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The present work proposes a simple method for direct determination of Cu and Mn in commercial fruit juices and nectars by graphite furnace atomic absorption spectrometry (GF AAS). We analyzed samples of different flavors (orange, mango, passion fruit, peach, and grape) and brands of Brazilian commercial fruit juices and nectars. We also carried out a study to define a suitable temperature program and to optimize the calibration conditions. It was possible to determine Cu and Mn in the samples just after a simple dilution of samples with a 0.70 mol L−1 HNO3 solution, except in the case of grape juice. We compared the results obtained with the proposed method to those obtained after a traditional treatment based on acid digestion in a microwave oven, and no significant differences were observed (except for grape juice). The accuracy of the method was assessed through a recovery test, which provided recovery percentages in the range of 81–117%. Precision was always better than 8%, and the limits of quantification for Cu and Mn were 6 μg L−1 and 9 μg L−1, respectively. We analyzed twenty-two samples, and the concentrations of Cu and Mn were in the range of 24.1–321 μg L−1 and 116–3296 μg L−1, respectively. Statistical analysis using a two-way analysis of variance (ANOVA) at 95% confidence level showed that flavor and brand impacted on the concentration of the analytes in the samples. Among the samples analyzed, the grape juice presented the highest concentrations of both Cu and Mn. [ABSTRACT FROM AUTHOR]

The concern about environmental contamination resulting from industrial processes has spread worldwide in the last decades. That concern has led the scientific community to make efforts in order to help industrial processes to become less aggressive to the environment without losing their efficiency. The idea of sustainable development proposes that the amount of residues generated in production steps should decrease and/or be reused in other industrial processes in an economically viable way. The steel industry is responsible for the emission of great amount and variety of solid residues. Nevertheless, the commercial utilization of these residues as alternative solid phases to remove metals and dyes from aqueous media is not common, what justifies alternative resolutions for this subject by the scientific community. In this work, solid waste coming from the dedusting systems from a steel industry in Rio de Janeiro − Brazil was studied in terms of its ability to remove dyes from aqueous textile industry effluents. The dye used as model to perform this study was Basic Violet 3 (BV3). The results show that this residue removes 90% of BV3 from aqueous media under optimized conditions: pH 4,75 and ionic strength at 0,170 mol L −1 by acetic acid/sodium acetate buffer solution, 70 mg of solid phase, 45 °C, stirring time of 175 min at 110 rpm and particle size of 250 mesh. Studies about the kinetic and thermodynamic characteristics of the adsorption process were also realized. The kinetic profile followed the pseudo-second order and Morris-Weber models. In terms of thermodynamics, data best fitted to Freundlich isotherm. [ABSTRACT FROM AUTHOR]

In this work the re-fixation of mobilized copper (Cu) that was released from a deactivated pilot Cu ore dressing plant in the tropical rain forest at Southeastern Amazon (Carajás) was studied. Samples of top soils, decay leaf litter deposited on soils, roots and leaves of standing biomass were taken for the determination of Cu concentration in order to evaluate the distribution of it between different environmental compartments. In the sampling points near to the now extinct plant, total Cu concentrations in the soil reached an average value of 2140μgg−1 above the natural level of about 40μgg−1, being that bioavailable Cu estimated by DTPA method varied from 1. 9 to 20. 7% of this total. From the data was possible to calculate that the soil compartment is able to hold around 10kgCu/m2 of ground. Roots of the standing biomass in that area hold around 17gCu/m2, while the Cu content in leaves showed to be largely independent of the Cu level in the soil. Copper in the leaves was estimated as around 1g/m2 of ground area. In turn, the decay leaf litter deposited on soil can hold about 1. 6gCu/m2. The terrestrial system surrounding the abandoned pilot plant demonstrated great buffer capacity to retain mobile Cu released by anthropogenic activities in the area. [Copyright &y& Elsevier]

[Display omitted] • We developed a HPLC-DAD method for the determination of cocaine adulterants in Brazilian Real banknotes. • Acetaminophen, levamisole, caffeine, lidocaine, cocaine, diltiazem and phenacetin were determined in the samples. • The substances were extracted from samples by mechanical agitation with with acetonitrile. • We analyzed 158 banknotes and only one did not presente any of the target substances. Cocaine is a tropane alkaloid extracted from coca leaves, a common bush found in Andean regions of South America. Many medicines are added to the final product to increase the profits, keeping similar or higher effects than cocaine alone. Stimulants, anesthetics, and sedatives are the most found adulterants. The goal of this work was to propose a novel analytical methodology to determine cocaine and the main medicines found in street cocaine in Real banknotes using high-performance liquid chromatography with diode array detection (HPLC-DAD). Under optimized conditions, the target substances were extracted with acetonitrile, and the cleanup of the obtained extracts was carried out by separating the fatty layer at low temperature (–20 °C). The volume of extract was reduced under nitrogen flow and adjusted to 2.5 mL with a solution containing 95% (v/v) of phosphate buffer (10 mmol L−1, pH = 2.5) and 5% (v/v) of acetonitrile. Under these conditions, it was possible to identify and quantify cocaine and its adulterants in the samples, with limits of quantification of 0.29, 0.012, 0.16, 0.22, 0.026, 0.078, and 0.14 µg per banknote for acetaminophen, levamisole, caffeine, lidocaine, cocaine, diltiazem, and phenacetin, respectively. We analyzed 158 samples, and only one did not present any of the tested substances. Higher amounts of the tested substances were verified in banknotes of lower value. [ABSTRACT FROM AUTHOR]

The present paper reports on the development of a novel extraction induced by emulsion breaking (EIEB) method for the determination of chloride in crude oils. The proposed method was based on the formation and breaking of oil-in-water emulsions with the samples and the consequential transference of the highly water-soluble chloride to the aqueous phase during emulsion breaking, which was achieved by centrifugation. The determination of chloride in the extracts was performed by ion chromatography (IC) with conductivity detection. Several parameters (oil phase:aqueous phase ratio, crude oil:mineral oil ratio, shaking time and type and concentration of surfactant) that could affect the performance of the method were evaluated. Total extraction of chloride from samples could be achieved when 1.0 g of oil phase (0.5 g of sample + 0.5 g of mineral oil) was emulsified in 5 mL of a 2.5% (m/v) solution of Triton X-114. The obtained emulsion was shaken for 60 min and broken by centrifugation for 5 min at 5000 rpm. The separated aqueous phase was collected, filtered and diluted before analysis by IC. Under these conditions, the limit of detection was 0.5 μg g −1 NaCl and the limit of quantification was 1.6 μg g −1 NaCl. We applied the method to the determination of chloride in six Brazilian crude oils and the results did not differ statistically from those obtained by the ASTM D6470 method when the paired Student- t -test, at 95% confidence level, was applied. [ABSTRACT FROM AUTHOR]

Abstract: This present work reports a multivariate optimization of a spectrophotometric method for copper determination in sugar-cane spirits, exploring the reaction of Cu(II) with phenylfluorone (PF) in the presence of cetylpyridinium chloride (CPC) and Triton X-100. The optimization strategy was based on the application of a two-level full factorial design for the screening of significant variables followed by a Doehlert design to determine the optimum conditions. The highest sensitivity was achieved when the pH was 8.0 and the PF and TX-100 concentrations were 6.2×10−5 and 1.0×10−2 molL−1, respectively. The optimized method presented a limit of detection of 3.4μgL−1 and a limit of quantification of 11μgL−1 and was applied in the determination of Cu in 17 samples. The obtained results were compared with those obtained by ICP OES and no statistical difference between the methods was observed. [Copyright &y& Elsevier]

The distribution and concentration of organic compounds in the environment have attracted great interest mainly due to their capability of bioaccumulation, dispersion, and danger to living organisms. Factors such as urbanization, population growth, and the emergence of new technologies contribute to the increase in pollutant emissions, especially volatile organic compounds (VOCs), such as benzene, toluene, ethylbenzene, and xylenes (BTEX). These compounds are emitted by several sources, becoming more common in work environments, influencing indoor air quality (IAQ), which can cause health damage, in addition to increasing the likelihood of cancer development. In this context, we developed a semipermeable membrane device (SPMD), consisting of low density polyethylene membrane (8 cm long × 3 cm wide), filled with 3 mL of acetonitrile, for passive sampling of toluene (and benzene) in gas phase. With this configuration, the SPMD needed 24 h exposure to the indoor air in order to achieve equilibrium. The target compounds were quantified in the acceptor phase by HPLC-DAD. The optimized SPMD was tested for the collection of toluene and benzene in six chemistry laboratories at Fluminense Federal University and in five nail salons in the city of Niterói, in the state of Rio de Janeiro, Brazil. The developed sampling method was able to identify the analytes in the indoor air of the studied environments, and was easy to operate, with no need to clean up the extracts, allowing their direct injection into the chromatographic system., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)