Qualitative and Quantitative Analysis of the New Sulfone Bactericide 2-(4-Fluorophenyl)-5-(Methylsulfonyl)-1,3,4-Oxadiazole and Identification of Its Degradation Pathways in Paddy Water

2020 ◽  
Vol 58 (9) ◽  
pp. 859-867
Author(s):  
Xingang Meng ◽  
Niao Wang ◽  
Xiaofang Long ◽  
Lingzhu Chen ◽  
Deyu Hu
Keyword(s):  
Rice Straw ◽  
Degradation Product ◽  
High Resolution Mass Spectrometry ◽  
Brown Rice ◽  
Nucleophilic Attack ◽  
Array Detector ◽  
Orthogonal Experimental Design ◽  
Degradation Pathways ◽  
Rice Soil ◽  
Paddy Water

Abstract Rapid and simple methods for the determination of Jiahuangxianjunzuo (JHXJZ) in paddy water, brown rice, soil and rice straw was developed and validated. This method involved the use of ultrahigh-performance liquid chromatography equipped with photodiode array detector. The most important factor was chromatographic conditions, as identified through an orthogonal experimental design. This method showed good recoveries and precisions, thereby indicating its suitability for monitoring of JHXJZ residues in paddy water, brown rice, soil and rice straw. Furthermore, hydrolysis experiment was conducted in the laboratory under pH = 7 buffer solutions, and its degradation product was identified as 2-(4-fluorophenyl)-5-methoxy-1,3,4-oxadiazole by high-resolution mass spectrometry. JHXJZ has a major degradation pathway in the water which the OH− nucleophilic attack the C5 of 1,3,4-oxadiazole ring. Then it leaves mesyl to form intermediate 5-(4-fluorophenyl)-1,3,4-oxadiazol-2-ol and the intermediate combined with methanol formed the degradation product 2-(4-fluorophenyl)-5-methoxy-1,3,4-oxadiazole by the loss of one H2O.The degradation pathways of JHXJZ under the present indoor simulation conditions were proposed.

scholarly journals Studies on Dissipations and Residues of Indoxacarb under Different Field and Environmental Conditions

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Ying-Hong Li ◽  
Xiang-Yun Wang ◽  
Wei Hua ◽  
Hu Zhang
Keyword(s):  
Rice Straw ◽  
Environmental Conditions ◽  
Paddy Soil ◽  
High Performance ◽  
Solid Phase ◽  
Brown Rice ◽  
Rice Hull ◽  
Selected Ion Monitoring ◽  
Paddy Water ◽  
Preharvest Interval

Indoxacarb is a broad-spectrum insecticide and widely used in agriculture. The dissipations and residues of indoxacarb were researched at three different field sites in Beijing, Hunan, and Zhejiang provinces in China. Analytical methods for determining the residue of indoxacarb in paddy water, paddy soil, rice straw, rice hull, and brown rice were described. Indoxacarb residues were extracted from samples, cleaned up by solid phase extraction, and determined by high-performance liquid chromatography coupled with tandem mass spectrometry in the selected ion monitoring mode. The recoveries in paddy water, paddy soil, rice straw, rice hull, and brown rice matrices at three spiking levels ranged from 79.7% to 98.3%, respectively. The field and environmental conditions would affect the dissipations and residues of indoxacarb. The time to dissipate 50% of indoxacarb in paddy water, paddy soil, and rice straw was less than 9 days. The terminal residues obtained from Beijing at preharvest interval of 14 and 21 days were higher than the maximum limit of European Union. Therefore, a dosage of 24 g a. i. ha−1 at 28 days preharvest interval with 3 spraying times was recommended. Such accumulation of measured data is necessary to provide guidance for the proper and safe use of this pesticide.

Validation of analytical method and evaluation of clothianidin residues in rice in a typical Chinese field ecosystem

2017 ◽  
Vol 155 (9) ◽  
pp. 1371-1380 ◽  
Author(s):  
Z. Y. ZHANG ◽  
Z. T. ZHENG ◽  
G. Y. ZHU ◽  
X. Y. YU ◽  
D. L. WANG ◽  
...  
Keyword(s):  
Rice Straw ◽  
Paddy Soil ◽  
Brown Rice ◽  
Rice Hull ◽  
Limit Of Quantification ◽  
Paddy Water ◽  
Relative Standard ◽  
Field Ecosystem ◽  
Validation Of Analytical Method

SUMMARYA liquid chromatography mass spectrometry method for determination of clothianidin in brown rice, straw, rice hull, paddy water and paddy sediment was developed and residue levels were determined in the different components. The limit of quantification was set at 0·01 mg/kg for the matrices studied. Clothianidin degradation in straw, paddy water and soil was studied, and clothianidin residues in brown rice, straw, hull and paddy soil were determined. Concurrent recoveries were between 85·6 and 92·5%, with relative standard deviations ranging from 1·3 to 6·8% at three fortification levels between 0·01 and 5·0 mg/kg. The half-lives in straw, paddy water and paddy sediment were found to be 1·9–4·9, 4·1–5·0 and 4·9–6·3 days, respectively. The maximum residues in brown rice, straw, hull and paddy soil samples were 0·38, 1·88, 1·38 and 0·14 mg/kg, respectively.

scholarly journals In vitro antileishmanial activity of Anacardium othonianum and isolated compounds against Leishmania amazonensis

2021 ◽  
Vol 5 (1) ◽  
pp. 44
Author(s):  
Tavane Aparecida Alvarenga ◽  
Osvaine Júnior Alvarenga Alves ◽  
Mariana Cintra Pagotti ◽  
Wilson Roberto Cunha ◽  
Márcio Luís Andrade e Silva ◽  
...  
Keyword(s):  
High Resolution Mass Spectrometry ◽  
Leishmania Amazonensis ◽  
Antileishmanial Activity ◽  
Anacardic Acid ◽  
Array Detector ◽  
Preparative Hplc ◽  
Moderate Activity ◽  
Phytochemical Study ◽  
Phenol Derivatives

This study analyzes the antileishmanial activity of the crude ethanol extract, fractions, and isolated compounds of A. othonianum nuts. Antileishmanial activity was evaluated against Leishmania amazonensis promastigotes in vitro. The phytochemical study was performed by high-performance liquid chromatography-high-resolution mass spectrometry-diode array detector (HPLC-HRMS-DAD) and by preparative HPLC. HPLC-HRMS-DAD analysis of the bioactive extract confirmed the presence of ten alkyl phenol derivatives that had previously been isolated from A. occidentale. Bioassay-guided isolation afforded cardanol triene, cardanol diene, cardanol monoene, cardol triene, anacardic acid triene, anacardic acid diene, and anacardic acid monoene. Cardol triene gave an IC50 of 80.66 µM. The obtained data suggest that the evaluated extract, fractions, and cardol triene had moderate activity against L. amazonensis promastigotes. This is the first description of alkyl phenols in A. othonianum.

scholarly journals Green Extraction of Alkaloids and Polyphenols from Peumus boldus Leaves with Natural Deep Eutectic Solvents and Profiling by HPLC-PDA-IT-MS/MS and HPLC-QTOF-MS/MS

Plants ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 242 ◽  
Author(s):  
Jeniffer Torres-Vega ◽  
Sergio Gómez-Alonso ◽  
José Pérez-Navarro ◽  
Edgar Pastene-Navarrete
Keyword(s):  
Mass Spectrometry ◽  
Phenolic Compounds ◽  
High Resolution Mass Spectrometry ◽  
Choline Chloride ◽  
Deep Eutectic Solvents ◽  
Total Phenolic ◽  
Array Detector ◽  
Green Extraction ◽  
Medicinal Tree ◽  
Natural Deep Eutectic Solvents

Peumus boldus Mol., is a Chilean medicinal tree used for gastrointestinal and liver diseases. Such medicinal properties are associated with the presence of bioactive flavonoids and aporphine alkaloids. In this study, a new green and efficient extraction method used seven natural deep eutectic solvents (NADES) as extraction media. The extraction efficiency of these NADES was assessed, determining the contents of boldine and total phenolic compounds (TPC). Chemical profiling of P. boldus was done by high-performance liquid chromatography coupled to photo diode array detector and electrospray ion-trap mass spectrometry (HPLC-PDA-ESI-IT/MS) and electrospray ionization quadrupole time-of-flight high-resolution mass spectrometry (HPLC-ESI-QTOF-MS). Among the NADES tested, NADES4 (choline chloride-lactic acid) and NADES6 (proline-oxalic acid) enable better extraction of boldine with 0.427 ± 0.018 and 2.362 ± 0.055 mg of boldine g−1 of plant, respectively. Extraction of boldine with NADES4 and NADES6 was more efficient than extractions performed with methanol and water. On the other hand, the highest TPC were obtained using NADES6, 179.442 ± 3.79 mg of gallic acid equivalents (GAE g−1). Moreover, TPC in extracts obtained with methanol does not show significant differences with NADES6. The HPLC-PAD-MS/MS analysis enable the tentative identification of 9 alkaloids and 22 phenolic compounds. The results of this study demonstrate that NADES are a promising green extraction media to extract P. boldus bioactive compounds and could be a valuable alternative to classic organic solvents.

scholarly journals On the Stability and Degradation Pathways of Venetoclax under Stress Conditions

Pharmaceutics ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 639
Author(s):  
Nina Žigart ◽  
Martin Črnugelj ◽  
Janez Ilaš ◽  
Zdenko Časar
Keyword(s):  
High Resolution Mass Spectrometry ◽  
Degradation Products ◽  
Single Agent ◽  
B Cell Lymphoma ◽  
Lymphocytic Leukemia ◽  
Stress Conditions ◽  
Forced Degradation ◽  
Degradation Pathways ◽  
Orally Bioavailable ◽  
The Stability

Venetoclax is an orally bioavailable, B-cell lymphoma-2 (BCL-2) selective inhibitor, used for the treatment of various types of blood cancers, such as chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL). In this study we investigated the degradation of venetoclax under various stress conditions including acidic, basic, oxidative, photolytic and thermolytic conditions. We isolated and identified six of its main degradation products produced in forced degradation studies. The structures of the isolated degradation products were determined by using nuclear magnetic resonance (NMR) spectroscopy, high resolution mass spectrometry (HRMS) and infrared (IR) spectroscopy. Additionally, one oxidation degradation product was identified with comparison to a commercially obtained venetoclax impurity. We proposed the key degradation pathways of venetoclax in solution. To the best of our knowledge, no structures of degradation products of venetoclax have been previously published. The study provides novel and primary knowledge of the stability characteristics of venetoclax under stress conditions. Venetoclax is currently the only BCL-2 protein inhibitor on the market. In addition to single agent treatment, it is effective in combinational therapy, so future drug development involving venetoclax can be expected. A better insight into the stability properties of the therapeutic can facilitate future studies involving venetoclax and aid in the search of new similar therapeutics.

A computational study of the main degradation product of antitumor drug imexon

2017 ◽  
Vol 16 (04) ◽  
pp. 1750037
Author(s):  
Djaffar Kheffache ◽  
Ourida Ouamerali
Keyword(s):  
Degradation Product ◽  
Density Functional ◽  
Computational Study ◽  
Water Environment ◽  
Bulk Water ◽  
Uv Spectra ◽  
Antitumor Drug ◽  
Point Of View ◽  
Degradation Pathways ◽  
Main Degradation Product

We theoretically study, from the thermodynamic point of view, the possibility of the two degradation pathways of antitumor drug of imexon. According to the theoretical results obtained at DFT level in both gas and aqueous phases, the two degradation pathways of imexon are characterized by negative reaction Gibbs free energies. It has been found that 4-imino-5-methylene-imidazolidin-2-one is the favored degradation product of imexon. Herein, the focus of this work has been on calculating the geometries, relative energies and electronic properties of all possible prototropic tautomers of 4-imino-5-methylene-imidazolidin-2-one using the DFT and MP2 levels. The bulk water environment has been simulated by continuum model using Solvation Model based on Density (SMD). The UV spectra of two dominant tautomers of 4-imino-5-methylene-imidazolidin-2-one are also predicted using time-dependent density functional theory and the results are compared with the available experimental data. The comparison of the simulated and the experimental absorption spectra has allowed us to accurately characterize the predominant tautomer of the degradation product in aqueous medium.

Effects of rice-straw and phosphorus application on production and emission of methane from tropical rice soil

2005 ◽  
Vol 168 (2) ◽  
pp. 248-254 ◽  
Author(s):  
Arun Kumar Rath ◽  
B. Ramakrishnan ◽  
V. R. Rao ◽  
N. Sethunathan
Keyword(s):  
Rice Straw ◽  
Rice Soil ◽  
Phosphorus Application
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