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).

In this study, antimicrobial activity of extracts and lupenone from A. inundata (Fabaceae, Mimosoideae), were tested. In addition, the multi-element composition of the leaves, bark and stems (heartwood) of A. inundata was evaluated using inductively coupled plasma optical emission spectrometry (ICP OES). Lupenone was isolated in the petroleum ether extract of leaves, for the first time. Biological assays were conducted to evaluate the antimicrobial (antibacterial, antifungal and antiparasitic) of extracts, their fractions and lupenone. The results showed antimicrobial and antileishmanial activity of these compounds, which may be useful for obtaining a chemical composition and biological activity database on Albizia species. For multi-element composition, we found the mean concentrations (minimum-maximum) of Al, Ca, Cr, Cu, Fe, K, Mg, Mn, Ni, P, V and Zn in the samples ranged between 0.06 and 265.41 µg g-1. Concentration ranges of Cu, Fe, Mn and Zn are large, which makes these samples as additional sources of these macronutrients.

Resumo Foram determinadas as concentrações de dez elementos (Cd, Cr, Cu, Fe, Ni, Pb, Se, Sr, V and Zn) em tecidos de músculos de treze espécies de peixes da Baía de Aratu, Bahia, Brasil, utilizando a espectrometria de emissão ótica com plasma indutivamente acoplado. A precisão e exatidão dos resultados foram analisadas utilizando dois materiais de referência certificada: BCR-422 cod muscle e o SRM 1566b oyster tissue. A concentração média dos elementos traço nas espécies de peixes variaram nas seguintes faixas, em μg g−1: Cr = 0,03-0,8; Cu = 2,0-33,7, Fe = 2,4-135,1, Se = 1,6-25,6; Sr = 1,6-35,1; Zn = 2.8-40.5. A espécie Diaptereus rhombeus (carapeba) apresentou as maiores concentrações de Se, Cu e Fe. Cromo e Se apresentaram níveis acima do limite de tolerância estabelecido pela Agência Nacional de Vigilância Sanitária (ANVISA). Os resultados ainda foram avaliados usando técnicas de análises multivariadas: análise de componente principal (PCA) e análise de agrupamento hierárquico (HCA).

Abstract Concentrations of ten elements (Cd, Cr, Cu, Fe, Ni, Pb, Se, Sr, V and Zn) were determinate in muscle tissues of 13 fish species from Aratu Bay, Bahia, Brazil by inductively coupled plasma optical emission spectrometry. The accuracy and precision of our results were checked by using two certified reference materials: BCR-422 cod muscle and SRM 1566b oyster tissue. The average trace element concentrations in the fish species varied in the following ranges, in μg g–1: 0.03-0.8 for Cr; 2.0-33.7 for Cu, 2.4-135.1 for Fe, 1.6-25.6 for Se; 1.6-35.1 for Sr; and 2.8-40.5 for Zn. The Diaptereus rhombeus (carapeba) specie presented the highest concentrations of Se, Cu and Fe. Chromium and Se were present at levels above the limit of tolerance allowed by the National Agency of Sanitary Vigilance (ANVISA). The results were also evaluated using the multivariate analysis techniques: principal component analysis (PCA) and hierarchical cluster analysis (HCA).

Resumo Esse estudo teve como objetivo avaliar as concentrações de elementos traço em tecidos da espécie de camarão Litopenaeus vannamei coletadas da zona costeira e de carciniculturas localizadas no nordeste do Brasil. Os elementos químicos foram determinados por espectrômetro de emissão óptica com plasma indutivamente acoplado (ICP OES). Foram encontradas as seguintes faixas de concentrações desses elementos nos tecidos (em mg g–1 peso seco): Al: 13,4-886,5; Cd: 0,93-1,80; Cu: 24,8-152; Fe: 3,2-4109; Mn: 0,36-24,4; Se: 0,094-9,81 and Zn: 20,3-109,4. O músculo do camarão investigado pode ser uma boa fonte de ferro (cerca de 88.9 mg-1g peso seco). A distribuição da concentração de Se nos tecidos apresentou muita variação entre as localidades, com níveis acima do estabelecido pela ANVISA para 67% dos musculos e 50% dos outros tecidos investigados, indicando evidências de bioacumulação do selênio. Houve correlações significativas entre os seguintes pares de elementos:: Fe-Zn (r= –0,70), Mn-Cu (r= –0,74), Se-Cu (r= –0,68), Se-Mn (r= 0,82) nos músculos, Fe-Al (r= 0,99), Mn-Al e Mn-Fe (r= 0,62), Se-Al (r = 0,88), Se-Fe (r= 0,87), Se-Mn (r= 0,58) no exoesqueleto e Cu-Zn (r = 068), Al-Cu (r= 0,88), Fe-Cu (r= 0,95) and Fe-Al (r= 0,97) nas vísceras.

Abstract In this study, concentrations of trace elements in tissues of shrimp species (Litopenaeus vannamei) from farming and zone natural coastal located in the northeastern Brazil were investigated. The elements determination was performed by optical emission spectrometry with inductively coupled plasma (ICP OES). The following ranges of concentrations in the tissues were obtained in µg g–1 dry weight: Al: 13.4-886.5, Cd: 0.93-1.80; Cu: 24.8-152; Fe: 3.2-410.9; Mn: 0.36-24.4; Se: 0.094-9.81 and Zn: 20.3-109.4. The shrimp muscle can be a good iron source (about 88.9 mg–1g dry weight). The distribution of Se concentration in tissues showed much variation between locations, and the concentration levels found in shrimp muscles of wild samples were high, where its levels in 67% of muscle and 50% of others tissues samples exceeded the ANVISA limit, indicating evidence of selenium bioaccumulation. Significant correlation was observed between the following pairs of elements: Fe-Zn (r= –0.70), Mn-Cu (r= –0.74), Se-Cu (r= –0.68), Se-Mn (r= 0.82) in the muscles; Fe-Al (r= 0.99), Mn-Al (r= 0.62), Mn-Fe (r= 0.62), Se-Al (r = 0.88), Se-Fe (r= 0.87), Se-Mn (r= 0.58) in the exoskeleton and Cu-Zn (r = 0.68), Al-Cu (r= 0.88), Fe-Cu (r= 0.95) and Fe-Al (r= 0.97) in the viscera.

Neste trabalho descreve-se a composição mineral das folhas de Lippia alba (Mill.) que são utilizadas na preparação de chá utilizado na medicina popular. Assim, as folhas da espécie foram coletadas em cidades brasileiras e as amostras foram digeridas usando ácido nítrico e peróxido de hidrogênio em placa aquecedora e, em seguida, foram analisadas empregando espectrometria de emissão óptica com plasma acoplado indutivamente (ICP OES). Para avaliação da exatidão foi utilizado o material de referência certificado, folhas de maçã - NIST SRM 1515. Os resultados demonstraram que cálcio, magnésio e fósforo têm conteúdo médio de 1.950, 2.856 e 2.335 mg 100 g-1 e variações de concentrações de 767-3.887, 314-8.591 e 247-9.214 mg 100 g-1, respectivamente. Os micro-elementos, bário, zinco, cobre, ferro, manganês e níquel têm conteúdos médios de 2,16; 2,95; 0,94; 11,2; 4,25 e 0,09 mg 100 g-1, para variações de concentrações de 0,66-7,1; 1,35-6,3; 0,33-1,7; 0,98-34; 0.82-7,4 e 0,03-0,15 mg 100 g-1, respectivamente. Os dados foram também avaliados usando análise de componentes principais (PCA).

Leaves of Lippia alba (Mill.) N.E. Brown are used for the preparation of tea infusions that are employed in folk medicine. In this paper, the mineral composition of Lippia alba (Mill.) leaves, collected from different Brazilian cities, was evaluated. The samples were digested using nitric acid and hydrogen peroxide on a hot plate and were analyzed using inductively coupled plasma optical emission spectrometry (ICP OES). SRM 1515 apple leaves from NIST were used for checking accuracy. The results demonstrated that calcium, magnesium and phosphorus have average contents of 1,950, 2,856 and 2,335 mg 100 g-1, respectively, and concentration ranges of 767-3,887, 314-8,591 and 247-9,214 mg 100 g-1, respectively. The microelements barium, zinc, copper, iron, manganese and nickel have average contents of 2.16, 2.95, 0.94, 11.2, 4.25 and 0.09 mg 100 g-1, respectively, and concentration ranges of 0.66-7.1, 1.35-6.3, 0.33-1.7, 0.98-34, 0.82-7.4 and 0.03-0.15 mg 100 g−1, respectively. The data were also evaluated using principal component analysis (PCA).

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.

Neste trabalho, foi avaliada a composição mineral da farinha de trigo consumida no Brasil. Na etapa de amostragem foram coletadas 54 amostras em 15 cidades, incluindo as principais cidades brasileiras como: São Paulo, Rio de Janeiro, Salvador, Porto Alegre, Recife e outras. Os elementos determinados foram: cálcio, cobre, magnésio, manganês, ferro, fósforo, potássio e zinco. As amostras foram digeridas usando acido nítrico e peróxido de hidrogênio em sistema aberto. A técnica analítica empregada foi a espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES). A validação do método (incluindo digestão e determinação) foi confirmada usando um material de referência certificado de farinha de trigo fornecido pelo National Institute of Standards & Technology (NIST). Considerando as 54 amostras analisadas, os resultados demonstraram que os macronutrientes: cálcio, magnésio, potássio e fósforo encontram-se em média de 0,27; 0,35; 1,71 e 1,92 mg g-1, com variação da concentração de 0,11-1,96; 0,19-0,51; 0,76-3,16 e 0,81-7,15 mg g-1, respectivamente. Os micronutrientes: cobre, ferro, manganês e zinco encontram-se em média de 1,84; 37,82; 8,25 e 9,41 µg g-1, com a variação de concentração de 1,00-2,80; 10,46-146,58; 3,89-14,74 e 5,07-13,93 µg g-1, respectivamente. Os resultados foram também avaliados usando as técnicas de análise multivariadas: análise de componente principal (PCA) e análise de agrupamento hierárquico (HCA).

In the present paper, the mineral composition of wheat flour consumed in Brazil was evaluated. In the sampling step 54 samples were collected in 15 cities, including principal Brazilian cities such as: São Paulo, Rio de Janeiro, Salvador, Porto Alegre, Recife and others. The elements determinate were: calcium, copper, magnesium, manganese, iron, phosphorus, potassium and zinc. The samples were digested using nitric acid and hydrogen peroxide in open system. The analytical technique employed was Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES). The method validation (including digestion and determination) was performed using a certified reference material of wheat flour furnished by National Institute of Standards & Technology (NIST). Considering the 54 samples analyzed, the results demonstrated that the macronutrients: calcium, magnesium, potassium and phosphorus have average contents of 0.27, 0.35, 1.71 and 1.92 mg g-1, for concentration ranges of 0.11-1.96, 0.19-0.51, 0.76-3.16 and 0.81-7.15 mg g-1, respectively. The micronutrients: copper, iron, manganese and zinc have average contents of 1.84, 37.8, 8.2 and 9.4 µg g-1, for concentration ranges of 1.00-2.80, 10.5-146.6, 3.9-14.7 and 5.1-13.9 µg g-1, respectively. The results were also evaluated using the multivariate analysis techniques: principal component analysis (PCA) and hierarchical cluster analysis (HCA).