Photochemical transformation of terbutaline (pharmaceutical) in simulated natural waters: degradation kinetics and mechanisms.
In this study, varied nature organic matter isolates were employed to investigate the indirect photo transformation of terbutaline, which is a major feed additive medicine to increase the proportion of lean meat in the livestock. In the indirect photolysis of terbutaline under solar simulated irradiation, (1)O2 plays an important role among the •OH and (3)DOM*. The reaction rate constant of (1)O2 was determined as (7.1 ± 0.3) × 10(6) M(-1) s(-1) at pH 7.0, while the reaction rate constant of •OH was (6.87 ± 0.43) × 10(9) M(-1) s(-1). The contribution of singlet oxygen to the indirect photolysis of terbutaline (19-44%) was higher than that of the hydroxyl radical (1-7%). The pseudo first order rate constants for the photodegradation of terbutaline increase with increasing pH, which indicates that pH mainly affects the reaction rate of the singlet oxygen with the phenolic part of the terbutaline. The Quinone was identified as the main photosensitized product through LC-MS/MS analysis. It is also proposed that the degradation pathway of terbutaline involves reaction between the phenolic part of terbutaline and singlet oxygen. This finding strongly suggests that singlet oxygen was important factor for the photodegradation of terbutaline in natural waters.
Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, PR China.
Wenli
W
Yang
Sihem
S
Ben Abdelmelek
Zheng
Z
Zheng
Taicheng
T
An
Danny
D
Zhang
Weihua
W
Song
D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical / Q000737:chemistry; D007700:Kinetics; D009930:Organic Chemicals / Q000302:isolation & purification; D010777:Photochemistry / Q000379:methods*; D010782:Photolysis; D026082:Singlet Oxygen / Q000737:chemistry; D013057:Spectrum Analysis; D013726:Terbutaline / Q000737:chemistry* / Q000302:isolation & purification; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000302:isolation & purification
D009930:Organic Chemicals; D014874:Water Pollutants, Chemical; D026082:Singlet Oxygen; D017665:Hydroxyl Radical; D013726:Terbutaline
DOM; Hydroxyl radical; Photodegradation; Singlet oxygen; Terbutaline