Mercury (Hg) concentration in fish commercialized in the São Luís fish market (MA) and potential exposure of consumers.

Fish consumption is the main path of human exposure to Hg and may represent a risk to public health, even with low Hg concentrations in fish, if consumption rates are high. This study quantifies, for the first time, the Hg concentrations in nine most commercialized species in the São Luís (MA) fish market, where fish consumption is high, and estimates human exposure. Average Hg concentrations were highest in carnivorous species, yellow hake (Cynoscion acoupa) (0.296 mg kg-1), the Atlantic croaker (Micropogonias undulatus) (0.263 mg kg-1), whereas lowest concentrations were recorded in iliophagous Mullets (Mugil curema) (0.021 mg kg-1) and the Shorthead drum Larimus breviceps (0.025 mg kg-1). Significant correlations were observed between Hg concentrations and fish length in two species: the Coco-Sea catfish (Bagre bagre) and the Atlantic bumper (Chloroscombrus crysurus), but not in the other species, since they presented relatively uniform size of individuals and/or a small number of samples. Risk coefficients, despite the relatively low Hg concentrations, suggest that consumers should limit their consumption of Yellow hake and Atlantic croaker, as they can present some risk to human health (EDI > RfD and THQ > 1), depending on the frequency of their consumption and the consumer's body weight.

Multivariate optimization of dispersive liquid-liquid microextraction using ionic liquid for the analysis of ultraviolet filters in natural waters.

In this work, a vortex-assisted dispersive liquid-liquid microextraction method, using an ionic liquid as the extracting solvent was developed, for the simultaneous analysis of three UV filters in different water samples. The extracting and dispersive solvents were selected in a univariate way. Then, the parameters such as the volume of the extracting and dispersive solvents, pH and ionic strength were evaluated using a full experimental design 24, followed by Doehlert matrix. The optimized method consisted of 50 µL of extracting solvent (1-octyl-3-methylimidazolium hexafluorophosphate), 700 µL of dispersive solvent (acetonitrile) and pH of 4.5. When combined with high-performance liquid chromatography, the method limit of detection ranged from 0.3 to 0.6 µg L-1, enrichment factors between 81 and 101%, and the relative standard deviation between 5.8 and 10.0%. The developed method demonstrated effectiveness in concentrating UV filters in both river and seawater samples, being a simple and efficient option for this type of analysis.

Solidified floating organic drop microextraction (SFODME) for the simultaneous analysis of three non-steroidal anti-inflammatory drugs in aqueous samples by HPLC.

In this work, a liquid-liquid microextraction methodology using solidified floating organic drop (SFODME) was combined with liquid chromatography and UV/Vis detection to determine non-steroidal anti-inflammatory drugs (NSAIDs) naproxen (NPX), diclofenac (DCF), and mefenamic acid (MFN) in tap water, surface water, and seawater samples. Parameters that can influence the efficiency of the process were evaluated, such as the type and volume of the extractor and dispersive solvents, effect of pH, agitation type, and ionic strength. The optimized method showed low detection limits (0.09 to 0.25 µg L-1), satisfactory recovery rates (90 to 116%), and enrichment factors in the range between 149 and 199. SFODME showed simplicity, low cost, speed, and high concentration capacity of the analytes under study. Its use in real samples did not demonstrate a matrix effect that would compromise the effectiveness of the method, being possible to apply it successfully in water samples with different characteristics.

Further insight into the role of Ca2+ in broiler pale, soft and exudative-like (PSE) meat through the analysis of moisture by TGA and strong cation elements by ICP-OES.

This study evaluated moisture content of broiler breast PSE meat by thermal gravimetric analysis and strong cation elements by inductively coupled plasma optical emission spectrometry. The weight changes were monitored within the temperature interval 9-750 °C and the most severe changes were observed at 9-160 °C (1A). This remarkable transition was attributed to water loss of about 64.74% in normal samples while PSE samples lost about 61.16%. There was, therefore, approximately 4.0% lower moisture in PSE meat samples in relation to normal meat. The analysis of cation elements showed significant differences (p < 0.05), with normal samples having 13.0% higher ∑[Ca2+] + [Mg2+] + [Na+]+[K+] than PSE meat samples while [Ca2+] in PSE meat was 10.81% higher than in the normal counterparts. We provided further evidence of the role of Ca2+ excess within the muscle sarcomere during the onset of PSE meat.