GC-MS and LC-MS evaluation of pesticide degradation products generated through advanced oxidation processes: An overview

Agüera, A.; Fernández‐Alba, Amadeo R.

doi:10.1051/analusis:1998160

Cited by 12 publications

(18 citation statements)

References 4 publications

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“…Hydrolysis, photolysis, using natural sunlight or xenon arc lamps, aquatic metabolism and field dissipation can also contribute to degradation. 7,8 In practice, the evaluation of degradation products is possible through identification by GC-MS. 9 Therefore, today, the removal of organic harmful pollutants present in water supplies is investigated through a variety of chemical procedures. Among them, oxidation by several agents besides chlorine, such as ozone, UV radiation and Fenton's reagent, have been extensively and successfully used.…”

Section: Introductionmentioning

confidence: 99%

“…Among them, oxidation by several agents besides chlorine, such as ozone, UV radiation and Fenton's reagent, have been extensively and successfully used. 9 The Advanced Oxidation Processes (AOPs), which are constituted by the combination of several oxidants, are characterized by the generation of very reactive and oxidizing free radicals in aqueous solutions, such as the hydroxyl radicals, which have a great destructive power. 10 Many of them are currently employed in the elimination of pesticides, 11,12 however no study has been published about procedures to degrade clomazone.…”

Section: Introductionmentioning

confidence: 99%

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Study of the degradation of the herbicide clomazone in distilled and in irrigated rice field waters using HPLC-DAD and GC-MS

Zanella¹,

Prímel²,

Gonçalves³

et al. 2008

J. Braz. Chem. Soc.

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Este estudo avaliou a degradação do herbicida clomazone em água destilada e de campos de arroz irrigado, através de irradiação UV e sob condições naturais. Após a etapa de pré-concentração por extração em fase sólida (SPE), a concentração remanescente foi determinada por cromatografia líquida de alta eficiência com detecção por arranjo de diodos (HPLC-DAD) e a identificação dos produtos de degradação foi efetuada por cromatografia gasosa com espectrometria de massas (GC-MS). Sob irradiação UV, o clomazone foi degradado mais rapidamente na água destilada que na água de superfície. Na água de irrigação, sob luz solar, o clomazone apresentou tempo de meia-vida médio de 3,2 dias em três safras consecutivas, e após a aplicação a concentração na água permaneceu acima de 0,1 µg L -1 por cerca de 20 dias. Diversos subprodutos, tais como 2-clorobenzaldeído e 2-clorobenzeno metanol, foram identificados por GC-MS, evidenciando que a concentração dos intermediários aumentou no início e então eles também sofreram degradação.This study evaluated the degradation of the herbicide clomazone in distilled water and from irrigated rice fields, through UV irradiation and under natural conditions. After a solid phase extraction (SPE) as preconcentration step, the remained concentration of clomazone was determined by high performance liquid chromatography with diode array detection (HPLC-DAD) and the identification of the degradation products was achieved by gas chromatography-mass spectrometry (GC-MS). Under UV irradiation, the clomazone was degraded faster in distilled water than in surface water. In irrigated rice water, under sunlight irradiation, clomazone presented a half-life time average of 3.2 days in three consecutive harvests, and after application the concentration in water remained higher than 0.1 µg L -1 for 20 days. Several by-products, like 2-chlorobenzaldehyde and 2-chlorobenzene methanol, were identified by GC-MS, which evidenced that the concentration of intermediates at the begining increase and then they also undergo degradation.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study of the degradation of the herbicide clomazone in distilled and in irrigated rice field waters using HPLC-DAD and GC-MS

Zanella¹,

Prímel²,

Gonçalves³

et al. 2008

J. Braz. Chem. Soc.

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“…In any case, the identification of unknowns in complex samples requires the application of analytical tools capable of providing the complementary information necessary to complete the puzzle, leading to the final structural assignment for the wide range of compounds expected in such studies. Gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry (GC/MS and LC/MS) techniques, because of their selectivity and sensitivity, are the most powerful methods for solving the problem simply and rapidly, even when a definitive assignment of chemical structures is not possible and, therefore, only tentative degradation pathways can be proposed9.…”

Section: Introductionmentioning

confidence: 99%

Application of time‐of‐flight mass spectrometry to the analysis of phototransformation products of diclofenac in water under natural sunlight

et al. 2005

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Exact mass capabilities of time-of-flight (TOF) mass spectrometry along with other mass spectrometric techniques have been evaluated to elucidate a complete range of dichlofenac phototransformation products. Photolysis experiments with diclofenac in water under direct solar irradiation were performed to characterise the main phototransformation products generated and to determine their stability. Photolysis experiments were performed in both demineralised water and reconstructed standard freshwater. Samples were extracted before analysis by solid phase extraction (SPE) with Oasis HLB and MAX cartridges. Separation and identification of the transformation products were accomplished by the combined use of gas chromatography-mass spectrometry (GC/MS) and liquid chromatography coupled with time-of-flight mass spectrometry (LC/TOFMS). Both techniques provided complementary information that enabled the identification of 13 phototransformation products. Six of them were identified by GC/MS through the structural information provided by the full scan mass spectra obtained under electron impact (EI) ionisation and the confirmation of the molecular mass provided by positive chemical ionisation (PCI) analyses. Accurate mass measurements obtained by LC/TOFMS provided the elucidation of seven polar transformation products. The low mass error observed (<2 ppm) enabled the assignment of highly probable empirical formulas as well as identification of a process dimerisation route. The photoproducts identified demonstrated that photolysis of diclofenac occurs by two main routes. One is the consequence of the initial photocyclisation of diclofenac into carbazole derivatives. The other route goes through the initial decarboxilation of diclofenac and further oxidation of the alkyl-chain, which are typical photolytic process reactions. The main photoproduct identified was 8-chloro-9H-carbazole-1yl-acetic acid.

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“…Nick et al (1992) conducted an investigation of the photodegradation kinetics of some herbicides in 4 cm 2 × 20 cm 2 quartz cells with an internal pathlength of 6 mm. Others ( Aaron and Oturan, 2001 ; Aguera and Fernandez‐Alba, 1998 ; Gong et al, 2001 ; Zeng et al, 2002 ) analyzed atrazine and its photochemical fate. Only Bourgine et al (1995) observed atrazine degradation in trial runs of an industrial‐scale UV chamber under irradiation of a medium‐pressure mercury lamp.…”

Section: Introductionmentioning

confidence: 99%

Photolytic Treatment of Atrazine‐Contaminated Water: Products, Kinetics, and Reactor Design

Ye¹,

Chen²,

Li³

et al. 2007

Water Environment Research

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This study investigates the products, kinetics, and reactor design of atrazine photolysis under 254-nm ultraviolet-C (UVC) irradiation. With an initial atrazine concentration of 60 lg/L (60 ppbm), only two products remain in detectable levels. Up to 77% of decomposed atrazine becomes hydroxyatrazine, the major product. Both atrazine and hydroxyatrazine photodecompose following the first-order rate equation, but the hydroxyatrazine photodecomposition rate is significantly slower than that of atrazine. For atrazine photodecomposition, the rate constant is proportional to the square of UVC output, but inversely proportional to the reactor volume. For a photochemical reactor design, a series of equations are proposed to calculate the needed UVC output power, water treatment capacity, and atrazine outlet concentration. Water Environ. Res., 79, 851 (2007).

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GC-MS and LC-MS evaluation of pesticide degradation products generated through advanced oxidation processes: An overview

Cited by 12 publications

References 4 publications

Study of the degradation of the herbicide clomazone in distilled and in irrigated rice field waters using HPLC-DAD and GC-MS

Study of the degradation of the herbicide clomazone in distilled and in irrigated rice field waters using HPLC-DAD and GC-MS

Application of time‐of‐flight mass spectrometry to the analysis of phototransformation products of diclofenac in water under natural sunlight

Photolytic Treatment of Atrazine‐Contaminated Water: Products, Kinetics, and Reactor Design

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