Banca de DEFESA: MARCOS DIOGO SOUZA PEREIRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : MARCOS DIOGO SOUZA PEREIRA
DATE: 19/12/2023
TIME: 13:30
LOCAL: Remota
TITLE:

USE OF A MICROSCOPIC CAMERA TO DETERMINE TOTAL Fe IN FRESH WATER BY DIGITAL COLORIMETRY IN SOLID PHASE

KEY WORDS:

digital colorimetry, microscope camera, solid phase, Fe content, fresh water.

PAGES: 50
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Analítica
SPECIALTY: Instrumentação Analítica
SUMMARY:

This work evaluates the total Fe concentration in drinking water by 1-(2- thiazolylazo)-2-naphthol (TAN) using C18 silica as solid support. For this purpose, a solid-phase digital colorimetry analytical method was developed. The image acquisition tool was a USB digital microscope 500x2 mp connected to a smartphone. The ImageJ software recorded and handled collected images in red–green–blue (RGB) color space. A flow system based on multi-commutation was employed to manage solutions to analysis. The physical and chemical parameters: (i) optical window diameter; (ii) pH (5.0 to 7.5); (iii) eluent solution concentration and volume (HCl 0.01 to 0.25 mol L^-1; 150 to 400 µL, respectively); (iv) sample volume (100 to 300 μL); and (v) flow rate (0.8 to 2.0 mL min^-1) were investigated and optimized. The microscope USB camera allowed the system to operate with a diameter of 0.1 cm for the optical Window, which led to 10 times solid support reduction (ca. 3.5 ± 0.1 mg) compared with the previously reported solid phase colorimetric methods. Furthermore, the obtained parameters were pH = 6.5, 350 μL of HCl 0.1 mol L^-1, 250 μL of the sample, and a flow rate of 2.0 mL min^-1 as optimized conditions for analysis. The proposed method showed a linear working range up to 1.0 mg L^-1 (R= 0.9992) with detection (LOD) and quantification limits (LOQ) of 0.025 and 0.085 mg L^-1, respectively. Drinking water samples were analyzed by the proposed method, and the observed Fe concentration found ranged from 0.17±0.05 to 0.44±0.01 mg L^-1,  showing no statistically significant difference (p= 0.05) compared with the reference method.

COMMITTEE MEMBERS:
Interno - ***.936.635-** - VALFREDO AZEVEDO LEMOS - UFBA
Interno - 1551430 - FABIO DE SOUZA DIAS
Externo à Instituição - ALLISON GONÇALVES SILVA - IFBA
Externo à Instituição - MADSON DE GODOI PEREIRA - UNEB