scholarly journals New Photodegradation Products of the Fungicide Fluopyram: Structural Elucidation and Mechanism Identification

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2940 ◽  
Author(s):  
Tessema F. Mekonnen ◽  
Ulrich Panne ◽  
Matthias Koch
Keyword(s):  
Current Knowledge ◽  
Aqueous Media ◽  
Structural Elucidation ◽  
Mass Measurements ◽  
Chromatography Tandem Mass Spectrometry ◽  
Isotopic Pattern ◽  
Accurate Mass Measurements ◽  
Liquid Chromatography Tandem Mass ◽  
Photodegradation Products ◽  
Living Organisms

Identifying the fate of agrochemicals is important to understand their potential risk for living organisms. We report here new photodegradation products (PPs) of the fungicide fluopyram. The PPs were produced by irradiating a fluopyram standard in 0.1% acetonitrile aqueous media by a 150-W medium pressure Hg-lamp that emits wavelengths between 200–280 nm. The structural elucidation of PPs was achieved by combining the retention time, isotopic pattern, targeted fragmentation, and accurate mass measurements using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and high resolution-MS (HRMS). In addition to previously known PPs, seven new PPs of fluopyram were identified in this work: mainly dihydroxyl and hydroxylimide fluopyram as well as mono, di, and trihydroxyl lactam. Additionally, two PPs were found to be formed by rearrangement after the loss of H2C=CH2. Hence, the results of the work contribute to extending the current knowledge regarding the photoinduced fate of agrochemicals, and fluopyram in particular.

scholarly journals Characterization and Diversity of Microcystins Produced by Cyanobacteria from the Curonian Lagoon (SE Baltic Sea)

Toxins ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 838
Author(s):  
Donata Overlingė ◽  
Anna Toruńska-Sitarz ◽  
Marija Kataržytė ◽  
Renata Pilkaitytė ◽  
Greta Gyraitė ◽  
...  
Keyword(s):  
Temporal Variations ◽  
Structure Identification ◽  
Curonian Lagoon ◽  
Peptide Structure ◽  
Toxicological Assessment ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass ◽  
Mcye Gene ◽  
Living Organisms ◽  
Significant Health

Microcystins (MCs) are the most widely distributed and structurally diverse cyanotoxins that can have significant health impacts on living organisms, including humans. The identification of MC variants and their quantification is very important for toxicological assessment. Within this study, we explored the diversity of MCs and their potential producers from the Curonian Lagoon. MC profiles were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, while the potential producers were detected based on the presence of genus-specific mcyE gene sequences. Among the numerous MCs detected, one new potential MC variant with m/z 1057 was partially characterized. Moreover, two other MCs with m/z 1075 and m/z 1068 might belong to new variants with serine (Ser), rarely detected in position one of the peptides. They might also represent MC-Y(OMe)R and MC-WR, respectively. However, the application of a low-resolution MS/MS system made the unambiguous identification of the MCs impossible. Based on this example, the problems of peptide structure identification are discussed in the work. Genetic analysis revealed that potential MCs producers include Dolichospermum/Anabaena, Microcystis spp., and Planktothrix agardhii. The diversity and temporal variations in MC profiles may indicate the presence of several chemotypes of cyanobacteria in the Curonian Lagoon.

scholarly journals Photodegradation of the H1 Antihistaminic Topical Drugs Emedastine, Epinastine, and Ketotifen and ROS Tests for Estimations of Their Potent Phototoxicity

Pharmaceutics ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 560
Author(s):  
Anna Gumieniczek ◽  
Anna Berecka-Rycerz ◽  
Urszula Hubicka ◽  
Paweł Żmudzki ◽  
Karolina Lejwoda ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Ultra Performance Liquid Chromatography ◽  
First Order ◽  
Ph Values ◽  
First Order Kinetics ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass ◽  
Photodegradation Products ◽  
Antihistaminic Drugs

In this study, important H1 antihistaminic drugs, i.e., emedastine (EME), epinastine (EPI), and ketotifen (KET), were irradiated with UV/Vis light (300–800 nm) in solutions of different pH values. Next, they were analyzed by new high performance liquid chromatography (HPLC) methods, in order to estimate the percentage of degradation and respective kinetics. Subsequently, ultra-performance liquid chromatography tandem-mass spectrometry (UPLC-MS/MS) was used to identify their photodegradation products and to propose degradation pathways. In addition, the peroxidation of linoleic acid and generation of singlet oxygen (SO) and superoxide anion (SA) were examined, together with the molar extinction coefficient (MEC) evaluation, to estimate their phototoxic risk. The photodegradation of all EME, EPI, and KET followed pseudo first-order kinetics. At pH values of 7.0 and 10.0, EPI was shown to be rather stable. However, its photostability was lower at pH 3.0. EME was shown to be photolabile in the whole range of pH values. In turn, KET was shown to be moderately labile at pH 3.0 and 7.0. However, it degraded completely in the buffer of pH 10.0. As a result, several photodegradation products were separated and identified using the UPLC-MS/MS method. Finally, our ROS assays showed a potent phototoxic risk in the following drug order: EPI < EME < KET. All of these results may be helpful for manufacturing, storing, and applying these substantial drugs, especially in their ocular formulations.

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