Banca de DEFESA: WILLIAM GRACILIANO CORRÊA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : WILLIAM GRACILIANO CORRÊA
DATE: 06/09/2022
TIME: 08:30
LOCAL: Plataforma Google Meet
TITLE:

Synthesis and characterization of a molecularly imprinted polymer as adsorbent in sample preparation techniques for the determination of dexamethasone in urine

KEY WORDS:

Dexamethasone. MIP. MEPS. DSPE.

PAGES: 75
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUMMARY:

Glucocorticoids' usage, especially dexamethasone (DEX), have been gaining attention due to its importance on the COVID-19 treatment, showing a decrease in mortality in patients who needed oxygen support and invasive mechanical ventilation. Besides, those substances are connected to a resistance gain on sports competitions, resulting in doping. However, the excessive use of these drugs, mainly during a large amount of time, can cause dangerous side effects. From this perspective, a simple and fast method to determine DEX on human urine samples have been developed using dispersive solid phase extraction (DSPE) and microextraction in packed sorbent (MEPS) and molecularly imprinted polymers (MIP) as adsorbent. Chromatographic analysis of DEX was made with an isocratic elution in an Agilent® Eclipse Plus C18 (100 mm × 4.6 mm, 5 μm) column, using acetonitrile: ultrapure water (35:65, v/v) as mobile phase. The flow rate was 0.75 mL min^-1, with an injection volume of 20 μL and detection wavelength at 240 nm. First, a MIP for selective determination of DEX in human urine was developed and characterized by thermogravimetry, Fourier transform infrared spectroscopy, scanning electron microscopy/ energy dispersive spectroscopy, wettability and PZC, to evaluate the main characteristics of the adsorbent material. To optimize the sample preparation techniques were studied the parameters: washing and elution solvent, sample pH, amount of adsorbent material, sample and eluent volume, number of aspersion and dispersion cycles, stirring time and reusability, obtaining a recovery of 65.3 ± 1.1 % and 83.0 ± 5.6 % for MEPS and DSPE, respectively. The method validation process was conducted using a range of 0.005-3 μg mL^-1, which presented satisfactory results, with correlation coefficient of 0.9986. The method showed good precision, accuracy and robustness, with relative standard deviation (RSD%) and relative errors (RE%) lower than 15%. The stability test showed that, comparing target samples and fresh samples, the RSD% values were lower than 15% and the p-values were above 0.05, showing that samples are stable regardless of their condition. The method was satisfactory applied on a sample of human urine collected 24 h after the oral administration of DEX by a healthy volunteer.

BANKING MEMBERS:
Presidente - 1872495 - KEYLLER BASTOS BORGES
Interno - 1721586 - CLEBIO SOARES NASCIMENTO JUNIOR
Externa à Instituição - RENATA PEREIRA LOPES MOREIRA - UFV