Este trabalho propõe método de análise de resíduos de Clorpirifós em amostras de alface por cromatografia a líquido de alta eficiência (CLAE). A análise foi realizada em cromatógrafo Shimadzu, com detector de ultravioleta ajustado em 229 nm, Coluna C-18, modelo Zorbax ODS (4,6 mm x 25 cm, 5 µm), fluxo de 1 mL/min e temperatura de 35ºC. Usou-se Metanol:Água (82:18) como fase móvel e volume injetado de 50 µL. Amostras de alface (20 g) foram trituradas e homogeneizadas na presença de 50 mL de Diclorometano (DCM). O material foi filtrado a vácuo e evaporado a temperatura de 50ºC. O resíduo foi retomado com fase móvel, agitado, desgaseificado, filtrado em membrana 0,22 µm e injetado no cromatógrafo (injetor automático). Os resultados do teste de repetitividade mostraram recuperação média de 101,91%. O método proposto é simples e rápido para determinação de resíduos de Clorpirifós em amostras de alface. METHOD FOR THE DETERMINATION OF CHLORPIRYFOS RESIDUES IN LETTUCE BY USING HPLC (High Performance Liquid Cromatograph) Abstract This paper suggests a method for the residual analysis of chlorpiryfos in lettuce samples by using HPLC (High Performance Liquid Cromatograph). The analysis has been carried out in a Shimadzu cromatograph, with ultraviolet detector adjusted to 229 nm, column C-18, model Zorbax ODS (4.6 mm x 25 cm, 5 µm), flux 1mL/min, temperature of 350C. The mobile phase used was methanol:water (82:18) and the injected volume of 50 µL. Lettuce samples have been triturated and homogenized in the presence of 50 mL of the solvent Dichlormethan (DCM). The vacuum filtered material was evaporated at the temperature of 500C. The residue has been retaken in a mobile phase, stirred, degasified, filtered in a 0.22 µm membrane and automatically injected in the HPLC. Good results were obtained in a repetitivity test, with an average recovery of 101.91%. The proposed test presents simplicity and quickness in the residual determination of Chlorpiryfos in lettuce samples.
This study was conducted to verify the damage of artificial infestation ofthe fall armyworm, Spodopterajrugiperda(1. E. Smith) to maize cultivars at different levels of AI saturation (low, medium and high) in an acid soil. The experiments were conducted in the field, at Sete Lagoas, MG, during three consecutive years in plots corrected with lime to provide three levels of aluminum saturation: toxic (m < 50%), intermediate (m < 20%), and without aluminum (m < 5%). Two maize cultivars, BR 136 (tolerant) and CMS 28 (sensitive) to toxic levels of AI saturation were used. The non-infested plots were maintained free from natural infestation ofthe fall armyworm using granular insecticide applied directly to the whorl. The treated plots were artificially infested with young larvae. The average yield losses due to fall armywom were 848 kglha (17.7%) and were constant across the treatrnents. The highest yield without infestation was 4792 kg/ha.
O presente estudo trata da viabilidade do uso de três compostos inseticidas diluídos para duas modalidades de aplicação, tratorizada e em irrigação, no controle da lagarta-do-cartucho do milho, Spodoptera frugiperda. A técnica baseou-se na imersão de círculos foliares de milho, nas diferentes caldas e diluições, e fornecimento durante 36 horas às formas jovens da praga. Após 14 e 38 horas do início do fornecimento, foram contabilizados os insetos mortos. Os resultados permitiram concluir que os compostos chlorpyrifos e fenitrothion não se diferenciam no controle, alcançando nas duas modalidades, 100% de mortalidade das formas jovens.
One of the factors decreasing maize yie]d iii Brazil is rclated to the soil insect complex and the lcsscr coro sta!khorcr, Elasnwpalpus lignosel/us (Zeiler). This study was conducted to evaluate carbo!iiran, carbosulfan and thiodicarh, alonc or in mixture with micronulrients (boron, zine and rnolybdenum), as seed treatnient to contro] the initial pests of maize, using the hyhrid BR 201. Evaluations were based on plant emergence, insect damage and yield parameters. The dosage o[ each product was 700 g of active ingredient / 100 kg of seed. Except for carbaryl, the use of insecticides as a seed freatment increased the number of plarits per unit arca up to 45 o/ compared to the check. The average maize yie!d from treated plots varied from 818 to 1414 kg/ ha, greater than the yield obtained from the check plots.
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