Matrix-induced transformation of arsenic species in seafoods

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.

Arsenolipids in raw and cooked seafood products in southwest China: A non-targeted analysis

Arsenolipids are the primary form of arsenic in the fat of marine organisms. Because seafood is a common source of arsenic exposure and some arsenolipids are toxic, studying the abundance and species of arsenolipids in seafood is crucial for health risk assessment. Current arsenolipid research is confined by analytical techniques and limited to raw seafood analysis, despite the fact that most seafood is ingested cooked. Therefore, the aim of this study is to evaluate which seafood contributes to arsenolipid dietary intake and investigate the changes in arsenolipids before and after cooking. In Chongqing, China, popular seafood such as clam, shrimp, oyster, abalone, hairtail, and yellow croaker were collected. The raw and cooked samples prepared from these seafood products were examined using a non-targeted screening approach established for arsenolipids, which coupled high-performance liquid chromatography with data-independent high-resolution quadrupole-time-of-flight electrospray ionization tandem mass spectrometry. Arsenic-containing hydrocarbons (AsHC330, AsHC332, and AsHC360), arsenic-containing fatty acids (AsFA362, AsFA390, AsFA404, AsFA418, and AsFA422), trimethylarsine oxide, and thiolated trimethylarsinic acid were detected. The species of arsenolipids in each type of seafood remained intact after heating in the microwave oven. In cooked samples, the concentrations of AsFA362 and AsFA390 were significantly lower than in raw samples, whereas the concentrations of other arsenolipids were unchanged. Microwave cooking did not result in the thiolation of the detected arsenolipids. The most detected species in raw and cooked samples were AsFA362, AsFA390, and AsFA418. Most arsenolipid species were found in the highest levels in hairtails and yellow croakers. It is the first time that arsenolipids have been found in the oyster, abalone, abalone liver, and yellow croaker. The present study contributes to a better understanding of arsenolipids exposure from seafood, which is useful for assessing the health risks of arsenic.

Arsenic species in mesopelagic organisms and their fate during aquafeed processing

A responsible harvest of mesopelagic species as aquafeed ingredients has the potential to address the United Nations Sustainable Development Goal 14, which calls for sustainable use of marine resources. Prior to utilization, the levels of undesirable substances need to be examined, and earlier studies on mesopelagic species have reported on total arsenic (As) content. However, the total As content does not give a complete basis for risk assessment since As can occur in different chemical species with varying toxicity. In this work, As speciation was conducted in single-species samples of the five most abundant mesopelagic organisms in Norwegian fjords. In addition, As species were studied in mesopelagic mixed biomass and in the resulting oil and meal feed ingredients after lab-scale feed processing. Water-soluble As species were determined based on ion-exchange high-performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC-ICP-MS). This was supplemented by extracting arsenolipids (AsLipids) and determining total As in this fraction. The non-toxic arsenobetaine (AB) was the dominant form in mesopelagic crustaceans and fish species, accounting for approximately 70% and 50% of total As, respectively. Other water-soluble species were present in minor fractions, including carcinogenic inorganic As, which, in most samples, was below limit of quantification. The fish species had a higher proportion of AsLipids, approximately 35% of total As, compared to crustaceans which contained 20% on average. The feed processing simulation revealed generally low levels of water-soluble As species besides AB, but considerable fractions of potentially toxic AsLipids were found in the biomass, and transferred to the mesopelagic meal and oil. This study is the first to report occurrence data of at least 12 As species in mesopelagic organisms, thereby providing valuable information for future risk assessments on the feasibility of harnessing mesopelagic biomass as feed ingredients.

Influence of phosphorus on the uptake and biotransformation of arsenic in Porphyra haitanensis at environmental relevant concentrations

Edible seaweeds are rich in essential vitamins and minerals, which made them a popular food worldwide. Porphyra haitanensis is one of the most commonly consumed seaweeds with the known ability to accumulate a high level of total arsenic (As). A large number of articles have shown arsenic and phosphorus (P) interactions in microalgae due to the plant's inability to differentiate arsenate from phosphate. However, very limited information is available for edible seaweed at environmentally relevant concentrations. In this study, P. haitanensis was treated with arsenic as As^V (As1: 0.06 μM, As2: 0.4 μM, As3: 1.2 μM) and phosphorous (P1: 3.2 μM, P2: 13 μM) in a filtered seawater matrix under laboratory condition for six days. A better growth rate was found in seaweeds grown in P2 treatments. Moreover, superoxide dismutase (SOD) activity and malondialdehyde (MDA) content measurements revealed that a higher P concentration prevent seaweeds from lipid peroxidation and oxidative stress. Transcriptome studies indicated the As replacement to P has the ability to target seaweed cell membrane composition, transmembrane transport, DNA and ATP binding. The inorganic As (iAs) had a concentration of 0.54 to 4.45 mg/kg in P. haitanensis on Day 6 with As1, As2, and As3 treatments under low P regime (P1), which exceeds the limits of iAs concentration (0.1-0.5 mg/kg) in National Food Safety Standard-Limits of Pollutants in Food (GB 2762-2017). High P regime (P2) not only reduced the total As but also iAs effectively, even in the highest As treatment (As3), the iAs concentration was less than 0.5 mg/kg on Day 6. These findings provide a good insight for seafood safety guarantees and are important for the management of coastal artificial seaweed farming.

Elemental and Speciation Analyses of Different Brands of Yerba Mate (Ilex paraguariensis)

In this work, a methodology for determination of As(III), As(V), dimethylarsinic acid (DMA), Fe(II) and Fe(III) in fifty-eight samples (forty-nine products of thirteen brands from three countries) commercial yerba mate (Ilex paraguariensis) was performed. The hyphenated high performance liquid chromatography inductively coupled plasma optical emission spectrometry (HPLC-ICP OES) technique was used. Arsenic was determined below the quantification limit in 38 samples of yerba mate. As(III) was found at the level 0.09 and 0.08 mg kg⁻¹. The As(V) content was in the range: 0.21 to 0.28 mg kg⁻¹. The content of DMA was found the highest of the three arsenic species in the range: 0.21 to 0.47 mg kg⁻¹. The content of Fe(II) and Fe(III) was found in the range: 0.61 to 15.4 mg kg⁻¹ and 0.66 to 43.1 mg kg⁻¹, respectively and the dominance of Fe(III) was observed. Moreover, total and extractable content of 16 elements were determined. The results have been subjected to statistical analysis in order to establish relationships between samples of the same origin (country), kind (type) and composition (purity).

[Determination of Inorganic Arsenic for Pet Food by LC-ICP-MS]

We have developed a quantitative determination method of the concentration of inorganic arsenic in pet foods using a liquid chromatograph-inductively coupled plasma-mass spectrometer (LC-ICP-MS). After adding 2 w/v% TMAH solution to a sample, inorganic arsenic was extracted by heating and the extract was collected by water. The pH of the solution was adjusted, and injected into a LC-ICP-MS to determine the concentration of inorganic arsenic. LC separation was carried out on an ODS column with 10 mmol/L sodium 1-butanesulfonate, 4 mmol/L malonic acid, 4 mmol/L TMAH and 0.05% methanol solution as a mobile phase. A collaborative study was conducted by nine laboratories using dry and wet-type pet foods, formed jerky, dried jerky and biscuit. Dry-type pet food and dried jerky was added with 2 mg/kg of As (III). Wet-type pet food was added with 0.5 mg/kg of As (III). Formed jerky was added with 1 mg/kg of As (III). Biscuit was added with 0.2 mg/kg of As (III). The mean recoveries, repeatabilities and reproducibilities in the form of relative standard deviation (RSD_r and RSD_R), and HorRat, were 95.4% to 98.3%, less than 2.9%, less than 9.1%, and 0.22 to 0.51, respectively.

New Method for Simultaneous Arsenic and Selenium Speciation Analysis in Seafood and Onion Samples

This paper presents a new method for the simultaneous speciation analysis of arsenic (As(III)-arsenite, As(V)-arsenate, DMA-dimethylarsinic acid, MMA-methylarsonic acid, and AsB-arsenobetaine) and selenium (Se(IV)-selenite, Se(VI)-selenate, Se-Methionine, and Se-Cystine), which was applied to a variety of seafood and onion samples. The determination of the forms of arsenic and selenium was undertaken using the High-Performance Liquid Chromatography Inductively Coupled Plasma Mass Spectrometry (HPLC-ICP-MS) analytical technique. The separation of both organic and inorganic forms of arsenic and selenium was performed using two analytical columns: an anion exchange column, Dionex IonPac AS22, containing an alkanol quaternary ammonium ion, and a double bed cation-anion exchange guard column, Dionex Ion Pac CG5A, containing, as a first layer, fully sulfonated latex for cation exchange and a fully aminated layer for anion exchange as the second layer. The ammonium nitrate, at pH = 9.0, was used as a mobile phase. The method presented here allowed us to separate the As and Se species within 10 min with a suitable resolution. The applicability was presented with different sample matrix types: seafood and onion.

Reliable, Rapid, and Robust Speciation of Arsenic in Urine by IC-ICP-MS

BACKGROUND

Arsenic is a naturally occurring element with varying species and levels of toxicity. Inorganic arsenic (e.g., arsenite (AsIII) and arsenate (AsV)) are toxic, while its metabolites (e.g., monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA)) are less toxic). Symptoms of exposure can include headaches, confusion, diarrhea, and drowsiness. As these symptoms overlap with many other conditions, arsenic exposure can often be overlooked as a cause. Arsenic toxicity may be treated with chelation and/or electrolyte replacement therapy. However, treatment is not without risks and is unnecessary for exposure to organic (nontoxic) forms of arsenic. This makes screening and differentiation of arsenic important for clinical testing.

METHOD

An IC-ICP-MS method was developed using a Dionex 5000 with ion exchange chromatography for separation and iCAP Q for detection. Nontoxic species are arsenobetaine and arsenocholine, and toxic species are AsIII, DMA, MMA, and AsV.

RESULTS

Precision, linearity, and specificity studies produced acceptable results. For accuracy, proficiency testing and method comparison samples were analyzed and produced acceptable results. Carryover studies demonstrated single species carryover from the diluter at levels of 500 µg/L, which can be avoided by analysis rules in the standard operating procedure. Limit of detection studies yielded a lower limit of quantitation of 1 µg/L per species.

CONCLUSIONS

Here, we present a rapid and reliable method for quantifying and differentiating toxic and nontoxic forms of arsenic to allow for swift and appropriate management of patients with exposure.

Biotransformation of arsenic and toxicological implication of arsenic metabolites

Arsenic is a well-known environmental carcinogen and chronic exposure to arsenic through drinking water has been reported to cause skin, bladder and lung cancers, with arsenic metabolites being implicated in the pathogenesis. In contrast, arsenic trioxide (As₂O₃) is an effective therapeutic agent for the treatment of acute promyelocytic leukemia, in which the binding of arsenite (iAs^III) to promyelocytic leukemia (PML) protein is the proposed initial step. These findings on the two-edged sword characteristics of arsenic suggest that after entry into cells, arsenic reaches the nucleus and triggers various nuclear events. Arsenic is reduced, conjugated with glutathione, and methylated in the cytosol. These biotransformations, including the production of reactive metabolic intermediates, appear to determine the intracellular dynamics, target organs, and biological functions of arsenic.

CRM rapid response approach for the certification of arsenic species and toxic trace elements in baby cereal coarse rice flour certified reference material BARI-1

With recently legislated maximum levels of inorganic arsenic (iAs) in white and brown rice in Canada, the regulatory bodies are evaluating the need for regulation of As levels in infant food products. Rice is a major part of infants' diet, and therefore, the presence of As in this staple food causes concerns. So far, the scientific community was lacking suitable certified reference material (CRM) which could be used to assess the accuracy of developed analytical methods for As speciation in infants' food products. As a result, we have developed BARI-1, a baby cereal coarse rice flour reference material which was certified for total arsenic (0.248 ± 0.018 mg kg^-1), cadmium (0.0134 ± 0.0014 mg kg^-1), mercury (0.0026 ± 0.0003 mg kg^-1), lead (0.0064 ± 0.0016 mg kg^-1), inorganic As (0.113 ± 0.016 mg kg^-1) and dimethylarsinic acid (DMA) (0.115 ± 0.010 mg kg^-1), and reference value for monomethylarsonic acid (MMA) (0.0045 ± 0.0008 mg kg^-1) was reported. We also observed trace amounts of an unknown As compound, with chromatographic retention time close to DMA. Participating laboratories were allowed to use their in-house-validated extraction and/or digestion methods, and the detection of total metals was done by ICP-MS whereas HPLC-ICP-MS was used for As speciation. Despite the diversity in sample preparation and quantitation methods, reported values were in good agreement. For iAs measurement, the comparison between hydride generation ICP-MS and HPLC-ICP-MS found iAs overestimation with the former method, possibly due to interference from DMA. The certification was accomplished with a CRM rapid response approach in collaborative, focused effort completing the CRM development in few months instead of the typical multiyear project. This approach allowed to respond to measurement needs in a timely fashion. Graphical abstract.

Market Basket Survey of Arsenic Species in the Top Ten Most Consumed Seafoods in the United States

The study focused on the determination of arsenic species in the top ten most consumed seafoods in the United States. Fifty-four samples were collected from local supermarkets, and their species identities were confirmed by DNA barcoding. The total arsenic in the samples varied greatly in the range of 8-22200 ng/g (wet mass). Speciation analysis based on extraction of water-soluble and nonpolar arsenic showed that inorganic arsenic (iAs) was found only in clams and crabs, while arsenobetaine (AsB) predominates in most samples. Among the other arsenicals, trimethylarsoniopropionate (TMAP) was found in most matrices with higher concentrations in crabs, and arsenosugars existed in most clams and crabs. Nonpolar arsenic accounted for 1-46% of the total arsenic in the samples. The accuracy of the analytical results was evaluated using standard reference materials and spike recovery tests. The survey showed that the iAs concentrations in America's most consumed seafood products are much lower than the tolerable intake set by the Joint FAO/WHO Expert Committee, even at the highest levels found in this study.