Characterization of low molecular weight sulfur species in seaweed from the Antarctic continent.

Antarctic seaweeds are vital components of polar marine ecosystems, playing a crucial role in nutrient cycling and supporting diverse life forms. The sulfur content in these organisms is particularly interesting due to its implication in biogeochemical processes and potential impacts on local and global environmental systems. In this study, we present a comprehensive characterization of seaweed collected in the Antarctic in terms of their total sulfur content and its distribution among different classes of species, including thiols, using various methods and high-sensitivity techniques. The data presented in this paper are unprecedented in the scientific literature. These methods allowed for the determination of total sulfur content and the distribution of sulfur compounds in different fractions, such as water-soluble and proteins, as well as the speciation of sulfur compounds in these fractions, providing valuable insights into the chemical composition of these unique marine organisms. Our results revealed that the total sulfur concentration in Antarctic seaweeds varied widely across different species, ranging from 5.5 to 56 g kg-1 dry weight. Furthermore, our investigation into the sulfur speciation revealed the presence of various sulfur compounds, including sulfate, and some thiols, which were quantified in all ten seaweed species evaluated. The concentration of these individual sulfur species also displayed considerable variability among the studied seaweeds. This study provides the first in-depth examination of total sulfur content and sulfur speciation in brown and red Antarctic seaweeds.

Characterization of halogen species in seaweeds from the Antarctic using a multi-technique approach.

BACKGROUND: Despite the recognized importance, the determination of halogens in Antarctic seaweeds remains understudied. Limited research exists due to challenges associated with sample preparation, and reliable analytical techniques for this type of analysis. Therefore, further investigations are necessary to bridge this knowledge gap and gain a comprehensive understanding of halogen metabolism in Antarctic seaweeds. METHODS: In this study, seaweeds from the coast of the Antarctic continent were characterized concerning the total content of halogens and their species. For this purpose, different sample preparation methods, based on extraction and combustion, combining highly selective and sensitive chromatographic and spectrometric multi-technique approaches were used. RESULTS: By using optimized methods, it was possible to determine total halogens content, the distribution of bromine and iodine in different classes of species (lipids, water-soluble, proteins, carbohydrates, and residue), as well as the identification of iodinated amino acids (MIT and DIT) in ten brown and red seaweeds. Bromate and iodate were not detected in the samples, which presented only bromide and iodide species in their composition. Additionally, unknown bromine and iodine species were observed in different extracts evaluated. Furthermore, 25 halogenated polyphenols were identified in seaweeds, of which only four were already reported in the literature. CONCLUSION: The results obtained in this study comprise unprecedented data in the literature on species of halogens present in seaweeds from the Antarctic environment.

Per and polyfluoroalkylated substances (PFAS) target and EOF analyses in ski wax, snowmelts, and soil from skiing areas.

Per and polyfluoroalkylated substances (PFAS) are common additives in ski waxes for their water repellent characteristic. Abrasion of ski wax leaves PFAS on the snow surface, however, little is known about the distribution and concentration of PFAS in snow and soil due to skiing. In this study we analysed different ski waxes, snowmelts and soil from family skiing areas from Alpine locations using targeted high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) to understand more about PFAS distribution in the environment. In general, we found a very diverse PFAS pattern in the analysed media. PFAS level was higher in skiing areas compared to the non-skiing ones that were used as control. ∑target PFAS ranged between <1.7 ng L-1 and 143 ng L-1 in snowmelt, <0.62 ng g-1 and 5.35 ng g-1 in soil and <1.89 and 874 ± 240 ng g-1 in ski wax samples. Snowmelt was dominated by short-chained PFAS, while soil and wax contained both short and long-chained PFAS. Extractable organic fluorine (EOF) was several orders of magnitude higher for waxes (0.5-2 mg g-1) than for soils (up to 0.3 µg g-1), while total fluorine (TF) content of the waxes was even higher, up to 31 210 ± 420 µg g-1. We also showed that the ∑ target PFAS accounts for up to 1.5% in EOF content, showing that targeted LC-MS/MS gives a limited measure of the pollution originated from ski waxes and non-targeted analysis and EOF is necessary for a better overview on PFAS distribution.

Determination of Halogens by Ion Chromatography in Edible Mushrooms after Microwave-Induced Combustion for Sample Preparation.

In this study, the microwave-induced combustion (MIC) method was evaluated for the sample preparation of the most consumed mushroom species in Brazil (Champignon, Shiitake, and Shimeji) and further halogen determination by ion chromatography (IC). For this, sample mass, combustion aid mass, and absorbing solution (H2O and 50 mmol·L-1, 100 mmol·L-1, or 150 mmol·L-1 NH4OH) were evaluated. Bromine and iodine concentrations, determined by IC, were lower than the limits of detection (LODs, Br: 6 mg·kg-1 and I: 24 mg·kg-1). Inductively coupled plasma mass spectrometry (ICP-MS) was also used for Br and I determination, and the LODs were lower (Br: 0.066 mg·kg-1 and I: 0.014 mg·kg-1) than those obtained by IC. Concentrations of Cl, obtained by IC, ranged from 523 mg·kg-1 to 13053 mg·kg-1 with LOD of 40 mg·kg-1. In turn, Br and I concentrations, obtained by ICP-MS, ranged from 2.49 mg·kg-1 to 5.50 mg·kg-1 and from <0.014 mg·kg-1 to 0.047 mg·kg-1, respectively. Fluorine concentrations, determined by IC, were always lower than LOD (23 mg·kg-1). The trueness of the proposed methods was evaluated by recovery tests using standard solutions and a reference material (RM NIST 8435). When using the standard solution, recoveries ranged from 95% to 103% for halogen determination by IC and from 105% to 109% for Br and I determination by ICP-MS. When using the RM, recoveries of 102% for Cl by IC and of 87% and 86% for Br and I by ICP-MS, respectively, were obtained.

Ion chromatography coupled to mass spectrometry as a powerful technique for halogens and sulfur determination in egg powder and its fractions.

RATIONALE: To increase the consumption of egg powder and its fractions a suitable quality control method is required to obtain more information on its nutritional composition. The proposed method enables the quantification of important elements for the functioning of the human organism, such as halogens and sulfur, in egg powder and its fractions. METHODS: Up to 350 mg of egg powder or its fractions (egg white powder and egg yolk powder) were digested by microwave-induced combustion using 20 bar pressure of oxygen. The analytes were absorbed in 100 mmol L-1 of NH4 OH solution. The determination of halogens (chlorine, bromine, fluorine, and iodine) and sulfur was performed in a single analysis using ion chromatography with conductivity detection coupled to mass spectrometry. RESULTS: Using the proposed method, spike recoveries between 99% and 104% for all analytes were obtained, and results agreed with certified values of reference materials (agreements were between 100% and 109%). The relative standard deviations were below 8%. The variation in elemental concentration over a wide range in different fractions (whole egg powder, egg white powder, and egg yolk powder) and different brands was also observed. CONCLUSIONS: The proposed method provides reliable information about minerals in whole egg powder and its fractions, contributing to better quality control of these products. Because these food products are widely consumed, these results suggest the safe ingestion levels of these elements.

Bromine and iodine determination in human saliva: Challenges in the development of an accurate method.

In this work, an analytical method for bromine and iodine determination in human saliva was proposed. A simple protocol based on centrifugation and direct analysis of supernatant by inductively coupled plasma mass spectrometry (ICP-MS) was investigated. Although this method was feasible for bromine determination, iodine was partially present in the supernatant and an agreement about 54% with reference value was obtained. In addition, microwave-induced combustion (MIC) and microwave-assisted dissolution were also evaluated. Using MIC, 0.2 mL of saliva added on 300 mg of microcrystalline cellulose were efficiently digested. A diluted solution (50 mmol L-1 NH4OH) was used for analytes absorption, and a reflux step of 5 min was applied to ensure quantitative recoveries of Br and I. Accuracy was evaluated by analyte recovery experiments, and recoveries between 94% and 98% were obtained. Microwave-assisted dissolution was evaluated for 2.0 mL of saliva using also a diluted alkaline solution (25 mmol L-1 NH4OH) and a microwave irradiation program of 35 min (including the cooling step). Results for this method agreed with those obtained using MIC. Although MIC has also been appropriated for further determination of Br and I in saliva, microwave-assisted dissolution can be considered a simpler sample preparation method and it was effective for high amount of sample (up to 2.0 mL). Moreover, final solutions were compatible with ICP-MS analysis, allowing the quantification of Br and I in human saliva at ultra-trace concentrations (limits of quantification were 0.052 µg mL-1 for Br and 0.022 µg mL-1 for I).