http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/4379 2026-04-17T13:57:40Z http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/8568 Título: Determinação de disruptores endócrinos (bisfenol A e ftalatos) em utensílios e brinquedos para lactentes usando HPLC-UV-VIS e estudo de bioacessibilidade Autor: LIMA, Gabriel Acioly de Primeiro orientador: LAVORANTE, André Fernando Abstract: Bisphenol A and phthalates are chemical compounds used in the production of polymers. Studies show that these compounds are endocrine disruptors and when in contact with the body affect the hormonal system, generating various health problems to the individual. Thus, this research aims to develop a method for the determination of bisphenol A and dibutyl phthalates (DBP), bis-2-ethylhexyl (DEHP), di-n-octyl (DNOP) and diisodecyl (DIDP) in utensils and toys intended for infants, as well as to evaluate the bioaccessibility of these compounds in artificial saliva. For this, ultrasound assisted liquid extraction and detection on HPLC-UV-VIS at 230 nm were performed. Gradient elution was performed with a binary mixture of methanol (solvent B) and deionized water (solvent A) ranging from 70% B to 93% B from 3 min to 5 min at a flow rate of 1.0 mL min-1. The column used was Agilent C18 and had a total elution time of 20 min. After establishing the analysis parameters, the method was validated, finding detection limits of 0.003 to 0.051 mg L-1 and quantitation limits of 0.011 to 0.155 mg L-1 for bisphenol A and phthalates analyzed. Extraction in an ultrasonic system was performed with chloroform and optimized with a factorial design 24, where optimal conditions were defined as 1.50 g of sample in 10 mL of chloroform, with ultrasound extraction time of 20 min at 65 °C. Matrix effect tests showed that the method does not suffer this type of interference and recovery studies showed values from 73.2 to 103 %. Ten commercially acquired samples from the city of Recife-PE were analyzed, and the results presented phthalate concentration values between 0.101 and 30.808 mg Kg-1, being considered below the limits established by ANVISA, and bisphenol A concentration values between 0.060 and 21.131 mg Kg-1. Migration tests with artificial saliva were performed and the results showed that all samples presented bisphenol A migrations in concentrations allowed by the current legislation. In nine samples, DBP migration values were detected above those allowed by ANVISA. One of the samples analyzed revealed inconsistencies in the packaging information as it claimed to have no phthalates. The proposed method has been shown to be suitable for analysis of endocrine disruptors in utensils and toys intended for infants within the parameters required by ANVISA. Instituição: Universidade Federal Rural de Pernambuco Tipo do documento: Dissertação 2019-12-20T00:00:00Z http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/8567 Título: Grilo preto (Gryllus assimilis) como candidato a material de referência certificado : um estudo de homogeneidade e massa mínima Autor: PEREIRA, Raphael Henrique de Moura Primeiro orientador: LAVORANTE, André Fernando Abstract: The analytical quality is a parameter of relevance in chemical analyses for guaranteeing the reliability and traceability of analytical results. Normally, it is achieved using Certified Reference Materials – CRM. However, not all matrices are available as CRMs in the market. As the edible insects are considered the future food in terms of meat substitution, the CRM production using this matrix type becomes fundamental. The present work has studied the utilization of black cricket insect (Gryllus assimilis) as a RM candidate by means of preparation, bottling and minimum mass determination and homogeneity assays, as well as the nutrient determination of this matrix. The sample preparation process consisted of milling, sieving and freeze-drying, followed by quartering and bottling of the material with posterior irradiation. The obtained batch was composed by 40 bottles containing 4 g of dried material and with maximum particle size of 80 μm. The residual humidity determination was carried out by the comparison of two drying methods (oven and freeze-dryer), while the mass minimum determination was performed by comparing the obtained values for analytical portions of 20 mg, 150 mg and 500 mg, applying the EDXRF (Cl, P and S) and FAAS (Cu, Fe, Mn and Zn) techniques. As the main property of the RM candidate, the homogeneity was assessed by the FAAS technique for evaluating the distribution of Cu, Fe, Mn and Zn in the material. The chemical characterization of the candidate was carried out through the EDXRF and ICP-OES techniques. The candidate showed residual water content of 7%, in which the best method for this determination was oven-drying. The results of minimum mass assay indicated that, among the analytical portions studied, 500 mg was the recommended minimum mass for the use of RM candidate, however, for some chemical elements, lower masses could be employed (between 150 e 500 mg). The preparation and bottling of the RM candidate was considered adequate since the homogeneity has been demonstrated for Cu, Fe, Mn and Zn at the 95% confidence level. With the chemical characterization, the material, besides of being protein source, had high concentrations of the Ca, Cl, K, Mg, Na, P and S nutrients, showing nutritional relevance. Instituição: Universidade Federal Rural de Pernambuco Tipo do documento: Dissertação 2019-12-19T00:00:00Z http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/8566 Título: Acumulação de Ra-226, Ra-228, Th-228 e K-40 em raízes de Ipomea batatas (L.) LAM Autor: LIMA, Ingrid Adriana Freire Soares Primeiro orientador: LAVORANTE, André Fernando Abstract: Studies relative to transfer of radionuclides in soil-vegetable system to plants grown in high radioactivity (NORM) soils are important for assessing food contamination and evaluate the level of ionizing radiation to which people are expose. Furthermore, radionuclide accumulator plant such as Ipomea potatoes (sweet potato) can increase the transport of radioactive contaminants if they are developed in soils with technologically concentrated naturally occurring radioactive (TENORM). Thus, the present work aimed to determine the soil-root transfer factors of I. potatoes growing in soils with natural radionuclides from the metropolitan region of Recife, as well as to evaluate the mobility of natural radionuclides in TENORM contaminated soils simulating undesirable radioactive contamination in soils under I. potato crops. Test 1 consisted of sampling of the enriched with natural radionuclides soil (NORM), assembly of vases for sweet potato cultivation. In Test 2, the soils were doped with oil fouling, with the purpose of obtaining theoretical statistics of 250, 500, 750 and 1000 Bq kg-1. After 5 months of greenhouse cultivation, root and soils on the profiles 0-5 cm, 5-10 cm and 10-15 cm depths. Succeeding drying, milling and sieving, followed by transfer of 30 g of soil and 7 g of root to petri dishes and sealing, the capsules remained for 21 days under controlled conditions to ensure the secular balance between the radionuclides and Rn-222, followed by natural radioactivity measurement by High Resolution Gamma Spectrometry with HPGe detectors. Radionuclides Ra-226, Ra-228, Th-228 and K-40 were quantified after 80.000 seconds of measurement for geological samples and 200.000 seconds for roots. The results obtained from the test attested to the accumulation of Ra-226, Ra-228, Th-228 and K-40 in the roots of the plants. The transfer factors (FT) values for Ra-226 found ranged from 0.14 to 0.40, 0.44 to 0.76, 0.27 to 0.80 and 1.44 to 12.93, respectively. The FT values for Ra-226 demonstrated preferential accumulation compared to Ra-228 and Th-228. In the second trial, it was found that there was no vertical migration of the radionuclides between doped soils with encrusted and the sweet potato. The roots of I. batatas plants did not respond to contamination, indicating that in a hypothetical soil contamination scenario, the contaminants would not be transferred to the food chain. Instituição: Universidade Federal Rural de Pernambuco Tipo do documento: Dissertação 2019-12-20T00:00:00Z http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/8565 Título: Estudo eletroquímico e eletroanalítico do biomarcador de estresse oxidativo 3-nitrotirosina em diferentes substratos eletroquímicos e de sua interação com o DNA Autor: NASCIMENTO, José Ailton Mota Primeiro orientador: OLIVEIRA, Severino Carlos Bezerra de Abstract: An electrochemical study of 3-nitro-tyrosine (3-NO2-Tyr), in aqueous medium, was performed on different electrochemical substrates, glassy carbon electrode (GCE), platinum and gold electrode, using voltammetric techniques, such as cyclic voltammetry (CV), square wave voltammetry (SWV) and differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS), to investigate its oxidation mechanism, as well as its reactivity / toxicity to the double-strands DNA molecule (dsDNA). para-Tyrosine electro-oxidation in aqueous media was also investigated and compared with 3-NO2-Tyr. Potentialities of 3-NO2-Tyr oxidation properties for electroanalytical applications were also studied. The electrochemical results, in general, showed that 3-NO2-Tyr undergoes electro-oxidation in aqueous medium in a single irreversible pH-dependent step, losing one electron and one proton in the phenolic group and forming non-electroactive products, that are adsorbed strongly on all used electrodes. In addition, the phenolic group present in the 3-NO2-Tyr structure was found to be more difficult to oxidize (~ 170 mV) when compared to its electro-oxidation in the para-tyrosine molecule, possibly due to the influence of the nitro group. an electron withdrawing group. The mass transport of 3-NO2-Tyr to the electrode surface was investigated at platinum electrode and it was established that it is predominantly diffusion controlled. Electroanalytical methods for detection and quantification of 3-NO2-Tyr were proposed at GCE, gold and platinum electrode, the detection limits (LOD) and quantification (LOQ) of these methods were calculated and compared. At GCE the LOD was 0.17 μmol L-1, in the platinum electrode was 6,81 μmol L-1, while in the gold electrode was 7,33 μmol L-1, demonstrating a better sensitivity for detection and quantification of 3-NO2-Tyr. at GCE. Finally, the DPV and gel electrophoresis results clearly demonstrated a 3-NO2-Tyr interaction with dsDNA molecule in physiological medium (pH = 7.0), since the DPV results over incubation time of 3-NO2-Tyr with DNA, detected a significant decrease or the complete disappearance of the anodic peak associated with 3-NO2-Tyr oxidation, at E = 0.70 V, while electrophoresis results detected a very significant decrease in the ethidium bromide fluorescence. Thus, it was established the interaction of 3-NO2-Tyr possibly via its intercalation in the DNA double helix and with formation of a stable 3-NO2-Tyr-dsDNA complex, hindering the oxidation of 3-NO2-Tyr on the GCE, as well as the intercalation of the fluorescent biomarker, ethidium bromide, on the dsDNA. Instituição: Universidade Federal Rural de Pernambuco Tipo do documento: Dissertação 2019-10-25T00:00:00Z