have previously used microbubble fabrication techniques for PDMS to produce highly-porous, millimeter-scale beads. Drop-casting a cross-linking emulsion of PDMS dispersed in water into a heated water bath results in rapid curing of the PDMS into millimeter-scale beads.…”