Fenitrothion and esfenvalerate stability during corn and wheat sample processing

Abstract

The presence of insecticide residues in cereals represents a risk for the consumer, because these substances are used in large scale to protect stored grains from the attack of pests. The effects of three processing methods for corn and wheat samples on the stability of stored-grain protective insecticides were here evaluated. Fenitrothion and esfenvalerate were applied so as to produce theoretical concentrations of 10 and 0.5 mg kg -1 , respectively. Two hours after treatment, the grains were processed and deposition was analyzed by gas chromatography. Grain species did not influence insecticide stability. This stability was only dependent upon the processing method and insecticide type. Grains processed together with dry ice provided the greatest percentage of recovery for both insecticides. Regardless of the processing method, more esfenvalerate than fenitrothion was recovered, thus demonstrating the greater stability of the pyrethroid during this operation. Key words: stored grain, insecticide degradation, dry ice, gas chromatography ESTABILIDADE DE FENITROTION E ESFENVALERATO DURANTE O PROCESSAMENTO DE AMOSTRAS DE MILHO E TRIGORESUMO: A presença de resíduos de inseticida em amostras de cereais representa um risco ao consumidor, pois estas substâncias são empregadas em larga escala na preservação de grãos armazenados. Neste sentido, o efeito de três métodos de processamento de amostras de milho e trigo na estabilidade de inseticidas protetores de grãos armazenados foram avaliados. O fenitrotion e o esfenvalerato foram aplicados de modo a produzir concentração teórica de 10 e 0,5 mg kg -1 , respectivamente. Duas horas após o tratamento, os grãos foram processados e os depósitos analisados mediante cromatografia gasosa. A espécie de grão não teve influência na estabilidade dos inseticidas, sendo que essa estabilidade apenas dependeu do método de processamento e do inseticida. Os grãos processados junto com gelo seco proporcionaram a maior porcentagem de recuperação de ambos os inseticidas. Independente do método de processamento utilizado, conseguiu-se recuperar mais esfenvalerado do que fenitrotion, demonstrando-se assim, a maior estabilidade do piretróide durante esta operação. Palavras-chave: grãos armazenados, degradação de inseticida, gelo seco, cromatografia gasosa

Peruvian Botanical Biopesticides for Sustainable Development and Protection of the Environment

“…The housefly, Musca domestica L. (Diptera: Muscidae), is considered a vector of viruses, bacteria, and protozoa that cause many diseases in humans and other mammals and has become an important public health concern (Urzúa et al, 2010a;Sripongpun, 2008). Management of M. domestica has been carried out through the application and extensive use of synthetic insecticides, which in turn have caused serious environmental problems, such as the development of pest resistance, ecological damage, and irreversible damage to human health (Vásquez, de Baptista, Trevizan, & Gadanha, 2008;Ahmed, Zain, & Irfanullah, 2004;Nivsarkar, Cherian, & Padh, 2001; Kristensen & Jespersen, 2003;Taşkin, Kence, & Göçmen, 2004;Khalaf, Hussein, & Shoukry, 2009).…”