Vortex-assisted matrix solid-phase dispersion: An eco-friendly alternative for the determination of halogens in edible seaweed.

Edible seaweed has been widely consumed around the world through oriental cuisine and it is important to monitor the levels of some elements, especially halogens. This study proposes, for the first time, the development of an analytical method using the vortex-assisted matrix solid-phase dispersion (VA-MSPD) combined with alkaline extraction of halogens (F, Cl, Br, and I) in edible seaweed for further determination by ion chromatography. The proposed method was evaluated using edible seaweed of the Nori (Porphyra spp.) type and applied to samples of the Wakame (Undaria pinnatifida), Kombu (Laminaria ochroleuca), and Hijiki (Hizikia fusiformis) types. Important VA-MSPD parameters were investigated and using 0.1 g sample, 1 g sea sand as solid support, 50 mmol L-1 (NH4)2CO3 as extraction solution, and 5 min of maceration, higher extraction efficiencies were obtained. The method was linear within the evaluated range (R2 > 0.99) for all elements and no matrix effect was observed. The detection limits of the method were 27, 26, 19, and 28 µg g-1 for F, Cl, Br, and I, respectively. The accuracy was evaluated by a recovery test (ranging from 92 to 108%) and analysis of certified reference materials for apple leaves (NIST 1515) and peach leaves (NIST 1547), which had a good agreement (ranging from 97 to 101%) with the certified values. Comparing the results with those obtained by inductively coupled plasma-mass spectrometry after microwave-induced combustion, no significant difference was found between the results, and the relative standard deviations were lower than 12%. The proposed method proved to be efficient for the determination of halogens in different algae species, showing advantages such as simplicity and low cost, combined to the use of a material from renewable sources (sea sand) as a solid support, contributing to the principles of Green Analytical Chemistry.

Selenium dietary intake, urinary excretion, and toxicity symptoms among children from a coal mining area in Brazil.

Selenium (Se) is necessary for several physiological functions in the human body; however, high concentrations of this element in coal mining areas raise the possibility of Se-related health risks. Children are much more vulnerable and at risk to environmental hazards than adults. The largest coal mining area of Brazil is located in the city of Candiota, where previous studies point to significant urinary Se concentrations among children. Food intake is the main Se source. The study aimed to evaluate dietary Se intake, as well as urinary Se excretion and classic symptoms of Se intoxication among children from Candiota and a control city in the same region. A cross-sectional study was carried out, with participation from 242 children between 6 and 12 years old in two cities in Rio Grande do Sul state, Brazil. Socioeconomic variables, dietary intake, and Se toxicity symptoms were evaluated through a structured questionnaire, and urinary Se levels were measured. Children from both cities had normal levels of Se intake and urinary excretion; however, children from Candiota had significantly higher levels of Se in both parameters in relation to the control city, especially for Se urinary excretion. There was low prevalence of Se toxicity symptoms. We conclude that coal mining activities may increase Se intake in children and consequently its urinary excretion.

Antifouling booster biocide extraction from marine sediments: a fast and simple method based on vortex-assisted matrix solid-phase extraction.

This paper reports the development of an analytical method employing vortex-assisted matrix solid-phase dispersion (MSPD) for the extraction of diuron, Irgarol 1051, TCMTB (2-thiocyanomethylthiobenzothiazole), DCOIT (4,5-dichloro-2-n-octyl-3-(2H)-isothiazolin-3-one), and dichlofluanid from sediment samples. Separation and determination were performed by liquid chromatography tandem-mass spectrometry. Important MSPD parameters, such as sample mass, mass of C18, and type and volume of extraction solvent, were investigated by response surface methodology. Quantitative recoveries were obtained with 2.0 g of sediment sample, 0.25 g of C18 as the solid support, and 10 mL of methanol as the extraction solvent. The MSPD method was suitable for the extraction and determination of antifouling biocides in sediment samples, with recoveries between 61 and 103% and a relative standard deviation lower than 19%. Limits of quantification between 0.5 and 5 ng g-1 were obtained. Vortex-assisted MPSD was shown to be fast and easy to use, with the advantages of low cost and reduced solvent consumption compared to the commonly employed techniques for the extraction of booster biocides from sediment samples. Finally, the developed method was applied to real samples. Results revealed that the developed extraction method is effective and simple, thus allowing the determination of biocides in sediment samples.