Determination Of Arsenic Species Research Articles

Simultaneous determination and distribution analysis of eleven arsenic species in vegetables

A highly sensitive and efficient method for simultaneous determination of arsenic species in vegetables has been developed. Eleven arsenic species were separated and detected using high performance ion exchange chromatography-inductively coupled plasma mass spectrometry (HPIEC-ICP-MS). The extraction efficiency and transformation of arsenic species in vegetables was investigated using five extraction methods and eight solvents. An online background removal technique was firstly established to exclude the influence of environmental arsenic. The gradient elution conditions were optimized and the optimal collision gas velocity for mass spectrometry was determined to be 4 mL min−1 to remove interference by 75ArCl. The detection limits for the method were 0.032–0.12 μg kg−1, and the quantitative limits of the method were 0.10–0.39 μg kg−1. In order to confirm the accuracy and practicability of the method, two food matrix-type certified reference materials were analyzed. The types and concentrations of arsenic species in six different kinds of vegetable were analyzed. The proportions of As (III) and As (V), as well as total arsenic concentrations, were significantly different.

Determination of Arsenic Species in Edible Insects by LC-ICP-MS.

Edible insects may contain arsenic. Analysis of arsenic species is necessary in order to accurately assess arsenic exposure. An analytical method was validated and used to determine and quantitate arsenic species in edible insects. Arsenic species were extracted from edible insects by heating at 100 °C in 0.3 mol/L nitric acid. The concentration of arsenic species was then determined by liquid chromatography inductively coupled plasma mass spectrometry (LC-ICP-MS) using an octadecylsilane (ODS) column with a mobile phase containing an ion-pair reagent. The limit of detection (0.007-0.012 mg/kg), limit of quantitation (0.021-0.038 mg/kg), repeatability (1.2-3.2%), intermediate precision (2.8-4.5%), and trueness (recoveries 97-102% based on spiked samples) of the proposed method were satisfactory for inorganic arsenic, dimethylarsinic acid, and arsenobetaine in edible insects. Total arsenic was detected in all samples obtained in Japan (Asian forest scorpion, diving beetles, giant water bug, grasshoppers, June beetles, mole crickets, male rhino beetle, female rhino beetle, sago worms, and silkworm pupae) and consisted of mostly inorganic arsenic. Beetles in particular showed relatively high levels. Arsenic content varies among edible insect species. Feed control is important, as arsenic concentrations in edible insects may be feed dependent. Arsenic species in edible insects were analyzed by LC-ICP-MS using an ODS column with a mobile phase containing an ion-pair reagent. Inorganic arsenic was detected in most samples, with concentrations ranging from <0.04 to 29.3 mg/kg.

Characterization and Quantification of Arsenic Species in Foodstuffs of Plant Origin by HPLC/ICP-MS.

Arsenic is a well-known carcinogenic, mutagenic and toxic element and occurs in the environment both as inorganic arsenic (iAs) and organoarsenical compounds (oAsCs). Since the toxicity of arsenic compounds depends on their chemical form, the identification and determination of arsenic species are essential. Recently, the European Food Safety Authority, following the European Commission request, published a report on chronic dietary exposure to iAs and recommended the development and validation of analytical methods with adequate sensitivity and refined extraction procedures for this determination. Moreover, the authority called upon new arsenic speciation data for complex food matrices such as seaweeds, grains and grain-based products. Looking at this context, an optimized, sensitive and fast analytical method using high performance liquid chromatography followed by inductively coupled plasma-mass spectrometry (HPLC/ICP-MS) was developed for the determination of iAs (sum of arsenite-AsIII and arsenate-AsV) and the most relevant oAsCs, arsenobetaine, dimethylarsinic acid and monomethylarsonic acid. The method was validated with satisfactory results in terms of linearity, sensitivity, selectivity, precision, recovery, uncertainty, ruggedness and matrix effect, and then successfully applied for the analysis of several matrices, i.e., processed and unprocessed cereal and cereal products, fruits, vegetables, legumes, seaweeds, nuts and seeds. The results obtained indicate that not only seaweed and rice matrices but also many cereals, legumes and plant-based foods for infants and young children contain significant concentrations of iAs and oAsCs. These findings contribute to the data collection necessary to assess the role of these matrices in the total arsenic exposure and if specific maximum limits have to be established.

Optimization of Extraction Conditions and Validation of the Method for Determination of Arsenic Species in Carrageenan-Producing Seaweed, Kappaphycus spp., Using HPLC-ICP-MS

Optimization of Extraction Conditions and Validation of the Method for Determination of Arsenic Species in Carrageenan-Producing Seaweed, Kappaphycus spp., Using HPLC-ICP-MS

Clinimetallomics: Arsenic Speciation in Urine from Patients With Arsenism by HPLC-ICP-MS

Clinimetallomics is proposed as a branch of metallomics that focuses on the study of the metallome in clinical samples of urine, blood, and tissues. As the clinical diagnosis of arsenic poisoning is mainly based on the concentration of total arsenic in urine, the toxicity of arsenic varies greatly in different speciation. Analysis of arsenic speciation with excessive total arsenic in urine can provide a basis for precise treatment. It can also be used to understand the fate of arsenic in the body of patients with arsenic poisoning after treatment with sodium dimercaptopropane sulfonate. In this study, a HPLC-ICP-MS method was established for the determination of arsenic species in urine samples from patients diagnosed with arsenism. Use the established method to detect urine samples, which can be directly assayed after simple sample dilution with 20 mmol/L EDTA-2Na. With the concentration of arsenic speciation in the range of 1.0~100.0 ng/mL, the linear correlation coefficient was higher than 0.99996. The recoveries were between 92.4% and 109.0%. The precision of the concentration and retention time (n = 3) were less than 3.0% and 0.3%, respectively, and the detection limit was between 1.42 ng/mL and 1.86 ng/mL. This method can be applied to arsenic speciation in the urine of healthy people, in patients treated for arsenic poisoning, and in patients diagnosed with arsenism.

A new method for highly efficient separation and determination of arsenic species in natural water using silica modified with polyamines

A simple and highly efficient method for the determination of highly toxic arsenic species using non-covalently aminated silica is proposed. The polyamines including poly(hexamethyleneguanidine), poly(4,9-dioxadodecane-1,12-guanidine), hexadimethrine, and poly(diallyldimethylammonium) were tested as silica modifiers. The prepared adsorbents allow effective preconcentration of anionic species of arsenic from aqueous solutions. It was found that As(V) can be quantitatively extracted from solutions at pH 4.5–7.0 by the anion exchange mechanism in less than 5 min, while neutral at this pH As(III) was not adsorbed at these conditions. A reaction with 2,3-dimercapto-1-propanesulphonic acid, which resulted in the formation of the negatively charged complex of As(III) with adsorbents was used for its quantitative extraction from solutions with a pH of 3.5–6.5. A system of two cartridges filled with poly(diallyldimethylammonium) modified silica and the on-line reaction of As(III) with 2,3-dimercapto-1-propanesulphonic acid proceeding between the cartridges was used for separate preconcentration and determination of As(V) and As(III) at pH 5. The proposed method was used for four-year monitoring of natural water pollution by arsenic in the area of residence of the indigenous peoples of Tyva Republic (Russia).

Determination of arsenic species using functionalized ionic liquid by in situ dispersive liquid-liquid microextraction followed by atomic absorption spectrometry

Synthesis and application of a task-specific ionic liquids (TSILs) as extracting solvents or chelating agents in dispersive liquid–liquid micro-extraction (DLLME) was evaluated. The developed method was based on the use of an ammonium pyrrolidine dithiocarbamate (APDC) bonded ionic liquid for chelation with As(III), followed by conversion of the As(III) chelated TSIL to a hydrophobic ionic liquid using KPF6 as an anion-exchange reagent. As(V) was reduced to As(III), using a 2/1 w/w blend of KI and Na2S2O3 and then the total amount of As was measured through ETAAS analysis. Under optimal conditions, linear dynamic ranges of 0.2–15 ng mL−1 and 0.2–20 ng mL−1 were observed in the determination of As(III) and total As respectively. The relative standard deviations (RSD%, n = 5) for the determination of As(III) (10 ng mL−1) was 3.2% and the limits of detection and quantitation were determined to be 0.01 ng mL−1 and 0.0.034 ng mL−1; respectively.

Ultrasound assisted dispersive solid phase microextraction of inorganic arsenic from food and water samples using CdS nanoflowers combined with ICP-OES determination

Direct determination of arsenic species in real samples is challenging due to their trace concentration and spectral interferences by coexisting ions. Herein, we proposed an ultrasound-assisted dispersive solid phase microextraction (DSPME) procedure for the analyses of the trace inorganic arsenic. The hydrothermally synthesized cadmium sulfide nanoparticles (CdS NPs) completely adsorbed both arsenic species within 20 s at the initial arsenic concentration of 100 µg L−1. The detection limit (3 S/m) of the proposed method was found to be 0.5 ± 0.2 and 0.8 ± 0.2 ng L−1 for As(III) and As(V), respectively. The accuracy of the method against the systematic and constant errors was confirmed by the analysis of the Standard Reference Material (SRM) (>95% recovery with <5% RSD). The Student’s t-test values were found to be less than the critical Student’s t value at a 95% confidence level. The method was successfully employed for the determination of arsenic in food samples.

Arsenic species in electronic cigarettes: Determination and potential health risk

Human exposure to contaminants from electronic cigarettes (e-cigarettes) and the associated health effects are poorly understood. There has been no report on the speciation of arsenic in e-liquid (solution used for e-cigarettes) and aerosols. We report here determination of arsenic species in e-liquids and aerosols generated from vaping the e-liquid. Seventeen e-liquid samples of major brands, purchased from local and online stores in Canada and China, were analyzed for arsenic species using high-performance liquid chromatography and inductively coupled plasma mass spectrometry. Aerosols condensed from vaping the e-liquids were also analyzed and compared for arsenic species. Six arsenic species were detected, including inorganic arsenate (iAsV), arsenite (iAsIII), monomethylarsonic acid (MMA), and three new arsenic species not reported previously. In e-liquids, iAsIII was detected in 59%, iAsV in 94%, and MMA in 47% of the samples. In the condensate of aerosols from vaping the e-liquids, iAsIII was detected in 100%, iAsV in 88%, and MMA in 13% of the samples. Inorganic arsenic species were predominant in e-liquids and aerosols of e-cigarettes. The concentration of iAsIII in the condensate of aerosols (median 3.27 μg/kg) was significantly higher than that in the e-liquid (median 1.08 μg/kg) samples. The concentration of inorganic arsenic in the vaping air was approximately 3.4 μg/m3, which approaches to the permissible exposure limit (10 μg/m3) set by the United States Occupational Safety and Health Administration (OSHA). According to the Environmental Protection Agency's unit risk factor (4.3 × 10−3 per μg/m3) for inhalation exposure to inorganic arsenic in the air, the estimated excess lung cancer risk from lifetime exposure to inorganic arsenic in the e-cigarette vaping air (3.4 μg/m3), assuming e-cigarette vaping at 1% of the time, is as high as 1.5 × 10−4. These results raise health concerns over the exposure to arsenic from electronic cigarettes.

Capillary electrophoresis coupled to electrospray mass spectrometry for the determination of organic and inorganic arsenic compounds in water samples

Some compounds of arsenic are extremely toxic to the human body even at low levels. Long-term exposure from drinking contaminated water causes adverse health effects. This has led the European Union and other global organizations to reduce the maximum residue limit for the total arsenic up to 10 μg L−1 in water for human consumption. The toxicity of arsenic depends on the oxidation state, chemical structure and solubility in the biological environment. Main analytical procedures report on the determination of arsenic species in water samples which have been developed based on atomic spectroscopy –speciation performed in the sample treatment step– and inductively coupled plasma-mass spectrometry (ICP-MS). In such cases, speciation is performed by coupling to high-performance liquid chromatography (HPLC). As far as we know, the determination of arsenic species in water samples at low concentration levels by capillary electrophoresis (CE) coupled to electrospray mass spectrometry (ESI-MS) has not been described up to now. In this research CE-ESI(−)-MS is proposed for the identification and simultaneous quantification of organic and inorganic arsenic species in water samples for human consumption. The target compounds were dimethylarsinate (DMA), mono-methylarsonate (MMA), arsenite (i-As(III)) and arsenate (i-As(V)). Optimization of the composition and nature of both the electrophoretic separation medium –using hexafluoro-2-propanol (HFIP) as an additive– and the sheath liquid was performed and aimed at achieving the best sensitivity and separation efficiency for the CE-ESI(−)-MS coupling. Two simple sample treatments were proposed: one based on dispersive liquid-liquid micro-extraction (DLLME) intended for a rapid determination of the total content of inorganic arsenic in the water sample; and the second based on partial evaporation of the water sample to detect each of the four main arsenic species. For the second, limits of detection between 0.02 and 0.04 μg L-1 were found, which are similar results as the ones achieved with methods based on HPLC-ICP-MS.The DLLME + CE-ESI(−)-MS method was applied to the determination of total inorganic arsenic in eleven water samples in the province of Salamanca (Spain). Five of the analyzed samples had values close to, or superior to the maximum residue limit for the total of arsenic in water intended for human consumption (10 μg L-1). The validated method CE-ESI(−)-MS for arsenic speciation was applied with success to the analysis of the weakly mineralized water sample (dry residue < 50 mg L-1) of both groundwater and bottled water.

Determination of arsenic species compound in blood by high performance liquid chromatographyatomic fluorescence spectrometry

Objective: To establish a method for determination of arsenic species in blood with high performance liquid chromatography-atomic fluorescence spectrometry (HPLC-AFS) . Methods: The effect of mobile phase about chromatography separation and sample pretreatment conditions and atomic fluorescence spectrometry detection parameters has been optimized to reliably measure the following four kinds of species arsenic compound including arsenic[As (III) ]、dimethylarsinic acid (DMA) 、monomethylarsonic acid (MMA) and arsenate[As (V) ] in acute intoxication human blood. The method of technical standard about within-run, between-run and recoveries of standard were optimized. Results: The method showed As (III) linear relationship was 2.63-100.00 μg/L, The detection limit was 2.63 μg/L. The relative coefficient (r) was 0.9999; DMA linear relationship was 3.21-100.00 μg/L, The detection limit was 3.21 μg/L. The r was 0.9992; MMA linear relationship was 3.41-100.00 μg/L, The detection limit was 3.41 μg/L. The r was 0.9998; As (V) linear relationship was 3.90-100.00 μg/L, The detection limit was 3.90 μg/L. The r was 0.9996. The average recovery of four species arsenic in tested samples ranged from 91.3%-99.8% with the relative standard deviation (RSD) from 2.39% to 4.05%. The within-run and between-run relative standard deviations (RSD) of repetitive measurement at 10.00, 40.00, 80.00 μg/L concentration levels were 1.99%-4.59% and 2.72%-4.53%. Conclusion: This method is low detection limit, good accurate and high sensitivity, proposed method had been applied to the analysis of arsenic species in blood samples those who acute intoxication or poisoning diagnosis.

In–spray chamber hydride generation by multi–mode sample introduction system (MSIS) as an interface in the hyphenated system of high performance liquid chromatography and inductivity coupled plasma optical emission spectrometry (HPLC/HG–ICP–OES) in arsenic species determination

The paper presents a new usage of a commercial in–spray chamber hydride generator, Multi–mode Sample Introduction System (MSIS) as a connector of high pressure liquid chromatography and inductivity coupled plasma optical emission spectrometry (HPLC/HG–ICP–OES). This hyphenated technique was applied in a determination of inorganic and organic arsenic species. The optimization of a hydride generation process in MSIS and a chromatographic separation (using anion–exchange HPLC column with phosphate buffer as a mobile phase) were carried out compositely. The method allowed to determine three arsenic forms, As(III), As(V) and dimethylarsinate (DMA) within 400s of a single analysis. The obtained limits of detection (LODs) were 2.08 μg L−1 for As(III); 6.97 μg L−1 for As(V); 6.15 μg L−1 for DMA and precision 2.7%, 4.8%, and 5.7%, respectively, for 100 μg L−1. The described method was used for environmental and food samples analyses.

Quantitative Determination of Arsenic Species from Fruit Juices Using Acidic Extraction with HPLC-ICPMS.

Throughout the US Food and Drug Administration’s routine monitoring of various juice samples for elemental contaminants, a limited number of samples exhibited unexpected behavior related to the arsenic content. Juice samples were subjected to total arsenic determination and those containing arsenic > 10 μg kg−1 were subjected to arsenic speciation analysis using FDA Elemental Analysis Manual (EAM) 4.10 method (AOAC First Action Method 2016.04) to determine the concentration of iAs and other common organic arsenicals. For a subset of samples, the sum of the arsenic species was significantly less than the total arsenic value (i.e., mass balance < 65%), which is uncommon for a liquid-based matrix. Juice types that have exhibited this behavior include pomegranate, prune, and cherry juices. Causes for this issue were explored which ultimately led to an alternate sample preparation technique, extraction with 0.28 M HNO3 along with heat, which resulted in drastically improved mass balances approaching 100%. The method proved robust, with both accurate and precise measurements for multiple juice samples analyzed by a total of four laboratories. Two laboratories performed a level 3 multilaboratory validation. This work discusses various issues that were encountered, attempts to determine the source of the problem, the eventual solution in the form of a modified extraction procedure, and the multilaboratory validation results.

A method for rapid determination of arsenic species in vegetables using microwave-assisted extraction followed by detection with HPLC hyphenated to inductively coupled plasma-mass spectrometry.

Driven by the significant need for characterization of the chemical speciation of arsenic in food, this work developed a method for rapid determination of four common arsenic species, namely, arsenite, arsenate, monomethyl arsenic acid, and dimethyl arsenic acid, in vegetables using microwave-assisted extraction, followed by detection with high-performance liquid chromatography hyphenated to inductively coupled plasma-mass spectrometry. Initial screening results showed that microwave-assisted extraction using 1% HNO3 exhibited the highest overall efficiencies for all arsenic species without causing significant degradation of the organic ones. With the aid of response surface methodology, the optimum conditions established for extraction of arsenic species from vegetables were: 500mg of freeze-dried vegetable sample, extracted by closed vessel microwave-assisted extraction using 10mL of 2% v/v HNO3 at 90°C for 17min. Application of the method in the analysis of 24 market vegetable samples indicates that the extraction efficiencies for total arsenic species were in the range of 91.4-106%. Arsenite and arsenate were found to be the predominant arsenic species in the vegetables, which suggests that vegetable consumption could be an important route of inorganic arsenic exposure for the population with a heavy vegetable diet in arsenic polluted regions.

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.

Determination of arsenic speciation in 17 commonly used traditional Chinese herbal medicines by HPLC-ICP-MS

The element speciation analysis for heavy metals in herbal medicines is still in the beginning stage. In this study,the total amount of arsenic( As) in 103 batches of 17 commonly used Chinese medicines( including 16 plant medicines and 1 medicinal fungus) was detected by inductively coupled plasma mass spectrometry( ICP-MS). Furthermore,based on HPLC-ICP-MS,the simultaneous detection methods of six As speciation kinds in traditional Chinese medicines were established. An AS7 anion exchange column was selected and the As forms in 17 traditional Chinese medicines was systematically analyzed. The results showed that the method of pretreatment of medicinal materials by microwave digestion and the detection of total amount of As by ICP-MS was stable and reliable. As for the speciation analysis of As,the high-speed ultrasonic extraction method was adopted,and it showed that the linear relationship of the six As speciation was satisfied with the correlation coefficient R2>0. 999 9. The LOQ of six kinds of As speciation were 0. 20,0. 10,0. 15,0. 10,0. 25,0. 10 μg·L~(-1) for arsenic betaine( As B),arsenious acid [As( Ⅲ) ],dimethyl arsenic( DMA),arsenic choline( As C),monomethyl arsenic( MMA),arsenic acid[As( Ⅴ) ],respectively. The recoveries were between 84. 24% and 121. 5%,and the relative standard deviations were 2. 7% to 11%. Among the 103 batches of medicinal materials,only one batch of sample As exceeded the Chinese Pharmacopoeia limit standard; As( Ⅲ) and As( Ⅴ) had high detection rate in 103 batches of Chinese herbal medicines,within which As( Ⅴ) was the main detected form,and inorganic As accounted for the ratio reached 80. 90%-98. 73%; some samples detected DMA,MMA and As B,As C was not detected in any batch. This study established an analytical method suitable for the speciation of As in Chinese herbal medicines,and provided basic data for As residual residue in Chinese herbal medicines,which can provide important reference for the risk assessment and quality standards.

Arsenic speciation in mushrooms using dimensional chromatography coupled to ICP-MS detector

This study concerns total arsenic (TAs) and arsenic species determination in three species of mushrooms collected in Yunnan, China. The purpose of this study was to check concentration level of arsenic in Boletus edulis, Tricholoma matsutake and Suillellus luridus, estimate arsenic bioaccessibility and find out which arsenic species occur in mushrooms to assess if they may pose a threat to human health. An analytical methodology based on ion chromatography (IC) hyphenated to inductively coupled plasma mass spectrometry (ICP-MS) with dynamic reaction cell (DRC) and size exclusion chromatography (SEC) with UV–Vis detection and ICP-DRC-MS detection. Ultrasound assisted extraction (UAE), microwave assisted extraction (MAE) and enzymatic assisted extraction (EAE) were applied. Quantification of As species in extracts was performed by IC/ICP-DRC-MS in the first dimension. Slightly better extraction efficiencies were obtained for MAE (from 75% to 90%) then for UAE. EAE was used for estimation of bioaccessibility by application of a modified BARGE bioaccessibility method (UBM) for in vitro studies. Bioaccessibility values were in the ranges of 73%–102%, 74%–115% and 18%–87% for step 1 (S1), for step 2 (S2) and for step 3 (S3) of EAE, respectively. Extracts obtained after EAE were subjected to SEC-UV-Vis/ICP-DRC-MS analysis as the second dimension. The main signal was obtained in the area of a molecular mass of ∼5 kDa for all mushroom extracts. Monitoring of an 50SO+ ion confirmed that this signal comes from As-protein. In sample of Boletus edulis additional signal occurred which is classified as unknown As-compound. Both signals require identification with another analytical technique.

A new method for the speciation of arsenic species in water, seafood and cigarette samples using an eggshell membrane

This work is based on the application of the eggshell membrane (ESM) of fresh chicken as a sorbent in a solid phase extraction procedure for arsenic speciation with detection by electrothermal atomic absorption spectrometry. The ESM can adsorb several heavy metal ions from a dilute aqueous solution with high affinity and short contact time, depending on pH and ionic characteristics. It thusly becomes a promising candidate as a solid adsorbent in extraction systems. The procedure is based on the solid phase extraction of the complex formed by As(III) with ammonium pyrrolidine dithiocarbamate (APDC). Solutions of As(III) were percolated through the eggshell membrane-filled minicolumn (ESM). Then, the analyte contained in the sorbent was desorbed by a 4.0 mol L−1 HNO3/ethanol solution (2:3). The influence of variables such as eluent, sample volume, pH effect, APDC volume, eluent volume, atomization, pyrolysis temperature, and sample flow was studied. Under optimized conditions, the method presented a limit of detection and enrichment factor of 0.01 μg L−1 and 17, respectively. Arsenic speciation was also tested because As(V) does not react with APDC, but is retained by ESM. Thus, the determination of total arsenic and As(V) allows the determination of both species. The procedure was applied to the determination of arsenic species in water, seafood, and cigarette samples.

Total Arsenic and Arsenic Species Determination in Freshwater Fish by ICP-DRC-MS and HPLC/ICP-DRC-MS Techniques.

Analytical methods for the determination of total arsenic (TAs) and arsenic species (arsenite—As(III), arsenate—As(V), monomethylarsenic acid—MMA, dimethylarsenic acid—DMA and arsenobetaine—AsB) in freshwater fish samples were developed. Inductively coupled plasma mass spectrometry with dynamic reaction cell (ICP-DRC-MS) and high-performance liquid chromatography hyphenated to ICP-DRC-MS were used for TAs and arsenic species determination, respectively. The DRC with oxygen as a reaction gas was used. Sample preparation, digestion, and extraction were optimized. Microwave assisted digestion and extraction provided good recovery and extraction efficiency. Arsenic species were fully separated in 8 min using 10 mmol L−1 of ammonium dihydrogen phosphate and 10 mmol L−1 of ammonium nitrate. Overlapping of AsB and As(III) of arsenic species in the presence of a high concentration of AsB and trace amounts of As(III) were studied. Detailed validation of analytical procedures proved the reliability of analytical measurements. Both procedures were characterized by short-term and long-term precision: 2.2% (TAs) up to 4.2% (AsB), and 3.6% (TAs) up to 7.2% (DMA), respectively. Limits of detection (LD) were in the range from 0.056 µg L−1 for TAs to 0.15 µg L−1 for As(V). Obtained recoveries were in the range of 85%–116%. Developed methods were applied to freshwater fish samples analysis.

Enzyme-assisted extraction and liquid chromatography-inductively coupled plasma mass spectrometry for the determination of arsenic species in fish

A sensitive, simple and rapid method for the simultaneous determination of eleven arsenic species has been developed. A high performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) technique was used for the analysis of eleven arsenic species in less than 17 min. Different extraction solutions were explored and the recovery results using water and aqueous acidic solvents, aqueous organic solvents and enzymes showed that 40 mg protease with 0.75 mL 0.5% hydrochloric acid (v/v) as the extraction agent gave the best experimental results. Species separation with ammonium carbonate solution as the mobile phase was conducted on an anion-exchange chromatographic column using gradient elution. The column temperature was 20 °C and kinetic energy discrimination (KED) was employed to eliminate spectral interference. The use of KED mode effectively removed interference from 75ArCl. The detection limit (LD) of the method was in the range of 0.11–0.59 μg kg−1. Repeatability values obtained for spiked real fish samples were in the range of 1.1%–7.6%. Accuracy was calculated based on the analysis of spiked real fish samples at five concentration levels. Obtained recoveries were 91%–106%. The validated method was used in a pilot study to analyze real samples of fish, the organic arsenic especially AsB was the major arsenic specie present in the analyzed samples, only trace amount of inorganic arsenic were detected. The analytical method should improve the assessment of human exposure associated with arsenic intake from fish.