Geochemistry of trace metals in surface sediments from the continental slope of the states of Sergipe and Alagoas, Northeastern Brazil.

Geochemical analyses were used to determine the origin and identify the main factors that lead to the metal trace distribution on the surface sediments from the continental slope of Sergipe in Brazil. Sediment samples were collected during the dry and rainy periods, from 36 sampling points distributed at water depths from 400 to 3000 m. In general, no effect of seasonality was observed on the metal concentrations and no significant differences were observed between the depth ranges. The correlation analysis indicated the continental origin as the most predominant, followed by authigenic deposition. Anthropogenic enrichment was not noted, nor was the possibility of adverse aquatic biota effects. The results made it possible to understand the contribution of rivers in the transport and transfer of particulate matter to the coastal region, in addition to providing new information on the content of trace metals in tropical Atlantic sediments.

Multielement determination (essential and potentially toxic elements) in eye shadows exposed to consumption in Brazil using ICP OES.

Worldwide, cosmetics (especially eye shadows) are widely consumed and have a great impact on the economy. The aim of this study was to determine the multielement composition, focusing on essential and potentially toxic elements, in cosmetics (eye shadow) exposed to consumption in Brazil. Concentrations of 17 elements (Al, As, Ba, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Sb, Se, Sr, Ti, V and Zn) were determined in samples (produced in China and Brazil) using a sequential optical emission spectrometer with inductively coupled plasma (ICP OES) after acid digestion, assisted by a closed digester block (6 mL of HNO3 + 2 mL of H2O2 + 1 mL of Triton ×-100 + 1 mL of ultrapure water). The method was validated by linearity, precision, accuracy, limits of detection (LoD) and quantification (LoQ). The elements were quantified (in µg g-1): Al (852-21,900), Ba (3.47-104), Cd (1.70-6.93), Cr (< 8.53-66.6), Cu (< 0.480-14.5), Mn (92.20-1,190), Ni (< 4.23-40.7), Pb (< 2.16-5.06), Sb (1.10-10.5), Sr (0.760-46.0), Ti (32.0-440), V (< 0.85-1.7) and Zn (24.90-2,600). As, Co, Mo and Se in all the investigated samples were found to be below the LoQ values of ICP OES. In this study, regardless of sample compositions and origins (Brazilian or Chinese), high levels of Al, Cd, Cr, Cu, Mn, Ni, Pb, Sb, Ti, V and Zn were observed, exceeding the recommended maximum tolerable limits, according to Brazilian and global legislations, which may present potential risks to human health and the environment.

A Review on Atmospheric Analysis Focusing on Public Health, Environmental Legislation and Chemical Characterization.

Atmospheric pollution has been considered one of the most important topics in environmental science once it can be related to the incidence of respiratory diseases, climate change, and others. Knowing the composition of this complex and variable mixture of gases and particulate matter is crucial to understand the damages it causes, help establish limit levels, reduce emissions, and mitigate risks. In this work, the current scenario of the legislation and guideline values for indoor and outdoor atmospheric parameters will be reviewed, focusing on the inorganic and organic compositions of particulate matter and on biomonitoring. Considering the concentration level of the contaminants in air and the physical aspects (meteorological conditions) involved in the dispersion of these contaminants, different approaches for air sampling and analysis have been developed in recent years. Finally, this review presents the importance of data analysis, whose main objective is to transform analytical results into reliable information about the significance of anthropic activities in air pollution and its possible sources. This information is a useful tool to help the government implement actions against atmospheric air pollution.

Chlorine determination via MgCl molecule in environmental samples using high resolution continuum source graphite furnace molecular absorption spectrometry.

This paper describes a method development for chlorine determination through the formation of MgCl molecule, applied for the first time for Cl quantification, by high resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS GF MAS) in environmental samples. Pyrolysis and vaporization temperatures were optimized as well as the use of chemical modifier. Determinations were carried out at the wavelength of 377.010 and the compromise conditions of the graphite furnace temperature program were 500°C and 2500°C for pyrolysis and vaporization, respectively, using 10µg of chemical modifier Pd. The concentration of reactants for the generation of MgCl molecule was optimized through Box-Behnken experimental design, using MgCl2 solution as source of chlorine. The optimum values according to the surface response were 5gL-1 Mg, 25mgL-1 of chlorine and 2% vv-1 of HNO3, condition in which the amount of Mg is at least 200 times higher than that of chloride. This excess of the forming agent ensures the complete formation of MgCl molecular species, since Cl is the limiting reactant. Certified reference materials, BCR 182 and NIST 8414, and addition and recovery tests were used to evaluate the accuracy of the method and good results were achieved at a 95% confidence level. The method was applied to direct determination of Cl in five produced water samples from offshore oil wellbore, high complex matrix, whose conventional methods require tedious treatment before the analysis.

Multivariate Optimization of Conditions for Digestion of Wet Feeds for Dogs and Cats Using a Closed Digester Block and Multielement Determination by ICP-OES.

A full 24 factorial design was applied to find the best combination of diluted reagents (HNO3 and H2O2), time, and temperature for the digestion of samples of wet feed for dogs and cats using a closed digestion block. The residual carbon concentration (RCC) was used as the response in the factorial design. All variables and their interactions significantly influenced the digestion of the feed samples, as indicated by the RCC. The conditions established for the digestion of 0.05 g (dry mass) wet feed samples were the addition of 3.0 mol/L HNO3 and 5.0% m/m H2O2 in a final volume of 10 mL, followed by heating in a closed digestion block at a temperature of 170°C for 120 min. Analyses were performed by inductively coupled plasma (ICP) optical emission spectrometry (OES). LOQs ranged from 0.2 µg/g (Mg and Sr) to 51 µg/g (P). Accuracy of the analytical method was confirmed through the analysis of the Standard Reference Materials Tomato Leaves (NIST 1573), Apple Leaves (NIST 1515), and Peach Leaves (NIST 1547). The agreement values achieved ranged from 80.2 ± 0.3% for Ba to 113.8 ± 7.1% for Zn (n = 3). Addition and recovery tests were carried out by adding the analytes to a feed sample at two concentration levels, and the recoveries were between 84 ± 6 and 114 ± 10% for macroelements (Ca, K, Mg, and P; n = 3) and between 88 ± 3 and 113 ± 7% for microelements and trace elements (B, Cu, Fe, Sr, and Zn; n = 3). The precision values achieved for the different elements, expressed as RSDs, were better than 7.3% (Zn; n = 3) except for Cu determination, that was 14.6% (n=3). The optimized analytical method was applied to 10 commercial samples of wet feed for cats and dogs, with the concentrations of Al, B, Ba, Ca, Cu, Fe, K, Mg, Mn, P, Sr, and Zn determined by ICP-OES.

Multivariate optimization of an analytical method for the analysis of dog and cat foods by ICP OES.

Experimental design methodology was used to optimize an analytical method for determination of the mineral element composition (Al, Ca, Cd, Cr, Cu, Ba, Fe, K, Mg, Mn, P, S, Sr and Zn) of dog and cat foods. Two-level full factorial design was applied to define the optimal proportions of the reagents used for microwave-assisted sample digestion (2.0 mol L(-1) HNO3 and 6% m/v H2O2). A three-level factorial design for two variables was used to optimize the operational conditions of the inductively coupled plasma optical emission spectrometer, employed for analysis of the extracts. A radiofrequency power of 1.2 kW and a nebulizer argon flow of 1.0 L min(-1) were selected. The limits of quantification (LOQ) were between 0.03 µg g(-1) (Cr, 267.716 nm) and 87 µg g(-1) (Ca, 373.690 nm). The trueness of the optimized method was evaluated by analysis of five certified reference materials (CRMs): wheat flour (NIST 1567a), bovine liver (NIST 1577), peach leaves (NIST 1547), oyster tissue (NIST 1566b), and fish protein (DORM-3). The recovery values obtained for the CRMs were between 80 ± 4% (Cr) and 117 ± 5% (Cd), with relative standard deviations (RSDs) better than 5%, demonstrating that the proposed method offered good trueness and precision. Ten samples of pet food (five each of cat and dog food) were acquired at supermarkets in Aracaju city (Sergipe State, Brazil). Concentrations in the dog food ranged between 7.1 mg kg(-1) (Ba) and 2.7 g kg(-1) (Ca), while for cat food the values were between 3.7 mg kg(-1) (Ba) and 3.0 g kg(-1) (Ca). The concentrations of Ca, K, Mg, P, Cu, Fe, Mn, and Zn in the food were compared with the guidelines of the United States' Association of American Feed Control Officials (AAFCO) and the Brazilian Ministry of Agriculture, Livestock, and Food Supply (Ministério da Agricultura, Pecuária e Abastecimento-MAPA).