Cylindrospermopsin (CYN) has become a significant concern to public health and the environment since it is extremely toxic and it has been recently found in several freshwater sources. Titanium dioxide photocatalytic process has been proven to be effective for CYN destruction. However, very limited information is available about the by-products and pathways of CYN photocatalytic degradation, which limits the complete assessment of this treatment technology. Therefore, the reaction by-products of CYN degradation by TiO2 photocatalysis were identified and studied in this work by using high-performance liquid chromatography combined with quadrupole time-of-flight electrospray ionization tandem mass spectrometry (LC/Q-TOF-ESI-MS). The reaction pathways were proposed based on the detected by-products and hydroxyl radical chemistry. The by-products can be formed through hydroxylation process by ?OH hydrogen abstraction and addition to double bonds, such as m/z 432.1 and 448.11. Sulfate elimination process can produce by-products without the sulfate group. By-products, m/z 392.12 and 375.10 for example, can be formed after ring opening by being attacked on the hydroxymethyl uracil moiety and tricyclic guanidine moiety. This work is important for the assessment of CYN photocatalytic treatment from fundamental mechanism aspects and provides insights that can help determine the level of treatment required by such advanced oxidation technologies.

Photocatalytic destruction of cylindrospermopsin: Identification of reaction by-products and unveiling of reaction pathways

248th National Meeting (2014)

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