The cosmetic modification of hair is a very common procedure used to mask or cover evidence at a crime scene. Deoxyribonucleic acid (DNA) tests are expensive and require good-quality collection of samples and a database profile. To overcome these challenges, direct analysis was performed on a large set of hair strands collected from individuals, denoted original samples, and the data were compared with those of the same samples after cosmetic modification performed by bleaching the samples in the laboratory. A total of 127 samples were evaluated in this study using two analytical techniques, wavelength-dispersive X-ray fluorescence (WDXRF) and laser-induced breakdown spectroscopy (LIBS). Instead of testing many algorithms to develop classification models for the original and bleached samples, a recent method was applied that combines information from 17 classifiers. Data fusion was also evaluated to improve the accuracy of the classification model, which was higher than 99.2%, with no requirements to select eigenvectors or thresholds.

An extraction method based on solid-phase extraction was developed to determine the major alkaloid components, N,N-dimethyltryptamine, harmine, harmaline, harmalol, and tetrahydroharmine, in ayahuasca using ultra-performance liquid chromatography-tandem mass spectrometry. Coconut charcoal and menthone-thiosemicarbazone polymer were tested as new adsorbent materials. Experiments carried out at levels of 1, 5, 10, 50, 100, and 250 µg mL-1 resulted in recoveries in the ranges 45.3-115.7% for menthone-thiosemicarbazone and 40.6-116.2% for coconut charcoal. The detection and quantification limits ranged from 0.003 to 0.016 µg mL-1 and from 0.009 to 0.043 µg mL-1, respectively. The method developed was linear over the tested range (0.05-1.0 µg mL-1), with correlation coefficients ranging from 0.9969 to 0.9998. The technique was applied for analysis of the compounds in an ayahuasca sample collected from a religious group located in the city of Fortaleza, obtaining concentrations in the range from 0.3 to 19.3 mg mL-1.

In order to quantify antioxidant capacity in food products, several methods have been proposed over the years. Among them, DPPH radical is widely used to determine the antioxidant capacity of different substrates. However, it is known that different types of extractants, providing different responses, can extract a variety of bioactive compounds. Besides, storage time seems to interfere in the stability of these substances. Integral use of fruits and vegetables has been proposed along the years as a means of reducing environmental pollution and give a better destination to by-products from food industries. Thus, this study aimed to evaluate the antioxidant potential of a fruit and vegetables residue flour (FVR) with sequential and non-sequential extraction, in order to evaluate its antioxidant activity and phenolic compounds. And these compounds stability during storage of 180 days. It was observed that in non-sequential extraction, water was able to reduce by 74% the radical; however, at sequential extraction process, using six different extractors, each one was able to reduce at least 40% of DPPH. The total soluble phenolic contents in sequential extraction were 22.49 ± 1.59 mg GAE/g FVR on the first day and 5.35 ± 0.32 mg GAE/g FVR after 180 days.

O fracionamento por tamanho molecular da matéria orgânica natural (MON) de amostras de água do Parque Nacional Serra de Itabaiana (Brasil) foi utilizado para caracterização temporal da complexação de íons metálicos. Um sistema de ultrafiltração em cinco estágios foi usado para separar a MON em seis frações (F1: > 100; F2: 100-50; F3: 50-30; F4: 30-10; F5: 10-5; F6: < 5 kDa). A distribuição obtida, inicialmente para amostra in natura, mostrou que metais (Al, Ba, Cr, Cu, Fe, Mn, Ni, Pb e Sr) foram complexados, preferencialmente, pela fração F1, a qual continha maior concentração de carbono orgânico dissolvido (COD). A seguinte ordem decrescente de distribuição de carbono foi obtida: F1 >> F3 > F2 = F4 > F6 > F5. As frações F2 e F5 foram as mais humificadas e F6 a menos humificada. Após 30 dias com adição de elevadas concentrações de metais nas amostras filtradas novas distribuições de COD e metais foram observadas. Maior COD ainda foi encontrado na F1 com teores de carbono decrescendo na seguinte ordem: F1 > F2 > F3 > F4 > F5 > F6. Os metais apresentaram distribuições similares e homogêneas em todas as frações. Valores de log K foram similares para as amostras in natura e para aquelas de 30 dias após a adição dos metais (7,1 e 7,0; 6,6 e 6,9; e 7,2 e 7,0 para Al, Cu e Fe-MON, respectivamente), indicando uma nova condição de equilíbrio na distribuição dos metais após 30 dias. As espécies formadas entre MON e os metais adicionados mostraram um modelo de distribuição que mudou em função do tempo de complexação, indicando uma transformação dos sítios de ligação da MON, sugerindo que o efeito coletivo das frações é mais importante que as propriedades individuais e confirmando que as frações mais humificadas exercem grande influência na complexação de metais em ambientes aquáticos.

Molecular size fractionation of the natural organic matter (NOM) in water samples from the Serra de Itabaiana National Park (Brazil) was used to characterize the temporal behavior of metal ion complexation. A special five-stage tangential-flow ultrafiltration device was used to separate NOM in six size fractions (F1: > 100; F2: 100-50; F3: 50-30; F4: 30-10; F5: 10-5; F6: < 5 kDa). The distribution patterns obtained for one in natura sample showed that metals (Al, Ba, Cr, Cu, Fe, Mn, Ni, Pb and Sr) were preferentially complexed by the F1 fraction, which contained higher concentration of dissolved organic carbon (DOC). The following decreasing order of carbon distribution in the different fractions was obtained: F1 >> F3 > F2 = F4 > F6 > F5. Fractions F2 and F5 were the most humified, and F6 the least. New distributions of DOC and metals were observed after 30 days when high concentrations of metals were added to filtered samples. Highest DOC was still found in F1, with carbon contents decreasing in the following order: F1 > F2 > F3 > F4 > F5 > F6. The studied metals presented similar and homogeneous distributions in all fractions. Values of log K were similar for samples in natura and 30 days after addition of metals (7.1 and 7.0, 6.6 and 6.9, and 7.2 and 7.0 for Al, Cu and Fe-NOM, respectively), indicating a new dynamic equilibrium in the metals distribution after 30 days. The species formed between NOM and spiked metals showed distribution patterns that changed as a function of complexation time, indicating a transformation of the NOM binding sites, suggesting that the collective effect of the fractions is more important than individual site properties, and confirming that the most humified fractions exert a large influence on the complexation of metals in aquatic environments.