DSpace Communidade:http://repositorio.ufgd.edu.br/jspui/handle/prefix/17372026-11-01T17:12:56Z2026-11-01T17:12:56ZPerformance e caracterização de um sensor eletroquímico utilizando MWCNT/Fe3O4 para a detecção do herbicida DiuronSena , Thiago da Silvahttp://repositorio.ufgd.edu.br/jspui/handle/prefix/71682026-10-24T05:08:13Z2026-07-01T00:00:00ZTítulo: Performance e caracterização de um sensor eletroquímico utilizando MWCNT/Fe3O4 para a detecção do herbicida Diuron
Autor(es): Sena , Thiago da Silva
Primeiro Orientador: Carvalho, Adriana Evaristo de
Abstract: This work describes the development and characterization of a carbon paste electrochemical sensor modified with multi-walled carbon nanotubes functionalized with iron oxide nanoparticles (MWCNT/Fe₃O₄) for the voltammetric detection of the herbicide diuron (DRN) in water samples. Material functionalization was confirmed by thermogravimetric analysis (TGA/DSC) and Fourier-transform infrared spectroscopy (FTIR). Electrochemical characterization by cyclic voltammetry in a [Fe(CN)₆]³⁻/⁴⁻
solution demonstrated that the redox process at both electrodes is diffusion-controlled, in agreement with the Randles-Ševčík equation. The MWCNT/Fe₃O₄ electrode presented an Ipa/Ipc ratio of 0.99 and R² = 0.993, indicating a quasi-reversible behavior and higher regularity in electron transfer compared to MWCNT-OX (R² = 0.844; Ipa/Ipc = 0.78). Electrochemical impedance spectra (EIS) revealed a lower charge transfer resistance for the MWCNT/Fe₃O₄ electrode (Rct = 231 Ω) compared to MWCNT-OX
(Rct = 343 Ω), confirming the kinetic superiority of the magnetic composite. The pH optimization study, conducted by DPV in 0.05 mol L⁻¹ Britton-Robinson buffer, indicated pH 3 as the optimum condition for DRN detection. The analytical curve showed two distinct linear ranges: from 0.05 to 1.0 µmol L⁻¹, with a LOD of 0.52 µmol L⁻¹ and LOQ of 1.74 µmol L⁻¹; and from 1.0 to 50 µmol L⁻¹, with a LOD of 5.85 µmol
L⁻¹ and LOQ of 19.50 µmol L⁻¹. The selectivity study demonstrated that most evaluated interferents did not significantly compromise the analytical response of the sensor, except for thidiazuron (TDZ), which showed significant interference. Application in a real tap water sample evidenced a matrix effect with analytical signal suppression. The results obtained demonstrate that the MWCNT/Fe₃O₄ sensor constitutes a promising electroanalytical platform for diuron monitoring in aqueous environmental matrices.
Editor: Universidade Federal da Grande Dourados
Tipo: Trabalho de Conclusão de Curso2026-07-01T00:00:00ZDesenvolvimento de plataforma eletroquímica impressa em 3D para determinação eletroanalítica de ciprofloxacinaSantos, Kethelyn Rodrigueshttp://repositorio.ufgd.edu.br/jspui/handle/prefix/71672026-10-24T05:08:09Z2025-12-11T00:00:00ZTítulo: Desenvolvimento de plataforma eletroquímica impressa em 3D para determinação eletroanalítica de ciprofloxacina
Autor(es): Santos, Kethelyn Rodrigues
Primeiro Orientador: Carvalho, Claudio Teodoro de
Abstract: 3D printing emerges as an innovative technology for the fabrication of customized analytical devices, offering advantages such as low cost, speed, and versatility. In this work, we applied this technology to the development of an integrated electrochemical platform for the determination of ciprofloxacin (CIPRO), a broad-spectrum antibiotic whose presence in water bodies represents an environmental risk. The rationale lies in the need for sensitive, sustainable analytical methods that simplify the analytical steps, integrating sample preparation and detection into a single system. The overall objective was to use 3D modeling and printing to create a functional and economical electrochemical cell capable of performing in situ dispersive liquid-liquid microextraction (DLLME) and subsequent electroanalysis of CIPRO. Specific objectives included: designing and manufacturing the 3D-printed device; optimizing
microextraction conditions with deep eutectic solvents (DES); and applying voltammetric techniques for analyte detection and quantification. The device was fabricated by fused deposition modeling (FDM) using ABS filament, with electrodes made of CB-PLA conductive filament, and incorporated a mechanical stirring system to promote extraction. DES composed of proline and citric acid (1:2) was used as the green extraction solvent. Among the voltammetric techniques evaluated (cyclic, square wave, and differential pulse – VPD), VPD was selected for its higher sensitivity. After optimization of
instrumental parameters and pH, an adequate electrochemical response for CIPRO was obtained. The analytical curve, constructed in the range of 0.010 to 0.150 µmol L⁻¹, showed good linearity (correlation coefficient of 0.985), with detection and quantification limits of 0.011 and 0.036 µmol L⁻¹, respectively. It is concluded that the developed 3D printed electrochemical platform proved to be effective, integrated, and low-cost for the determination of CIPRO in aqueous matrices. The system reduces the number of
analytical steps, simplifies the procedure, and shows potential for applications in environmental monitoring, in addition to opening perspectives for the development of portable devices for in situ analysis.
Editor: Universidade Federal da Grande Dourados
Tipo: Trabalho de Conclusão de Curso2025-12-11T00:00:00ZDesenvolvimento de sensores eletroquímicos impressos em papel do tipo reagent˗free modificados com polianilina para a determinação de paracetamol em amostras ambientais e biológicas.Duarte , Gabrielly Ramoshttp://repositorio.ufgd.edu.br/jspui/handle/prefix/71662026-10-23T20:07:38Z2026-07-02T00:00:00ZTítulo: Desenvolvimento de sensores eletroquímicos impressos em papel do tipo reagent˗free modificados com polianilina para a determinação de paracetamol em amostras ambientais e biológicas.
Autor(es): Duarte , Gabrielly Ramos
Primeiro Orientador: Barros , Willyam Róger Padilha
Abstract: Paracetamol, also known as acetaminophen (AC), is a drug widely used as an analgesic and antipyretic, making its detection important for pharmaceutical quality control and environmental monitoring. This work proposes the development of an electrochemical platform based on reagent-free screen-printed paper electrodes modified with polyaniline. This process was performed by cyclic voltammetry - CV from (-0.2 to 1.2 V vs. graphite pseudo-reference), using 0.0075 mol L−1 of the aniline monomer. The formation of the polymeric film on the working electrode (referred to as PAni/SPE), was achieved after 40 cycles, improving electron transfer and increasing the electroactive surface area from 3.55 to 6.98 mm², accompanied by an increase in the real area from 125.7 to 256.9%. The electrochemical characterization of the PAni/SPE platform was performed by CV, from (-0.8 to 0.8 V vs. graphite pseudo-reference), in 1.0 mol L−1 [Fe(CN)₆]³⁻/⁴⁻ in 0.1 mol L−1 KCl. The morphology and hydrophobicity evaluation of the platforms were assessed by scanning electron microscopy (MEV) and contact angle measurements, respectively. AC detection was performed by differential pulse
voltammetry (DPV), using a 0.1 mol L−1 PBS solution at pH 7.0 as the electrolyte. A pH optimization study was carried out for the detection of 2 × 10−4 mol L−1 AC in 0.1 mol L−1 PBS, within the pH range of 6.0 to 9.5, with pH 7.0 being the optimal value for detection. AC was studied over a concentration range from 1.0 to 100 μmol L−1, yielding two linear ranges with different R² values (0.997 and 0.993) and achieving limits of detection (LOD) and quantification (LOQ) of 0.026 μmol L−1 and 0.0853 μmol L−1, respectively. The interference study demonstrated that, although compounds such as caffeine, diclofenac, ibuprofen, losartan, and progesterone caused variations in the peak current, the platform maintained a selective response toward AC. In addition, recovery assays in lake water, tap water, and synthetic urine samples presented values between 75.28% and 99.8%, with a relative standard deviation lower than 2.51%, demonstrating the applicability of the sensor in complex samples. Thus, the results demonstrate that the PAni/SPE platform is a promising, portable, sensitive, low-cost, and
environmentally friendly alternative for the electrochemical determination of paracetamol.
Editor: Universidade Federal da Grande Dourados
Tipo: Trabalho de Conclusão de Curso2026-07-02T00:00:00ZAnálises químicas qualitativas para verificar adulterações em leite pasteurizadoOliveira , Gabrielly Cargnin dehttp://repositorio.ufgd.edu.br/jspui/handle/prefix/71652026-10-24T05:08:19Z2025-12-12T00:00:00ZTítulo: Análises químicas qualitativas para verificar adulterações em leite pasteurizado
Autor(es): Oliveira , Gabrielly Cargnin de
Primeiro Orientador: Santos , Daniele Mignolo dos
Abstract: The objective of this study was to evaluate the quality of pasteurized milk through physical-chemical analyses and qualitative tests in order to verify its state of preservation and identify possible adulteration. Samples of pasteurized milk from two dairies in Dourados, MS, were analyzed. The physical-chemical analyses performed to determine pH, titratable acidity (°Dornic), and density followed official methodologies from the Ministry of Agriculture. All samples had density values within the standards established for bovine milk, indicating no dilution or skimming. Acidity and pH values
were also within the expected range, except for one sample that showed slight acidification due to its proximity to the expiration date. In addition, qualitative tests were applied to identify common frauds: the alizarin test to detect sodium hydroxide (NaOH) and the iodine solution test to detect starch. The evaluators were able to distinguish the adulterated samples based on characteristic color changes, demonstrating the effectiveness of these rapid methods. The UV-Vis absorption spectra of the reagents
reinforced the interpretation of the visual results. The study of the physical-chemical analyses and qualitative tests as essential to ensure the milk quality and to prevent fraud.
Editor: Universidade Federal da Grande Dourados
Tipo: Trabalho de Conclusão de Curso2025-12-12T00:00:00Z