Soils that had received successive applications of retorted oil shale (ROS) in an experiment under field conditions were used in this study, aiming to evaluate the availability of trace elements. In the batch tests, we observed that toxic elements present in the ROS are not desorbed from the matrix in significant amounts to contaminate soil and groundwater. The element Ca represents the greatest nutrient contribution, which has high mobility and ease release into the soil solution. Concerning the results obtained from the soil extracts analysis; we observed that the undesirable elements released into the extracts are not directly related to the presence of ROS in the soil samples. Comparing the behavior of soil samples with and without ROS it is possible to infer that many of the trace elements are derived from soil constituents, from previous fertilizer and pesticides applications. The study suggested that the ROS can be used as a soil conditioner for agricultural purposes without adding harmful elements to the environment.

A pyrolyzed oil shale by-product known as retorted shale was functionalized with HCl, HNO3, H2SO4, H3PO4, HNO3/H2SO4 (3:1), Fenton's reagent, (NH4)2S2O7, NaOH, and KMnO4 using either ultrasound (Route 1) or reflux (Route 2). The products obtained were evaluated in terms of cation exchange capacity (CEC). Structural characterization was performed using X-ray diffraction, X-ray fluorescence, and infrared spectroscopy to identify the functional groups present. The best results were achieved using Route 2 with solutions of either H3PO4 or HNO3/H2SO4 (3:1), giving CEC values of 315 and 316 mmolc kg-1, respectively. The pyrolyzed oil shale functionalized using Route 2 (reflux) with NaOH as the activating agent showed the highest sorption of methylene blue (35.6 mg g-1). The main mechanisms observed for oil shale by-product functionalization were oxidation, nitration, and CaO leaching.

Neste trabalho, propõe-se a determinação de fenol e o-cresol por análise por injeção em fluxo (FIA) com detecção espectrofotométrica, utilizando a reação com 4-aminoantipirina, a fim de quantificar essas espécies em extratos de solo. Após otimização das condições por planejamento fatorial, constatou-se uma maior frequência de amostragem em comparação com o método convencional, bem como valores de recuperação, limites de detecção e de quantificação comparáveis para ambos os métodos. Tais aspectos sugerem que esse método pode ser uma alternativa viável para a determinação de compostos fenólicos em extratos de solos.

Phenol and o-cresol determination by flow injection analysis (FIA) with spectrophotometric detection, employing the 4-aminoantipyrine reaction, is proposed in this work in order to quantify these species in soil extracts. The method was improved by a factorial planning, being verified a higher sampling rate in comparison with the conventional method, and recovery values, limits of detection and quantification similar for both methods. These aspects suggest this method as a feasible alternative for phenolic compound determinations in soil extracts.

A determinação espectroscópica multivariada da associação lamivudina-zidovudina foi realizada por regressão de mínimos quadrados parciais. O modelo foi desenvolvido a partir de 20 misturas sintéticas utilizando-se dados espectrais centrados na média adquiridos entre 190 e 350 nm e 3 variáveis latentes. A validação externa foi realizada a partir de 6 misturas sintéticas, observando-se erros médios de previsão de aproximadamente 1%. Na análise de medicamentos foram obtidos bons resultados, com erros de previsão inferiores a 10%. A metodologia multivariada foi validada de acordo com os critérios do International Conference on Harmonization (ICH), demonstrando precisão, exatidão e robustez compatíveis com a legislação vigente.

The multivariate spectroscopic determination of lamivudine-zidovudine associations was carried out by partial least square regression (PLS). This model was developed from 20 synthetic mixtures using mean-centered spectral data acquired from 190 to 350 nm and with 3 latent variables. External validation was performed with 6 synthetic mixtures providing prediction errors close to 1%. Moreover, the analysis of commercial drugs showed good results with prediction errors lower than 10%. The multivariate methodology was validated according to International Conference on Harmonization (ICH) criteria, demonstrating precision, accuracy and robustness within legal requirements.

In this work the antioxidant capacity of red wine samples was characterized by conventional spectroscopic and chromatographic methodologies, regarding chemical parameters like color, total polyphenolic and resveratrol content, and antioxidant activity. Additionally, multivariate calibration models were developed to predict the antioxidant activity, using partial least square regression and the spectral data registered between 400 and 800 nm. Even when a close correlation between the evaluated parameters has been expected many inconsistencies were observed, probably on account of the low selectivity of the conventional methodologies. Models developed from mean-centered spectra and using 4 latent variables allowed high prevision capacity of the antioxidant activity, permitting relative errors lower than 3%.

O objetivo deste estudo foi o de monitorar o nível de poluição de sedimentos subaquáticos de florestas de mangue utilizando espectroscopias de ressonância paramagnética eletrônica (EPR) e de infravermelho próximo (NIR) e análises químicas. A espectroscopia de EPR foi útil para determinar a presença de radicais livres orgânicos de semiquinonas, bem como, fornecer informações sobre a presença de ferro trivalente em domínios diluídos e concentrados nos espectros das amostras. Concluiu-se que, o uso de EPR e NIR, no intervalo espectral adequado, tornou possível avaliar, de forma não destrutiva, o nível de poluição ambiental em sedimentos subaquáticos costeiros de florestas de mangue. Assim, em um período relativamente curto e imprescindível, as autoridades podem tomar as decisões necessárias a fim de evitar danos ambientais.

The objective of this study was the monitoring of the pollution level of underwater mangrove sediments using electron paramagnetic resonance (EPR), near-infrared (NIR) spectroscopy and chemical analyses. EPR spectroscopy was useful to determine the presence of organic free radical semiquinone, as well as, to provide information about the presence of trivalent iron in diluted and concentrated or clustered dominion in the sediment samples spectra. It was concluded that by using EPR and NIR spectroscopy measurement, in the appropriate spectral range, it was possible to nondestructively assess the environmental pollution level of coastline underwater mangrove sediments. Though, in a relatively small period of time, the authorities can take the necessary decisions to avoid environmental damages.