MÉTODO PARA DETERMINAÇÃO DE HEPTACLORO, ALDRIN, DIELDRIN E ENDRIN EM PRÓPOLIS

Desenvolveu-se método para determinação de Heptacloro, Aldrin, Dieldrin e Endrin em própolis (sólida e solução). Após homogeneização da amostra com Celite, a extração dos pesticidas foi efetuada com hexano e o extrato purificado em cartucho de Florisil. A eluição dos pesticidas foi realizada com hexano:diclorometano (9:1 v/v) e o eluato concentrado e analisado por cromatografia em fase gasosa com detecção por captura de elétrons (CGDCE). A eficiência do método proposto foi demonstrada pelos valores médios de recuperação entre 79 e 100%, com valores de desvio padrão relativo entre 2,7 e 16,6%, obtidos nas análises de recuperação realizadas com amostras fortificadas nos níveis 0,6 e 1,2 µg/g. METHOD FOR THE DETERMINATION OF HEPTACHLOR, ALDRIN, DIELDRIN AND ENDRIN IN PROPOLIS Abstract A method for the determination of Heptachlor, Aldrin, Dieldrin and Endrin in propolis (solid and solution) was developed. After the samples homogenization with Celite the pesticides extraction was carried out with hexane and the extract was purified in Florisil cartridge. The pesticides elution was processed with hexane:dichloromethane (9:1 v/v) and the concentrated eluate was analysed using gas-liquid chromatography with electron capture detection (GCECD). The efficiency of the proposed method was demonstrated by mean recoveries, ranging from 79 to 100% with relative standard deviation values between 2.7 to 16.6%, obtained in the recovery analysis with fortified samples at levels of 0.6 and 1.2 µg/

MSPD procedure combined with GC-MS for the determination of procymidone, bifenthrin, malathion and pirimicarb in honey

A method based on matrix solid-phase dispersion and gas chromatography-mass spectrometry to determine procymidone, malathion, bifenthrin and pirimicarb in honey is described. The best results were obtained using 1.0 g of honey, 1.0 g of silica-gel as dispersant sorbent and acetonitrile as eluting solvent. The method was validated by fortified honey samples at three concentration levels (0.2, 0.5 to 1.0 mg kg-1). Average recoveries (n=7) ranged from 54 to 84%, with relative standard deviations between 3.7 and 8.5%. Detection and quantification limits attained by the developed method ranged from 0.02 to 0.08 mg kg-1 and 0.07 to 0.25 mg kg-1 for the honey, respectively

Tropical peat as a versatile material for solid-phase extraction of pesticides from medicinal plant Cordia salicifolia

Natural peat was tested for solid-phase extraction of acephate, chlorpropham, pirimicarb, bifenthrin, tetradifon and phosalone from the medicinal plant Cordia salicifolia, using gas chromatography-mass spectrometry with selected ion monitoring (GC/MS, SIM). Considering that there are no Brazilian regulations concerning maximum permissible pesticide residue concentrations in medicinal herbs, recovery experiments were carried out (three replicates) at two arbitrary fortification levels (0.5 and 1.0 mg kg-1), resulting in recoveries ranging from 64% to 118% and relative standard deviations between 5.6% and 26.4% for peat sorbent. Detection and quantification limits for herb ranged from 0.10 to 0.15 mg kg-1 and from 0.15 to 0.25 mg kg-1, respectively, for the different pesticides studied. The developed method was linear over the range assayed, 0.1-5.0 μg g-1, with correlation coefficients ranging from 0.9975 to 0.9986 for all pesticides. Comparison between natural peat and conventional sorbent (neutral alumina) showed similar performance of peat for the six pesticides tested

Desenvolvimento e aplicação de métodos para análise de resíduos dos fungicidas Pirimetanil, Procloraz e Fluquinconazol e dos acaricidas Clofentezina e Cihexatina em frutas

Fungicidas, como pirimetanil, fluquinconazol e procloraz, e acaricidas, como clofentezina e cihexatina, são aplicados tanto no período de pré-colheita, como para preservar a qualidade e as características de cor e sabor das frutas durante a armazenagem, o transporte e a comercialização (procloraz). Contudo, devido à persistência dos seus resíduos nas frutas, monitoramentos devem ser realizados, empregando-se técnicas analíticas sensíveis, para avaliar se os resíduos de tais pesticidas atendem aos limites estabelecidos pelas legislações dos países exportadores e importadores. Um número reduzido de métodos para análise de resíduos dos fungicidas pirimetanil, procloraz e fluquinconazol e dos acaricidas cihexatina e clofentezina, usados no controle de doenças e pragas em culturas de frutas, estão descritos na literatura. Aliando este dado à importância econômica da produção de frutas em nosso país, foram desenvolvidos e/ou adaptados métodos eficientes, rápidos e simples para a determinação destes fungicidas e acaricidas na casca e na polpa de mamão (papaia), manga e laranja e no fruto inteiro de morango e uva. As metodologias são baseadas em extração líquido-líquido e análise individual por cromatografia a gás com detecção por captura de elétrons para procloraz e cihexatina e detecção termiônica...Fungicides, as pyrimethanil, prochloraz and fluquinconazole, besides acaricides, as clofentezine and cyhexatin, have been used to preserve the quality of perishable fruits during their production, storage and commercialization. Also, these fungicides and acaricides are employed in the pre-harvest period. However, the presence of pesticide residues in fruits representes a serious problem, once the pesticides could become a risk to human consumption. So, the development of analytical methods looking for a rapid screening can ensure that the pesticide concentrations are below of the maximum residue limits allowed by the regulatory agencies. In the literature, some methods for the determination of pyrimethanil, prochloraz, clofentezine and cyhexatin in fruit matrices have been described. Respecting fluquinconazole, there is only a German review. Considering the subjects mentioned and that Brazil plays an important role in the worldwide production of fresh fruit, the purpose of this work was to develop simple and efficient methods for the determination of these fungicides and acaricides in peel and pulp of papaya, mango and orange, besides in grape and strawberry (entire fruit). The methodologies are based on liquid-liquid extraction. The analyses were performed by means of gas chromatography with thermionic specific detection for pyrimethanil and electron-capture detection for prochloraz and cyhexatin. In addition, pyrimethanil, prochloraz, fluquinconazole and clofentezine were analyzed employing a liquid...(Complete abstract, click electronic access below)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

A Simple and Rapid Extraction for Gas Chromatographic Determination of Thiabendazole and Imazalil Residues in Lemons

A rapid and efficient method is described for the determination of thiabendazole and imazalil residues in lemons (peel and pulp). The procedure is based on the extraction with an hexane:ethyl acetate mixture (1:1, v/v) and gas chromatographic analysis using thermionic specific detection (TSD). The possibility of matrix effect was also studied. Mean recoveries from 8 replicates of fortified samples ranged from 79% to 109%, with relative standard deviation values between 2.4% to 12.8%. The detection and quantification limits of the method were 0.2 mg kg-1 and 0.5 mg kg-1, respectively

PROCEDIMENTO SIMPLIFICADO DE EXTRAÇÃO PARA ANÁLISE DE RESÍDUOS DE CARBENDAZIM EM UVA POR CROMATOGRAFIA À LÍQUIDO DE ALTA EFICIÊNCIA

Descreve-se método para a determinação de resíduos do fungicida Carbedazim em amostras de uva. O procedimento compreende extração simples com hexano:acetato de etila (1:1 v/V) e análise por cromatografia à líquido de alta eficiência, empregando coluna de fase reversa, fase móvel composta de metanol:solução aquosa 1% de fosfato ácido de potássio (65:35) e detecção e quantificação na faixa ultra violeta visível (UVVIS) a 286 nm. Os valores percentuais de recuperação de seis análises para cada um dos três diferentes níveis de fortificação (0,5; 1,0; 5,0 mg/Kg) variaram de 76 a 101%, com coeficientes de variação entre 4,5 e 10,4. Os limites de detecção e de quantificação do método foram de 0,2 e 0,5 mg/Kg, respectivamente. Estes resultados sugerem que o método estudado é sensível e eficiente para determinação de resíduos de Carbendazim em uva

A simplified procedure for determination of clofentezine residues in fruits by liquid chromatography with UV detection

A rapid and sensitive method is described for the determination of clofentezine residues in apple, papaya, mango and orange. The procedure is based on the extraction of the sample with a hexane:ethyl acetate mixture (1:1, v/v) and liquid chromatographic analysis using UV detection. Mean recoveries from 4 replicates of fortified fruit samples ranged from 81% to 96%, with coefficients of variation from 8.9% to 12.5%. The detection and quantification limits of the method were of 0.05 and 0.1 mg kg-1, respectively