Speciation Analysis of Trace Arsenic, Mercury, Selenium and Antimony in Environmental and Biological Samples Based on Hyphenated Techniques

Simultaneous speciation analysis of arsenic and iodine in human urine by high performance liquid chromatography-inductively coupled plasma mass spectrometry

A high-performance liquid chromatography-inductively coupled plasma mass spectrometry-based method was developed for the simultaneous determination of four iodine species (i.e. iodate, 3-iodo-tyrosine, 3,5-diiodo-tyrosine, and iodide) and six arsenic species (i.e. arsenobetaine, arsenite, dimethylarsinic acid, arsenocholine, methylarsonic acid, and arsenate) in human urine. The chromatographic separation was performed on a Dionex IonPac As7 anion exchange column. The mobile phase was initiated with 0.5 mmol/L ammonium carbonate solution, followed by 50 mmol/L ammonium carbonate/100 mmol/L ammonium nitrate solution (with 4% methanol). The limits of quantification of the analytes ranged from 0.045 to 2.26 μg/L. At three spiked levels (10.0, 20.0, 50.0 μg/L), the average recoveries (%) ranged from 87.4 to 113.1%, and the relative standard deviations (RSD, %) ranged from 0.4 to 17.2%. The ratio of the sum of six arsenic species to the total arsenic measured by ICPMS ranged from 77.4 to 121.2%, and the ratio of the sum of the four iodine species to the total iodine ranged from 70.7 to 114.7%, indicating a good agreement between these two methods for both arsenic and iodine.

Selenium volatilization in plants, microalgae, and microorganisms

The augmented prevalence of Se (Se) pollution can be attributed to various human activities, such as mining, coal combustion, oil extraction and refining, and agricultural irrigation. Although Se is vital for animals, humans, and microorganisms, excessive concentrations of this element can give rise to potential hazards. Consequently, numerous approaches have been devised to mitigate Se pollution, encompassing physicochemical techniques and bioremediation. The recognition of Se volatilization as a potential strategy for mitigating Se pollution in contaminated environments is underscored in this review. This study delves into the volatilization mechanisms in various organisms, including plants, microalgae, and microorganisms. By assessing the efficacy of Se removal and identifying the rate-limiting steps associated with volatilization, this paper provides insightful recommendations for Se mitigation. Constructed wetlands are a cost-effective and environmentally friendly alternative in the treatment of Se volatilization. The fate, behavior, bioavailability, and toxicity of Se within complex environmental systems are comprehensively reviewed. This knowledge forms the basis for developing management plans that aimed at mitigating Se contamination in wetlands and protecting the associated ecosystems.

Polymeric Materials in Speciation Analysis Based on Solid-Phase Extraction

Speciation analysis is a relevant topic since the (eco)toxicity, bioavailability, bio (geo)chemical cycles, and mobility of a given element depend on its chemical forms (oxidation state, organic ligands, etc.). The reliability of analytical results for chemical species of elements depends mostly on the maintaining of their stability during the sample pretreatment step and on the selectivity of further separation step. Solid-phase extraction (SPE) is a matter of choice as the most suitable and widely used procedure for both enrichment of chemical species of elements and their separation. The features of sorbent material are of great importance to ensure extraction efficiency from one side and selectivity from the other side of the SPE procedure. This review presents an update on the application of polymeric materials in solid-phase extraction used in nonchromatographic methods for speciation analysis.

Effect of cooking temperature on metal concentrations and speciation in fish muscle and seal liver

Fish and marine mammals constitute a significant part of the country food diet of many Indigenous communities in Canada. These animals sometimes accumulate essential elements as well as elevated levels of toxic metals. We experimentally assessed how changes in cooking temperature (23-99 °C by boiling) modified elemental concentrations in whitefish muscle and grey seal liver (two organs commonly consumed in some northern communities). Wet and dry elemental concentrations changed linearly as a function of temperature, and two patterns were observed: methylmercury, selenium, and rare earth elements tended to remain associated with the food during cooking, whereas alkali, alkaline-earth metals, and arsenic were significantly transferred to cooking juices. Mass balances indicated that speciation of mercury was stable during cooking. Because elements generally behaved similarly as those of their periodic table group or their ecotoxicological classes (A, B, intermediate), we propose that elemental behavior during cooking is partly a function of chemical affinity, and this relationship can be used to predict the behavior of data-poor elements of emerging concern, such as technology-critical elements. Furthermore, the marked increases and decreases in elemental concentrations during cooking (e.g., -14% As and +39% Se in whitefish; -22% Cd and +55% Hg in seal liver, on a wet weight basis) should be considered when assessing risk because current exposure models usually only consider elemental concentrations in raw food.

Selenium mitigates the inhibitory effect of TBBPA on NETs release by regulating ROS/MAPK pathways-induced carp neutrophil apoptosis and necroptosis

Tetrabromobisphenol A (TBBPA) is one of the most common and persistent organic pollutants found in the environment. When TBBPA is ingested by organisms through various pathways and stored in the body, it shows obvious harmful effects. Selenium (Se) works as an antioxidant in the body, allowing it to withstand the poisonous effects of dangerous substances. The effects and mechanisms of Se and TBBPA on carp neutrophil immune function, apoptosis, and necroptosis, however, are unknown. As a result, we created TBBPA exposure and Se antagonism models using carp neutrophils as study objects, and we investigated the expression of genes implicated in extracellular traps (NETs), cytokines, apoptosis, and necroptosis. The findings demonstrated that extracellular traps neutrophils in the TBBPA group displayed the inhibition of NETs, apoptosis, and necrosis, as well as an increase in Reactive oxygen species (ROS) levels and activation of the MAPK pathway. The expression of genes related to the mitochondrial apoptosis pathway (Bax, Cyt-c, Bcl-2 and Caspase-3) and necroptosis pathway (MLKL, RIPK1, RIPK3, Caspase-8 and FADD) were activated. The expression of inflammatory factors IL-1 and TNF-α were increased, and the expression of IL-2 and IFN-γ were decreased. But an appropriate concentration of Se can mitigate the effects of TBBPA. Our results suggest that Se can mitigate the inhibitory effect of TBBPA on NETs release by regulating apoptosis and necroptosis of carp neutrophil via ROS/MAPK pathways. These results provide a basis information for exploring the toxicity of TBBPA, and enrich the anti-toxicity mechanism of trace element Se in the body.

Metal Profiles in Autism Spectrum Disorders: A Crosstalk between Toxic and Essential Metals

Since hundreds of years ago, metals have been recognized as impacting our body's physiology. As a result, they have been studied as a potential cure for many ailments as well as a cause of acute or chronic poisoning. However, the link between aberrant metal levels and neuropsychiatric illnesses such as schizophrenia and neurodevelopmental disorders, such as autism spectrum disorders (ASDs), is a relatively new finding, despite some evident ASD-related consequences of shortage or excess of specific metals. In this review, we will summarize past and current results explaining the pathomechanisms of toxic metals at the cellular and molecular levels that are still not fully understood. While toxic metals may interfere with dozens of physiological processes concurrently, we will focus on ASD-relevant activity such as inflammation/immune activation, mitochondrial malfunction, increased oxidative stress, impairment of axonal myelination, and synapse formation and function. In particular, we will highlight the competition with essential metals that may explain why both the presence of certain toxic metals and the absence of certain essential metals have emerged as risk factors for ASD. Although often investigated separately, through the agonistic and antagonistic effects of metals, a common metal imbalance may result in relation to ASD.

The speciation of arsenic in the muscle tissue of inland and coastal freshwater fish from a remote boreal region

Elevated concentrations of total arsenic (As) have been reported in boreal freshwater fish in both human-impacted and relatively pristine areas. We assessed the arsenic speciation profiles in muscle tissue of six fish species (n = 300) sampled from nine locations across a remote freshwater watershed in northern Ontario, Canada, extending from inland headwater lakes to the coastal marine confluence. Of the five arsenic species measured, only arsenobetaine (AsB) and dimethylarsinic acid (DMA) were detected in these fish. Riverine fish had up to 10-fold higher total [As] when compared to lacustrine fish. On average, these riverine fish also had higher percentages of AsB (%AsB, 60 ± 26%) and lower percentages of unmeasured arsenic (%UNM, 20 ± 21%), compared to lacustrine fish (28 ± 18% and 52 ± 21% %AsB and %UNM, respectively). DMA percentages (%DMA) were relatively consistent across the watershed, averaging 20 ± 21% across all fish. We examined ecological drivers of As speciation and found that %AsB increased slightly with fish weight in large-body predatory fish, but not in forage fish or insectivores. Furthermore, %AsB was positively related to trophic elevation (inferred from δ¹⁵N) in lacustrine fish across 3 out of 4 communities and within some populations. Lastly, riverine fish with a more marine-based diet had markedly higher %AsB when compared to fish with more freshwater-based diets, indicating an effect of anadromy on arsenic speciation. Overall, knowledge on arsenic speciation in freshwater fish has been limited and these results indicate potential drivers that can be considered in future studies. Furthermore, the absence of toxic inorganic As species in these boreal fish is an important consideration for future environmental monitoring practices and risk assessments, some of which assume 10-20% of total [As] in fish is present as toxic inorganic As. Additional studies on As bioaccumulation and biotransformation are needed in freshwater systems, particularly at the base of aquatic food webs.

The importance and status of the micronutrient selenium in South Africa: a review

Selenium (Se) is a vital micronutrient with widespread biological action but leads to toxicity when taken in excessive amounts. The biological benefits of Se are mainly derived from its presence in active sites of selenoproteins such as glutathione peroxidase (GPx). An enzyme whose role is to protect tissues against oxidative stress by catalysing the reduction of peroxidase responsible for various forms of cellular damage. The benefits of Se can be harvested when proper regulations of its intake are used. In South Africa, Se distribution in people's diets and animals are low with socio-economic factors and heterogeneous spread of Se in soil throughout the country playing a significant role. The possible causes of low Se in soils may be influenced by underlying geological material, climatic conditions, and anthropogenic activities. Sedimentary rock formations show higher Se concentrations compared to igneous and metamorphic rock formations. Higher Se concentrations in soils dominates in humid and sub-humid areas of South Africa. Furthermore, atmospheric acid deposition dramatically influences the availability of Se to plants. The studies reviewed in this article have shown that atomic absorption spectroscopy (AAS) is the most utilised analytical technique for total Se concentration determination in environmental samples and there is a lack of speciation data for Se concentrations. Shortcomings in Se studies have been identified, and the future research directions of Se in South Africa have been discussed.

Ferrihydrite enrichment in the rhizosphere of unsaturated soil improves nutrient retention while limiting arsenic and uranium plant uptake

Improvement of nutrient use efficiency and limiting trace elements such as arsenic and uranium bioavailability is critical for sustainable agriculture and food safety. Arsenic and uranium possess different properties and mobility in soils, which complicates the effort to reduce their uptake by plants. Here, we postulate that unsaturated soil amended with ferrihydrite nanominerals leads to improved nutrient retention and helps reduce uptake of these geogenic contaminants. Unsaturated soil is primarily oxic and can provide a stable environment for ferrihydrite nanominerals. To demonstrate the utility of ferrihydrite soil amendment, maize was grown in an unsaturated agricultural soil that is known to contain geogenic arsenic and uranium. The soil was maintained at a gravimetric moisture content of 15.1 ± 2.5%, typical of periodically irrigated soils of the US Corn Belt. Synthetic 2-line ferrihydrite was used in low doses as a soil amendment at three levels (0.00% w/w (control), 0.05% w/w and 0.10% w/w). Further, the irrigation water was fortified (~50 μg L^-1 each) with elevated arsenic and uranium levels. Plant dry biomass at maturity was ~13.5% higher than that grown in soil not receiving ferrihydrite, indicating positive impact of ferrihydrite on plant growth. Arsenic and uranium concentrations in maize crops (root, shoot and grain combined) were ~ 20% lower in amended soils than that in control soils. Our findings suggest that the addition of low doses of iron nanomineral soil amendment can positively influence rhizosphere geochemical processes, enhancing nutrient plant availability and reduce trace contaminants plant uptake in sprinkler irrigated agroecosystem, which is 55% of total irrigated area in the United States.

Low Au-content CoAu electrodes for environmental applications

Six cobalt gold (CoAu) electrodes were prepared by electroless deposition using different gold-containing solutions (acidic and weakly acidic) and different Au deposition times. Characterization of CoAu electrodes was done by scanning electron microscopy with energy-dispersive X-ray spectroscopy, N₂-sorption, and X-ray powder diffraction techniques. The possibility of using the prepared electrodes in environmental applications, i.e., for the electrochemical sensing of a trace amount of arsenic(iii) in weakly alkaline media was assessed. Employing the CoAu electrode (prepared by immersing Co/Cu into 1 mM HAuCl₄ (pH 1.8) at 30 °C for 30 s) under optimized conditions (deposition potential −0.7 V and deposition time of 60 s), a low limit of detection of 2.16 ppb was obtained. Finally, this CoAu electrode showed activity for arsenic oxidation in the presence of Cu(ii) as a model interferent as well as in real samples. Furthermore, the use of CoAu electrode as an anode in fuel cells, namely, direct borohydride – hydrogen peroxide fuel cells was also assessed. A peak power density of 191 mW cm⁻² was attained at 25 °C for DBHPFC with CoAu anode at a current density of 201 mA cm⁻² and cell voltage of 0.95 V, respectively. The peak power density further increased with the increase of the operating temperature to 55 °C.

A low Au-content CoAu electrode prepared by simple electroless deposition outperforms a pure Au electrode for versatile environmental applications: As(iii) sensing in water or as electrodes in direct borohydride-hydrogen peroxide fuel cells.

Arsenic (III) and/or Antimony (III) induced disruption of calcium homeostasis and endoplasmic reticulum stress resulting in apoptosis in mice heart

Arsenic (As) and antimony (Sb) are known as an environmental contaminant with cardiotoxicity properties. The endoplasmic reticulum (ER) is the largest calcium reservoir in the cell, and its calcium homeostasis disorder plays a vital role in endoplasmic reticulum stress (ERS) and apoptosis. The objective of this study was to investigate whether As and Sb induced apoptosis via endoplasmic reticulum stress (ERS) linked to calcium homeostasis disturbance. In this study, thirty-two adult mice were gavage-fed daily with As₂O₃ (4 mg/kg), SbCl₃ (15 mg/kg) and co-treat with SbCl₃ (15 mg/kg) and As₂O₃ (4 mg/kg) daily for 60 days. It was observed that As or/and Sb caused histopathological lesions and ER expansion of the heart. Meanwhile, the gene expression of ER Ca²⁺ release channels (RyR2 and IP3R) and calmodulin-dependent protein kinase II (CaMKII) increased while the levels of mRNA and protein of ER Ca²⁺ uptake channel (SERCA2) downregulated significantly compared to the controls. Then, As or/and Sb induced ERS and triggered the ER apoptotic pathway by activating unfolded protein response (UPR)-associated genes ((PERK, ATF6, IRE1, XBP1, JNK, GRP78), and apoptosis-related genes (Caspase12, Caspase3, p53, CHOP). Above indicators in As + Sb group became more severe than that of As group and Sb group. Overall, our results proved that the cardiotoxicity caused by As or/and Sb might be concerning disturbing calcium homeostasis, which induced apoptosis through the ERS pathway.

Selected Instrumental Techniques Applied in Food and Feed: Quality, Safety and Adulteration Analysis

This review presents an overall glance at selected instrumental analytical techniques and methods used in food analysis, focusing on their primary food science research applications. The methods described represent approaches that have already been developed or are currently being implemented in our laboratories. Some techniques are widespread and well known and hence we will focus only in very specific examples, whilst the relatively less common techniques applied in food science are covered in a wider fashion. We made a particular emphasis on the works published on this topic in the last five years. When appropriate, we referred the reader to specialized reports highlighting each technique's principle and focused on said technologies' applications in the food analysis field. Each example forwarded will consider the advantages and limitations of the application. Certain study cases will typify that several of the techniques mentioned are used simultaneously to resolve an issue, support novel data, or gather further information from the food sample.

A review on analytical methods with special reference to electroanalytical methods for the determination of some anticancer drugs in pharmaceutical and biological samples

It is widely accepted that cancer, the second leading cause of death, is a morbidity with big impacts on the global health. In the last few years, chemo-therapeutic treatment continually induces alone most lengthy consequents, which is extremely harmful for the physiological and psychological health of the patients. In the present research, we discuss the recent techniques for employed for extraction, and quantitative determination of such compounds in pharmaceutical, and biological specimens. In the frame of this information, this review aims to provide basic principles of chromatography, spectroscopy, and electroanalytical methods for the analysis of anticancer drugs published in the last three years. The review also describes the recent developments regarding enhancing the limit of detection (LOD), the linear dynamic range, and so forth. The results show that the LOD for the chromatographic techniques with the UV detector was obtained equaled over the range 2.0 ng mL^-1-0.2 μg mL^-1, whereas the LOD values for analysis by chromatographic technique with the mass spectrometry (MS) detector was found between 10.0 pg mL^-1-0.002 μg mL^-1. The biological fluids could be directly injected to capillary electrophoresis (CE) in cases where the medicine concentration is at the contents greater than mg L^-1 or g L^-1. Additionally, electrochemical detection of the anticancer drugs has been mainly conducted by the voltammetry techniques with diverse modified electrodes, and lower LODs were estimated between 3.0 ng mL^-1-0.3 μg mL^-1. It is safe to say that the analyses of anticancer drugs can be achieved by employing a plethora of techniques such as electroanalytical, spectroscopy, and chromatography techniques.

A dual colorimetric probe for rapid environmental monitoring of Hg2+ and As3+ using gold nanoparticles functionalized with d-penicillamine

A highly sensitive and selective colorimetric assay for the dual detection of Hg2+ and As3+ using gold nanoparticles (AuNPs) conjugated with d-penicillamine (DPL) was developed. When Hg2+ and As3+ ions coordinate with AuNP-bound DPLs, the interparticle distance decreases, inducing aggregation; this results in a significant color change from wine red to dark midnight blue. The Hg4f and As3d signals in the X-ray photoelectron spectra of Hg2+ (As3+)-DPL-AuNPs presented binding energies indicative of Hg2+-N(O) and As3+-N(O) bonds, and the molecular fragment observed in time-of-flight secondary ion mass spectra confirmed that Hg2+ and As3+ coordinated with two oxygen and two nitrogen atoms in DPL. The detection of Hg2+ and As3+ can be accomplished by observing the color change with the naked eye or by photometric methods, and this was optimized to provide optimal probe sensitivity. The assay method can be applied for environmental monitoring by first selectively quantifying Hg2+ in water samples at pH 6, then estimating the As3+ concentration at pH 4.5. The efficiency of the DPL-AuNP probe was evaluated for the sequential quantification of Hg2+ and As3+ in tap, pond, waste, and river water samples, and absorbance ratios (A 730/A 525) were correlated with Hg2+ and As3+ concentrations in the linear range of 0-1.4 μM. The limits of detection in water samples were found to be 0.5 and 0.7 nM for Hg2+ and As3+, respectively. This novel probe can be utilized for the dual determination of Hg2+ and As3+, even in the presence of interfering substances in environmental samples.

A new procedure for the determination of 21 macro- and trace elements in human fetal urine using an inductively coupled plasma mass spectrometry with dynamic reaction cell (ICP-DRC-MS) equipped with a micro-flow nebulizer

The procedure for determination of 21 macro- and trace elements - Li, Na, Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Cu, Zn, Se, Sr, As, Cd, Sb, Ba, Pb and U - in human fetal urine by inductively coupled plasma mass spectrometry (ICP-MS) was developed and validated. The application of a micronebulizer and a dynamic reaction cell (DRC) allowed to perform a full analysis of small volumes (200 μL) of urine collected from human fetuses without the need for sample digestion with closed microwave systems. The procedure and ICP-MS instrument was thoroughly optimized in order to reliably determine both macroelements and ultra-trace concentrations of elements. The internal standard method (Ge, Rh and Tb) was applied in order to encompass signal drift and non-spectral interferences. The rules of metrology were used in order to ensure the quality of the results: (1) the procedure was validated, (2) the uncertainty of the measurement results was estimated and (3) the traceability of the measurement result was established by using the certified reference material with matching matrix (Seronorm Trace Elements Urine L-1). Also, the analyte addition method to the artificial urine was employed for additional confirmation of trueness of the procedure. The selected parameters of the procedure were as follows: (a) limits of detection - (0.00023-53 μg L^-1) for U and Ca, respectively, (b) recoveries of the reference value - 81%-136% for Mn and Cd, respectively (c) linearity expressed as R - greater than 0.999, and (d) expanded relative uncertainties (k = 2) - 13%-66% for Sr and Cd, respectively. The developed and validated procedure was applied to 58 samples of urine collected from human fetuses. The samples were diluted with nitric acid and analyzed without further treatment. The procedure allowed to reliably determine both macro- and trace elements in very low volume of sample in a single analytical run.

Monitoring and analysis of selenium as an emerging contaminant in mining industry: A critical review

Selenium is an indispensable trace element for humans, however, its release at high concentrations becomes a major concern for terrestrial and aquatic ecosystems due to its bioaccumulation potential. Mining and metal-mineral processing are among the main sources of selenium released into the environment. Excessive levels of selenium may induce toxicity in human as selenosis, in grazing animals as alkali disease and in aquatic organisms as larval and developmental deformities and mortality. Due to the introduction of new policies for Se monitoring in the mining industry mainly setting the guidelines for selenium level in freshwaters as recommended by the Canadian Council of Ministers of Environment and Environment and climate change Canada, an improved understanding of Se occurrence, mobility, bioavailability and treatment technologies for efficient removal is timely and required. In this context, this review updated the understanding of mining-related selenium occurrence in surface water, soil and plant, with a focus on its mobility and bioavailability. Selenium uptake, translocation, accumulation, and metabolism in plants are further presented. Selenium monitoring and treatment is the key to adopt the corrective measures to mitigate highly contaminated effluent and to minimize the associated adverse health effects. Future research directions and recommendations for selenium analysis and treatment processes are also discussed.

Levels of Trace Elements in the Aqueous Humor of Cataract Patients Measured by the Inductively Coupled Plasma Optical Emission Spectrometry

Trace elements play an important role in the pathogenesis of several serious ophthalmological disorders, such as glaucoma, age-related macular degeneration (AMD), diabetic retinopathy, cataract, etc. This study aimed to measure alterations of chemical elements' (67) levels in the aqueous humor of patients undergoing cataract surgery. The pilot study included 115 patients, (age 74 ± 7.27, female 64.35%, male 35.65%). The aqueous levels of elements were measured by the use of the inductively coupled plasma optical emission spectrometry (ICP-OES), quality controlled with certified standards. The classification of elements based on their concentration was achieved by hierarchical cluster analysis. This is the first screening study that quantifies over 60 elements which are present in the fluid from the anterior chamber of the eye of cataract patients. The obtained results can be suitable for understanding and identifying the causes that may play a role in the initiation and progression of lens opacity.