DSpace Collection:https://repositorio.ufu.br/handle/123456789/217732026-08-11T16:55:07Z2026-08-11T16:55:07ZDeterminação voltamétrica de ácido salicílico em amostras de leite com um eletrodo de fio de cobrehttps://repositorio.ufu.br/handle/123456789/490312026-07-24T06:19:34Z2026-03-13T00:00:00ZTitle: Determinação voltamétrica de ácido salicílico em amostras de leite com um eletrodo de fio de cobre
Abstract: Salicylic acid (SA) is widely used in the dermatological and pharmaceutical industries
due to its antiseptic, anti-inflammatory, and exfoliating properties; however, its use as a
food additive is not permitted. Despite this prohibition, cases of milk adulteration with
SA are frequently reported in several countries. Besides compromising the quality of milk
and dairy products, this adulteration represents a serious health risk to consumers,
demonstrating the relevance of efficient analytical methods for the quantification of SA
in complex matrices such as milk. This work presents an environmentally friendly
voltammetric method for the determination of SA in milk, using a working electrode made
of commercial copper wires, subsequently subjected to a chemical modification in an
alkaline medium to form a CuO-rich layer that protects against electrode fooling and
improves the electrochemical response of SA. The technique employed was Differential
pulse voltammetry, which, after parameter optimization, yielded a linear range of 10 to
500 µmol L⁻¹ and a detection limit of 3.0 µmol L⁻¹. Another highlight is the sample
treatment using only ZnSO₄ and NaOH, the former precipitates milk proteins, while the
latter ionizes the SA, facilitating its extraction and subsequent detection. This procedure
reduces reagent and sample consumption, eliminates organic solvents, and allows for
rapid pre-treatment of multiple samples simultaneously. In the spike-and-recovery study
for fortified samples, the recovery percentages of AS ranged from 91 to 107%, with RSD
values from 2.1 to 5.3%, results consistent with the AOAC guidelines for evaluating the
performance of analytical methods. Therefore, this work offers a low-cost procedure,
more sustainable than the established method for determining AS in food, and with
satisfactory analytical performance, representing a promising strategy for the
quantification of AS in milk samples.2026-03-13T00:00:00ZO novo ensino médio e a base nacional comum curricular no ensino de química: revisão bibliográfica dos anais do ENEQ (2023 e 2024)https://repositorio.ufu.br/handle/123456789/468422025-09-17T06:19:25Z2025-09-11T00:00:00ZTitle: O novo ensino médio e a base nacional comum curricular no ensino de química: revisão bibliográfica dos anais do ENEQ (2023 e 2024)
Abstract: Esta monografía tiene como objetivo identificar los trabajos publicados en las actas de las dos últimas ediciones del Encuentro Nacional de Enseñanza de la Química (ENEQ) (2023 y 2024), en lo que respecta a la temática del Nuevo Bachillerato (NEM) y de la Base Nacional Común Curricular (BNCC). Dicho evento constituye el encuentro científico más importante en el área de la Enseñanza de la Química en Brasil y, por lo tanto, se destaca por promover reflexiones pertinentes a la comunidad académica y escolar involucrada en la Educación Química. Para ello, en un primer momento se desarrolla una revisión documental de los archivos del NEM, de la BNCC y del Currículo de Referencia de Minas Gerais (CRMG). Posteriormente, se realiza una revisión bibliográfica que toma como material dieciocho trabajos que constituyen el corpus de la investigación, los cuales fueron publicados en las actas de la XXI y XXII ediciones del ENEQ (2023 y 2024). Los resultados de la investigación señalan que ha habido un aumento de trabajos publicados en las actas de los ENEQ en relación con la temática del NEM y de la BNCC. Además, que las principales temáticas abordadas son: BNCC y sus desarrollos; Currículos estatales e itinerarios formativos; Enfoques didácticos alternativos y ludicidad; Condiciones de trabajo docente; y Formación docente y prácticas pedagógicas. Por lo tanto, este estudio muestra hasta qué punto el NEM y la BNCC se han convertido en un campo de interés e investigación en lo que respecta a las producciones y estudios en la Enseñanza de la Química.
Notes: 1002025-09-11T00:00:00ZUma análise das percepções dos estudantes sobre a escola de educação básica: resultados de uma pesquisa desenvolvida no âmbito do Programa Residência Pedagógicahttps://repositorio.ufu.br/handle/123456789/460962025-06-11T06:18:33Z2025-04-30T00:00:00ZTitle: Uma análise das percepções dos estudantes sobre a escola de educação básica: resultados de uma pesquisa desenvolvida no âmbito do Programa Residência Pedagógica2025-04-30T00:00:00ZEstudo de degradação forçada do cloridrato de ranitidina para avaliação da geração de nitrosaminashttps://repositorio.ufu.br/handle/123456789/459472025-05-29T06:19:21Z2025-05-30T00:00:00ZTitle: Estudo de degradação forçada do cloridrato de ranitidina para avaliação da geração de nitrosaminas
Abstract: The administration of medications was a turning point in history, allowing previously deadly diseases to become treatable. The pharmaceutical industry is one of the largest sectors of the global economy. According to ANVISA, the sale of medications generates more than 130 billion reais per year in Brazil. This scenario implies large-scale production for consumption, making it essential to rigorously verify the quality and safety of medications to ensure that they do not pose health risks. Recently, studies indicated the formation of N-nitrosodimethylamine (NDMA), a potentially toxic compound, in medicines with the active pharmaceutical ingredient (API) ranitidine hydrochloride. The ban on marketing was worldwide, and the episode revealed the need for greater control over production. Considering the possibility of formation of these compounds with carcinogenic potential, in the present study, a forced degradation study of the drug ranitidine, used to treat gastric ulcers, was carried out to evaluate the degradation products generated and the potential generation of NDMA. The drug was subjected to stress conditions: thermolysis, acid hydrolysis, basic hydrolysis, oxidation, and photolysis. The method used was based on the ANVISA degradation guide, Resolution No. 4/2015, to evaluate the generation of nitrosamines, especially NDMA. Chromatographic analysis was performed by high-performance liquid chromatography (HPLC), using a C18 column and mobile phase composed of ACN:H2O with gradient elution and detection performed by a diode array detector at 228 nm. Forced degradation tests led to the formation of seven ranitidine degradation products (DPs). Under more extreme conditions (prolonged time and/or higher concentrations of degrading agents), complete degradation of the drug was observed. Of these DPs formed, the formation of the toxic compound NDMA stood out, observed specifically in hydrolytic degradations under heating. Confirmation of the identity of NDMA was performed by comparison with analysis of the analytical standard of NMDA, under the same analysis conditions. Ranitidine DPs were identified through chromatographic profile analysis and comparison with the ranitidine chromatograms and byproducts published in the literature. Thus, the forced degradation of ranitidine proved efficient and valuable in evaluating the potential generation of toxic products from the degradation of ranitidine hydrochloride.2025-05-30T00:00:00Z