Exploratory analysis in the evaluation of stress due to aluminum presence in Physalis angulata L. and multielement determination by microwave-induced plasma optical emission spectrometry (MIP OES).

The present work aimed to analyze the mineral nutrition of Physalis angulata L. under stress by aluminum in the nutrient solution. The treatments consisted of five different concentrations of aluminum in the nutrient solution (0, 0.04, 0.08, 0.12, and 0.16 mmol L-1) in the AlCl3 form. The plants were exposed to Al for 30 days. Subsequently, nutritional and aluminum analyses were performed on plant tissue. The data were submitted to analysis of variance (p < 0.05), and, in case of significance, the regression study was performed as well as hierarchical cluster analysis (HCA) and principal component analysis (PCA) were used. The formation of four groups occurred, where we can observe the similarity and differences in the treatments between them. The separation of the treatments into groups reflected the heterogeneity of the treatments about the aluminum levels in the nutrient solution, evidencing its phytotoxicity level in Physalis angulata plants. Among the analyzed variables, P, K, Ca, Mg, Fe, Mo, and Zn were the most influential ones demonstrated by principal component analysis (PCA). The stress of 0.16 mmol L-1 of Al increased the phosphorus contents in the stems and roots and the potassium, copper, and molybdenum contents in all parts of the plants. In contrast, Al reduced the levels of calcium, magnesium, iron, and zinc in P. angulata plants. Iron being the micronutrient that showed the largest reduction, followed by zinc in the leaves. The highest levels of aluminum were found in the roots.

Characterization of honey of stingless bees from the Brazilian semi-arid region.

The physicochemical characteristics of honey vary according to bee species, climate, region, period of collection, processing and storage. In this context, this work aimed to perform a comparative study of the physicochemical characteristics of Melipona subnitida and M. fasciculata honey collected at different periods and regions of the State of Piauí, Brazil. Twenty-nine honey samples were collected and evaluated by principal component analysis from physicochemical analysis data. Twenty-two percent of the parameters analyzed differed between species. Evaluating the collection period, the honey of M. subnitida and M. fasciculata presented differences among themselves. The study revealed a similarity between the physicochemical parameters of the honey of the two species of bees, in addition, the time was one of the determining factors in the formation of clusters.

D-optimal mixture design for the optimization of extraction induced by emulsion breaking for multielemental determination in edible vegetable oils by microwave-induced plasma optical emission spectrometry.

A sample pretreatment based on an extraction process by emulsion breaking for multi-element determination in edible oils was developed. The determination of eight trace elements (Al, Ba, Cu, Cr, P, Ni, Ti, and Zn) was carried out by microwave-induced plasma optical emission spectrometry (MIP OES) after the extraction procedure. A D-optimal mixture experimental design was used to obtain the best experimental conditions for the extraction induced by emulsion breaking (EIEB). The proportion of HNO3 solution, Triton X-100 solution and sample was evaluated in a multivariate manner. The best recovery efficiency was obtained with 1.0 mL of 30% (v/v) HNO3, 1.0 mL of 30% (w/v) Triton-X 100 and 3.0 mL of the sample. The precisions, established as the relative standard deviation (RSD, %), were better than 2.5% for all analytes. The developed method was applied to the analysis of commercial vegetable oils with low limits of detection and good precision.

Assessing the internal standardization of the direct multi-element determination in beer samples through microwave-induced plasma optical emission spectrometry.

An evaluation of different elements (Be, Ga, In, Sc, and Y) as internal standards was performed to determine the content of Al, Ba, Co, Cr, Cu, Fe, Mn, Ni, Sr, Zn, Ca, Mg, Na, K in beer samples through microwave induced plasma optical emission spectrometry. The analytes were determined after simple dilutions of the samples with a 1.0 M nitric acid solution at a 1:4 ratio (sample: acid solution) with the addition of the IS. The analytical performance for each potential IS was established based on the limit of detection, limit of quantification, addition and recovery tests and accuracy obtained in the determination of each analyte. Each analyte responded differently when internal standardization was applied, and as such, the evaluation of each IS is important in the development of the method. In the presence of the recommended internal standard, the limit of detection varied, in µg L-1, from 0.23 to 4.6 for the microelements and between 10 and 620 for the macroelements. The limit of quantification, in µg L-1, was between 0.78 and 15.4 and between 30 and 970 for the microelements and macroelements, respectively. The precisions of the measurements, expressed as the relative standard deviation (n = 10; 0.50 and 3.0 mg L-1 of each analyte), were lower than 1.0% for all analytes. The proposed method was applied for the multi-element determination in commercial beer samples and the results were compared with those obtained by inductively coupled plasma optical emission spectrometry after sample digestion.

Metals in geopropolis from beehive of Melipona scutellaris in urban environments.

Geopropolis, a different type of propolis, presents a mixture of resin and exudates, containing wax, silt, and sand particles. This product has been the subject of research interest for its physicochemical properties, economic importance, and likely for environmental monitoring. The determination of toxic metals in hive products has been reported as an efficient tool for environmental monitoring. As the honey production is now common in urban environments, this study aimed to determine the concentration of toxic metals in the Melipona scutellaris geopropolis of the Metropolitan Region of Salvador, Bahia. Geopropolis and soil samples were collected from seven important beehives between June 2015 and July 2016. After EPA 3050B acid digestion procedure, metals were determined by ICP OES. As the geopropolis is partially made from soil, the values of Cr and Fe were extremely more important than the values reported in propolis, wax, and honey found in other worldwide studies. It gives different characteristics to this product depending on the location of the hive and characterizes it as an efficient integrating indicator of soil pollution. Using the enrichment factor, we determined that the soils around the meliponary are not or only slightly polluted by Cu, Cr, Ni, Pb and Zn. However, there was a shift in the particle size of geopropolis, being loamier and less sandy than the surrounding soil. In such case, a higher metal content could be expected, though no metal enrichment in the geopropolis was found, even a decrease in zinc, possibly due to the exclusion of metals by bees, was noted. Nevertheless, the results on the proportions of lithogenic metal and anthropogenic metal indicate that some metals have an external origin (about 20% for Ni and Cu). Geopropolis can be considered as a good environmental indicator even in low contaminated areas.