Abstract This study shows the results obtained of evaluation and comparison of chemical analysis and ecotoxicity for evaluated the quality of water contaminated with gasoline after Fenton process. The process Fenton was efficient to remove the aromatics organic compounds such as benzene, toluene and xylenes from water contaminated with gasoline. At 90 minutes of reaction time, the concentration measured of aromatics compounds by gas chromatography were less than limit of quantification (0.05mg L-1). This value is in accordance with the limits established by Brazilian legislation for the effluents discharge. On the other hand, analysis of total phenols and dissolved organic carbon demonstrated at 120 minutes that all dissolved organic compound and total phenols are not totally removed even though benzene, toluene and xylenes were almost completely removed. Phytotoxicity tests using Sinapis alba as biological response showed that water contaminated with gasoline are not toxic, however these results was probably influenced by volatilization of aromatics compounds during the assay. Differently, the ecotoxicity using Daphnia magna showed that water contaminated with aromatic compounds is toxic, but after 120 minutes of treatment the toxicity was reduced more than 50%. Then, Daphnia magna was the better bioindicator to evaluate the efficiency of Fenton process since these results were according with response of dissolved organic carbon and total phenol showing the toxicity of intermediates produced during the Fenton process.

This paper presents and discusses socioeconomic aspects and expectations of chemistry students at the State University of Ponta Grossa. Six classes, in the period from 2011 to 2013, were consulted during the first academic week through questionnaires. It was possible to verify that a significant part of students has the expectation to become teachers and pursue studies in postgraduate courses.

This paper describes a simple and rapid spectrophotometric method for quantitative determination of sildenafil citrate based on its reaction with p-chloranil accelerated by hydrogen peroxide, producing a stable purple compound (λmax= 535 nm). In the absence of peroxide this reaction is very slow. The experimental conditions were optimized by using response surface methodologies. Beer's law is obeyed in a concentration range of 8.52 x 10-5 - 1.70 x 10-3 mol L-1 (r = 0.999). The detection limit was 1.96 x 10-5 mol L-1. The method was successfully applied for the determination of sildenafil citrate in medicines with good accuracy and precision.