Determination of arsenic by cathodic stripping voltammetry with a hanging mercury drop electrode

Holak, Walter

doi:10.1021/ac50063a044

Cited by 115 publications

(53 citation statements)

References 18 publications

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“…Voltammetry scans (1,000 mV/sec; initial holding potential of Ϫ0.1 V between Ϫ0.1 and Ϫ1.8 V [versus that for Ag/AgCl]) were acquired via a glass Auamalgam solid-state working electrode, a platinum wire counter electrode, and a Ag/AgCl reference electrode constructed like that of Brendel and Luther (7). The H 2 S signal assignment and calibrations were conducted by using spring water doped with freshly prepared standards (16). Vertical measurements of O 2 were carried out with a Clark-type microsensor and micromanipulator, using field methods, calibration techniques, and temperature compensation as described previously (32).…”

Section: Methodsmentioning

confidence: 99%

Relative Importance of H ₂ and H ₂ S as Energy Sources for Primary Production in Geothermal Springs

D’Imperio

Lehr

Oduro

et al. 2008

Appl Environ Microbiol

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Geothermal waters contain numerous potential electron donors capable of supporting chemolithotrophybased primary production. Thermodynamic predictions of energy yields for specific electron donor and acceptor pairs in such systems are available, although direct assessments of these predictions are rare. This study assessed the relative importance of dissolved H 2 and H 2 S as energy sources for the support of chemolithotrophic metabolism in an acidic geothermal spring in Yellowstone National Park. H 2 S and H 2 concentration gradients were observed in the outflow channel, and vertical H 2 S and O 2 gradients were evident within the microbial mat. H 2 S levels and microbial consumption rates were approximately three orders of magnitude greater than those of H 2 . Hydrogenobaculum-like organisms dominated the bacterial component of the microbial community, and isolates representing three distinct 16S rRNA gene phylotypes (phylotype ‫؍‬ 100% identity) were isolated and characterized. Within a phylotype, O 2 requirements varied, as did energy source utilization: some isolates could grow only with H 2 S, some only with H 2 , while others could utilize either as an energy source. These metabolic phenotypes were consistent with in situ geochemical conditions measured using aqueous chemical analysis and in-field measurements made by using gas chromatography and microelectrodes. Pure-culture experiments with an isolate that could utilize H 2 S and H 2 and that represented the dominant phylotype (70% of the PCR clones) showed that H 2 S and H 2 were used simultaneously, without evidence of induction or catabolite repression, and at relative rate differences comparable to those measured in ex situ field assays. Under in situ-relevant concentrations, growth of this isolate with H 2 S was better than that with H 2 . The major conclusions drawn from this study are that phylogeny may not necessarily be reliable for predicting physiology and that H 2 S can dominate over H 2 as an energy source in terms of availability, apparent in situ consumption rates, and growth-supporting energy.Thermophiles dominate the deepest and shortest branches of the Bacteria and Archaea domains in the tree of life, suggesting that they are likely ancestors of Earth's contemporary microbial populations (8,35). Consequently, these organisms have attracted considerable attention due to interest in the origin of enzymes and metabolic pathways that are thought to have evolved from such organisms. Chemolithotrophic metabolism is foundational to primary productivity in geothermal environments where temperatures exceed the limit of photosynthesis. The bioenergetics of such systems have been examined from the perspective of theoretical energy yield as a way of discussing the relative importance of the various electron donors and acceptors that could support primary productivity (3)(4)(5)22). Other studies have sought to link the inferred physiology of microbial populations with the predicted energy yields obtainable from the inorganic constituents present (4...

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Section: Methodsmentioning

confidence: 99%

Relative Importance of H ₂ and H ₂ S as Energy Sources for Primary Production in Geothermal Springs

D’Imperio

Lehr

Oduro

et al. 2008

Appl Environ Microbiol

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“…Arsenite (As III ) concentrations were determined by the Voltammetry introduced by Holak (1980). The Voltammetry applied for natural waters has an advantage to reduce interference by dissolved salts.…”

Section: Sampling and Analysismentioning

confidence: 99%

“…Reproducibility of the analytical data was within 5%, and the analytical error estimated to be <10%, based on the analytical results of standard stock solutions independently prepared from the commercially distributed standard solution using a standard calibration line. The lower limit of quantification of As was 1 ppb.Arsenite (As III ) concentrations were determined by the Voltammetry introduced by Holak (1980). The Voltammetry applied for natural waters has an advantage to reduce interference by dissolved salts.…”

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confidence: 99%

Distribution of highly arsenic and fluoride contaminated groundwater from east Punjab, Pakistan, and the controlling role of anthropogenic pollutants in the natural hydrological cycle

et al. 2007

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This paper reports the extended study from a previously-described study on As and F contaminated groundwater from a small village, Kalalanwala, in east Punjab, Pakistan (Farooqi et al., 2007). Of the 147 groundwater samples investigated, 91% exceeded the WHO standard (10 µg/L) for As and 75% exceeded the WHO standard (1.5 mg/L) for F -. The highly contaminated As (max. 2400 µg/L) and F -(max. 22.8 mg/L) groundwaters were found from shallow depths down to 30 m from the surface. The contaminated groundwaters are characterized by high pH (max. 8.8), alkalinity (HCO 3 -up to 1281 mg/L), SO 4 2-(max. 960 mg/L), Na + (max. 1058 mg/L) and maximum electric conductivity >4.6 mS/cm. Fluoride concentrations showed positive correlations with those of Na + and HCO 3 -and negative ones with Ca 2+and Mg 2+ . The alkaline waters were saturated with calcite in spite of the low Ca 2+ concentrations. Fluoride concentration is governed by fluorite solubility. Speciation analysis showed As is mostly in the form of As V . There was a positive correlation between As and pH, while there is no relationship between As vs. Fe and F -. Thus, the fluoride and As contamination occurred in the oxidizing and alkaline conditions of the groundwater. However, F -and As are derived from two or more sources. Suspected contaminant sources in the study area contained considerable amounts of F -and As; fertilizers (DAP, n = 5) contained leachable F -ranging from 53-255 mg/kg, and As 5-10 mg/kg, and coals (n = 8) contained F -ranging from 5-20 mg/kg. Sulfur isotopic ratios indicated that the high SO 4 2-in groundwater (3.2-7.0‰, CDT) is mainly derived from coal combusted atmospheric pollutants, fertilizers and household wastes. Nitrogen isotope data (8-30‰, Air) showed that NO 3 --N is attributed to animal waste distributed in the study area. The major chemical characteristics of the groundwaters are related with anthropogenic activities on the ground surface. The resultant major chemistry, especially highly alkaline and low Ca 2+ and Mg 2+ concentrations, must promote the high concentrations of F -and As in the studied groundwaters.Keywords: environmental pollution, phosphorus, semiarid climate, Indus Basin nitrogen and sulfur isotopes tion (WHO) guideline of As concentration in drinking water was reduced from 50 µg/L to 10 µg/L in 1993 (WHO, 1993). According to the WHO recommendation many developed countries changed the maximum admissible concentrations to 10 µg/L, however the developing countries, where arsenicosis is more widespread, are still using the previous guideline value (50 µg/L) due to the lack of facilities to analyze smaller concentrations precisely (Nickson et al., 2005). High F -groundwater causes fluorosis in several regions of the world; East Africa (Nanyaro et al., 1984), India (Rao et al., 1993), and Inner Mongolia in China (Wang et al., 1999). The drinking water limit (DWL) for F -is 1.5 mg/L (WHO, 1994). Fluoride in drinking water has a narrow optimum concentration range in relation to human health. It prevents dental caries in ...

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“…The HMDE offers the advantage of continuous renewal of the electrode surface, and it is even possible to use it as static mercury drop electrode (SMDE) for which a minimal amount of mercury is used [20][21][22][23][24][25][26][27][28][29][30][31] . CSV is used to determine low concentrations of As, it is necessary to carry out the As (III) deposition in the surface of mercury, the formation of an intermetallic compound, being Cu 29,31 and Se 28 used for this purpose.…”

Section: Introductionmentioning

confidence: 99%

Determination of Arsenic (Iii) by Differential Pulse Polarography in the Waters of Camarones Area, Chile

Gamboa

Cornejo

Acarapi³

et al. 2013

J. Chil. Chem. Soc.

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As (III) was determined by differential pulse polarography (DPP) in 1 mol L -1 HCl as supporting electrolyte. For quantification, the -0.35 V peak (versus Ag/ AgCl) was chosen. The obtained detection and quantification limits were 2.7 (3 SD) and 8.9 (10 SD) μg L -1 respectively. The method was used for the determination of As (III) on surface water samples from Camarones River, located in Camarones area, province of Arica, Chile (this area's water contain high levels of salinity). The results indicate that the proposed methodology is a suitable analytical alternative for As determination in natural waters with high levels of dissolved salts, as the waters of Camarones River. The method is not time consuming, nor tedious no prior treatment of the sample is required. The results show that As (III) concentrations in waters of Camarones River are about 10 times higher than the guide values established by WHO for water intended for human consumption.

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Determination of arsenic by cathodic stripping voltammetry with a hanging mercury drop electrode

Cited by 115 publications

References 18 publications

Relative Importance of H ₂ and H ₂ S as Energy Sources for Primary Production in Geothermal Springs

Relative Importance of H ₂ and H ₂ S as Energy Sources for Primary Production in Geothermal Springs

Distribution of highly arsenic and fluoride contaminated groundwater from east Punjab, Pakistan, and the controlling role of anthropogenic pollutants in the natural hydrological cycle

Determination of Arsenic (Iii) by Differential Pulse Polarography in the Waters of Camarones Area, Chile

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Determination of arsenic by cathodic stripping voltammetry with a hanging mercury drop electrode

Cited by 115 publications

References 18 publications

Relative Importance of H 2 and H 2 S as Energy Sources for Primary Production in Geothermal Springs

Relative Importance of H 2 and H 2 S as Energy Sources for Primary Production in Geothermal Springs

Distribution of highly arsenic and fluoride contaminated groundwater from east Punjab, Pakistan, and the controlling role of anthropogenic pollutants in the natural hydrological cycle

Determination of Arsenic (Iii) by Differential Pulse Polarography in the Waters of Camarones Area, Chile

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Relative Importance of H ₂ and H ₂ S as Energy Sources for Primary Production in Geothermal Springs

Relative Importance of H ₂ and H ₂ S as Energy Sources for Primary Production in Geothermal Springs