Bisphenol A (BPA) is an environmental endocrine disrupting chemical, which can lead to various adverse health effects. Aiming to develop effective tools for the detection of BPA, this work reports a low cost and stable film based on casein (CAS) and Carbon Black (CB). The proposed material (CAS‐CB) showed structures of CAS surrounded by CB agglomerates observed by Scanning Electron Microscopy while Fourier Transform Infrared Spectroscopy analysis illustrated characteristic bands of casein. Cyclic Voltammetry (CV) and linear sweep voltammetry (LSV) were used to investigate the electrochemical behavior of BPA using the CAS‐CB. Under optimal conditions, LSV detection presented a limit of detection of 0.25 μmol L−1 in a linear range from 0.49 to 24 μmol L−1. Additionally, the working electrode (GC) modified by the proposed film (CAS‐CB) was applied for BPA sensing in environmental and milk samples. The results showed recoveries between 95.4 to 114 % attesting the efficiency of this new material, which has simplicity in the preparation, high conductivity, and adsorption capability.

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Resumo: o presente artigo relata uma experiência desenvolvida no âmbito das atividades de estágio em uma escola estadual pública, no interior de São Paulo. A partir das vivências no contexto da EJA, foram realizadas atividades de caráter investigativo para o ensino de Química por um grupo de estagiários que evidenciou a necessidade de planejar, desenvolver e avaliar atividades que proporcionassem a participação efetiva dos alunos, desde a oralidade e a escrita, explicitando suas expectativas e trajetórias, até o envolvimento nas discussões, reflexões, levantamento de hipóteses e organização de trabalho em grupo. As atividades desenvolvidas compreenderam técnicas da Química Forense e a realização de experimentos de caráter investigativo e contextualizado, direcionadas para as condições e realidade das turmas de EJA acompanhadas durante o ano de 2017. A atividade possibilitou o envolvimento de toda comunidade escolar, estudantes, professores, equipe de gestão escolar e estagiários, futuros professores de química, em um processo reflexivo sobre a formação e profissão docente.Palavras-chave: educação de jovens e adultos. Química. Atividades investigativas. Química forense.Abstract: this article reports an experience developed in the scope of the internship activities in a public state school, in the countryside of São Paulo. From the experiences in the context of the EJA, research activities were carried out for the teaching of Chemistry by a group of trainees who showed the need to plan, develop and evaluate activities that would provide effective oral and written participation of the students; this participation would include explaining their expectations and trajectories, involvement in the discussions, reflections, hypothesis gathering and group work organization in the space of Chemistry classes. The activity provided a teaching proposal based on techniques of Forensic Chemistry and conducting experiments of an investigative and contextualized character, directed to the conditions and reality of the classes of EJA accompanied during the year of 2017. The activity made possible the involvement of all the school community, students, teachers, school management team and trainees, future chemistry teachers, in a reflective process on teacher training and profession.