Concentrations of eleven representative metals (Al, Ca, Cd, Cr, Cu, K, Mg, Mn, Na, Pb and Zn) in forty-two propolis samples were measured by electrothermal atomization and flame atomic absorption spectrometry after calcination in a muffle furnace. Samples were collected from different regions from Paraná State - Brazil where apiculture is an important economic activity. Results showed that the average content of Al, Ca, K, Mg, Mn, Na and Zn in propolis was 0.68, 1.66, 7.59, 1.27, 0.08, 0.58 and 0.02 mg g(-1), respectively. Levels of Al, Ca, and Mg were statistically different in some regions of Paraná and could be used to assign the geographical origin of the propolis. The average concentration of the Cd, Cr, and Pb in raw propolis was 0.13, 5.53 and 9.85 μg g(-1), respectively, and allowed for identification of specific areas with environmental contamination.
Usually, the methodologies found in the literature on biological tissue digestion are usually time consuming and use high amounts of reagents. In this study, two methods of preparation of bovine testis samples were evaluated: acid digestion using nitric acid and alkaline solubilization using tetramethylammonium hydroxide. The analytical validation study evaluated the parameters of linearity, limits of detection (acid digestion 0.10; 1.02; 0.16; 0.67 mg kg-1 for Cu, Fe, Mn and Zn, respectively; alkaline solubilization 0.12; 0.74; 0.16; 0.23 mg kg-1 for Cu, Fe, Mn and Zn, respectively) and quantification (acid digestion 0.34; 3.40; 0.53; 2.20 mg kg-1 for Cu, Fe, Mn and Zn, respectively; alkaline solubilization 0.41; 2.50; 0.54; 0.77 mg kg-1 for Cu, Fe, Mn and Zn, respectively), precision (RSD < 7.3% for repeatability and RSD < 15.0% for intermediary precision) and accuracy, being that the percentage of recovery obtained in the acid digestion of 105.50% (Cu), 103.30% (Fe), 94.90% (Mn) and 89.60% (Zn) and in the alkaline solubilization 100.80% (Cu), 98.70% (Fe), 103.70% (Mn) and 95.70% (Zn), therefore, the two procedures were efficient for this type of matrix. The times required for acid digestion and an alkaline solubilization were 1h30min and 1h, respectively.
The aim of this work was to develop and validate methodology to reduce the digestion time and reagent consumption in the determination of minerals in maize flour. The standard methodology employed in Brazil is that described by AOAC. It consists of the calcination of the sample at high temperatures for a long period of time, making the process expensive and slow. In this work, a wet sample digestion method using HNO 3 was employed, heating on a block digester with final dissolution in an ultrasonic bath. The validation tests involved linearity and working range studies, and the determination of the detection and quantification limits, accuracy and precision. The sample digestion time was 1:30 h and the percent recoveries for the metals were 93% for Ca, 98% for Cu, 110% for Fe, 97% for Mg, 101% for Mn and 106% for Zn. Keywords: Metals; Maize flour; Acid digestion; Sonification.Resumo O objetivo deste trabalho consiste em desenvolver e validar uma metodologia que reduza o tempo de digestão e o consumo de reagentes para determinar minerais em farinha de milho. No Brasil, a metodologia padrão utilizada é a descrita pelo AOAC, que consiste na calcinação da amostra em altas temperaturas, por longo período, o que torna o processo dispendioso e moroso. Neste trabalho, aplicou-se a digestão por via úmida das amostras usando HNO 3 , aquecimento em bloco digestor e solubilização final em banho ultrassom. Os testes de validação envolveram estudos de linearidade e faixa de trabalho, limites de detecção e de quantificação, precisão e exatidão. O tempo de digestão das amostras foi de 1h30min e as porcentagens de recuperação dos metais foram de 93% para Ca, 98% para Cu, 110% para Fe, 97% para Mg, 101% para Mn e 106% para Zn. Palavras
Hesperidin is a natural compound which is found in citric fruits and presents antitumor and antimicrobial activities. However, the in vivo efficacy of Hesperidin is reduced due to its low oral bioavailability. Protein-based nanoparticles have been applied to improve biological parameters of drugs and natural compounds. Gliadin is a monomeric protein present in wheat. In this study, gliadin-based nanoparticles containing hesperidin were obtained by desolvation technique and a Taguchi orthogonal array design was employed to optimize the formulation. The independent variables were set as concentration of CaCl2 (0.5; 1 or 2%) and stabilizing agent (Pluronic F68, Tween 80 or sodium caseinate). The dependent variables consisted of mean diameter, polydispersity index, zeta potential, and encapsulation efficiency. The results showed significant effects on the dependent variables when 1% CaCl2 and Pluronic F68 were used. The optimized formulation was coated with chitosan to increase the physical stability of the nanoparticles. The final nanoparticles presented a mean diameter of 321 nm and polydispersity index of 0.217, and spherical shape. After coating, the Zeta potential was +21 mV, and the encapsulation efficiency was 73 %. The in vitro release assay showed that about 98% of the drug was released from the nanoparticles after 48 h. Moreover, HIGHLIGHTS A Taguchi design optimized the development of hesperidin-loaded gliadin nanoparticles. A chitosan-coating was added to improve the physical stability of nanoparticles. Nanoparticles reduced the hesperidin cytotoxicity over healthy Vero cells. Nanoparticles improved the hesperidin cytotoxicity over tumor cells.
Essential metals are important in the normal functioning of the body. However, tissues or organs can be affected when there are inappropriate concentrations of these elements. In the literature, there are works indicating that essential elements may be related to the emergence of neoplasms. Therefore, it is important to determine the metal species in biological samples in order to relate the concentration of these species to the emergence of neoplasms. This study reports the application of the Flame Atomic Absorption Spectroscopy (FAAS) for the quantification of Cu, Fe, Mn and Zn in 31 samples of canine tissue (11 of mammary glands, 4 of pancreas, 3 of skin and 13 of testicles) with and without neoplasms, using alkaline solubilization as sample preparation method. The concentration of these metals was used as co-variables for the construction of models of logistic regression. The concentration of Zn in breast and Fe in pancreas was significant (p < 0.05) in the logistic models. The findings of this study describe that the elements Fe and Zn play a major role in the carcinomas development, since high levels of these metals were observed in neoplastic tissues.
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