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.

Comparison of Salivary Electrolytes Profile in Oral Potentially Malignant Disorders and Oral Squamous Cell Carcinoma.

OBJECTIVES: to determine salivary electrolyte concentration of oral potentially malignant disorders (OPMD) and oral squamous cell carcinoma (OSCC) patients. A related systematic review was performed. METHODS: Observational study. Unstimulated saliva from 18 patients with OSCC, 18 with OPMD, and 18 without oral lesions was collected. A biochemical analysis was performed to evaluate the salivary concentrations of potassium (K), phosphorus (P), sodium (Na), calcium (Ca), magnesium (Mg), zinc (Zn), copper (Cu), and iron (Fe). Kruskal-Wallis test was performed, and p < 0.05 was interpreted as statistically significant. The literature search for the systematic review retrieved 9 studies that associated salivary electrolyte levels with presence and progression of OSCC. RESULTS: A highly significant increase was found in the salivary Mg levels in the OPMD group (5.41 µg/mL) in comparison with the OSCC (3.71µg/mL) and control group (3.51 µg/mL) (p = 0.041). No differences were observed in other salivary levels elements. The results of the systematic review revealed that one article indicated a decrease, and three papers reported an increase in salivary Na levels in patients with OPMD and OSCC. Two articles indicated a decrease in salivary K levels in OSCC, and the other two reported high Mg levels in OPMD and OSCC. CONCLUSION: High salivary Mg levels can be a potential biomarker indicating the presence of OPMD, however, the evidence is still contradictory and more studies are required.

Improvement of non-motor and motor behavioral alterations associated with Parkinson-like disease in Drosophila melanogaster: Comparative effects of treatments with hesperidin and L-dopa.

Non-motor alterations such as anxiety and memory deficit may represent early indications of Parkinson's disease (PD), and therapeutic strategies that reduce non-motor alterations are promising alternatives for the treatment. Therefore, the search for natural compounds that act on motor and non-motor complications is highly relevant. In this sense, we demonstrated the role of hesperidin (Hsd) as a citrus flavonoid and its pharmacological properties as an antioxidant and neuroprotective agent. Our objective was to evaluate Hsd in developing motor and non-motor alterations in a Drosophila melanogaster model of Parkinson-like disease induced by iron (Fe) exposure. The flies were divided into six groups: control, Hsd (10 µM), L-dopa (positive control, 1 mM), Fe (1 mM), Fe + Hsd, and Fe + L-dopa. Motor coordination tests, memory assessment through aversive phototaxy, and anxiety-like behaviors characterized in flies, such as grooming and aggressiveness, were performed. The Hsd attenuated motor and non-motor alterations, such as motor coordination, memory deficits and anxiety-like behaviors, attenuated monoaminergic deficits, and lowered Fe levels in the head of flies. In addition, Hsd prolonged the life of the flies, thereby standing out from the L-dopa-treated group. Thus, Hsd can protect the dopaminergic system from insults caused by Fe, preventing non-motor alterations in PD; Hsd also reduced Fe levels in the flies' heads, suggesting that iron chelation may represent an important mechanism of action, in addition to its antioxidant action.

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.

Iron overload during the embryonic period develops hyperactive like behavior and dysregulation of biogenic amines in Drosophila melanogaster.

Iron (Fe) is used in various cellular functions, and a constant balance between its uptake, transport, storage, and use is necessary to maintain its homeostasis in the body. Changes in Fe metabolism with a consequent overload of this metal are related to neurological changes and cover a broad spectrum of diseases, mainly when these changes occur during the embryonic period. This work aimed to evaluate the effect of exposure to Fe overload during the embryonic period of Drosophila melanogaster. Progenitor flies (male and female) were exposed to ferrous sulfate (FeSO4) for ten days in concentrations of 0.5, 1, and 5 â€‹mM. After mating and oviposition, the progenitors were removed and the treatment bottles preserved, and the number of daily hatches and cumulative hatching of the first filial generation (F1) were counted. Subsequently, F1 flies (separated by sex) were subjected to behavioral tests such as negative geotaxis test, open field test, grooming, and aggression test. They have evaluated the levels of dopamine (DA), serotonin (5-HT), octopamine (OA), tryptophan and tyrosine hydroxylase (TH), acetylcholinesterase, reactive species, and the levels of Fe in the progenitor flies and F1. The Fe levels of F1 flies are directly proportional to what is incorporated during the period of embryonic development; we also observed a delay in hatching and a reduction in the number of the hatch of F1 flies exposed during the embryonic period to the 5mM Fe diet, a fact that may be related to the reduction of the cell viability of the ovarian tissue of progenitor flies. The flies exposed to Fe (1 and 5 â€‹mM) showed an increase in locomotor activity (hyperactivity) and a significantly higher number of repetitive movements. In addition to a high number of aggressive encounters when compared to control flies. We can also observe an increase in the levels of biogenic amines DA and 5-HT and an increase in TH activity in flies exposed to Fe (1 and 5 â€‹mM) compared to the control group. We conclude that the hyperactive-like behavior demonstrated in both sexes by F1 flies exposed to Fe may be associated with a dysregulation in the levels of DA and 5-HT since Fe is a cofactor of TH, which had its activity increased in this study. Therefore, more attention is needed during the embryonic development period for exposure to Fe overload.

Influence of culinary treatment on the concentration and on the bioavailability of cadmium, chromium, copper, and lead in seafood.

BACKGROUND: Seafood present important advantages for human nutrition, but it can also accumulate high levels of toxic and potentially toxic elements. Culinary treatments could influence seafood chemical element content and element bioavailability. In this study, the influence of culinary treatments on the total concentration and on the bioavailability of Cd, Cr, Cu and Pb in shark, shrimp, squid, oyster, and scallop was assessed. METHODS: Boiling, frying, and sautéing with or without seasonings (salt, lemon juice and garlic) were evaluated. Total concentration and bioavailability of Cd, Cr, Cu and Pb in seafood after all these culinary treatments were compared with those in uncooked samples. Analytes were determined by triple-quadrupole inductively coupled plasma mass spectrometry (ICP-MS/MS). An alternative to express the results avoiding underestimated or overestimated values was proposed. RESULTS: The analytes concentration in seafood without culinary treatment varied from 0.0030 µg g-1 (shrimp) to 0.338 µg g-1 (oyster) for Cd; 0.010 µg g-1 (squid) to 0.036 µg g-1 (oyster) for Cr; 0.088 µg g-1 (scallop) to 8.63 µg g-1 (oyster) for Cu, and < 0.005 µg g-1 (shrimp, squid and oyster) to 0.020 µg g-1 (shark) for Pb. Only Cd (in scallop) was influenced by culinary treatments (reduction from 37 to 53 % after boiling, frying, and sautéing). Bioavailability percentage varied from 11% (oyster) for Cd; 18% (oyster) to 41% (shark) for Cr; 6% (shark) for Cu, and 8% (oyster) for Pb. Bioavailability percentage was not influenced by culinary treatments. CONCLUSION: Cadmium concentration was reduced in scallop after some culinary treatments (reduction o 37-53% after boiling, frying, and sautéing), but bioavailability percentage was not influenced. The employed analytical method was adequate for the purpose, presenting import results for food safety assessment about the influence of culinary treatments on metals concentration and bioavailability in seafood.

Protective effect of gamma-oryzanol against manganese-induced toxicity in Drosophila melanogaster.

Manganese (Mn) is an essential element that, in excess, seems to be involved in the development of different neurodegenerative conditions. Gamma-oryzanol (Ory) was previously reported to possess antioxidant and neuroprotective properties. Thus, we conducted this study to test the hypothesis that Ory can also protect flies in an Mn intoxication model. Adult wild-type flies were fed over 10 days with Mn (5 mM) and/or Ory (25 µM). Flies treated with Mn had a decrease in locomotor activity and a higher mortality rate compared to those in controls. Mn-treated flies also had a significant increase in acetylcholinesterase (AChE) activity, in Mn accumulation and in oxidative stress markers. Moreover, flies treated with Mn exhibited a significant decrease in dopamine levels and in tyrosine hydroxylase activity, as well as in mitochondrial and cellular viability. Particularly important, Ory protected against mortality and avoided locomotor and biochemical changes associated with Mn exposure. However, Ory did not prevent the accumulation of Mn. The present results support the notion that Ory effectively attenuates detrimental changes associated with Mn exposure in Drosophila melanogaster, reinforcing its neuroprotective action/potential.

Introduction to celebrating Latin American talent in chemistry.

In celebration of the excellence and breadth of Latin American research achievements across the chemical sciences, we are delighted to present an introduction to the themed collection, Celebrating Latin American talent in chemistry.

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.

Toxic and potentially toxic elements determination in cosmetics used for make-up: A critical review.

The daily use of cosmetics may expose consumers to localized skin problems and systemic effects caused by absorption of chemical elements. The requirements for suitable quality control and maximum limits for toxic and potentially toxic elements in cosmetics have attracted the attention of the scientific community and of the official institutions around the world. Maximum limits for chemical elements in some cosmetics have been set, but there are disagreements between them. In the same context, many analytical methods have been proposed in the literature, but several challenges during the sample preparation and determination steps related to the high complexity of cosmetics' matrices composition still remain. It is extremely difficulty to establish suitable methods, free of interference, even using modern technology. In this review, methods for determining toxic and potentially toxic elements in cosmetics used for make-up on the lips and on the eye area, covering the period since 2000, are presented. Techniques enabling direct analysis and those requiring a sample preparation step prior to the analysis are also discussed. This review focused on cosmetics for make-up on the lips and on the eye area because the risks of percutaneous absorption and oral ingestion of toxic and potentially toxic elements is higher than in other body regions.

Role of 7-chloro-4-(phenylselanyl) quinoline as an anti-aging drug fighting oxidative damage in different tissues of aged rats.

This study investigated whether subacute treatment with 7-chloro-4-(phenylselanyl) quinoline (4-PSQ) presented antioxidant action in oxidative stress associated with aging in different rat tissues. We also investigated whether plasma selenium levels were altered by aging, as well as the contribution of 4-PSQ administration to these levels. Aged Wistar male rats (23month old) were intragastrically treated with 4-PSQ (5mg/kg) for seven days. On the 14th day of the experimental protocol, plasma was collected to determine selenium levels and biochemical markers of renal and hepatic damage. Furthermore, liver, kidney, spleen and cerebral cortex were removed to determine thiobarbituric acid reactive species (TBARS), non-protein thiols (NPSH), glutathione S-transferase (GST), catalase (CAT) and δ-aminolevulinate dehydratase (ALA-D). Our results showed that one or more parameters changed markedly in the liver, kidney, spleen and cerebral cortex of aged rats. Moreover, biochemical markers of renal and hepatic damage and selenium levels are changed in the plasma of aged rats. Treatment with 4-PSQ repaired redox homeostasis in tissues of aged rats, as well as plasma biochemical markers of renal and hepatic damage and selenium levels. In conclusion, 4-PSQ presented an antioxidant effect in tissues of aged rats, restoring selenium levels, and contributing to the restoration of the damage caused by aging. Thus, 4-PSQ could be a potential candidate for the management of age-related oxidative damage, acting as an anti-aging drug.

Feasibility of microwave-induced combustion combined with inductively coupled plasma mass spectrometry for bromine and iodine determination in human nail.

RATIONALE: Bromine and iodine have important physiological functions; however, in inadequate concentration, they can also cause several physiological problems. Their mobility assessment in human organisms through biological sampling may help clarify some doubts related to metabolic routes, which are still not well elucidated. In this context, a suitable analytical method for this purpose should be developed. METHODS: An analytical method for determining ultratrace levels of bromine and iodine in human nail samples was developed. Inductively coupled plasma mass spectrometry (ICP-MS) using a conventional nebulization system was immediately chosen as the determination tool because of its powerful sensitivity and selectivity. Sample preparation methods including microwave-induced combustion (MIC), microwave-assisted extraction, and microwave-assisted digestion were evaluated. The compatibility of the final solutions with ICP-MS analysis was considered while the method was developed. RESULTS: MIC was chosen as the most suitable method for the sample preparation for determining the levels of bromine and iodine in human nail samples using ICP-MS. Unlike other sample preparation methods, this one fully eliminated interferences related to the carbon content and memory effects. Sample masses up to 100 mg were efficiently digested, and the analytes were quantitatively absorbed using only 50 mmol L-1 NH4 OH solution. Recoveries ranged from 93% to 102%, and the relative standard deviation was < 8%. CONCLUSIONS: The proposed analytical method presents important characteristics for routine analysis. It allows ultratrace determination even when low sample masses are used because of the low blank values, reduced volume of reagents, and powerful detectability using ICP-MS.

Single analysis of human hair for determining halogens and sulfur after sample preparation based on combustion reaction.

A single analysis of hair for determining halogens (chlorine, bromine, fluorine, and iodine) and sulfur by ion chromatography with suppressed conductivity and mass spectrometry detection (IC-MS) was proposed. Inductively coupled plasma optical emission spectrometry (ICP OES) and inductively coupled plasma mass spectrometry (ICP-MS) were also used to compare the results. For this purpose, 300 mg of human hair were digested by microwave-induced combustion (MIC) using 20 bar of oxygen pressure. The analytes were absorbed in 100 mmol L-1 NH4OH. Trueness of the proposed method was evaluated by analysis of a CRM of human hair; by recovery tests, using standard solution at two levels (50% and 100%), and by comparison of results with those obtained by ICP OES (Cl and S) and ICP-MS (Br and I). Suitable recoveries (ranging from 92 to 105%) were obtained, and the results from CRM analysis did not differ significantly from those described in the certificate. Moreover, results obtained by IC-MS did not present significant differences (p > 0.05) from those obtained by ICP OES and by ICP-MS. Precision was evaluated in terms of repeatability and intermediate precision, and the relative standard deviations were always lower than 8%. The proposed method presented good accuracy and it is a reliable strategy for human hair analysis. Final digests obtained using the MIC method were fully compatible with all proposed determination techniques. Compared to others reported in the literature, the proposed method presents several advantages, especially given that it is possible to determine halogens and sulfur in a single analysis. Graphical abstract.

Are there feasible strategies for determining bromine and iodine in human hair using interference-free plasma based-techniques?

An effective analytical method for bromine and iodine determination in human hair using interference-free inductively coupled plasma mass spectrometry (ICP-MS) was developed. Human hair was digested based on combustion reaction to obtain compatible solutions with ICP-MS analysis. Using microwave-induced combustion (MIC), masses of human hair ranging from 50 to 300 mg were efficiently digested. Only a diluted alkaline solution (100 mmol L-1 NH4OH) was used for the absorption of both analytes, which was fully compatible with ICP-MS analysis. Using these conditions low limits of detection were obtained (LOD of 0.01 µg g-1 for Br and 0.004 µg g-1 for I). Recovery tests at two levels (50% and 100%) using a standard solution or mixtures of the sample with certified reference materials (CRMs) were carried out to evaluate the suitability of proposed method and recoveries between 94% and 102% were always obtained. Accuracy was evaluated by analysis of a human hair CRM, and the Br and I concentrations obtained by the proposed method did not differ significantly from those described in the certificate. Repeatability (RSDs ≤ 4%) and reproducibility (RSDs ≤ 7%) of the results using proposed method were always very suitable. The digests obtained using the MIC method were fully compatible with ICP-MS and the interferences currently found using conventional digestion methods were completely eliminated. Ultra-trace concentrations of Br and I were determined in human hair, demonstrating that the proposed method is a suitable strategy, and it presents several advantages compared to others published in the literature.

7-chloro-4-(phenylselanyl) quinoline prevents dopamine depletion in a Drosophila melanogaster model of Parkinson's-like disease.

Neurodegeneration in Parkinson's disease appears to be caused by multiple factors, including oxidative damage and an increase in acetylcholinesterase expression that can culminate in loss of dopaminergic neurons. A selenium-containing quinoline derivative, 7-chloro-4-(phenylselanyl) quinoline (4-PSQ), shows important pharmacological actions mainly attributed to its antioxidant and anticholinesterase properties. Thus, this study investigated the neuroprotective effect of 4-PSQ in a model of Parkinson's-like disease induced by rotenone (ROT) in Drosophila melanogaster and verified whether these effects are related to selenium levels. Adult flies were divided into: [1] control, [2] 4-PSQ (25 µM), [3] ROT (500 µM), and [4] 4-PSQ (25 µM) + ROT (500 µM) groups and exposed to a diet containing ROT and/or 4-PSQ for 7 days, according to their respective groups. Survival, behavioral, and ex vivo analyses were performed. Dopamine levels, reactive species levels (RS), lipid peroxidation (LPO), superoxide dismutase (SOD) and catalase (CAT) activity, and proteic thiol (PSH) and non-proteic thiol (NPSH) content in the head region were analyzed, while acetylcholinesterase (AChE) activity and selenium levels in the head and body regions were analyzed. 4-PSQ was able to reverse the ROT-induced deficits in flies, reestablish dopamine and selenium levels, reverse cholinergic deficits, improve motor function, and ameliorate mortality. Furthermore, 4-PSQ also reduced RS levels and LPO, and restored the activities of the antioxidant enzymes, SOD and CAT. Interestingly, a positive relationship between dopamine and selenium levels could be seen. Our results demonstrate the neuroprotective effect of 4-PSQ, and we suggest that the compound may act via different mechanisms, such as improving antioxidant defenses and consequently reducing oxidative damages, as well as having an anticholinesterase action, which together can prevent dopamine depletion, as these actions were correlated with the presence of selenium in the 4-PSQ molecule.

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).

A feasible method for As speciation in several types of seafood by LC-ICP-MS/MS.

A method for arsenic speciation in shark, shrimp, squid, oyster and scallop using liquid chromatography coupled to inductively coupled plasma triple quadrupole mass spectrometry (LC-ICP-MS/MS) was proposed. Suitable sensitivity and selectivity by LC-ICP-MS/MS were obtained using 10 mmol L-1 (NH4)2HPO4 diluted in 1% methanol (pH 8.65) as mobile phase. Recoveries from 90 to 104% for arsenobetaine (AsB), arsenite [As(III)], dimethylarsinic acid (DMA), monomethylarsonic acid (MMA) and arsenate [As(V)] were obtained for all samples. A certificated reference material was also analyzed and the sum of As species was in agreement with the total As concentration. Limits of quantification (LOQ) for AsB, As(III), DMA, MMA, and As(V) were 6, 30, 6, 12 and 26 ng g-1, respectively. Higher concentration of AsB was found in all seafood, while As(III) and DMA were found only in oyster. Arsenate was found in squid and scallops, and MMA was below the LOQ in all samples.