Banca de QUALIFICAÇÃO: TABATA NATASHA FEIJOÓ ZAMBRANO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : TABATA NATASHA FEIJOÓ ZAMBRANO
DATE: 31/07/2025
TIME: 09:00
LOCAL: videoconferência
TITLE:

Differential pulse voltammetry as an analytical tool for organic compound detection in complex matrices.

KEY WORDS:

ELECTROANALYSIS; DPV; GLASSY CARBON ELECTRODE; ANTIOXIDANTS; METHYL RED

PAGES: 109
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Analítica
SPECIALTY: Eletroanalítica
SUMMARY:

In recent decades, the analysis of organic compounds in complex matrices has gained increasing relevance in fields such as environmental chemistry, food science, and quality control. Natural antioxidants in foods and synthetic organic pollutants like dyes in wastewater highlight the need for analytical methodologies that are accurate, sensitive, and adaptable to different sample types. Conventional techniques like UV-Vis spectrophotometry and HPLC are widely used but often demand extensive preparation, high costs, and hazardous reagents. In contrast, electroanalytical methods such as Differential Pulse Voltammetry (DPV) offer high sensitivity, minimal reagent use, rapid analysis, and real-time monitoring. This thesis evaluated DPV for two applications: determining the antioxidant capacity of frozen açaí pulp and monitoring the degradation of methyl red dye, a toxic and persistent azo dye. For açaí analysis, ethanolic extracts obtained via ultrasound-assisted extraction were analyzed using cyclic voltammetry and DPV with a glassy carbon electrode, revealing an oxidation peak and an electrochemical quantitative index of approximately 2.3 µA/V, supporting its strong antioxidant potential and phenolic content confirmed by DPPH and Folin–Ciocalteu assays. For methyl red, DPV effectively monitored its electrochemical mediated oxidation in synthetic and real waters using a glassy carbon electrode and a dimensionally stable anode for electrolysis, achieving complete decolorization within 30 minutes under optimal acidic conditions (0.001 M chloride) and following pseudo-first-order kinetics. Calibration curves constructed by DPV presented excellent linearity (R2 > 0.99) and low detection limits, comparable to UV-Vis and HPLC analyses, even in lagoon and well water samples. These results demonstrate that DPV is a robust, versatile, and precise analytical tool with significant potential for food quality evaluation and environmental monitoring of organic pollutants.

COMMITTEE MEMBERS:
Interna - 2140818 - AMANDA DUARTE GONDIM
Presidente - 1645110 - CARLOS ALBERTO MARTINEZ HUITLE
Externo à Instituição - DANYELLE MEDEIROS DE ARAUJO - IFRN