Identification of photodegradation products from commonenvironmental pollutants using gas chromatography coupled withhigh resolution mass spectrometry

Abstract: Photodegradation is a major degradation mechanism for many environmental contaminants, both in indoor environments as well as in outdoor environments, and many of the contaminants are persistent and toxic. However, there is a lack of knowledge about the exact degradation process for many of them. It is important to not only monitor and study environmental contaminants that are commonly found. But it is also important to be able to identify their degradation products, however, due to lack of standards there is a difficulty to conduct identification. There is also the drawback with most spectral libraries used for identification being recorded at low resolution, when new instruments are being developed for using high resolution. This makes it challenging to identify compounds with spectral peaks that differ only slightly in their mass-to-charge ratio (m/z). Thus, the aim of this study was to determine potential degradation products from different compounds commonly found in indoor environments and then add these findings to a spectral library for high resolution mass spectrometry. This was conducted by first exposing the standards to ultraviolet (UV) light, and then the chemical analysis was performed using a gas chromatography coupled with a high resolution mass spectrometer. All data was then processed in different software in order to determine potential products. Many of the compounds did not indicate any degradation using the experimental settings, and for some not even the parent compound could be identified. In total, four potential degradation products were found in this study; degradation products were identified for hexabromobenzene (HBB) with penta-, tetra-, and tribromobenzene, as well as one potential product for 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EHTBB).