Hydride Generation Atomic Absorption Spectrometry Research Articles

Rapid synergistic cloud point extraction based on hydrophobic deep eutectic solvent combined with hydride generation atomic absorption spectrometry for determination of selenium in tea samples

Herein, hydrophobic deep eutectic solvents (HDESs) were created for the fast preconcentration of Se(IV) from tea samples at room temperature. A facile and rapid synergistic cloud point extraction (HDES-RS-CPE) procedure was used, followed by hydride generation atomic absorption spectrometry (HG-AAS). The selected synergistic DES included glycine and lauric acid (molar ratio 3:1). 2-hydroxy-5-p-tolylazobenzaldehyde (HTAB) and Triton X-114 were utilized as chelating reagent and non-ionic surfactant, respectively. The experimental parameters that impact extraction recovery were examined and optimized. The detection limit, quantification limit, preconcentration factor, and enhancement factor for Se(IV) under optimum circumstances were 0.02 μg L−1, 0.06 μg L−1, 125, and 149, respectively. The method exhibited analytical linearity in the range up to 700.0 μg L−1. The procedure was used effectively for the quantification of Se(IV) in tea and certified samples. Moreover, the National Environmental Method Index (NEMI), the analytical greenness scale for sample preparation (AGREEprep), and the Green Analytical Procedure Index (GAPI) criteria have been used to measure the greenness score of the extraction procedure. To further highlight the environmental friendliness of this method, a detailed evaluation has been performed.

Geochemical background and geopedological interactions of selenium in soils from Piauí state, Northeastern Brazil

ABSTRACT Although Selenium (Se) plays a role as a micronutrient for humans through vegetable consumption, it is also recognized as toxic when present in excessive quantities. Therefore, quantifying Se contents in soils can prevent diseases influenced by crop Se deficiency or excess. We aimed to measure background contents, establish quality reference values (QRV) for Se in soils from two Brazilian biomes (Cerrado and Caatinga), and assess how geopedological factors affect Se content and spatial variability. Two hundred and eight composite topsoil samples were analyzed for Se content, covering an area of about 251,578 km². Sampling sites were under the minimal anthropogenic influence to represent Se background contents. Selenium contents were determined by hydride generation atomic absorption spectroscopy (HGAAS), ranging from 0.002 to 4.78 mg kg -1 . Most soils had contents below the world average of 0.44 mg kg -1 but still above the soil content that causes human Se deficiency (0.125 mg kg -1 ). Soils from Cerrado and Caatinga biomes showed similar average contents of Se, 0.41 and 0.47 mg kg -1 , respectively. Organic carbon content and soil particle size (clay fraction) were the main factors governing Se content in the soils. Our results contribute to understanding the Se content and spatial distribution in tropical soils and the factors governing them. They also provide a tool for agriculture and environmental decision-makers to plan public policies regarding the management of Se levels in these and similar tropical soils in the world.

Magnetic graphene oxide functionalized dimercaptosuccinic acid/putrescine as a selective and stable solid-phase extraction adsorbent for preconcentration and speciation of arsenic (III) in water samples

ABSTRACT It is challenging for environmental scientists to identify the trace value of arsenite (As(III)) as an essential hazardous material in the presence of arsenate (As(V)) and other metal ions. This paper proposes a method of magnetic solid-phase extraction (MSPE) for the trace analysis of As(III) using magnetite graphene oxide (MGO) covalently functionalised with dimercaptosuccinic acid (DMSA) and putrescine (PUT). The hydrothermally synthesised MGO/DMSA-PUT adsorbent was carefully characterised by using energy-dispersive X-ray spectroscopy analysis, Fourier transform infrared, dynamic light scattering, scanning electron microscopy, zeta potential analyser, X-ray diffraction, and vibrating sample magnetometer techniques in detail. Maximum adsorption capacity of MGO/DMSA-PUT for As(III) was determined 144 mg g−1 which considerably improved vs. graphene oxide with the adsorption capacity of 54.8 mg g−1. Sample pH of 6 with a volume of 50 mL, contact time of 5 minutes, initial concentration of 50 μg L−1, adsorbent dosage of 0.1 g and volume of eluent 3 mL were obtained as the optimised parameters for the developed MSPE procedure. According to experimental data obtained with hydride generation atomic absorption spectroscopy, the linear range and detection limit of the proposed method for As(III) measurement was found to be 0.4–5000 µg L−1 and 9.914 ng L−1, respectively. According to experimental results, a preconcentration limit (PL) of 1.72 µg L−1 was achieved for As(III), corresponding to a preconcentration factor of 965. Statistical analysis of standard reference materials confirmed the accuracy of the method against systematic and constant errors (>95% recovery with <5% RSD). Because of the selectivity of MGO/DMSA-PUT towards the As(III), the developed MSPE procedure is capable for successful speciation and determination of As(III) in water samples with satisfactory analytical results.

Switchable hydrophilicity solvent-assisted solidified floating organic drop microextraction for separation and determination of arsenic in water and fish samples

The aim of the current study was to separate and determine arsenic in water and fish samples using a novel and green solidified floating organic drop microextraction (SFODME), which is based on switchable hydrophilicity solvent (SHS)-assisted procedure followed by hydride generation atomic absorption spectrometry (HG-AAS). The 4-((2-hydroxyquinoline-7-yl)diazenyl)-N-(4-methylisoxazol-3-yl)benzene sulfonamide (HDNMBA) and tertiary amine (4-(2-aminoethyl)-N,N-dimethylbenzylamine (AADMBA) were used as ligand and SHS, respectively. The use of SHS promotes quantitative extraction of arsenic complexes into an extraction solvent (1-undecanol). Some factors that impact extraction recovery were studied. Under optimal conditions, the limit of detection (LOD) and limit of quantification (LOQ) were 0.005 μg L−1 and 0.015 μg L−1, respectively. The calibration graph was linear up to 900.0 μg L−1 arsenic, with the enrichment factor is 267. The proposed SHS-SFODME methodology for arsenic quantification in water and fish samples was successfully implemented. The environmental friendliness and safety of proposed method were approved by the Analytical Greenness Calculator (AGREE) and the Blue Applicability Grade Index (BAGI) tools.

A robust method for the determination of lead in water samples using flow injection hydride generation atomic absorption spectrometry

Flow injection hydride generation atomic absorption spectrometry (FI-HGAAS) is a sensitive technique for the quantification of trace amounts of lead. However, plumbane generation is not straightforward and usually HG methods for lead are not robust enough for routine analysis. The optimum pH range for Pb HG is very narrow, so strict control of the acidity of the reaction medium is required for reliable results and in some cases even acid concentrations used for sample preservation can interfere. Moreover, some elements, like Cu, can interfere in the HG reaction suppressing the Pb signal. In this paper we report the development and validation of a method for the determination of Pb in water samples that is robust towards acidity and Cu levels usually found in water samples.All hydride generation parameters were optimized, but special emphasis was put on robustness. The use of borate as a buffer significantly improved the robustness of the method towards acidity, compared to the typical non-buffered HG. Furthermore, the interference of Cu, Sb and Sn in the HG reaction was overcome using thiocyanate as a masking agent. Other elements do not interfere at levels typically found in water samples. The limit of quantification achieved (0.9 μg L−1) is below the current guideline value for Pb in drinking water (10 μg L−1). The linearity of the method was verified between the LOQ and up to 15 μg L−1. An analytical frequency of 25 samples per hour with 3 measurement replicates each was achieved. The method was applied to the analysis of 50 water samples. The concentrations found ranged from <LOD (0.3 μg L−1) and up to 88.8 μg L−1.The proposed method is robust, cost-effective, easily automated and does not require unconventional or expensive equipment. It can be applied for routine analysis of different types of water samples.

Design and construction of pilot sludge drying package for the excess sludge in petrochemical industries: Heavy metals determination in sludge by polarography and atomic absorption spectrometry

In this research, according to the high amount of sludge in a petrochemical company, an iron package type of drying sludge bed was made/designed with carbon steel. Then, the drying sludge pond was filled with layers of sand with different mesh sizes. The excess sludge from the sedimentation pond was passed over this bed, and the amount of sludge removed by the bed was obtained at %96. The values of heavy metal and microbial forms were determined using the proposed method based on activated sludge after wastewater treatment. For the validation process, 10 mL of deionized water (DW) was mixed with 1.0 g of dried sludge with pure nitric acid (2% HNO3), and then the solid phase was filtered with the Whatman filter (WF). The concentration of heavy metals (As, Cd, Cu, Pb, Hg, Mo, Ni, Co, Se, Zn) in the remaining solution of sludge (mg kg-1) and wastewater (µg L-1) was extracted/ separated based on sulfur-doped graphene oxide adsorbent (SDGO) by solid-phase microextraction procedure (SPME) before being determined by the flame and hydride generation atomic absorption spectrometry (F-AAS; HG-AAS) which had similar range to the polarography analysis. The LOD, linear range and preconcentration factor (PF) for metals were obtained.

Novel Palladium Coated Tungsten Coil Atom Trap for Ultra-Trace Determination of Selenium by Hydride Generation Atomic Absorption Spectrometry (HGAAS)

A new ultra-sensitive method was developed for selenium (Se) determination by combining a Pd-coated W-coil atom trap with hydride generation atomic absorption spectrometry (HGAAS). Firstly, gaseous hydrogen selenide, generated using a hydride generation system, was transported to an externally heated atom trap for in-situ preconcentration, where it was accumulated at 210 °C. Subsequently, the atom trap temperature was adjusted to 930 °C for revolatilization, resulting in the acquisition of a transient analyte signal within a very short time. The detection limit of 2.6 ng L−1 Se for a 90 s collection and a relative standard deviation of 2.4% for 0.01 µg L−1 Se (n = 14) were obtained. The devised trapping technique exhibited a remarkable 38-fold increase in sensitivity when compared to the conventional HGAAS method, as indicated by the characteristic concentration (C 0). The surface morphology was examined using scanning electron microscopy and energy dispersive spectroscopy. The proposed technique was validated by the analysis of certified reference materials (CRMs) and employed in the assessment of tap water samples. Statistical analysis using a t-test was conducted on CRMs and water samples, and the results showed no significant error.

Development of a New and Highly Sensitive Method for Arsenic Determination in Drinking Water Samples Using Au‐Coated W‐Coil Atom Trap Hydride Generation Atomic Absorption Spectrometry

AbstractA novel ultra‐sensitive gold‐coated tungsten‐coil atom trap coupled with HGAAS was developed for the first time for the determination of arsenic. The analytical methodology was based on transporting and in‐situ trapping of arsine produced by the hydride generation system onto a gold‐coated W‐coil trap for preconcentration via Ar and H2 gases. The trap surface was examined using scanning electron microscopy and energy‐dispersive X‐ray spectroscopy. SEM images revealed that the surface is covered with hexagonal and pentagonal structures on a micro scale with gold. The experimental parameters were optimized for both trap and non‐trap method. The enhancement factor for the characteristic concentration (C0) was determined to be 15.3 when compared with the non‐trap methods. For the trapping time of 120 s using the developed method, the limit of detection (LOD) and the precision were determined as 4.8 ng L−1 and 3.6 %, respectively. The interference effects of various hydride‐forming ions were examined in detail. The accuracy of this ultrasensitive methodology was successfully verified by analysis of certified reference materials and some drinking water samples.. t‐test was implemented to the water samples, the added and measured concentrations exhibited no statistically meaningful distinction at the 95 % confidence level.

A novel block copolymer containing gadolinium oxide nanoparticles in ultrasound assisted-dispersive solid phase microextraction of total arsenic in human foodstuffs: A multivariate optimization methodology

A new poly(3-hydroxy butyrate)-b-poly(dimethyl amino ethyl methacrylate) amphiphilic block copolymer containing gadolinium oxide nanoparticles (PHB-PDMAEMA-Gd2O3-NPs) were synthesized and used as composite adsorbent for extraction of total arsenic. Characterization of the composite adsorbent material PHB-PDMAEMA-Gd2O3-NP was studied using spectroscopic techniques. Plackett-Burman design and central composite design were employed to screening and optimization of the experimental parameters. This composite adsorbent was utilized in ultrasound assisted-dispersive solid phase microextraction (UA-dSPµE) for the determination of total inorganic arsenic in foodstuffs through hydride generation atomic absorption spectrometry (HG-AAS). It demonstrates a linear relationship across arsenic concentration range of 0.07–1.12 µg/L with a correlation coefficient (0.996). It’s showed an enrichment factor of 128 and a limit of detection 0.02 µg/L for total inorganic arsenic determination. Accuracy of the developed method was confirmed through the analysis of certified reference materials with 96.0–98.5% recovery. It proved to be significantly useful UA-dSPµE method for determining total inorganic arsenic in different foodstuffs.

Arsenic accumulation pattern in water-soil-rice systems: A study of tolerance mechanisms and associated health risks

Regardless of the daunting challenge of arsenic (As) contamination in Pakistan, literature on tolerance and responsible factors in paddy fields remain elusive. In this regard, we aimed to explore physiochemical factors responsible for As availability in water-soil-rice systems. The study highlighted rice defense mechanisms to mitigate As toxicity on growth and yield. In the present study, basmati rice samples were collected along with irrigation and soil samples from control (<10 μg/L), low (11–25 μg/L), medium (26–100 μg/L), and high (>100 μg/L) contaminated regions. Oxidative stress markers (MDA and H2O2) and antioxidant enzymatic assays (SOD, CAT, POD, APX) were measured by spectrophotometer. The Durov diagram was constructed by using Grapher software to identify prevalent water types in irrigation wells. Total As was measured in water, soil, and rice tissues by hydride generation-atomic absorption spectroscopy (HG-AAS). The Durov diagram showed that the majority of irrigation water was Ca-Mg-Cl type. Furthermore, the FTIR analysis identified different organic compounds, i.e., OH, CC, CI, and CBr, particularly in soil from high regions. The results indicated higher accumulation and translocation of As in the water-soil-rice system from a high region compared to control and other regions. Phenotypic traits, i.e., grain yield, biological yield, chlorophyll, and root parameters were significantly impacted under high As-contaminated region. A concentration-dependent increase was indicated in oxidative stress and antioxidant activities except for APX. Risk assessment indicated a higher hazard quotient (1.09) and carcinogenic risk (5.0 × 10−03) due to grain consumption in high As-contaminated regions. The present study emphasized the need for strict regulations and policies to mitigate As calamity at the local level and protect human health.

Quantification of Arsenic in Soil Samples Collected in an Industrial Area of Brindisi (Apulia, Italy): Speciation Analysis and Availability

Arsenic (As) is a well-known toxic metalloid, but environmental risks due to excessive As content in soils or sediments depend on the chemical forms present and their relative mobility. Long-term exposure to arsenic may cause several diseases. In order to assess the possible risks in the heavily impacted Consorzio per lo Sviluppo Industriale e di Servizi Reali alle Imprese (Consortium for Industrial Development and Effective Services for Business, S.I.S.R.I.) industrial area of Brindisi (Apulia, southern Italy), 38 soil samples were collected in the area, from 18 sampling points previously determined as outliers. Total As determination, speciation analysis, and a cession test with acetic acid were performed. Speciation analysis was performed by HPLC coupled to hydride generation-atomic absorption spectroscopy (HG-AAS). Total As determination obtained by mineralization showed a concentration range between 51.8 and 169.6 mg kg−1, which is higher than the limit of 50 mg kg−1 established by D.M. (Ministerial Decree) 471/99 for industrial areas. The highest concentrations of extracted As were obtained in the top-soil layers. As(III) and As(V) were detected in all the samples, while the concentrations of the organic species monomethyl arsonic acid (MMAA) and dimethyl arsenic acid (DMAA) were always under the detection limit. The samples releasing the highest As quantities in the acetic acid cession test were in every circumstance collected from the superficial soil levels. The different amounts of As determined in the sampling sites could depend on the distance from the specific sources of pollution, even if it is very difficult to identify them in a very complex industrial zone such as the S.I.S.R.I. area of Brindisi. In this study, As occurs mainly as relatively immobile or slowly exchangeable forms: for this reason, it is more abundant in the top-soil and is little affected by the action of rainwater, which transports only reduced quantities of As into the deeper layers.

UV-photochemical vapor generation coupled to hydride generation AAS in the study of dietary intake of Se, Hg, Cd, and Pb from fish

The consumption of fish by pregnant and lactating women is at the center of attention both from the point of view of ensuring healthy nutrition for fetal and neonatal development, and from the toxicological point of view. This research included a questionnaire survey on the frequency of fish consumption and the particular fish species consumed by 180 pregnant and lactating women in the Czech Republic, as well as the determination of Se, Hg, Cd, and Pb in the most commonly consumed species available on the Czech market. For this purpose, an analytical method for the determination of total selenium in biological samples using UV-photochemical vapor generation coupled to hydride generation atomic absorption spectrometry (UV-PVG-HG-AAS) was developed. This unique UV-photoreactor enables accurate and precise determination of Se with a detection limit of 0.007 mg/kg. Fish consumption by female respondents was generally low compared to the EU average. The determined Se contents in samples indicate a low intake of Se from fish in the Czech Republic; one third of the samples had Se contents below the detection limit. The highest Se contents were observed in the species Scomber scombrus, Sander lucioperca, and Thunnus albacares. The Hg content in fish samples did not exceed the EU maximum permissible values for mercury and methylmercury. The Tolerable Weekly Intake (TWI), which is 1.3 μg/kg of body weight per week, was not exceeded by any of the respondents. The maximum permissible value for Cd given by the European Commission was exceeded in the case of one sample of Scomber scombrus. Most of the samples had Cd content below the detection limit (0.002 mg/kg). The content of Pb in the analyzed samples was below the detection limit (0.013 mg/kg).

Cellular uptake and biotransformation of arsenate by freshwater phytoplankton under salinity gradient revealed by single-cell ICP-MS and CT-HG-AAS

Environmental context Freshwater phytoplankton are involved in the biogeochemical cycling of arsenic within aquatic ecosystems via uptake processes. Rather than determining the mean arsenic content in a population of freshwater phytoplankton, we investigate the heterogeneity of arsenic uptake by single-cell ICP-MS. Our data show that arsenic distribution within a cell population may be highly heterogeneous, measured at the femtogram per cell level, and are affected by species and salinity. Rationale An advanced technique has been developed for analysing intracellular elements at the single-cell level using single-cell inductively coupled plasma mass spectrometry (SC-ICP-MS). Compared with conventional inductively coupled plasma mass spectrometry (ICP-MS) analysis, SC-ICP-MS provides uptake data with greater biological relevance. In this study, the use of SC-ICP-MS enabled the quantification of metal concentrations on an individual cell basis down to the femtogram (fg) per cell level. Methodology Three freshwater phytoplankton cells, namely Staurastrum paradoxum (S. paradoxum), Pediastrum duplex (P. duplex) and Scenedesmus acutus (S. acutus), were incubated in 0.1 µmol L−1 arsenate (AsV) solution for 14 days at varying salinity. Cold trap hydride generator atomic absorption spectrometry (CT-HG-AAS) was used to investigate the biotransformation of arsenate under varying salinity conditions. Results The results reveal that cellular arsenic levels decreased as salinity increased in P. duplex and S. paradoxum but increased in S. acutus. The SC-ICP-MS data, which show uptake of AsV by freshwater phytoplankton, were in good agreement with those produced using ICP-MS analysis. Various arsenic management strategies were seen in the phytoplankton species: P. duplex converted it to methylated forms; S. acutus produced organoarsenicals; and S. paradoxum reduced arsenate (AsV) to arsenite (AsIII) and excreted it. Our study also showed changes in the physiological status of phytoplankton following salt stress and arsenic exposure. Discussion Our results confirm the efficacy of SC-ICP-MS in precisely determining arsenic distribution at the single-cell level and reveal differences in intraspecies mechanisms for arsenic cycling in freshwater ecosystems.

Speciation of Inorganic Arsenic in Retorted Oil Shale Slurry by Hydride Generation Atomic Absorption Spectrometry (HG AAS) after Ultrasound-Assisted Acid Extraction

An analytical method for determination of inorganic arsenic species in retorted oil shale slurry by atomic absorption spectrometry coupled to hydride technique with ultrasound assisted acidic extraction is reported. Trivalent arsenic measurement employed sample stabilization with a pH 4.5 prior to reaction with the reducing agent and analysis. In contrast, total inorganic As depended upon the pre-reduction of As(V) to As(III) with KI and ascorbic acid in 6.0 M HCl and of As(V) was estimated by the difference of the total inorganic As and As(III) concentrations. The limit of quantification was 3.7 mg kg−1 for As(III) and 1.3 mg kg−1 for itAs.

Assessment of selenium content in tropical fish species using hydride generation atomic absorption spectrometry

The present work aimed to investigate the chemical sides in hydride generation atomic absorption spectrometry (HG-AAS) (i.e., a simple, low-cost, and sensitive approach) for selenium (Se) analysis in fish samples, and to assess the Se content in different tropical fish species. The limits of detection and quantification were of 0.25 and 0.75 µg/L, respectively, which were comparable to other similar methods employing HG-AAS. Good linearity (R2 = 0.9999) was achieved within Se concentrations (0.50 to 10.0 µg/L). Favourable repeatability (RSDr = 1.9%) and reproducibility (RSDR = 3.5%) were obtained. DORM-4, a certified reference material, was used to evaluate the accuracy of the analytical method, and there was no statistically significant difference between the certified and measured values at the confidence level of 95%. For 24 collected samples of tropical fish species, the Se contents in marine fish were generally higher than those in freshwater fish (1,131.2 – 2,109.5 vs. 119.7 – 472.1 µg/kg) with high recoveries obtained from all spiked samples (95.1 to 99.1%).

Development of a New Sensitive Method for Lead Determination by Platinum-Coated Tungsten-Coil Hydride Generation Atomic Absorption Spectrometry.

A novel very sensitive and rapid analytical method was improved where gaseous lead formed was transported to and trapped on an externally heated platinum-coated tungsten-coil atom trap for in situ preconcentration. The analytical performance of the developed method with the graphite furnace atomic absorption spectrometry (GFAAS) method was compared. All critical parameters affecting the performance of both methods were optimized. The limit of quantitation (LOQ) was found as 11.0 ng L-1 and the precision was 2.3% in terms of percent relative standard deviation (RSD%). Characteristic concentration (Co) of the developed trap method was indicating a 32.5-fold enhancement in sensitivity compared to the GFAAS method. In order to investigate the surface morphology of the W-coil, scanning electron microscope-energy-dispersive X-ray (SEM-EDS) analyzes were performed. The accuracy of the trap method was tested by certified reference materials: NIST SRM 1640a (the elements in natural water) and DOLT:5 (dogfish liver). Interferences from other hydride-forming elements were investigated. Application of the trap method was demonstrated by the analysis of some drinking water and fish tissue samples. The t test was applied to drinking water samples, and the results indicated that there was no statistically significant error.

Ultrasound assisted dispersive solid phase microextraction using polystyrene-polyoleic acid graft copolymer for determination of Sb(III) in various bottled beverages by HGAAS

A new polyoleic acid-polystyrene (PoleS) block/graft copolymer was synthesized and applied as adsorbent for ultrasound assisted dispersive solid phase microextraction (UA-DSPME) of Sb(III) in different bottled beverages and analysis using hydride generation atomic absorption spectrometry (HGAAS). Adsorption capacity of the PoleS was 150 mg g−1. Several sample preparation parameters such as sorbent amount, solvent type, pH, sample volume and shaking time were optimized (based on central composite design (CCD) approach) and evaluated in respect to the recovery of Sb(III). The method revealed a high tolerance limit of matrix ions presence. Under optimized conditions, linearity range, the limit of detection, the limit of quantitation, extraction recovery, enhancement factor, preconcentration factor were 5–800 ng L−1, 1.5 ng L−1, 5.0 ng L−1, 96%, 82, 90, respectively. Accuracy of the UA-DSPME method was confirmed based on different certified reference materials and standard addition method. Factorial design was utilized to estimate the influences of variables of recovery of Sb(III).

Genotoxicity and mutagenicity in blood and drinking water induced by arsenic in an impacted gold mining region in Colombia

Arsenic (As) is one of the most dangerous substances that can affect human health and long-term exposure to As in drinking water can even cause cancer. The objective of this study was to investigate the concentrations of total As in the blood of inhabitants of a Colombian region impacted by gold mining and to evaluate its genotoxic effect through DNA damage by means of the comet assay. Additionally, the concentration of As in the water consumed by the population as well as the mutagenic activity of drinking water (n = 34) in individuals were determined by hydride generator atomic absorption spectrometry and the Ames test, respectively. In the monitoring, the study population was made up of a group of 112 people, including inhabitants of four municipalities: Guaranda, Sucre, Majagual, and San Marcos from the Mojana region as the exposed group, and Montería as a control group. The results showed DNA damage related to the presence of As in blood (p < 0.05) in the exposed population, and blood As concentrations were above the maximum allowable limit of 1 μg/L established by the ATSDR. A mutagenic activity of the drinking water was observed, and regarding the concentrations of As in water, only one sample exceeded the maximum permissible value of 10 μg/L established by the WHO. The intake of water and/or food containing As is potentially generating DNA damage in the inhabitants of the Mojana region, which requires surveillance and control by health entities to mitigate these effects.

Aqueous phase synthesis of ion-imprinted cryogel for paper-based colorimetric detection of As(V) with high selectivity.

A novel hydrophilic As(V) ion-imprinted cryogel (IIC) was green prepared by cryogelation in aqueous environment which was coincident with the adsorption condition and can improve the specific recognition performance. The methacrylamido propyl trimethyl ammonium chloride (MPTAC) was selected as the functional monomer and the saturated adsorption capacity of the prepared IIC and NIC were 55.0mg/g and 29.4mg/g, and with high imprinting factor of 1.87. Additionally, the prepared IIC showed admirable reusability and highselectivity, and the recovery was in the range 81.2-97.9% with RSD range of 1.9-4.3%, which was similar to the value obtained by hydride generationatomic absorption spectrometry. IIC can be used as solid material for colorimetric detection at the ultraviolet wavelength of 858nm without color interference of material matrix, in the range 5-200μg/L (R2 = 0.990)with a detection limit of 0.970 µg/L. Obviously, this synthetic strategy provides a simple, efficient, and green method for the preparation of water-compatible ion-imprinted polymers providingselectiveseparation and detection of trace As(V) in real complex samples.

Investigation of arsenic contamination in groundwater using hydride generation atomic absorption spectrometry.

The validated hydride generation atomic absorption spectrometry (HG-AAS) method has been used to investigate total arsenic in groundwater. Under optimal experimental conditions, the concentration of arsenic in groundwater can be analysed in the range of 0.5 to 50µg/L, with a method detection limit of 0.15µg/L. Its recovery in the field is from 96.3 to 99.8%, with high repeatability. The method was used to observe the total arsenic pollution in groundwater collected in Phu Tho Province, Vietnam. A total of 364 groundwater samples were analysed. The results showed that arsenic pollution was significant, with 15.93% of the samples higher than the maximum permissible level of arsenic. About 20.69% of the contaminated samples had a total arsenic ten times higher (100µg/L) than the maximum permissible level of arsenic. The pollution source was also considered by comparing the arsenic level in the groundwater with arsenic in the surface water in the same areas. Thus, the use of the high-accuracy and sensitive method, HG-AAS, supplies valuable data on groundwater pollution for water resources management and environmental protection.