Bibliometric reviews, carried out from access to databases of scientific articles associated with software for data processing, can be helpful for qualitative and quantitative assessments of existing publications on a given topic. Several petroleum hydrocarbons are carcinogenic and immunotoxic agents, causing adverse effects on the biota, and the study of metabolites generated in bioremediation processes has been the object of current research. Therefore, in this work, the use of bibliometric analysis as a tool for surveying studies on the applied metabolomics bioremediation of areas impacted by hydrocarbons is presented. A bibliometric review was carried out in the Scopus Preview and Web of Science databases with data analysis using RStudio software with the bibliometrix package. The survey gathered the studies and prominent publications of the last seven years, making it possible to present gaps and opportunities in the area. reviews processing topic agents biota research Therefore work presented package years area

The present work aimed to direct amino acid (AA) sensing by quantum dots (QD) and development of an analytical method for potential fast clinical tests. Notably, AA with a positive charge or neutral polar chains, namely L-histidine (His) and L-threonine (Thr), responded to glutathione-coated CdTe (GSH-CdTe) (ΔF ≤ 90%, variation of fluorescence intensity). However, in ammoniacal buffer (0.25 mol L-1) at pH 8.0, 2.2 nm GSH-CdTe responded only to His. Static quenching with complex association constant (Ksv) varying from 2.81 to 0.94 (10 L mol-1) as well as van der Waals forces and/or hydrogen bonding were predicted for His-QD quenching mechanism and binding type. Additionally, thermodynamic parameters as ΔH = -76.5 kJ mol-1 (enthalpy), ΔS = -227.4 J K-1 mol-1 (entropy) and ΔG from -9.8 until -6.4 kJ mol-1 (Gibbs free energy) at 20 to 35 °C were estimated by van’t Hoff equation. Under optimal conditions, the developed method presented a linear range from 0.42 to 35 mmol L-1 (with correlation coefficient (r) of 0.9970, n = 7), good precision (relative standard deviations (RSD) < 2.5% for 2.5 and 20 mmol L-1; n = 6) and limit of detection 1.6 × 10-4 mol L-1 (0.025 mg mL-1). Recovery tests were performed on artificial urine and human urine samples with recoveries ranging from 78.7 to 127.6%.

The development of a method based on extraction induced by emulsion breaking (EIEB) aiming copper determination in gasohol using graphite furnace atomic absorption spectrometry (GF AAS) is reported. Emulsification of the gasohol samples was carried out using nitric acid solution, (1,1,3,3-tetramethylbutyl)phenyl-polyethylene glycol surfactant (Triton X-114), and ultrasound energy. The variables related to the extraction efficiency were optimized by multivariate approaches (two-level factorial fractional design and Doehlert design). The best results were obtained when the emulsion was formed with 5.0 mL of the sample, 0.200 mL of 2.4 mol L-1 HNO3, 0.100 mL of 10% Triton X-114 and 10 min of sonication. A fast and efficient emulsion breaking was performed at 90 ºC. A volume of 6.65 mL of the copper-rich hydroalcoholic phase was extracted, separated from the organic phase and analyzed. Under these conditions, the following analytical characteristics were obtained: 0.61 and 2.0 µg L-1 for limits of detection and quantification, respectively; precision (percentage of relative standard deviation, 10 µg L-1) of 2.8%; and analytical sensitivity of 0.011 L µg -1. Accuracy was assessed by spike tests, and values in the range of 95-110% were achieved. The method was applied in the determination of copper in Brazilian gasoline samples (gasohol with 27% ethanol).

Levulinic acid is a reactive polar organic compound deemed as a building block for several products with relevant applications, replacing traditional substances in the petrochemical industry. Considered a platform molecule, levulinic acid is industrially produced from the acid hydrolysis of biomass - mainly plant-based - using hydrochloric or sulfuric acid in homogenous catalysis. However, considering the World Market for levulinic acid is expected to reach US$ 71.9 million in 2027, growing annually at 14.1%, and its applications in agriculture, pharmaceuticals, plasticizers, cosmetics, and food additives, the development of alternative production processes is sought. Hence, a survey was performed on publications considering the alternatives for biomass-based levulinic acid production processes: I) alternative homogenous catalysts to avoid using noble materials in the reactor; II) heterogeneous catalysis to facilitate and reduce the catalyst’s separation and recovery costs; III) ionic liquids, exploiting their high solvency, stability, and catalytic capacity. Additionally, biomass alternatives for obtaining levulinic acid are presented, showing that other agricultural residues and animal biomass options are being considered, targeting process flexibilization while reducing costs and producing derivatives at more competitive prices. Thus, it can be stated that levulinic acid is an important platform molecule for biorefineries’ economics, replacing fossil fuels with renewable raw materials.

Itaconic acid (IA) is a very promising platform molecule due to the possibility of it being used to obtain products such as methyl methacrylate and synthetic latex, with the prospect that its global market will grow at an average annual rate of 2.8% (CAGR) from 2021 to 2026, exceeding US$ 116.6 million in sales. The main technological route used to obtain itaconic acid is fermentation using different strains of Aspergillus terreus fungi. The main advancements are related to genetic engineering, as Aspergillus terreus is the most tolerant of the microorganisms employed in the process synthesis and optimization. The main substrate used is glucose (52%), followed by glycerol (25%). Among the results presented in this paper, the best production was achieved using Ustilago maydis, with 220 g L-1 of IA, yielding 0.33 g g-1, using glucose as a carbon source. Moreover, it is necessary to continue optimizing the biological process of IA production, since it is a platform molecule with major economic potential.

Cloud point extraction (CPE) in association with graphite furnace atomic absorption spectrometry (GF AAS) was proposed for preconcentration and quantification of trace amounts of copper and cadmium in samples of saline produced formation water from petroleum exploration. The procedure was based on the formation of hydrophobic complexes of the analytes with 1,5-diphenylthiocarbazone (dithizone) in a micellar media of the surfactant (1,1,3,3-tetramethyl butyl) phenyl-polyethylene glycol (Triton X-114). Constrained mixture design was performed for the optimization of the proportions of the three solutions employed in the CPE: Triton X-114, dithizone, and buffer solution. Under the recommended conditions, the CPE GF AAS procedure allowed to obtain enrichment factors of 18 and 11 times, limits of quantification of 0.030 and 0.12 µg L-1 and precision, expressed as relative standard deviation (RSD, n = 8, 2.0 µg L-1), of 1.1 and 4.3% for copper and cadmium, respectively. The CPE GF AAS method was applied to the determination of copper and cadmium in samples of saline produced formation water from petroleum exploration, and its accuracy was accessed by analyzing certified reference material CASS-5 (Nearshore Seawater Reference Material for Trace Metals) from National Research Council (Canada).

A petrochemical effluent is usually a matrix of very high complexity and composition variability, requiring robust and suitable methods for routine analysis. In this paper, the feasibility of applying a voltammetric technique for the determination of metals species in the petrochemical industry effluent was demonstrated after UV-assisted digestion procedure. Voltammetric (electrolyte volume, deposit time, pulse time, pulse amplitude and scan rate) and digestion variables (hydrogen peroxide volume, nitric acid volume and digestion time) were studied using a 2-level factorial design. The developed voltammetric method using anodic stripping voltammetry (ASV) presented limits of quantification of 11, 5, 15 and 5 µg L−1 for Zn, Cd, Pb and Cu, respectively, and was effective to analyze petrochemical effluents after UV-digestion.

AbstractA device comprising a lab-made chamber with mechanical stirring and computer-controlled solenoid valves is proposed for the mechanization of liquid-liquid extractions. The performance was demonstrated by the extraction of ethanol from biodiesel as a model of the extraction of analytes from organic immiscible samples to an aqueous medium. The volumes of the sample and extractant were precisely defined by the flow-rates and switching times of the valves, while the mechanic stirring increased interaction between the phases. Stirring was stopped for phase separation, and a precise time-control also allowed a successful phase separation (i.e., the absence of the organic phase in the aqueous extract). In the model system, a linear response between the analytical response and the number of extractions was observed, indicating the potential for analyte preconcentration in the extract. The efficiency and reproducibility of the extractions were demonstrated by recoveries of ethanol spiked to biodiesel samples within 96% and 100% with coefficients of variation lower than 3.0%.

A cloud-point extraction (CPE) method using the surfactant (30)p-tert-octylphenol polyoxyethylene (OPEO30) was proposed as the preceding step for the determination of polycyclic aromatic hydrocarbons (PAHs) by gas chromatography-mass spectrometry (GC-MS). Given the need for surfactant derivatization before the chromatographic analysis, the reaction conditions of coacervate derivatization were studied. The extraction process was also optimized, where surfactant concentration, temperature and time were analyzed as variables. The limits of detection obtained were between 0.02 and 0.05 µg L-1, and the recoveries of analytes were between 70 and 98%, with coefficient of variation better than 10.3%. The analytical method developed provides an efficient, precise and accurate method for the determination of the 16 priority PAHs, generating results in accordance with the USEPA 3510C method. The method was applied to the analysis of groundwater samples collected from artesian wells located at retail fuel stations.

Nesse estudo um planejamento experimental de misturas de biodieseis é utilizado para avaliar e otimizar a estabilidade oxidativa de amostras de biodiesel de soja contendo diferentes teores de biodiesel de sebo e de mamona. As misturas de biodieseis foram preparadas com teores que variaram entre 80-86% (v/v) para a soja, 5-15% (v/v) para o sebo e 1-10% (v/v) para a mamona. O período de indução da amostra de biodiesel de soja puro serviu de base para a comparação com a estabilidade das misturas. A estratégia de planejamento experimental de misturas mostrou-se adequada para a formulação de misturas de biodiesel com ótima estabilidade oxidativa. O modelo quadrático obtido na etapa de otimização ajustou-se adequadamente aos dados experimentais, sendo capaz de prever as proporções ótimas para misturas com maior estabilidade oxidativa. O melhor período de indução foi obtido com as seguintes proporções: 82,5% (v/v) de soja, 7,5% (v/v) de sebo e 10,0% (v/v) de mamona.

This study proposes an experimental design of biodiesel constrained mixtures to evaluate and optimize the oxidative stability of soybean biodiesel mixed with different amounts of tallow and castor bean biodiesels. To prepare the biodiesel blends, the proportions of each type of biodiesel were varied, producing mixtures that contained 80-86% (v/v) soybean, 5-15% (v/v) tallow, and 1-10% (v/v) castor bean biodiesel. The induction period of pure soybean biodiesel served as the baseline for comparing the stability of the mixtures. The experimental design strategy was capable of producing the best oxidative stability for biodiesel mixtures. The quadratic model obtained in the optimization stage fits the experimental data well. The higher induction period occurred at the following composition: 82.5% (v/v) soybean, 7.5% (v/v) tallow and 10.0% (v/v) castor bean.

Nesse trabalho, um método sonoquímico de síntese de nanoestruturas de sulfeto de bismuto em 1D e 3D foi desenvolvido e comparado com uma rota sintética empregando aquecimento sob refluxo. O método sonoquímico monstrou ser mais rápido e eficiente na obtenção de nanoestruturas com alta homogeneidade morfológica. A forma e qualidade dos nanocristais foram dependentes do tipo de solvente empregado na síntese. Superestruturas em 3D semelhantes a flores foram obtidas quando etileno glicol puro foi utilizado como solvente, enquanto estruturas em 1D na forma de nanobastões foram obtidas quando utilizada uma mistura de dimetilsulfóxido e etileno como solvente.

In this work, a sonochemical method to synthesize nanostructures of bismuth sulfide in 1D and 3D framework was developed and compared with a synthetic route with heating under reflux. The sonochemical method showed to be faster and more efficient than refluxing method to obtain nanostructures with high morphological homogeneity. Form and quality of the nanocrystals were dependent on the type of solvent employed in the synthesis procedure. 3D flower-like superstructures were obtained when ethylene glycol was used as solvent, while 1D nanorods were obtained when a mixture of dimethyl sulfoxide and ethylene glycol was used as solvent.

A sensitive spectrophotometric method was developed for sulphate determination in automotive ethanol fuel. The method based on the reaction of the analyte with barium-dibromosulphonazo(III) complex lead to a decrease in the magnitude of the absorbance signals monitored at 649 nm. No sample pretreatment is required and the proposed method allows sulphate determination in the 0.45 - 6.50 mg L-1 range with R.S.D. < 2% and limit of detection of 0.14 mg L-1. The method has been successfully applied for sulphate determination in automotive ethanol fuel and the results agreed with the reference chromatographic method.

Desenvolveu-se um procedimento para determinação de cobre, ferro, chumbo e zinco em amostras de gasolina. O procedimento foi baseado na pré-concentração dos metais empregando uma resina modificada com o ácido 3,4-dihidroxibenzóico (XAD-DHB), seguida da dessorção com solução ácida. Os analitos no eluato foram determinados por espectrometria de absorção atômica em chama multielementar seqüencial (FS-FAAS). As amostras de gasolina foram preparadas como microemulsões misturando-se 80 mL de amostra com 17 mL de propan-1-ol e 3 mL de solução tampão (pH 10). As variáveis físico-químicas que influenciam no processo de extração foram otimizadas. Os LODs obtidos foram 2,2 µg L-1 para Fe, 3,1 µg L-1 para Cu, 2,3 µg L-1 para Pb, e 2,6 µg L-1 para Zn. Os valores de RSDs das concentrações dos analitos nas amostras enriquecidas com 0,05 e 0,1 mg L-1 de cada metal variaram de 5,8 a 9,7%. As recuperações variaram de 82 a 99%. O método foi aplicado na determinação dos analitos em níveis de µg L-1 em amostras de gasolinas coletadas em postos revendedores de Salvador, BA, Brasil.

A procedure was developed for determination of copper, iron, lead and zinc in gasoline. The procedure was based on the preconcentration of metals using a resin modified with 3,4-dihydroxybenzoic acid (XAD-DHB), followed by desorption with an acid eluent. The components in the eluate were then determined by fast sequence flame atomic absorption spectrometry (FS-FAAS). The gasoline samples were prepared as microemulsions by mixing 80 mL of sample with 17 mL of propan-1-ol and 3 mL of a buffer solution (pH 10). The chemical and physical variables influencing the extraction were optimized. The LODs obtained were 2.2 µg L-1 Fe, 3.1 µg L-1 Cu, 2.3 µg L-1 Pb and 2.6 µg L-1 Zn. The RSDs ranged from 5.8 to 9.7% in samples spiked with 0.05 and 0.1 mg L-1 of each metal and recoveries varied from 82 to 99%. The procedure was suitable for determination of the analytes at µg L-1 levels in gasoline samples collected from several gas stations in Salvador, State of Bahia, Brazil.

Contextualized overview of the Biodiesel Production Chain, from the lab bench to the industry, with critical evaluation of state-of-art and technological development through scientific articles and patents, focusing on feedstock, reaction/production, first and second generation processes, specification and quality, transport, storage, co-products (effluents and sub-products), and emissions. Challenges are identified and solutions are proposed based on the Brazilian feedstock, edaphoclimatic conditions, process monitoring in remote regions, state policy, and environment preservation, among others. Forecasts are made based on the technology assessment, identifying future trends and opportunities for R&D&I.

In the present work three ferroin reagents were studied for the simultaneous spectrophotometric determination of iron and copper: 1,10-phenanthroline, 2,2'-bipyridine and 2,4,6-tri(2-pyridyl)-1,3,5-triazine. Effect of pH, conditions, order reagent addition, interferences, amount of reagents, lineal range, sensitivity and stability of each system were compared. The 2,4,6-tri(2-pyridyl)-1,3,5-triazine can be used for determination of iron in the presence of copper with a detection limit of 5 µg L-1 and coefficient of variation of 2.0%; However it was not possible to determine directly copper in the presence of iron with this reagent. 1,10-phenanthroline can be used for simultaneous determination of the metallic ions with detection limits of 7 and 8 mg L-1 and coefficients of variation of 1.8 and 2.3% in the determination of iron and copper, respectively. The results showed also that 2,2'-bipyridine can be used for simultaneous determination of the metallic ions with detection limits of 11 and 32 µg L-1 and coefficients of variation of 1.9 and 2.5% in the determination of iron and copper, respectively. The reagents were used for spectrophotometric determination of iron and copper in ethanol fuel.