Improved sample pretreatment of the carbon disulfide evolution method for the determination of dithiocarbamate residues in lettuce

Vuik, Johan; Dinter, Rob. Van; Vos, Rudi H. De

doi:10.1021/jf00016a015

Cited by 17 publications

(13 citation statements)

References 6 publications

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“…While planning the field experiments on plants it was observed that, for the recovery of remaining pesticide, when thiram was triturated with plant material it decayed almost instantaneously. Similar observations on carbamates with fruit juices have been reported (Vuik et al , ; Heise et al , ; Malik et al , ). Therefore, in order to present a true picture of the decay, homogenization of the plant material with the pesticide has to be avoided.…”

Section: Methodssupporting

confidence: 86%

Degradation of thiram in water, soil and plants: a study by high‐performance liquid chromatography

Gupta

Rani

Kumar

2011

Biomedical Chromatography

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A comprehensive study was conducted to evaluate the persistence of thiram in water and soil under controlled conditions and on two plants, namely tomato and radish, in field conditions. In order to follow the decay of the pesticide, an HPLC procedure was developed employing an octadecyl endcapped RP-C18 column using a mixture of acetonitrile and water as the mobile phase and an ultraviolet detector. Studies conducted in water at different temperature, pH and organic content revealed that the persistence of the pesticide decreases with the increase in all the three variables. In the three different types of soils studied, the effect of pH was more or less apparent on a similar line. On average a slower decay was observed in the case of plants than in water and soil.

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Section: Methodssupporting

confidence: 86%

Degradation of thiram in water, soil and plants: a study by high‐performance liquid chromatography

Gupta

Rani

Kumar

2011

Biomedical Chromatography

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“…Similar observation on carbamates with fruit juices has been reported earlier. [14][15][16] In order to represent a true picture of the metabolic pathways of thiram, the metabolites were identified in surface washout and in crushed samples. The leaves and roots of radish and tomato fruits of four-week old plants were spotted with a known amount (100 mg L −1 ) of the thiram and subsequently after a definite interval of time the particular part was removed and pesticide was extracted.…”

Section: Degradation Studiesmentioning

confidence: 99%

Identification of degradation products of thiram in water, soil and plants using LC-MS technique

Gupta

Rani

Kumar

et al. 2012

Journal of Environmental Science and Health, Part B

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In order to evaluate the deleterious effects of exposure to pesticides on a target population, a comprehensive study on their degradation in the various segments of ecosystem under varying environmental conditions is needed. In view of this, a study has been carried out on the metabolic pathways of thiram, a dithiocarbamate fungicide, in a variety of matrices namely water and soil under controlled conditions and plants in field conditions. The identification of degradation products was carried out in samples collected at various time points using LC-MS. The degradation products identified can be rationalized as originating by a variety of processes like hydrolysis, oxidation, N-dealkylation and cyclization. As a result of these processes the presence of some metabolites like dimethyl dithiocarbamate, bis(dimethyl carbamoyl) disulphide, bis(dimethyl dithiocarbamoyl) trisulphide and N-methyl-amino-dithiocarbamoyl sulphide was observed in all the cases. However, some different metabolites were observed with the change in the matrix or its characteristics such as cyclised products 2(N, N-dimethyl amino)thiazoline carboxylic acid and 2-thioxo-4-thiazolidine were observed only in plants. The investigations reflect that degradation initiates with hydrolysis, subsequently oxidation/dealkylation, followed by different types of reactions. The pathways seem to be complex and dependent on the matrices. Dimethyl dithiocarbamate and oxon metabolites, which are more toxic than parent compound, seem to persist for a longer time. Results indicate persistence vis-a-vis toxicity of pesticide and its metabolites and also provide a data bank of metabolites for forensic and epidemiological investigations.

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“…A obtenção de amostras artificialmente contaminadas para o ensaio de proficiência de ditiocarbamatos encontrou algumas dificuldades: pequena estabilidade dos ditiocarbamatos quando em mistura com polpas de frutas e legumes, levando a sua rápida degradação, possivelmente por ação enzimática 17 ; baixa solubilidade destas substâncias em água e na maioria de solventes orgânicos, característica esta que gerou publicações somente para estudos interlaboratoriais em matrizes como uvas secas e produtos inertes como lactose e amido 10,18 . Por outro lado, a introdução de ditiocarbamatos a materiais inertes sólidos pode gerar uma variável nova, referente à homogeneização entre sólidos.…”

Section: Resultados Dos Participantes E Discussõesunclassified

Ensaio de proficiência para análise de ditiocarbamatos em polpa de banana

Bastos¹,

Góes²,

Cardoso³

et al. 2007

Quím. Nova

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Recebido em 8/9/05; aceito em 7/4/06; publicado na web em 11/8/06 PROFICIENCY ASSAY OF THE DITHIOCARBAMATES IN BANANA PULP ANALYSIS. A proficiency assay of the determination of dithiocarbamate pesticide residues in banana was carried out. Fourteen laboratories participated in this study. Homogeneity and stability testing were performed by INCQS on the samples sent to the laboratories. Analytical results supplied by the pesticide residues laboratory of the VWA/KvW, Amsterdam, Holland, were used to define the designated value for the thiram concentration in the study samples. Results: Fifty percent of the participating laboratories had satisfactory results. Efforts are needed to improve the precision of the analytical results and to decrease the number of false negative results observed.Keywords: pesticides; dithiocarbamates; interlaboratorial. INTRODUÇÃOO Brasil, como um país de extensa área rural e clima favorá-vel, é um dos maiores produtores e exportadores de produtos agrí-colas do mundo. Entretanto, muitos agricultores ainda não seguem as boas práticas agrícolas e, muitas vezes, utilizam agrotóxicos indiscriminadamente, tanto no que se refere à quantidade como à qualidade desses produtos. Tal fato torna-se uma preocupação para a saúde pública, devido aos danos causados ao trabalhador rural e ao consumidor.Os ditiocarbamatos (DTCs) pertencem a um grupo de agrotóxicos organossulfurados empregados na agricultura com ação fungicida. No Brasil existem registrados seis tipos de substâncias da classe dos ditiocarbamatos como ingredientes ativos, para quarenta e um diferentes tipos de cultura 1 .A relevância toxicológica dessas substâncias deve-se a seus dois maiores produtos de degradação, etileno tiouréia (ETU) e propilenotiouréia (PTU), suspeitos de serem bociogênicos, carcinogênicos e mutagênicos em ratos 2,3 . No Brasil, o uso de ditiocarbamatos em culturas é intenso, conforme relatado pelo programa gerenciado pela Agência Nacional de Vigilância Sanitária (ANVISA), o Programa Nacional de Análise de Resíduos de Agrotóxicos em Alimentos (PARA) 4 .O monitoramento de agrotóxicos em alimentos é importante para avaliar os níveis das frutas e verduras produzidas e comercializadas no país; verificar se os limites máximos de resíduos permitidos (LMR) estabelecidos pela legislação brasileira estão sendo de fato respeitados; verificar se agrotóxicos não registrados na ANVISA estão sendo utilizados ilegalmente no país; investigar se agrotóxicos devidamente registrados na ANVISA estão sendo utilizados de forma inadequada e, obter dados mais confiáveis para a estimativa da ingestão diária de resíduos de agrotóxicos pela população, uma informação fundamental ao realizar o registro de novos agrotóxicos e/ ou renovar o registro dos já autorizados 5 .Poucos são os laboratórios que realizam ensaio de determinação de resíduos de agrotóxicos em alimentos no Brasil. Os objetivos das análises realizadas por esses laboratórios normalmente são controle da qualidade de produção, pesquisa, exportação e proteção da saúde pública. Os labora...

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Improved sample pretreatment of the carbon disulfide evolution method for the determination of dithiocarbamate residues in lettuce

Cited by 17 publications

References 6 publications

Degradation of thiram in water, soil and plants: a study by high‐performance liquid chromatography

Degradation of thiram in water, soil and plants: a study by high‐performance liquid chromatography

Identification of degradation products of thiram in water, soil and plants using LC-MS technique

Ensaio de proficiência para análise de ditiocarbamatos em polpa de banana

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