This paper reports the development of a fully automated method for the multianalyte determination of twenty pesticides belonging to different classes (triazines, phenylureas, organophosphates, anilines, acidic, propanil, and molinate) in natural and treated waters. The method, based on on-line solid-phase extraction-liquid chromatography-electrospray-tandem mass spectrometry, is highly sensitive (limits of detection between 0.004 and 2.8 ng L(-1)), precise (relative standard deviations between 2.0 and 12.1%), reliable (two selected reaction-monitoring transitions are monitored per compound), rapid (45 min per sample), and simple. The application of this method to the monitoring of the target compounds in a waterworks revealed the presence of the pesticides investigated at concentrations up to 516 and 82 ng L(-1) (total pesticide concentration) in river water and ground water, respectively, used as sources, and their gradual removal through the purification process.

This work describes the optimization of a liquid chromatography-electrospray-tandem mass spectrometry (LC-ESI-MS-MS) method for the multianalyte determination of twenty pesticides, selected based on current regulations and extent of use. Chromatographic separation was carried out on a Purospher STAR RP-18e column using gradient acetonitrile-water as mobile phase. Triazines, phenylureas, organophosphates, anilines, and molinate were determined in the positive ionization mode, and acidic pesticides and propanil in the negative ion mode. Two different precursor ion-product ion transitions were selected for each analyte and monitored under time scheduled multiple reaction monitoring (MRM) conditions. The optimized method was shown to be linear in the range 1 to 1000 ng/mL with correlation coefficients higher than 0.99 for all but one (diazinon) of the analytes, very sensitive (with limits of detection between 0.010 and 4.528 ng/mL), and repeatable (with relative standard deviations, calculated from the replicate analysis of standard mixtures, lower than 14%). The present work was also devoted to the elucidation of the structures of the principal fragment ions obtained after collision-induced dissociation of the pesticides investigated, an aspect often overlooked in the literature.

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_____________________________________________________________________________________ RESUMOA legislação ambiental em vigor impõe padrões de emissões cada vez mais restritivos às indústrias geradoras de efluentes. Considerando essas exigências, as empresas precisam se adequar a essas políticas, tornando seus processos produtivos mais eficazes e menos poluentes. A combustão de carvão mineral em usinas termoelétricas gera cinzas pesadas que retornam aos produtores do insumo mineral e constituem um passivo ambiental. Neste estudo, as cinzas pesadas foram utilizadas para testes na síntese hidrotérmica (Hidrogel), em meio alcalino, visando à formação de zeólita Na-P1. Para comprovar a sua efetiva formação, foram realizadas análises por difração de raios X, fluorescência de raios X e capacidade de troca catiônica com solução padrão de cloreto de amônio, cujo valor em termos de equivalentes foi de 23,7 mg g -1 . Os resultados comprovaram a formação da zeólita Na-P1. Foram avaliados três efluentes industriais de três empresas distintas. A concentração final de nitrogênio amoniacal encontrada para os três efluentes após testes de adsorção de amônio em reator de leito fluidizado apresentaram uma redução de 49% ± 2 e os valores obtidos em termos de equivalentes foram de 21,8 mg g -1 , 22,9 mg g -1 e 22,7 mg g -1 . As Resoluções CONAMA 357/2005 430/2011 determinam padrões de qualidade de águas para diversas substâncias; no caso da amônia é de 20 mg L -1 de N/NH 3 . Considerando a grande dificuldade para reduzir os teores de nitrogênio amoniacal em determinados efluentes industriais, novas tecnologias vêm sendo implantadas, como a síntese de zeólitas a partir das cinzas pesadas de carvão. Esse estudo comprovou que a zeólita Na-P1 tem um grande potencial de adsorção para a redução de nitrogênio amoniacal de efluentes industriais.Palavras-chave: zeólita Na-P1, adsorção, nitrogênio amoniacal, efluente industrial. _____________________________________________________________________________________ ABSTRACTEnvironmental legislation in the country always requires more stringent standards for effluent generating industries. Companies must adapt to these laws making the industrial processes more efficient and less polluting. Burning coal in power plants produces bottom ash. This material returns to the coal producers and constitutes an environmental liability to the company. In this study, bottom ash was used in tests for the hydrothermal synthesis, under alkaline conditions, to generate zeolite Na-P1. Analyses by X-ray diffraction, X-ray fluorescence and cation exchange capacity with standard solution of ammonium chloride confirmed to the generation of zeolite Na-P1, and the value of the cation exchange capacity of the equivalent was 23.7 mg g -1 . Three industrial effluents from three different companies were collected and evaluated. Tests for ammonia adsorption in a fluidized bed reactor were performed in the three effluents. The results for the final ammonia concentration showed a reduction of 49% ±2, and the values obtained ar...