TY - JOUR

T1 - New insights into mechanism of direct UV photolysis of p-arsanilic acid

AU - Tyutereva, Yuliya E.

AU - Sherin, Petr S.

AU - Parkhats, Marina V.

AU - Liu, Zizheng

AU - Xu, Jing

AU - Wu, Feng

AU - Plyusnin, Victor F.

AU - Pozdnyakov, Ivan P.

N1 - Publisher Copyright: © 2018 Elsevier Ltd

PY - 2019/4/1

Y1 - 2019/4/1

N2 - The mechanism of direct UV photolysis of p-arsanilic acid (p-ASA), a widely used veterinary drug, was revised by means of laser flash photolysis coupled with high resolution liquid chromatography – mass spectrometry (LC-MS). None of p-ASA triplet state or singlet oxygen was found to directly participate in the photodegradation of p-ASA as it was assumed in previous works. Here we demonstrate that the main primary photoprocess is a monophotonic ionization (ϕion 266nm = 0.032) leading to the formation of hydrated electron and corresponding anilinyl cation radical. These primary species react with dissolved oxygen yielding secondary reactive oxygen species. The final organic photoproducts, such as aminophenol and different dimeric products, originate from various reactions between these secondary species. The generation of inorganic arsenic, both As(V) and As(III), was also observed in agreement with previous works. For the first time we report the quantum yield of p-ASA photodegradation, which decreases from 0.058 to 0.035 with the excitation wavelength from 222 to 308 nm.

AB - The mechanism of direct UV photolysis of p-arsanilic acid (p-ASA), a widely used veterinary drug, was revised by means of laser flash photolysis coupled with high resolution liquid chromatography – mass spectrometry (LC-MS). None of p-ASA triplet state or singlet oxygen was found to directly participate in the photodegradation of p-ASA as it was assumed in previous works. Here we demonstrate that the main primary photoprocess is a monophotonic ionization (ϕion 266nm = 0.032) leading to the formation of hydrated electron and corresponding anilinyl cation radical. These primary species react with dissolved oxygen yielding secondary reactive oxygen species. The final organic photoproducts, such as aminophenol and different dimeric products, originate from various reactions between these secondary species. The generation of inorganic arsenic, both As(V) and As(III), was also observed in agreement with previous works. For the first time we report the quantum yield of p-ASA photodegradation, which decreases from 0.058 to 0.035 with the excitation wavelength from 222 to 308 nm.

KW - Hydrated electron

KW - Organic radicals

KW - p-arsanilic acid

KW - Photoionization

KW - Reactive oxygen species

KW - Transient species

KW - PATHWAYS

KW - ANILINE

KW - OXYGEN

KW - QUANTUM YIELD

KW - KINETICS

KW - WAVELENGTH

KW - WATER

KW - Reactive Oxygen Species

KW - Arsanilic Acid/radiation effects

KW - Oxygen/chemistry

KW - Ultraviolet Rays

KW - Photolysis

KW - Lasers

UR - http://www.scopus.com/inward/record.url?scp=85059548692&partnerID=8YFLogxK

U2 - 10.1016/j.chemosphere.2018.12.179

DO - 10.1016/j.chemosphere.2018.12.179

M3 - Article

C2 - 30597365

AN - SCOPUS:85059548692

VL - 220

SP - 574

EP - 581

JO - Chemosphere

JF - Chemosphere

SN - 0045-6535

ER -