Acta Scientiarum. Technology ISSN: 1806-2563 [email protected] Universidade Estadual de Maringá Brasil Bastos Borges, Keyller; Figueiredo Freire, Ellen Simultaneous determination of organophosphorous insecticides in bean samples by gas chromatography - flame photometric detection Acta Scientiarum. Technology, vol. 36, núm. 3, julio-septiembre, 2014, pp. 531-535 Universidade Estadual de Maringá Maringá, Brasil Available in: http://www.redalyc.org/articulo.oa?id=303231059020 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative Acta Scientiarum http://www.uem.br/acta ISSN printed: 1806-2563 ISSN on-line: 1807-8664 Doi: 10.4025/actascitechnol.v36i3.19272 Simultaneous determination of organophosphorous insecticides in bean samples by gas chromatography - flame photometric detection Keyller Bastos Borges1* and Ellen Figueiredo Freire2 1Departamento de Ciências Naturais, Universidade Federal de São João del Rei, Praça Dom Helvécio, 74, 36301-160, São João del Rei, Minas Gerais, Brazil. 2Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil *Author for correspondence. E-mail: [email protected] ABSTRACT. The indiscriminate use of organophosphorous pesticides (OPPs) in crops may leave residues in food and may cause poisoning in the applicators. A method was developed for the determination of five OPPs in bean samples by Gas Chromatography-Flame Photometric Detection (GC-FPD). Validation parameters comprised linearity between 0.24 and 8.56 μg g-1 (r = 0.9985) for diazinon; 0.23 and 8.14 μg g-1 (r = 0.9959) for methyl parathion; 0.28 and 10.25 μg g-1 (r = 0.9987) for methyl pirimiphos; 0.52 and 18.87 μg g-1 (r = 0.9955) for malathion; 0.86 and 13.67 μg g-1 (r = 0.9919) for ethion. The limits of quantification (equal to those of detection) were the lowest rates of ranges mentioned above for each compound. The extraction method showed approximately 95% recovery, with CV% 15%. Although twenty-eight bean samples obtained in the southern region of the state of Minas Gerais, Brazil, were analyzed, they failed to match any of the OPPs under analysis. The absence of OPPs in the samples could be due to the degradation that occurred between the use of OPPs and bean commercialization, levels below the detection /quantification limits and the non-use of OPPs in bean cultivation. Keywords: GC-FPD, organophosphorous insecticides, beans. Determinação simultânea de pesticidas organofosforados em feijão por cromatografia gasosa com detecção fotométrica de chama RESUMO. O uso indiscriminado de pesticidas organofosforados (POFs) em lavouras pode deixar resíduos no alimento, além de provocar intoxicações nos aplicadores. Desta forma, foi desenvolvido um método para a determinação de cinco POFs em amostras de feijão por cromatografia gasosa com detecção fotométrica de chama (GC-FPD). Alguns parâmetros de validação obtidos foram: linearidade entre 0,24 e 8,56 μg g-1 (r = 0,9985) para a -1 -1 diazinona, 0,23 e 8,14 μg g (r = 0,9959) para o parationa metílica, 0,28 e 10,25 μg g (r = 0,9987) para o -1 -1 pirimifós metílico, 0,52 e 18,87 μg g (r = 0,9955) para o malationa e 0,86 e 13.67 μg g (r = 0,9919) para o etion. Os limites de quantificação (iguais aos de detecção) foram os menores valores dos intervalos acima citados para cada composto. O método de extração apresentou recuperação em torno de 95% com %CV 15%. Foram analisadas 28 amostras de feijão adquiridas na região sul de Minas Gerais, mas não se encontrou nenhum dos POFs estudados. A ausência destes POFs nas amostras pode ser atribuída à degradação ocorrida entre o uso dos POFs e a comercialização do feijão, à presença de níveis abaixo dos limites de detecção/quantificação do método, como também à não utilização de POFs no cultivo de feijão. Palavras-chave: GC-FPD, inseticidas organofosforados, feijão. Introduction diversity limit the coverage of a single analytical method. It is also impossible to monitor all the Extensive use of pesticides in agriculture and pesticides used against one particular type of food since environment pollution caused by industrial emissions several methods are employed. Thus, analytical during production have produced residues of laboratories require fast and efficient multiresidue chemicals and their metabolites in food commodities, methods to maximize the coverage of their monitoring water and soil (KAMPIOTI et al., 2005). So that a high activities. Researchers have actually reported many yield of food grains could be generated, several multiresidue analytical methods (COOK et al., 1999; pesticides have been developed, which in turn has FILLION et al., 2000; UENO et al., 2004; MARIANI facilitated the prosperity of populations and brought et al., 2010). relief to farmers. In fact, pesticide residues have been The determination of organophosphorus pesticides focused by many environmental studies. Each class has (OPPs) in food and vegetables is a matter of public a different target and their physical properties and concern since these pesticides are widely applied and Acta Scientiarum. Technology Maringá, v. 36, n. 3, p. 531-535, July-Sept., 2014 532 Borges and Freire their residues constitute a potential risk to human All chemicals were of analytical-grade and highest health. Measurement of pesticide residues in different purity available. Acetone, dichloromethane, hexane and matrices involves two basic steps, namely, sample methanol pesticide-grade were obtained from Grupo preparation (extraction and clean up) and instrumental Química (Rio de Janeiro State, Brazil). Water was analysis. Generally, trace analysis of complex samples distilled and purified using a Millipore Milli-Q Plus requires the preparation of good samples to reduce system (Bedford, USA). HPLC-grade ethanol and acetonitrile were purchased from Merck (Darmstadt, matrix interference and enrich the analytes. A sample Germany). preparation should ideally be rapid, simple, cheap, environment friendly and must provide clean extracts Instrumentation and analytical conditions (STAJNBAHER; ZUPANCIC-KRALJ, 2003). A GC 1000 equipped with a flame photometric Beans (Phaseolus vulgaris L.) are mainly consumed in detector (FPD, Ciola Gregori Ltda., São Paulo State, the northeastern and southeastern regions of Brazil. Brazil), a splitless injector inlet liner interfaced to a PC The food is one of the most traditional in Brazilian diet with DANI DS 1000 integrator (Dani Strumentazione as it provides nutrients, such as protein, iron, calcium, Analitica, Monza, Italy) and IQ3 software for data magnesium, zinc, carbohydrates, fiber and vitamins, acquisition were used. The simultaneous resolution of especially B-complex, essential to humans. Since beans organophosphorous pesticides under analysis was rank third among the food consumed and contain performed on a Supelco-SPB 35 column (30 m x 0.53 11.2% of total calories ingested, they are the main mm id, 0.5 μm film thickness; Supelco, Bellefonte, PA, source of protein and calories ingested by low-income USA) with detector temperature at 245oC, injector populations. temperature at 275oC, and initial temperature of the Therefore, current investigation proposes the oven at 160°C with ramp of 2.5°C min.-1 to 205°C, development and validation of a simple and maintained for 2.5 min., followed by ramp 20°C min.-1 economical GC-FPD method for the simultaneous up to 275°C, maintained for 2.5 min. and carrier gas -1 determination of diazinon, ethion, malathion, flow rate of N2 (99.999%) at 8 mL min. ; injector methyl parathion and methyl pirimiphos (Figure 1) operation in splitless mode; 1 μL of the sample was in bean samples from the southern region of the injected. state of Minas Gerais, Brazil. Bean samples Bean samples were purchased in the southern region of Minas Gerais (real samples). Beans samples without any kind of OPPs (organic production, blank samples) were used for the method´s optimization and validation. Real samples, collected in five towns from the southern region of Minas Gerais (Figure 2), were frozen and stored at –20oC, not exceeding 72h before analysis. Figure 1. Molecular structures of diazinon (1), methyl parathion (2), methyl pirimiphos (3), fenitrothion (I.S) (4), malathion (5) ethion (6). Material and methods Experimental Standard solutions and chemicals Diazinon (98.7%), ethion (99%), fenitrothion (98%, internal standard – I.S.), malathion (99%), methyl parathion (99%) and methyl pirimiphos (99.5%) were obtained from Chem Service (West Chester, USA). Stock standard solutions of OPPs were prepared by dissolution of each drug in ethyl acetate Figure 2. Map and location of the five towns in southern of and stored at -20°C, in the absence of light. Minas Gerais where bean samples were purchased. Acta Scientiarum. Technology Maringá, v. 36, n. 3, p. 531-535, July-Sept., 2014 Determination of OPPs in beans by GC-FPD 533 Extraction procedure – Liquid-Liquid Extraction (LLE) over five analytical runs (FDA, 2001), was obtained Beans were ground in a blender and 50 g were by bean samples (n = 5) spiked at different weighed in a 200-mL beaker. Sample was then placed concentrations of analytes. in a 500-mL beaker to which were added 50 mL Quality control samples were used for distilled water, 30 g sodium chloride and 200 mL precision and accuracy assays: whereas precision acetone. The mixture was strongly stirred for 3-5 was calculated as coefficient of variation (CV, %) minutes and filtered with a vacuum Buchner funnel. of within-day (n = 3) and between-day (n = 3) The filtrate was transferred to a separator funnel, analysis, accuracy was determined as the percentage of 150 mL dichloromethane were added and strongly deviation between nominal and measured stirred for 3-5 minutes. The aqueous phase was concentration (relative error, RE%).