Resumo em Português:

With the increase in industrial production, there is a direct increase in waste generation. Milk processing industries are one of these cases that results in a complex effluent with a high organic load. If the effluent is discarded without proper treatment, it can compromise the survival of biota in water courses. Advanced oxidation processes (AOP) are one of the main technologies used in the treatment of effluents, especially the Photocatalysis-Self-Fenton System (PF) type. The present study aimed to evaluate the efficiency of the PF process and to optimize the parameters of dairy effluent treatment. The raw effluent was characterized considering the parameters: conductivity, pH, chemical oxygen demand (COD), solids, and oils and greases. Through an experimental design, the variation of the concentrations of Fe2+, H2O2 and the reaction time were optimized, and the influence of these three variables on the removal of COD was evaluated. Statistical analysis showed that all variables were statistically significant, and the model used had a coefficient of determination of 0.97, confirming that the model was well adjusted. The ideal conditions for COD removal, reaching 79%, were obtained in 60 min, 0.625 g L-1 of Fe2+ and 0.829 mL L-1 of H2O2.

Resumo em Inglês:

Silver(I) complexes of amantadine (atdH), memantine (mtnH) and rimantadine (rtdH), named Ag-atd, Ag-mtn and Ag-rtd, respectively, were recently synthesized and described in the literature as promising antibacterial agents. In the present study, the cytotoxicity of such complexes was evaluated against cultures of primary epidermal keratinocytes (HaCaT) and murine melanoma tumor cells (B16-F10), and mutagenicity was studied by the Ames test to investigate their abilities to induce gene mutations. The Ames test was performed using Salmonella Typhimurium strains (TA98, TA100, TA102 and TA97a) capable of detecting frameshift and base pair substitution gene mutations, in experiments with and without metabolic activation (microsomal fraction S9). This study revealed significant cytotoxic activity against tumor cells and selectivity of Ag-atd and Ag-rtd complexes when compared to non-tumor human keratinocyte cells. Moreover, the Ag(I) complexes did not induce a significant growth in the number of revertant colonies when comparing with the negative control, both in the experiments without and with metabolic activation, indicating absence of mutagenic activity. The results are encouraging and collaborate in the genotoxicological investigations necessary for understanding the interaction and ability of the silver complexes to induce mutations and contribute to ensure their uses as future antibacterial or antitumor agents.

Resumo em Inglês:

Cancer is a severe disease that causes a significant number of deaths worldwide every year. Treatments have been available, such as cisplatin, to help combat this disease. However, recent studies have shown that the enzyme system glutathione/glutathione S-transferases (GSH/GST) can cause resistance of tumor cells to this type of cancer treatment. Fortunately, there are alternatives, such as using palladium complexes such as [PdCl(C2,N-dmba)(tu)], which have demonstrated effectiveness against cancer cells. However, even these metallopharmaceuticals can be inhibited by GSH/GST system, which can modify the chemical structure of the complex and prevent it from working as an anticancer agent. That's why it's crucial to study the reaction between the complex [PdCl(C2,N-dmba)(tu)] and L-cysteine using techniques such as NMR, mass spectroscopy, UV-Vis spectroscopy, and stopped-flow. The study of this type of reaction will help researchers understand how these organometallics work in biological systems and how we can improve them to treat cancer more effectively.

Resumo em Inglês:

Controlling the chemical parameters of the anaerobic digestion (AD) process is essential for the bioconversion of organic matter to methane; among these parameters include the presence and concentration of volatile fatty acids (VFAs). It is thus necessary to use efficient analytical methods that are capable of identifying and quantifying VFAs in reactor effluents in order to obtain an immediate response to their conditions. In this study, the liquid-liquid extraction (LLE) method was optimized and validated - through an adaptation of the official method, using acetone and KHSO4, and gas chromatography with flame ionization detector (GC-FID) was used for the determination of acetic, propionic, isobutyric, butyric, isovaleric and valeric acids present in the effluents. The limit of detection (LOD) and limit of quantification (LOQ) obtained were 1.2-2.5 mg L-1 and 1.9-3.7 mg L-1, respectively, for all analytes. These low LODs and LOQs are essentially important because the presence of isobutyric and isovaleric acids above 5.0 mg can be considered indicative of imbalances in AD. The proposed method, which presented satisfactory results with good repeatability (4.2-20.7%) and recovery (90.9-104.0%) rates, was applied for the analysis of effluent samples from three continuous stirred-tank reactors (CSTR).

Resumo em Português:

A new ruthenium polypyridine complex, cis-[Ru(bpy)2(1-meimN)(4-pyCHO)](PF6)2 (WP1), where 1-meimN and pyCHO are the ligands 1-methylimidazole and 4-pyridinecarboxaldehyde, respectively, was prepared as a prototype for use in phototherapeutic process. This compound was characterized by electronic absorption in UV-Visible, FTIR, 1H and 13C NMR, cyclic voltammetry, besides DFT that supported its molecular structure. The compound WP1 was photoreactive, where blue or green light promoted the release of 4-pyCHO ligand. Additionally, this compound was able to interact with DNA, mainly through electrostatic interactions showing photoinduced nuclease activity. There is also photoproduction of superoxide ions using blue or green light suggesting a route for DNA damage. These promising results opened new opportunities for the potential use of this system and analogues as phototherapeutic agents, which is an ongoing study in our lab.

Resumo em Inglês:

The use of antibiotics is still intensive in animal production. Among the most used veterinary products in pig farming, tetracyclines can be highlighted. When used in excess, these substances can leave residues in food, which depending on the concentration pose a risk on consumers. Brazil, as one of the world’s largest producer and exporter of animal protein, must be attentive to the laws and ensure that their meat products are safe for human health. So, the concentration of veterinary residues eventually detected must be below the maximum residue limits (MRLs) stipulated by the regulatory agencies. To contribute with subsidies for decision making in pork safety to the annual monitoring program, performed by the Ministry of Agriculture and Livestock, this study aimed to evaluate the residues of tetracyclines in swine muscle from the federal inspection system, by validated and officially accepted analytical methodology (HPLC-UV). Any suspect results obtained from the HPLC-UV analysis can be confirmed immediately by injecting the samples onto a LC-MS/MS system. The results showed that all evaluated samples had concentrations of tetracycline residues below the MRL, and therefore, can be considered safe for human consumption.

Resumo em Português:

There are many stilts and industry, which discharge sewage, domestic garbage and industrial effluents in the Pouca Saúde River from the port environment of Santos, São Paulo (SP) State. However, ecotoxicological studies in this river are rare. In this study, we seek to fill this gap by analyzing physicochemical, toxicological, and chemical conditions. Surface water and sediment samples were collected at 2 sampling sites with riparian community activities and industrial activities in the summer, autumn, winter and spring. The parameters analyzed were pH, alkalinity, turbidity, salinity, oils, greases, dissolved oxygen (DO), toxicological and cytotoxicity with mitotic index (MI) of onion roots using Allium cepa roots, and concentration of Pb, Zn, Hg, Ni and Cd. Our results showed alterations in the DO, turbidity, oils/greases and reduction of MI when compared to the respective control. Ni and Zn in sediment samples presented concentrations exceeding levels occasionally associated with adverse biological effects “threshold effect level”. These results suggested that the water quality of the Pouca Saúde River is influenced by both presences of heavy metals contamination and the seasons, i.e. by the tide. Thus, the toxic potential monitoring carried out in this study is of paramount importance to this river.

Resumo em Português:

The present study investigated the sources of variability in the water quality of surface springs that supply the Metropolitan Region of Belém (Pará, Brazil), as well as the treated water produced by the main water treatment station in the region. Data provided by Companhia de Saneamento do Pará were used, referring to physical-chemical and bacteriological analyzes carried out in the period from 2010 to 2020. In addition, precipitation data were considered in this study, in units of mm of rain, obtained by consulting the database of the National Institute of Meteorology. The application of principal component analysis, as an exploratory data analysis tool, allowed the grouping of the most relevant parameters of the results and proved to be efficient in reducing the data set, explaining more than 65% of the total variance, in all objects of study. Thus, it was possible to observe a general profile of the quality of surface water investigated, and, in this way, demonstrate the impact of urban pressure on the environment, as well as the need for maintenance and conservation of surface water resources.

Resumo em Português:

Lapachol, a naphthoquinone discovered in 1858, is a natural product with a broad spectrum of therapeutic activities, along with its derivatives and analogues. Initially found in several species of the Bignoniaceae family, lapachol can also be found in other families. Lapachol arouses great interest and knowledge due to its crucial role in medicinal chemistry, playing an important role in the rational planning of research in search of bioactive substances with pharmacological action, whether as a source of raw material or helping directly or indirectly. This work aims to describe a new methodology for extracting lapachol, which differs from the conventional acid-base method, providing a highly efficient, simple and easy-to-apply process.

Resumo em Inglês:

Capillary electrophoresis (CE) methods have unique potential for applications in quality control of pharmaceutical formulations. Here, we show that a single and ultra-fast CE method can be used for the determination of hydrochlorothiazide (HCT) in combination with nine other active ingredients in a single run in different pharmaceutical samples: atenolol (ATE), metoprolol (MET), propranolol (PRO), benazepril (BEN), captopril (CAP), enalapril (ENA), lisinopril (LIS), ramipril (RAM), and valsartan (VAL). This goal was achieved using a single and simple background electrolyte (BGE) composed of 10 mmol L-1 of boric acid with pH adjusted to 9.0 with sodium hydroxide. All samples can be analyzed in less than 1 min with the attainment of good analytical performance, such as high-resolution separation (r > 1.3), low sample and reagents consumption (environmentally friendly method), low relative standard deviation (RSD) values for peak area (< 4.0%) and migration times (< 1.7%), and linear relationships with good correlation coefficients (> 0.995). Furthermore, recovery tests showed good results (100 ± 5%) for all evaluated compounds.

Resumo em Inglês:

The unique fundamental force related to chemical bonds, hydrogen bonds, and van der Waals interactions is the electromagnetic force, where the electrostatic force plays the major role. But, to our knowledge, no paper so far has explored the use of the electrostatic force explicitly to account for any molecular property (boiling point, solubility, etc.), except for the book Introductory Organic Chemistry and Hydrocarbons.1 This work uses the electrostatic force applied to chemistry to explain some molecular properties in organic chemistry. It also evaluates the understanding of Brazilian undergraduate students with respect to some topics of organic chemistry based on the electrostatic force. One questionnaire was applied to chemistry undergraduate students about Coulomb’s law and its application to organic chemistry, and the results indicate that most undergraduate students understand the electrostatic force equation applied to chemical education.

Resumo em Português:

ABSTRACT Mixture designs are becoming frequently used as a powerful tool in modern chemical research. Their versatility opens the door to countless applications, making it a must-have tool in any experimental environment. Mixture designs combined with mathematical regressions allow us to understand how component proportions affect a measured response leading to system optimization at minimum cost and providing an accurate description of system behaviour. Dedicated software is often used to perform data analysis in mixture design experiments, but many of them are only commercially available hindering the use of mixture designs by scientific groups. The availability of free software would make these designs even more attractive, allowing users to benefit from the creative potential of this toolset without the prohibitive cost of proprietary tools. RStudio and LibreOffice are some of the free software with the capability to perform the necessary data analysis accompanying mixture designs. To exemplify how mixture design analysis can be executed the book “Como Fazer Experimentos” was used as reference material. Both software presented good results and the potential to be used to perform data analysis for mixture design experiments.