UV degradation of carbofuran insecticide in aqueous solution: identification and toxicity evolution of by-products

2004 ◽  
Vol 4 (5-6) ◽  
pp. 313-319
Author(s):  
G. Mascolo ◽  
A. Lopez ◽  
A. Detomaso ◽  
L. Guzzella
Keyword(s):  
Mass Spectrometry ◽  
Aqueous Solution ◽  
High Pressure ◽  
Liquid Chromatography Mass Spectrometry ◽  
Uv Degradation ◽  
Radical Coupling ◽  
Carbamate Group ◽  
Uv Lamp ◽  
Hydrolysis Of ◽  
By Products

The paper reports the results of an investigation about the UV degradation of carbofuran, a widely used insecticide in Europe. Specific objectives were the identification of the by-products formed and the evaluation of the toxicity of the irradiated solution compared to that of carbofuran. The experimental results, obtained treating an aqueous carbofuran solution (50 mg/L) by high pressure UV lamp (125 W), show that the insecticide is completely removed within 120 min. Several intermediate by-products have been identified by liquid chromatography-mass spectrometry (LC-MS) as a result of hydroxylation process of the 2,3-dihydro benzofurane ring and other reactions such as the cleavage of the carbamate group, the hydrolysis of ethereal moiety, radical coupling and decarboxylation processes. After 270 min of reaction the identified by-products were completely degraded and COD and TOC removals of 35 and 20% were measured, respectively. Toxicological analyses performed using the comparison procedure of the MicrotoxTM assay provided interesting clues concerning toxic effects of the photodegradation by-products. The results revealed a substantial increase of the toxicity during the first 15 min proving that photodegradation of organic contaminant could even lead to an increase of the toxicity of treated solution.

scholarly journals Flow Chemistry System for Carbohydrate Analysis by Rapid Labeling of Saccharides after Glycan Hydrolysis

2020 ◽  
Vol 25 (4) ◽  
pp. 356-366
Author(s):  
Wei-Ting Hung ◽  
Yi-Ting Chen ◽  
Chung-Hsuan Chen ◽  
Yuan Chuan Lee ◽  
Jim-Min Fang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Flow System ◽  
Flow Chemistry ◽  
Composition Analysis ◽  
Laser Desorption Ionization ◽  
Liquid Chromatography Mass Spectrometry ◽  
Ionization Time ◽  
Flight Mass Spectrometry ◽  
Rapid Labeling ◽  
Hydrolysis Of

This study demonstrates the utilization of a flow chemistry system for continuous glycan hydrolysis and saccharide labeling to assist with the existing methods in glycan structural analysis. Acidic hydrolysis of glycans could be accelerated in a flow system. Aldoses and α-ketoacid-type saccharides were effectively labeled with naphthalene-2,3-diamine (NADA) at 60 °C for 10 min to form the fluorescent naphthimidazole (NAIM) and quinoxalinone (QXO) derivatives, respectively. The NADA-labeled derivatives improved the structural determination and composition analysis for their parent saccharides by using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), liquid chromatography mass spectrometry (LC-MS), and nuclear magnetic resonance (NMR). Furthermore, this protocol was applied to determine the SA–Gal–Glc sequence of GM3-sugar out of six possible permutations.

scholarly journals Catechin Photolysis Suppression by Aluminum Chloride under Alkaline Conditions and Assessment with Liquid Chromatography–Mass Spectrometry

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5985
Author(s):  
Meei-Ju Yang ◽  
Shwu-Yuan Lee ◽  
Chieh-I Liu ◽  
Shih-Hsuan Chen ◽  
Iou-Zen Chen ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Aqueous Solution ◽  
Liquid Chromatography ◽  
Aluminum Chloride ◽  
Superoxide Anion ◽  
Anion Radical ◽  
Structural Changes ◽  
Liquid Chromatography Mass Spectrometry ◽  
Relative Percentage ◽  
Alkaline Conditions

Tea is rich in catechins and aluminum. In this study, the process of catechin photolysis was applied as a model for examining the effects of aluminum chloride (AlCl3) on the structural changes of catechin and the alteration of aluminum complexes under blue light irradiation (BLI) at pH 8 using liquid chromatography and mass spectrometry techniques. Additionally, the effects of anions on catechin upon the addition of AlCl3 and treatment with BLI were also studied. In this study, when 1 mM catechin was treated with BLI, a superoxide anion radical (O2•−) was generated in an air-saturated aqueous solution, in addition to forming a dimeric catechin (proanthocyanidin) via a photon-induced redox reaction. The relative percentage of catechin was found to be 59.0 and 95.7 for catechin treated with BLI and catechin upon the addition of 1 mM AlCl3 treated with BLI, respectively. It suggested that catechin treated with BLI could be suppressed by AlCl3, while AlCl3 did not form a complex with catechin in the photolytic system. However, under the same conditions, it was also found that the addition of AlCl3 inhibited the photolytic formation of O2•−, and reduced the generation of proanthocyanidin, suggesting that the disconnection of proanthocyanidin was achieved by AlCl3 acting as a catalyst under treatment with BLI. The influence of 1 mM fluoride (F−) and 1 mM oxalate (C2O42−) ions on the photolysis of 1 mM catechin upon the addition of 1 mM AlCl3 and treatment with BLI was found to be insignificant, implying that, during the photolysis of catechin, the Al species were either neutral or negatively charged and the aluminum species did not form a complex with anions in the photolytic system. Therefore, aluminum, which is an amphoteric species, has an inherent potential to stabilize the photolysis of catechin in an alkaline conditions, while suppressing the O2•− and proanthocyanidin generation via aluminum ion catalysis in the catechin/Al system under treatment with BLI.

Formation and hydrolysis of polynuclear Th(IV) complexes – a nano-electrospray mass-spectrometry study

2008 ◽  
Vol 96 (7) ◽  
Author(s):  
C. Walther ◽  
M. Fuss ◽  
S. Büchner
Keyword(s):  
Mass Spectrometry ◽  
Aqueous Solution ◽  
Electrospray Mass Spectrometry ◽  
Mass Spectrometry Study ◽  
Hydrolysis Of

Polynuclear hydroxide complexes play an important role for the hydrolysis of tetravalent thorium ions in aqueous solution, in particular for Th(IV) concentrations exceeding some [Th(IV)]=10

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