A chemical enhancement method for the spectrophotometric determination of trace amounts of arsenic.
TL;DR: A highly sensitive spectrophotometric method for the determination of 0.03-1.0 microg of arsenic content in plant materials, high purity iron, copper base alloys and inorganic arsenic levels of natural waters is described.
Abstract: A highly sensitive spectrophotometric method for the determination of 0.03-1.0 microg of arsenic is described. After extraction as AsI(3) into benzene, it is selectively stripped into water. Both the arsenic(III) and iodide present in the aqueous phase are made to react with iodate in acidic medium in the presence of chloride to form the anionic chloro complex, ICl(-)(2). The determination is completed after extraction of ICl(-)(2) species as an ion-pair with Rhodamine 6G into benzene and measuring the absorption of the extract at 535 nm. The coefficient of variation is 1.5% for 10 determinations of 0.5 microg of arsenic. The method has been applied to the determination of arsenic content in plant materials, high purity iron, copper base alloys and inorganic arsenic levels of natural waters.
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TL;DR: In this paper, the authors provide a general description of the occurrence of arsenic in the environment, its toxicity, health hazards, and measurement techniques for speciation analysis, viz., spectrometric, chromatographic, electrochemical, etc.
Abstract: The occurrence of arsenic in natural water has received significant attention during recent years. Arsenic exists in the environment in a number of valency states. The valency state of arsenic plays an important role for its behavior and toxicity in the aqueous system. The toxicity and bioavailability of arsenic can only be determined if all its forms can be identified and quantified. Therefore, the aim of this article is to provide a general description of the occurrence of arsenic in the environment, its toxicity, health hazards, and measurement techniques for speciation analysis. Different techniques used for speciation of arsenic, viz., spectrometric, chromatographic, electrochemical, etc. have been discussed.
953 citations
TL;DR: A review of various sources, processes, health effects and treatment technologies available for the removal of As from arsenic contaminated water is presented in this article, where As is a toxin that dissolves in the bloodstream, rendering the victim susceptible to disease of the skin, bones and also cancer of liver, kidney, gall bladder and intestines.
Abstract: Impact of arsenic (As) contaminated groundwater on human health, through drinking and irrigation practices, is of grave-concern worldwide. This paper present the review of various sources, processes, health effects and treatment technologies available for the removal of As from arsenic contaminated water. Groundwater with high As concentration is detrimental to human health and incidents of As contamination in groundwater had been reported from different parts of the globe. More serious known As contamination problem as well as largest population at risk are found in Bangladesh, followed by West Bengal state in India along the Indo-Gangetic plains. Large scale natural As contamination of groundwater is found in two types of environment such as strongly reducing alluvial aquifers (ex. Bangladesh, India, China and Hungary) and inland basins in arid or semi-arid areas (ex. Argentina and Mexico). The provisional guideline of 10 ppb (0.0 l mg/l) has been adopted as the drinking water standard by World Health Organization (WHO). In the aquatic environment, the release, distribution and remobilization of As depend on temperature, redox potential, speciation, and interaction between liquid solution and solid phases. As predicaments in the environment is due to its mobilization under natural geogenic conditions as well as anthropogenic activities. Arsenic mineral is not present in As contaminated alluvial aquifer but As occurs adsorbed on hydrated ferric oxide (HFO) generally coat clastic grains derived from Himalayan mountains. As is released to the groundwater mainly by bio-remediated reductive dissolution of HFO with corresponding oxidation of organic matter. The development of strongly reductive dissolution of mineral oxides (Fe and Mn) at near-neutral pH may lead to desorption and ultimately release of As into the groundwater. As release through geochemical process is more important factor in alluvial aquifers causing As contamination rather than sources of arsenic. As is a toxin that dissolves in the bloodstream, rendering the victim susceptible to disease of the skin, bones, and also cancer of liver, kidney, gall bladder and the intestines. It is necessary to adopt highly successful technology to treat As contaminated water into the acceptable limit for human consumption. Universally accepted solutions are not developed/available even after the lapse of almost forty years since slow As poisoning identification in tens of millions of people especially in Bengal delta. The issue poses scientific, technical, health and societal problems even today.
84 citations
TL;DR: A review of various sources, processes, health effects and treatment technologies available for the removal of As from arsenic contaminated water is presented in this article , where As is released to the groundwater mainly by bio-remediated reductive dissolution of hydrated ferric oxide (HFO) with corresponding oxidation of organic matter.
Abstract: Impact of arsenic (As) contaminated groundwater on human health, through drinking and irrigation practices, is of grave-concern worldwide. This paper present the review of various sources, processes, health effects and treatment technologies available for the removal of As from arsenic contaminated water. Groundwater with high As concentration is detrimental to human health and incidents of As contamination in groundwater had been reported from different parts of the globe. More serious known As contamination problem as well as largest population at risk are found in Bangladesh, followed by West Bengal state in India along the Indo-Gangetic plains. Large scale natural As contamination of groundwater is found in two types of environment such as strongly reducing alluvial aquifers (ex. Bangladesh, India, China and Hungary) and inland basins in arid or semi-arid areas (ex. Argentina and Mexico). The provisional guideline of 10 ppb (0.0 l mg/l) has been adopted as the drinking water standard by World Health Organization (WHO). In the aquatic environment, the release, distribution and remobilization of As depend on temperature, redox potential, speciation, and interaction between liquid solution and solid phases. As predicaments in the environment is due to its mobilization under natural geogenic conditions as well as anthropogenic activities. Arsenic mineral is not present in As contaminated alluvial aquifer but As occurs adsorbed on hydrated ferric oxide (HFO) generally coat clastic grains derived from Himalayan mountains. As is released to the groundwater mainly by bio-remediated reductive dissolution of HFO with corresponding oxidation of organic matter. The development of strongly reductive dissolution of mineral oxides (Fe and Mn) at near-neutral pH may lead to desorption and ultimately release of As into the groundwater. As release through geochemical process is more important factor in alluvial aquifers causing As contamination rather than sources of arsenic. As is a toxin that dissolves in the bloodstream, rendering the victim susceptible to disease of the skin, bones, and also cancer of liver, kidney, gall bladder and the intestines. It is necessary to adopt highly successful technology to treat As contaminated water into the acceptable limit for human consumption. Universally accepted solutions are not developed/available even after the lapse of almost forty years since slow As poisoning identification in tens of millions of people especially in Bengal delta. The issue poses scientific, technical, health and societal problems even today.
82 citations
TL;DR: In this paper, a method for the separation of no-carrier-added arsenic radionuclides from the bulk amount of proton-irradiated GeO2 targets as well as from coproduced radiogallium was developed.
Abstract: A method for the separation of no-carrier-added arsenic radionuclides from the bulk amount of proton-irradiated GeO2 targets as well as from coproduced radiogallium was developed. The radionuclides 69Ge and 67Ga produced during irradiation of GeO2 were used as tracers for Ge and Ga in the experiments. After dissolution of the target the ratio of As(III) to As(V) was determined via thin layer chromatography (TLC). The extraction of radioarsenic by different organic solvents from acid solutions containing alkali iodide was studied and optimized. The influence of the concentration of various acids (HCl, HClO4, HNO3, HBr, H2SO4) as well as of KI was studied using cyclohexane. The optimum separation of radioarsenic was achieved using cyclohexane with 4.75 M HCl and 0.5 M KI and its back-extraction with a 0.1% H2O2 solution. The separation leads to high purity radioarsenic containing no radiogallium and <0.001% [69Ge]Ge. The overall radiochemical yield is 93 ± 3%. The practical application of the optimized procedure in the production of 71As and 72As is demonstrated and batch yields achieved were in the range of 75–84% of the theoretical values.
24 citations
TL;DR: An overview of current analytical methodologies for arsenic speciation in environmental samples can be found in this article, where the use of the alga Chlorella vulgaris is proposed for the separation of arsenic(III) from the other arsenic species.
Abstract: An overview is given of current analytical methodologies for arsenic speciation in environmental samples. Most of these are conventional instrumental methods – mainly chromatographic techniques (HPLC, GC, etc.) coupled with a variety of detectors. However, methods using micro-organisms are increasingly being applied for the removal of metal ions and other metal species from aqueous solutions. The use of the alga Chlorella vulgaris is proposed for the separation of arsenic(III) from the other arsenic species. The arsenic concentration is measured by hydride generation atomic absorption spectrometry.
20 citations
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TL;DR: Details for applying simplex optimization to chemical problems are presented and a design matrix is given for locating the vertices of the initial simplex for up to 10 factors and a form is included for calculating the new points.
Abstract: An experiment design based on the simplex configuration offers an efficient approach to determining which levels of the controlling variables (or factors) give the maximum response from a system. This paper presents details for applying simplex optimization to chemical problems. A design matrix is given for locating the vertices of the initial simplex for up to 10 factors and a form is included for calculating the new points. A graphical technique is described for tlie two-factor case.
113 citations
TL;DR: A method is described for the neutron activation analysis or arsenic and antimony simultaneously in biological materials at submicrogram level, based on the differences in the extraction behaviour of the iodides from sulphuric acid-potassium iodide medium with toluene.
Abstract: A method is described for the neutron activation analysis or arsenic and antimony simultaneously in biological materials at submicrogram level, based on the differences in the extraction behaviour of the iodides from sulphuric acid-potassium iodide medium with toluene Both elements are first extracted from the sulphuric acid solution of the wet-ashed residues and then successively and selectively washed out of the organic phase in quantitative yield Checks on losses during wet ashing, the validity of the extraction steps, and the complete procedure for both elements are reported Results are presented for Bowen's standard kale and the NBS standard, orchard leaves SRM 1571 Errors and interferences are discussed
45 citations
TL;DR: Thiosulphate, a reducing agent for arsenate, was added to water samples, and the absorbance of the solution, A(P), was measured as described above.
Abstract: A simple and rapid method for the determination of trace amounts of phosphate and arsenate in water is proposed. Molybdophosphate-and molybdoarsenate-Malachite Green aggregates, formed by reaction of a reagent consisting of a mixed solution of ammonium molybdate and Malachite Green, were selectively collected on a nitrocellulose membrane filter (pore size 3 µm) and dissolved in methylcellosolve together with the membrane filter. The absorbance (λ= 627 nm), denoted A(P + As), was proportional to the sum of the concentrations of phosphate and arsenate with a molar absorptivity of 2.7 × 105 l mol–1 cm–1. Thiosulphate, a reducing agent for arsenate, was added to water samples, and the absorbance of the solution, A(P), was measured as described above. The absorbance A(P) corresponds to the concentration of phosphate alone. The difference, A(P + As)–A(P), then corresponds to the arsenate concentration. The proposed method makes it possible to determine phosphate and arsenate at levels ranging from 0.3 to 150 p.p.b.
43 citations
TL;DR: In this article, the solvent extraction with toluene of 17 elements as iodides from sulphuric acid-potassium iodide media has been investigated with a view to developing separation methods, particularly for neutron activation analysis.
Abstract: The solvent extraction with toluene of 17 elements as iodides from sulphuric acid-potassium iodide media has been investigated with a view to developing separation methods, particularly for neutron activation analysis. Extraction curves at four or more potassium iodide molarities are presented as a function of acidity for the extractable elements As, Ge, Hg, Sb and Sn. Information is given for the elements Au, Bi, Br, Cd, Cu, Ga, In, Mo, Pb, Se, W and Zn over a range of conditions. The extraction curves are characteristic and enable a number of clean and useful separations to be made.
35 citations
TL;DR: In this article, the liquid-liquid extraction of inorganic arsenite and arsenate and of methylarsonate and dimethylarsinate was investigated by using the corresponding arsenic species labeled with arsenic-74.
Abstract: The liquid-liquid extraction of inorganic arsenite and arsenate and of methylarsonate and dimethylarsinate is investigated by using the corresponding arsenic species labeled with arsenic-74. The extraction systems tested are halides (chloride, bromide and iodide), diethylammonium diethyldithiocarbamate, didodecyltin dichloride, and pyrogallol/tetraphenylarsonium chloride. All the arsenic species were quantitatively extracted in the iodide system; from the log D values obtained in extraction and back-extraction, they are probably extracted as the corresponding tervalent species because of reduction with iodide. Appropriate conditions for selective extraction of As(III), As(V) and methylarsonate are described.
30 citations