Recebido em 22/1/12; aceito em 6/7/12; publicado na web em 31/8/12 ANALYSIS OF PESTICIDES IN WATER USING LIQUID-LIQUID EXTRACTION WITH PARTITION AT LOW TEMPERATURE AND HIGH PERFORMANCE LIQUID CHROMATOGRAPHY. This study optimized and validated the liquid-liquid extraction technique with partition at low temperature (LLE-PLT) for identification and quantification of four pesticides (chlorpyrifos, λ-cyhalothrin, permethrin, bifenthrin) in water samples. Analyses were performed by HPLC-UV. The technique was efficient for pesticide recovery with extraction exceeding 86%. Chromatographic response was linear for the four compounds in the 10-45 µg L -1 range, with correlation coefficients greater than 0.99. Limits of detection and quantitation were less than 3.5 µg L -1 and equal to 10 µg L -1 , respectively. The proposed method was applied to 29 water samples from the Jaíba Project in northern Minas Gerais.Keywords: LLE-LTP; pesticides; HPLC-UV. INTRODUÇÃOO Projeto Jaíba é um amplo projeto de irrigação de grande importância para todo o Norte de Minas.1 A água utilizada para irrigação é coletada em canais próximos às próprias plantações (Figura 1S, material suplementar), apresentando elevado risco de contaminação devido a sua localização geográfica, fenômenos de lixiviação 2,3 e aplicações de agrotóxicos por via aérea. 4 Os agrotóxicos são largamente empregados para minimizar perdas na produtividade, atribuídas ao ataque de pragas. 5,6 A aplicação de agrotóxicos pode gerar resíduos no ar, solo e na água, expondo indiretamente o ser humano.7 Por isso, as agências reguladoras estabelecem limites máximos de resíduo permitido (LMR) em diversas matrizes. 8,9 Esses valores de LMR são estabelecidos levando em consideração vários fatores, dentre eles a toxicidade do composto para seres humanos e o limite de quantificação dos métodos instrumentais de análises. Devido à exigência da legislação e à toxicidade destas substâncias, o consumo desta água ou sua reutilização na agricultura pode resultar em riscos à saúde pública.A região do Projeto Jaíba se destacou nos últimos anos na produção de banana prata, limão tahiti e manga.10 Nestas culturas, clorpirifós, λ-cialotrina, permetrina e bifentrina representam agrotóxicos comuns para o controle de pragas.9 Embora destes quatro agrotóxicos apenas a permetrina seja regulamentada pela Portaria 518 de 2004 em amostras de água, 11 o uso constante dessas substâncias torna a análise e o monitoramento fundamentais para preservar a saúde humana e o meio ambiente.O primeiro passo para análise e monitoramento destas substâncias em água envolve o desenvolvimento da técnica de extração. Esta etapa visa remover seletivamente resíduos de agrotóxicos destas amostras e pré-concentrá-los. 12 As principais técnicas existentes são a extração em fase sólida, 13-15 microextração em fase sólida, 16-19 microextração líquido-líquido 20-23 e microextração em gota única. 24Apesar do elevado número de técnicas existentes, a extração líquido-líquido com partição em baixa temperatura (ELL-PBT) tem se apresentado...

Catharanthus roseus(L.) G. Don is a medicinal plant known for its important constituent aromatic compounds. In the literature, no detailed studies elucidating the methods of extraction of phenolic compounds for this species are available. Therefore, the present study was aimed at evaluating the maceration parameters for determining the total phenols content in C. roseus. The parameters of plant mass, extraction phase composition, homogenization type, extraction time, and temperature were evaluated in terms of improving the extraction conditions. The plant extracts were subjected to specific spectrophotometric analysis designed for each parameter, and the total phenols content was determined. After establishing the optimal conditions, the extracts were prepared from C. roseus cultivars, followed by evaluation of antioxidant activity using spectrophotometry, phenolic acid content using GC-MS, and dissimilarity using Unweighted Pair Group Method in combination with the Arithmetic Mean method. The optimal extraction conditions obtained were: 30 mg of dry plant tissue in 0.72 mL of extraction phase ethanol:water, 50:50 (v/v) at 50 °C for 1 h. The average total phenols content was 30.3 mg g-1 of gallic acid equivalents (GAE) and 20.0 mg g-1 of flavonoid quercetin equivalents (QE). The antioxidant activities determined using the DPPH, ABTS, and FRAP methods were 19.4, 11.8, and 23.3 mg g-1 of Trolox equivalent antioxidant capacity (TEAC), respectively. There was a predominance of ferulic (42%-56%) and caffeic (21%-52%) acids in the leaf extracts of C. roseus. The extraction process increased the total phenol content by 55%, from 18 to 28 mg GAE.

In this work, the direct determination methodology of glyphosate and aminomethylphosphonic acid (AMPA) by high performance liquid chromatography (HPLC) using inductively coupled plasma with triple quadrupole mass spectrometer (ICP-MS/MS) was compared with the conventional method using diode array detector (HPLC-DAD). Both methods were selective, but the chromatographic analysis using ICP-MS/MS as detector was four times faster than DAD. The methodology using ICP-MS/MS as detector was linear from 27 to 218 μg L-1 , while by the conventional method it was 1 to 8 mg L-1. Detection limits of the glyphosate achieved with the HPLC-ICP-MS/MS and HPLC-DAD methods were 8.2 and 300 μg L-1 , respectively. The direct determination using ICP-MS/MS as detector showed a lower number of stages in sample preparation because it did not need the derivatization step. Seven real samples were analyzed by HPLC-ICP-MS/MS and the results showed that these analytes were not detected.

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Organochlorine pesticides present in sewage sludge can contaminate soil and water when they are used as either fertilizer or agricultural soil conditioner. In this study, the technique solid-liquid extraction with low temperature purification was optimized and validated for determination of ten organochlorine pesticides in sewage sludge and soil samples. Liquid-liquid extraction with low temperature purification was also validated for the same compounds in water. Analyses were performed by gas chromatography-mass spectrometry operating in the selective ion monitoring mode. After optimization, the methods showed recoveries between 70% and 115% with relative standard deviation lower than 13% for all target analytes in the three matrices. The linearity was demonstrated in the range of 20 to 70 µg L, 0.5 to 60 µg L, and 3 to 13 µg L, for sludge, soil, and acetonitrile, respectively. The limit of quantification ranged between 2 and 40 µg kg, 1 and 6 µg kg, and 0.5 µg L for sludge, soil, and water, respectively. The methods were used in the study of pesticide lixiviation carried out in a poly vinyl chlorine column filled with soil, which had its surface layer mixed with sludge. The results showed that pesticides are not leached into soil, part of them is adsorbed by the sewage sludge (4-40%), and most pesticides are lost by volatilization.

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