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

Determination of fluquinconazole, pyrimethanil, and clofentezine residues in fruits by liquid chromatography with ultraviolet detection

A simple method was developed for the determination of fluquinconazole, pyrimethanil, and clofentezine in whole fruit; peel; and pulp of mango, apple, and papaya. These compounds were extracted from fruit samples with a mixture of ethyl acetate-n-hexane (1 + 1, v/v). An aliquot (2 mL) of the extract was evaporated to near dryness under a stream of nitrogen, and the residue was dissolved with 2 mL methanol. The analysis was performed by means of liquid chromatography with ultraviolet detection at 254 nm using a gradient solvent system. The method was validated with fortified fruit samples at concentration levels of 0.05, 0.10, 0.20, and 0.50 mg/kg. Average recoveries (4-8 replicates) ranged from 80 to 95% with relative standard deviations between 3.5 and 12.7%. Detection limits ranged from 0.03 to 0.05 mg/kg for fruit pulp and 0.03 mg/kg for whole fruit. The quantitation limits ranged from 0.05 to 0.10 mg/kg for fruit pulp and 0.05 mg/kg for whole fruit. The analytical method was applied to fruit samples obtained from local markets

Determination of organochlorine pesticides and polychlorinated biphenyls residues in municipal solid waste compost by gas chromatography with electron-capture detection

A simple and efficient method for the simultaneous gas chromatographic determination of ten organochlorine pesticides (alpha-HCH, beta-HCH, gamma-HCH, p,p'-DDT, o,p'-DDT, p,p'-DDD, p,p'-DDE, aldrin, endrin, and dieldrin) and six congeners of PCBs (PCB 28, 52, 118, 138, 153, and 180) in municipal solid waste compost is described. The procedure involves a solid-phase dispersion matrix using celite as dispersant sorbent, alumina as clean up sorbent and hexane-dichloromethane (7:3, v/v) mixture as eluting solvent. An additional purification step with copper was necessary to eliminate sulphur. Analysis of the sample was performed by GC-ECD. The method was validated with fortified samples at two concentration levels (0.025 and 0.05 mg kg(-1)). Average recovery ranged from 77 to 121% with relative standard deviation between 1 and 18%. The detection limits, which ranged from 0.003 to 0.01 mg kg-1, were lower than those established by the Baden-Wurttemberg directive (0.033 mg kg(-1))

Prochloraz residue levels in ginger submitted to Sportak 450 CE postharvest treatment

Um estudo preliminar foi realizado para determinar os níveis de concentração de procloraz em amostras de gengibre tratadas por imersão em solução aquosa com a formulação Sportak 450 CE (procloraz como ingrediente ativo) nas concentrações de 450 e 900 µg mL-1, sob condições de laboratório e armazenadas por 15 dias em câmara fria a 10°C e com 89% de UR. Amostras de gengibre tratadas foram analisadas após 10 e 15 dias do armazenamento. Os resíduos de procloraz foram analisados por CG-DCE. Os níveis encontrados variaram entre 3,6 e 10,6 mg Kg-1 para procloraz.A preliminary study was conducted to determine the residue levels of prochloraz in ginger samples treated with Sportak 450 CE® (prochloraz as active ingredient) under laboratory conditions and cold-storage for 15 days at 10°C and 89% RH. Sampling was carried out at 10 and 15 days after Sportak 450 CE® dip treatment (450 and 900 µg mL-1). Pesticide residues were determined by GCECD. During the study, residue levels in ginger ranged between 3.6 and 10.6 mg Kg-1 for prochloraz.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES