Photooxidation of squalene on titanium dioxide particles

Madeline Byrd
Marissa Kaak, Pepperdine University
Jane A. Ganske, Pepperdine University

Abstract

The TiO2-mediated photoxidation of squalene, a 30-carbon isoprenoid in human skin oil and plant oils, was investigated using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), solid-phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS), and UV-Vis spectrophotometry. The oxidation proceeds under UVA radiation (λmax = 365 nm) as well as under longer wavelengths into the blue light spectrum. Oxidation photoproducts included aldehydes, ketones and surface-bound carboxylates, coordinated in a bidentate fashion to the particle surface. The kinetics of the loss of squalene –CH2 and –CH3 absorptions and the rise of carbonyl features were studied, and proposed mechanisms are consistent with kinetics and photoproducts identified using DRIFTS, SPME/GC-MS and UV-Vis spectrophotometry.

 
Apr 1st, 2:00 PM Apr 1st, 3:00 PM

Photooxidation of squalene on titanium dioxide particles

Waves Cafeteria

The TiO2-mediated photoxidation of squalene, a 30-carbon isoprenoid in human skin oil and plant oils, was investigated using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), solid-phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS), and UV-Vis spectrophotometry. The oxidation proceeds under UVA radiation (λmax = 365 nm) as well as under longer wavelengths into the blue light spectrum. Oxidation photoproducts included aldehydes, ketones and surface-bound carboxylates, coordinated in a bidentate fashion to the particle surface. The kinetics of the loss of squalene –CH2 and –CH3 absorptions and the rise of carbonyl features were studied, and proposed mechanisms are consistent with kinetics and photoproducts identified using DRIFTS, SPME/GC-MS and UV-Vis spectrophotometry.