Hydride Generation Atomic Absorption Spectrometry Research Articles

Characterization and mutual comparison of new electrolytic cell designs for hydride generation-atomic absorption spectrometry with a quartz tube atomizer using Se as a model analyte and 75Se as a radioactive indicator

Fifteen electrolytic flow-through cells belonging to three different design groups (non-membrane, thin-layer and tubular) have been constructed and characterized in this work. Atomic absorption spectrometry with a quartz tube atomizer has been employed as a detector and Se chosen as a model analyte. At first optimization of relevant working parameters was performed and basic analytical characteristics were evaluated under the optimum experimental conditions for all cells. Mutual comparisons of the electrolytic cells were performed thereafter and 5 cells with best performance were selected for further evaluation. Finally, a 75Se radioactive indicator was employed to quantify the generation efficiency of selane as well as to visualize the spatial distribution of the analyte in the apparatus and track potential analyte losses. With respect to all relevant requirements the best performance was found for the thin-layer electrolytic cell (225 mm3 cathode chamber volume) with efficiency of electrochemical hydride generation reaching 75% and a limit of detection (LOD) of 0.31 ng mL−1 Se. A generation efficiency of 78% and an LOD of 0.40 ng mL−1 Se were obtained for the tubular cell (43 mm3 cathode volume). High generation efficiency, fast response and low cathode chamber volume make the tubular cell an ideal candidate even for flow-injection and speciation analysis measurements.

Changes in serum thioredoxin among individuals chronically exposed to arsenic in drinking water

It is well known that oxidative damage plays a key role in the development of chronic arsenicosis. There is a complex set of mechanisms of redox cycling in vivo to protect cells from the damage. In this study, we examined the differences in the levels of serum thioredoxin1 (TRX1) among individuals exposed to different levels of arsenic in drinking water and detected early biomarkers of arsenic poisoning before the appearance of skin lesions. A total of 157 subjects from endemic regions of China were selected and divided into arsenicosis group with skin lesions (total intake of arsenic: 8.68–45.71mg-year) and non-arsenicosis group without skin lesions, which further divided into low (0.00–1.06mg-year), medium (1.37–3.55mg-year), and high (4.26–48.13mg-year) arsenic exposure groups. Concentrations of serum TRX1 were analyzed by an ELISA method. Levels of water arsenic and urinary speciated arsenics, including inorganic arsenic (iAs), monomethylated arsenic (MMA), and dimethylated arsenic (DMA), were determined by hydride generation atomic absorption spectrometry. Our results showed that the levels of serum TRX1 in arsenicosis patients were significantly higher than that of the subjects who were chronically exposed to arsenic, but without skin lesions. A positive correlation was seen between the levels of serum TRX1 and the total water arsenic intake or the levels of urinary arsenic species. The results of this study indicate that arsenic exposure could significantly change the levels of human serum TRX1, which can be detected before arsenic-specific dermatological symptoms occur. This study provides further evidence on revealing the mechanism of arsenic toxicity.

Total and inorganic arsenic concentrations in different species of economically important algae harvested from coastal zones of Chile

Chile is one of the major producers of phytocolloids extracted from seaweed. Multicellular algae are considered to be primary accumulators of arsenic. We analyzed 14 species of algae belonging to the groups Rhodophyceae (10), Phaeophyceae (3) and Chlorophyceae (1) from different coastal zones of Chile in 2003–2004. Dry ashing mineralization (for total As) and acid digestion (for inorganic As) together with quantification by flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS) were employed. In general, total arsenic concentrations varied between 3.0 and 68mgkg−1, whereas inorganic arsenic concentrations ranged between 0.15 and 1.06mgkg−1. The algal species Durvillaea antarctica and Porphyra columbina, used for direct human consumption, did not have inorganic arsenic levels that represent a health risk to consumers. Among species used for phytocolloids production, such as Macrocystis piryfera, Gracilaria chilensis and Gigartina skottsbergii, observed levels of inorganic arsenic were greater than 1mgkg−1, the limit value established by the regulations of some countries. Among the 14 species of algae tested, inorganic arsenic levels were between 0.8% and 13% of the total arsenic concentrations; that is, arsenic present in these algae was found primarily as organic arsenic.

Ultra-trace Arsenic Determination in Urine and Whole Blood Samples by Flow Injection-Hydride Generation Atomic Absorption Spectrometry after Preconcentration and Speciation Based on Dispersive Liquid-Liquid Microextraction

A noble method for pre-concentration and speciation of ultra trace As (III) and As (V) in urine and whole blood samples based on dispersive liquid-liquid microextraction (DLLME) has been developed. In this method, As (III) was complexed with ammonium pyrrolidine dithiocarbamate at pH = 4 and Then, As (III) was extracted into the ionic liquid (IL). Finally, As (III) was back-extracted from the IL with hydrochloric acid (HCl) and its concentration was determined by flow injection coupled with hydride generation atomic absorption spectrometry (FI-HGAAS). Total amount of arsenic was determined by reducing As (V) to As (III) with potassium iodide (KI) and ascorbic acid in HCl solution and then, As (V) was calculated by the subtracting the total arsenic and As (III) content. Under the optimum conditions, for 5-15 mL of blood and urine samples, the detection limit (3σ) and linear range were achieved 5 ng L �1 and 0.02-10 μg L �1 , respectively. The method was applied successfully to the speciation and determination of As (III) and As (V) in biological samples of multiple sclerosis patients with suitable precision results (RSD < 5%). Validation of the methodology was performed by the standard reference material (CRM).

Inorganic arsenic speciation by hydride generation atomic absorption spectrometry in water samples collected from some regions of Turkey

Inorganic arsenic speciation by hydride generation atomic absorption spectrometry in water samples collected from some regions of Turkey

Automated method for the determination of total arsenic and selenium in natural and drinking water by HG-AAS

A multicommutated flow system was designed and evaluated for the determination of total arsenic and selenium by Hydride Generation Atomic Absorption Spectrometry (HG-AAS). It was applied to the determination of arsenic and selenium in samples of natural and drinking water. Detection limits were 0.46 and 0.08 μg l(-1) for arsenic and selenium, respectively; sampling frequency was 120 samples h(-1) for arsenic and 160 samples h(-1) for selenium. Linear ranges found were 1.54-10 μg l(-1) (R = 0.999) for arsenic and 0.27-27 μg l(-1) (R = 0.999) for selenium. Accuracy was evaluated by spiking various water samples and using a reference material. Recoveries were in the range 95-116%. Analytical precision (s ( r ) (%), n = 10) was 6% for both elements. Compared with the Standard Methods, APHA, 3114B manual method, the system consumes at least 10 times less sample per determination, and the quantities of acid and reducing agent used are significantly lower with a reduction in the generation of pollutants and waste. As an additional advantage, the system is very fast, efficient and environmentally friendly for monitoring total arsenic and selenium levels in waters.

DETERMINANTS OF URINARY ARSENIC CONCENTRATION IN A MEXICAN POPULATION

Background and Ams. Millions of people worldwide are exposed to inorganic arsenic (iAs), a known carcinogen, in drinking water. This study examined potential predictors of urinary arsenic concentration in two areas in central Mexico with historically high iAs levels in village water supplies. Methods. Participants were adults and children age •5 years residing in the La Laguna and Zimapán regions in Durango-Coahuila and Hidalgo states, respectively. Information on residential history and water use was obtained by questionnaire and participants provided samples of drinking water and spot urine. Concentrations of iAs in water and As species in urine, iAs, MAs and DMAs, were determined by hydride-generation atomic absorption spectrometry. Potential predictors of iAs in water and urine were examined using linear regression and linear mixed models on log-transformed concentrations. Results. The concentration of iAs in water samples was significantly associated with the source of drinking water and place of residence, including the village as well as the region. Interactions of location and water source were significant. Total arsenic (tAs) in urine was significantly associated with iAs concentration in water, source of drinking water and region of residence, as well as with sex and urinary creatinine. Higher urinary tAs concentrations were observed among those drinking municipal tap water rather than bottled water or water from springs or dug wells. Other environmental and personal factors including source of cooking water, length of residence, duration of water use, recent absence from the area, age and obesity were not associated with urinary tAs. Trivalent and pentavalent species of iAs in urine were associated with tAs in urine but not with environmental or personal factors. Conclusions. The level of tAs is strongly related to the concentration of iAs in drinking water, but sex and factors specific to location also play a role.

ASSOCIATION OF DIABETES WITH ARSENIC EXPOSURE, ARSENIC METABOLITES AND AS3MT POLYMORPHISM

Background and Aims. Exposure to inorganic arsenic (iAs) is suspected of causing diabetes mellitus and other diseases. This study examined associations of diabetes with exposure to iAs in drinking water, metabolites of iAs in urine and AS3MT polymorphism. Methods. Participants were adults and children age •5 years living in Durango-Coahuila and Hidalgo states, Mexico. Information on water used and residential and medical history was obtained by questionnaire and participants provided samples of drinking water and spot urine. Prevalent diabetes was classified by fasting blood glucose (FBG) (≥125 mg/dl), oral glucose tolerance test (OGTT) (≥200 mg/dl) and self-report of diabetes diagnosis or treatment. iAs and its metabolites in urine were analyzed by hydride generation-atomic absorption spectroscopy. Associations between diabetes and iAs and urinary metabolites of iAs were estimated by logistic regression with adjustment for age, sex, hypertension and obesity. Urinary creatinine was evaluated as a covariate in analyses of urinary metabolites of iAs. Results. Odds ratios (ORs) for diabetes classified by FBG and OGTT were similar. The OR increased about 1% per ppb of As in water (95% CI 1.01-1.02). Diabetes was associated with current iAs exposure, but cumulative arsenic exposure, or with total urinary arsenic concentration or total tri- or pentavalent iAs in urine. However, the OR for urinary dimethyl-AsIII was 1.07 (95% CI 1.01-1.13) per ng As/ml after adjustment for creatinine (1.05 without adjustment). Neither methyl-AsIII nor pentavalent methylated arsenicals in urine were associated with diabetes. Met287Thr polymorphism was associated with FBG •126 mg/dl (OR = 2.36) and OGTT •200 mg/dl (OR = 2.86), although neither association was statistically significant. Conclusions. This study links diabetes with exposure to iAs and is the first to suggest that the dimethyl-MAsIII may be a marker of risk of developing diabetes.

Application of geostatistics with Indicator Kriging for analyzing spatial variability of groundwater arsenic concentrations in Southwest Bangladesh

This article seeks to explore the spatial variability of groundwater arsenic (As) concentrations in Southwestern Bangladesh. Facts about spatial pattern of As are important to understand the complex processes of As concentrations and its spatial predictions in the unsampled areas of the study site. The relevant As data for this study were collected from Southwest Bangladesh and were analyzed with Flow Injection Hydride Generation Atomic Absorption Spectrometry (FI-HG-AAS). A geostatistical analysis with Indicator Kriging (IK) was employed to investigate the regionalized variation of As concentration. The IK prediction map shows a highly uneven spatial pattern of arsenic concentrations. The safe zones are mainly concentrated in the north, central and south part of the study area in a scattered manner, while the contamination zones are found to be concentrated in the west and northeast parts of the study area. The southwest part of the study area is contaminated with a highly irregular pattern. A Generalized Linear Model (GLM) was also used to investigate the relationship between As concentrations and aquifer depths. A negligible negative correlation between aquifer depth and arsenic concentrations was found in the study area. The fitted value with 95 % confidence interval shows a decreasing tendency of arsenic concentrations with the increase of aquifer depth. The adjusted mean smoothed lowess curve with a bandwidth of 0.8 shows an increasing trend of arsenic concentration up to a depth of 75 m, with some erratic fluctuations and regional variations at the depth between 30 m and 60 m. The borehole lithology was considered to analyze and map the pattern of As variability with aquifer depths. The study has performed an investigation of spatial pattern and variation of As concentrations.

The Simultaneous Arsenic, Antimony, and Selenium Determination in Water Samples by Batch Hydride Generation Atomic Absorption Spectrometry

The purpose of this paper is to present a procedure for the simultaneous determination of metalloids: arsenic, antimony, and selenium. Hydride generation was provided in a reaction vessel connected with the atomic absorption spectrometer (AAS) in a fast sequential mode. Two different types of water samples were used while developing the application: seawater and groundwater. The methodology of liquid samples analysis was developed with detection limits of 0.05, 0.03, and 0.06 ng · mL−1 for arsenic, antimony, and selenium, respectively, in 10 mL samples. This methodology was used to determine arsenic, antimony, and selenium in natural water samples.

Levels of total arsenic in edible fish and shellfish obtained from two coastal sectors of the Atacama Desert in the north of Chile: Use of non-migratory marine species as bioindicators of sea environmental pollution

The Camarones (CB) and Vitor (VB) Bays are situated in the middle of Atacama Desert, and their economies are based on activities entirely associated with the extraction of marine produce. The aim of this study was to determine the total arsenic content in three species of fish and seven species of shellfish from these two bays. The quantification of the total arsenic content in these products was performed by Hydride-Generation Atomic Absorption Spectrometry, HG-AAS. The results showed that marine species associated with the CB sector had higher total arsenic levels than the same species in the area of VB, a finding attributed to much higher total arsenic concentrations in the water and soils of CB than VB. The species with the highest total arsenic concentration was the Venus antique (7.50 mg kg −1) from the CB, and the lowest total arsenic content was found in Cheilodactylidae variegatus (0.34 mg kg−1) from VB.

Separation and determination of selenium in water samples by the combination of APDC coprecipitation: X-ray fluorescence spectrometry

A sensitive and non chromatographic analytical procedure for the separation of inorganic selenium species in natural water has been performed. A combination of APDC coprecipitation and determination by an absolute thin layer Energy dispersive X-ray fluorescence spectrometry method was used. The influence of various analytical parameters such as element concentration, oxidation states and pH on the recoveries of Se (IV) was examined. The presence of organic matter and bicarbonate anions, typical components in Cuban groundwater samples, was also tested. Negligible matrix effects were observed. At pH 4 a 100% recovery was found for Se (IV). The coprecipitation recovery of the oxidized selenium species (Se (VI)) was null for the selected concentration range (5–100 μg L−1). When the Se (VI) was reduced by heating the solution with 4 mol L−1 HCl, quantitative recovery was also obtained. The determination of total selenium was conducted by the application of the oxidation–reduction process and the analytical procedure for Se (IV). Se (VI) content was calculated as the difference between total selenium and Se (IV). The detection limit was 0.13 μg L−1. The relative standard deviation was lower than 3.5% for 5 μg L−1 of Se (IV). The trueness of the method was verified by using standardized hydride generation-atomic absorption spectrometry technique. The results obtained using the EDXRF technique were in good agreement with the ones determined by HG-AAS. The proposed method was applied to the determination of Se (IV) in surface water and groundwater samples.

Geochemistry of environmentally sensitive trace elements in Permian coals from the Huainan coalfield, Anhui, China

Abstract To study the geochemical characteristics of 11 environmentally sensitive trace elements in the coals of the Permian Period from the Huainan coalfield, Anhui province, China, borehole samples of 336 coals, two partings, and four roof and floor mudstones were collected from mineable coal seams. Major elements and selected trace elements were determined by inductively coupled plasma optical emission spectrometry (ICP-OES), inductively coupled plasma mass spectrometry (ICP-MS), and hydride generation atomic absorption spectrometry (HAAS). The depositional environment, abundances, distribution, and modes of occurrence of trace elements were investigated. Results show that clay and carbonate minerals are the principal inorganic constituents in the coals. A lower deltaic plain, where fluvial channel systems developed successively, was the likely depositional environment of the Permian coals in the Huainan coalfield. All major elements have wider variation ranges than those of Chinese coals except for Mg and Fe. The contents of Cr, Co, Ni, and Se are higher than their averages for Chinese coals and world coals. Vertical variations of trace elements in different formations are not significant except for B and Ba. Certain roof and partings are distinctly higher in trace elements than underlying coal bench samples. The modes of occurrence of trace elements vary in different coal seams as a result of different coal-forming environments. Vanadium, Cr, and Th are associated with aluminosilicate minerals, Ba with carbonate minerals, and Cu, Zn, As, Se, and Pb mainly with sulfide minerals.

Determination of inorganic arsenic species by hydride generation atomic absorption spectrometry in water samples after preconcentration/separation on nano ZrO 2/B 2O 3 by solid phase extraction

A solid phase preconcentration procedure using hybrid sorbent based on nano zirconium dioxide–boron oxide for the speciation and determination of As(III), As(V) and total As in water samples by hydride generation atomic absorption spectrometry (HGAAS) was presented. Experimental parameters including pH, sample volume, flow rate, volume and concentration of eluent that affect the recovery of the arsenic species have been optimized. Under optimized experimental conditions, analytical parameters including limit of detection, limit of quantification, linear working range, precision and accuracy have also been determined. Interfering effects of matrix constituent on the recovery of the arsenic were studied. The reusability and adsorption capacity of the new hybrid sorbent were also investigated. The hybrid sorbent was successfully applied for preconcentration and speciation of arsenic(V) from various samples with recovery of 99 ± 5%. The analytical limit of detection was found 9.25 ng/L. The hybrid sorbent was stable up to 100 runs. Adsorption capacities of the hybrid sorbent were 98.04 mg/g for As(V). The accuracy of the method was tested by analyzing certified reference material (SPS-WW1 Waste Water) and spiked real samples. The method has been applied for the determination of analytes in tap water, underground water.

Determination of ultra trace arsenic species in water samples by hydride generation atomic absorption spectrometry after cloud point extraction

Cloud point extraction (CPE) methodology has successfully been employed for the preconcentration of ultra-trace arsenic species in aqueous samples prior to hydride generation atomic absorption spectrometry (HGAAS). As(III) has formed an ion-pairing complex with Pyronine B in presence of sodium dodecyl sulfate (SDS) at pH 10.0 and extracted into the non-ionic surfactant, polyethylene glycol tert-octylphenyl ether (Triton X-114). After phase separation, the surfactant-rich phase was diluted with 2 mL of 1 M HCl and 0.5 mL of 3.0% (w/v) Antifoam A. Under the optimized conditions, a preconcentration factor of 60 and a detection limit of 0.008 μg L −1 with a correlation coefficient of 0.9918 was obtained with a calibration curve in the range of 0.03–4.00 μg L −1. The proposed preconcentration procedure was successfully applied to the determination of As(III) ions in certified standard water samples (TMDA-53.3 and NIST 1643e, a low level fortified standard for trace elements) and some real samples including natural drinking water and tap water samples.

Adsorption and Preconcentration Capabilities of Nano-Barium-Strontium Titanate Powder Coated by Dithizone for Trace Bismuth

A new method for the adsorption and preconcentration of bismuth in urine was described. The methodology combines determined using a hydride generation-atomic absorption spectrometry (HG-AAS) with pre-concentration and separation of the bismuth on the nano-barium-strontium titanate powder coated by dithizone (BST-dithizone). The experimental conditions for the pre-concentration and separation of the bismuth, including pH value of the medium, shaking time, eluent condition and co-existing ions have been investigated. The result showed that the bismuth in urine could be adsorbed on the BST-dithizone. The adsorption percentage was affected by the pH value of medium and shaking time. In the medium of pH 6.0, the adsorption capacity of BST-dithizone to bismuth (III) was 13.4 mg·g-1 when the shaking time was 10 min. The bismuth adsorbed on the BST-dithizone could be completely eluated by 2 mol·L-1 HNO3. The enrichment factor was 100. The detection limit of bismuth (III) was 5.1 ng·L−1.The method has been applied to the pre-concentration and separation of bismuth in the human urine and tap water with satisfied results.

Feasibility study for the preparation of a tuna fish candidate reference material for total As determination

This work describes the evaluation of several parameters for the preparation of a tuna fish candidate as a reference material (RM) in order to measure the total As mass fraction by slurry sampling graphite furnace atomic absorption spectrometry (SLS-GF AAS) and slurry sampling hydride generation atomic absorption spectrometry (SLS-HG AAS). The main parameters investigated were the homogeneity, analyte segregation and composition during material production. For candidate RM preparation, tuna fish was collected at a local market, cleaned, freeze-dried and treated using different procedures as follows: (1) ground in a cutting mill and separated in different particle sizes (2) ground in cryogenic mill. The mass fraction of As in the cryogenically ground sample was (4.77 ± 0.19) μg g−1 for SLS-GF AAS and (4.61 ± 0.34) μg g−1 for SLS-HG AAS. The accuracy of the procedures was checked with tuna fish certified reference material (BCR 627) with recoveries of 102 and 94% for SLS-GF AAS and SLS-HG AAS, respectively. The homogeneity factor was calculated for different pretreatment procedures and for particle sizes in the range of 500–150 μg, indicating good homogeneity, except for raw fish. There was no observed analyte segregation and no losses, no contamination and no changes in the microdistribution of material during preparation.

Determination of arsenic leaching from glazed and non-glazed Turkish traditional earthenware

Glazed and non-glazed earthenware is traditionally and widely used in Turkey and most of the Mediterranean and the Middle East countries for cooking and conservation of foodstuff. Acid-leaching tests have been carried out to determine whether the use of glazed and non-glazed earthenware may constitute a human health hazard risk to the consumers. Earthenware was leached with 4% acetic acid and 1% citric acid solutions, and arsenic in the leachates was measured using hydride generation atomic absorption spectrometry. Arsenic concentrations in the leach solution of non-glazed potteries varied from 30.9 to 800 μg L − 1 , while the glazed potteries varied generally from below the limit of detection (0.5 μg L − 1 ) to 30.6 μg L − 1 , but in one poorly glazed series it reached to 110 μg L − 1 . Therefore, the risk of arsenic poisoning by poorly glazed and non-glazed potteries is high enough to be of concern. It appears that this is the first study reporting arsenic release from earthenware into food.

Correlation Between Arsenic Concentration in Fish and Human Scalp Hair of People Living in Arsenic-Contaminated and Noncontaminated Areas of Pakistan

The effects of arsenic (As) toxicity due to frequent consumption of arsenic-contaminated fish was estimated by the analysis of scalp hair of adult males, living near arsenic-contaminated area of Pakistan. For comparison purposes, scalp hair samples were also collected from the inhabitants of Hyderabad city consuming fish species with low levels of As, collected from Indus River. Concentration of As in scalp hair samples was analyzed by using hydride generation atomic absorption spectrometry (HG AAS), after microwave-assisted acid digestion. The accuracy of the As measurement was tested simultaneously analyzing certified reference material. The concentration of As in muscle tissues of fish species were found in the range of 2.11 to 14.1μg/g and 1.92 to 12.2μg/g, collected from arsenic-contaminated and noncontaminated areas, respectively. Exposed subjects had significantly elevated levels of As in scalp hair samples (0.72-4.94μg/g) as compared with referent subjects (0.21-1.484μg/g; p < 0.01). The As levels in scalp hair was positively correlated with As levels in fish.

Determination of Lead in Human Teeth by Hydride Generation Atomic Absorption Spectrometry

Problem statement: The determination of lead in human teeth at concentration levels of μg/ml is proposed using Hydride Generation Atomic Absorption Spectrometry (HG-AAS). To do this, 2% (wv) lanthanum chloride solution was employed as matrix modifying reagent to increase sensitivity and remove matrix interferences. Approach: About 100 μL of sample and 100 μL of 3.0% (m/v) NaBH4 are simultaneously injected into carrier streams. The detection of limit of 0.46 μg L-1 for Pb was achieved and the relative standard deviation of 3.0% for 10 μg L-1 lead was obtained. The recovery percentage of the method had been found to be (92.8-100.5%) for known quantities of lead added to teeth sample which were completely recovered. A comparison of the proposed method with standard addition method showed nearly results in the same samples of teeth and results compared with other studies in the world. Results: The method was shown to be satisfactory for determination of traces of lead in teeth samples with excellent accuracy. Teeth analysis reveals that intact teeth contained the highest amounts of lead which provide an evidence that lead may reduce the prevalence of dantal caries. Statistically significant differences (p<0.001) were observed between persons living in city centre and others who living in outskirt for concentrations of lead. Geographical influences are thought to be the main source of variability. No significant difference was shown for lead contents of teeth samples as a function of sex. Conclusion: Statistically significant difference between age groups are seen in the mean value of lead concentrations in human teeth, the concentration of lead increased with age. The differences may be due to the exposure of lead and others factors such as differences in diet and drinking water.