Degradação eletroquímica de ibuprofeno e naproxeno usando processo eletro- Fenton monitorado por fluorescência e métodos quimiométricos

The use of fluorescence spectra and chemometric methods to monitor the electrochemical degradation of the drugs ibuprofen (IBU) and naproxen (NAP) using electro-Fenton process with boron-doped diamond (BDD) is the aim of this work. The variables of the degradation process were studied and optimized using design of experiments. Percentage of chemical oxygen demand removal was used as response in the design of the experiments. The results of the central composite design showed that the best conditions to perform the degradation were 60 mA cm -2 of current density, 5500 mg L -1 of Na 2 SO 4 as support electrolyte and 30 mg L -1 of Fe 2+ as catalyst. Solutions of 30 mg L -1 of the drugs were degraded, and aliquots were taken during 1h. TOC removal, fluorescence spectra, and HPLC were used to evaluate the degradation solutions of IBU, NAP and the mixture of the compounds (MIX). The fluorescence spectra were treated with chemometric methods, i.e., parallel factors analysis (PARAFAC), multivariate curve resolution with alternating least squares (MCR-ALS) and partial least squares regression (PLSR). Models were built for each method and compared. The best fit was obtained with MCR-ALS method using fixed excitation wavelength (242 nm), and emission spectra scanned from 260 to 410 nm. The MCR-ALS was capable of recovering the pure emission spectra of the drugs and some byproducts generated. Also, the concentrations profiles of each compound were obtained. The fluorescence spectra of the compounds decreased significantly in less than 1 hour, which suggests a possible reduction of the toxicity of the solution. Results of separation and quantification obtained by HPLC with fluorescence detection were compared to the results obtained with MCR-ALS and fluorescence. Correlations high than 0.99 were achieved demonstrating that fluorescence spectroscopy associated with MCR-ALS method can substitute HPLC-fluorescence analysis in this application. Percentages of TOC removal were 77%, 65% and 63% to IBU, NAP, and MIX solution, respectively. The degradation process studied was efficient, and the monitoring method employing fluorescence and MCR-ALS showed to be fast, adequate and reliable.O uso de espectros de fluorescência e métodos quimiométricos para monitorar a degradação eletroquímica dos fármacos ibuprofeno (IBU) e naproxeno (NAP) utilizando processo eletro-Fenton com diamante dopado com boro (BDD) é o objetivo deste trabalho. As variáveis do processo de degradação foram estudadas e otimizadas empregando planejamentos experimentais. A resposta usada nos planejamentos foi a remoção da demanda química de oxigênio. Os resultados do planejamento composto central mostraram que as melhores condições para realizar a degradação foram densidade de corrente de 60 mA cm -2 , 5500 mg L -1 de Na 2 SO 4 como eletrólito suporte e 30 mg L -1 de Fe 2+ como catalisador. Soluções de 30 mg L -1 dos fármacos foram degradadas e alíquotas foram retiradas durante 1h. O monitoramento das degradações das soluções de IBU, NAP e da mistura dos compostos (MIX) foi realizado empregando remoção de carbono orgânico total (TOC), espectros de fluorescência e HPLC. Os espectros de fluorescência foram tratados com métodos quimiométricos, i.e., análise dos fatores paralelos (PARAFAC), resolução multivariada de curvas com quadrados mínimos alternantes (MCR-ALS) e a regressão com quadrados mínimos parciais (PLSR). Modelos foram construídos para cada método e comparados. O melhor ajuste foi obtido com o método MCR-ALS fixando o comprimento de onda de excitação em 242 nm e com emissão obtida entre 260 e 410 nm. O MCR-ALS foi capaz de recuperar os espectros puros dos fármacos e de alguns subprodutos formados além dos perfis de concentração de cada um. O sinal de fluorescência dos compostos diminuiu significantemente em menos de 1 hora, o que sugere uma diminuição da toxicidade da solução. Resultados das separações e quantificações obtidos usando o HPLC com detecção de fluorescência foram comparados com os resultados obtidos usando fluorescência e o método MCR-ALS. Correlações superiores a 0.99 foram encontradas, demonstrando que a espectroscopia de fluorescência aliada ao método MCR-ALS é capaz de substituir as análises por HPLC- fluorescência nesta aplicação. As porcentagens de remoção de TOC foram 77%, 65% e 63% para as soluções de IBU, NAP e MIX, respectivamente. O processo de degradação estudado foi eficiente e o método de monitoramento empregando fluorescência e MCR- ALS se apresentou rápido, adequado e confiável.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

A simplistic portable LED-Based photometer for in situ determination of copper in sugarcane spirits

A low-cost and portable LED-based photometer was developed and applied for in situ determination of copper in sugarcane spirit. The determination was based on the chelation reaction between copper(II) and cuprizone (bis(cyclohexanone)oxalyldihydrazone). After optimizing the best experimental variables, a dynamic linear range to determine copper(II) was linear from 1.0 to 12.0 mg L−1 (r2 = 0.999) with the limits of detection and quantification of 0.20 and 0.70 mg L−1, respectively. The recovery of copper ranged from 96.5 to 104.4%. The paired t test was performed, and the results agreed at 95% level of confidence. The analytical method LED-based photometer demonstrated that it can be employed to determine copper in sugarcane spirit for quality purpose, e.g., small rural producers can evaluate the drink quality before bottling due to the easy handling, portability, fast response, and low-cost of the materials used

In situ determination of urea in milk employing a portable and low-cost LED photometer

A low-cost and portable LED photometer was developed and applied for the in situ determination of urea in milk. The determination was based on Berthelot’s reaction. After optimization, the best experimental variables, the detection limit and quantification limit were 1.8 × 10^−4 and 8.0 × 10^−4 mol L^−1, respectively. The percentage recovery varied between 95.6 and 105%. The paired t test was performed for the cow and goat milk determination and the results agreed at a 95% level of confidence for the in situ determination. Supported by the results, the analytical method based on LED photometer demonstrated that it can be employed for urea determination in food production for quality purpose, and small rural producers can evaluate the quality of herd feeding due to the easy handling, portability, fast instrumental response, and low cost of the materials used

NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics

Xenarthrans—anteaters, sloths, and armadillos—have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, 10 anteaters, and 6 sloths. Our data set includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the southern United States, Mexico, and Caribbean countries at the northern portion of the Neotropics, to the austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n = 5,941), and Cyclopes sp. have the fewest (n = 240). The armadillo species with the most data is Dasypus novemcinctus (n = 11,588), and the fewest data are recorded for Calyptophractus retusus (n = 33). With regard to sloth species, Bradypus variegatus has the most records (n = 962), and Bradypus pygmaeus has the fewest (n = 12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other data sets of Neotropical Series that will become available very soon (i.e., Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans data set. Please cite this data paper when using its data in publications. We also request that researchers and teachers inform us of how they are using these data

NEOTROPICAL ALIEN MAMMALS: a data set of occurrence and abundance of alien mammals in the Neotropics

Biological invasion is one of the main threats to native biodiversity. For a species to become invasive, it must be voluntarily or involuntarily introduced by humans into a nonnative habitat. Mammals were among first taxa to be introduced worldwide for game, meat, and labor, yet the number of species introduced in the Neotropics remains unknown. In this data set, we make available occurrence and abundance data on mammal species that (1) transposed a geographical barrier and (2) were voluntarily or involuntarily introduced by humans into the Neotropics. Our data set is composed of 73,738 historical and current georeferenced records on alien mammal species of which around 96% correspond to occurrence data on 77 species belonging to eight orders and 26 families. Data cover 26 continental countries in the Neotropics, ranging from Mexico and its frontier regions (southern Florida and coastal-central Florida in the southeast United States) to Argentina, Paraguay, Chile, and Uruguay, and the 13 countries of Caribbean islands. Our data set also includes neotropical species (e.g., Callithrix sp., Myocastor coypus, Nasua nasua) considered alien in particular areas of Neotropics. The most numerous species in terms of records are from Bos sp. (n = 37,782), Sus scrofa (n = 6,730), and Canis familiaris (n = 10,084); 17 species were represented by only one record (e.g., Syncerus caffer, Cervus timorensis, Cervus unicolor, Canis latrans). Primates have the highest number of species in the data set (n = 20 species), partly because of uncertainties regarding taxonomic identification of the genera Callithrix, which includes the species Callithrix aurita, Callithrix flaviceps, Callithrix geoffroyi, Callithrix jacchus, Callithrix kuhlii, Callithrix penicillata, and their hybrids. This unique data set will be a valuable source of information on invasion risk assessments, biodiversity redistribution and conservation-related research. There are no copyright restrictions. Please cite this data paper when using the data in publications. We also request that researchers and teachers inform us on how they are using the data