No abstract

Este trabalho descreve as atividades desenvolvidas por oito licenciandas do curso de licenciatura em química da UNESP, Campus de Presidente Prudente, com alunos do ensino médio, visando ao processo de formação inicial de professores de química. As atividades consistiram na aplicação de experimentos abrangendo conceitos de química e práticas do cotidiano, com o intuito de incentivar o interesse dos alunos para uma melhor compreensão dos fenômenos químicos e sua relação com os fatos do dia a dia. Os resultados foram analisados por meio da aplicação de um questionário, usado como ferramenta investigativa, que foi aplicado a 50 alunos do ensino médio por meio de amostragem. Os resultados analisados, a partir da interpretação do questionário, apontaram um maior aproveitamento das aulas de química pelos alunos com a realização dos experimentos. As atividades desenvolvidas permitiram que estas fossem inseridas no ambiente escolar, adquirindo experiência e habilidades pedagógicas para a prática da docência. experimentos, ensino de química, escola pública

Sulfonamides (SAs) are low-cost synthetic antimicrobials widely used in veterinary and human medicine to treat diseases and prevent infections. However, long periods of exposure to sulfonamides can cause adverse effects such as allergic reactions. This work aims to study dispersive solid-liquid microextraction as an alternative method for extracting total SAs in meat samples. The procedure uses a colorimetric reaction based on the formation of a pink compound (imine salt) to determine total sulfonamides (sulfamethazine, sulfadimethoxine, sulfathiazole) with digital measurements. A linear response was observed between 33-233 μg kg-1 for total sulfonamides, and the coefficient of variation (n = 11; 67 μg kg-1 of total SAs) and the limit of detection were estimated to be 0.63% and 10 μg kg-1, respectively. For a 750 mg meat sample, 0.11 mg of 4-dimethylaminocinnamaldehyde, 2.60 mg of sodium dodecyl sulfate, and 275 μL of 1-butanol were consumed per sample, and consequently, generating only 335 μL of residue. Besides this, addition-recovery tests were performed, resulting in a 71-100% recovery range, indicating the trueness of the proposed method.

The present study evaluated the spatiotemporal variation in concentration of cadmium, lead and copper ions in groundwater wells in the stratigraphic subdivision “Santo Anastácio” that belongs to the Bauru aquifer system in the western region of São Paulo State. Exploratory statistics methods were employed to investigate the response of the concentration of these metals in the aquifer through the pluviometric index of the region. The results show a direct dependence of the mean monthly flow of the metals in the groundwaters to the monthly rainfall flow. The observed behavior was cyclic with a gradual increase and decrease in the flow throughout time. Two groups of cyclic variation were identified. The seasonality of the mean monthly flow of Cd2+ and Pb2+ was inversely proportional to the magnitude of the pluviometric index of the region studied. Meanwhile, the seasonality of Cu2+ was directly correlated to the seasonable rainfall variability. These behaviors lead us to point out that cadmium and lead come from minerals present in the aquifer itself and the presence of copper in groundwater is associated with an anthropogenic action due to the region’s agricultural activity. The study helps us better comprehend the behavior of the whole groundwater system through a comparison with temporal hydrogeochemistry.