Low-cost field test kits for arsenic detection in water
01 Jan 2014-Journal of Environmental Science and Health Part A-toxic\/hazardous Substances & Environmental Engineering (J Environ Sci Health A Tox Hazard Subst Environ Eng)-Vol. 49, Iss: 1, pp 108-115
TL;DR: Though the kits were meant for qualitative assay, the results with unknown concentrations of real samples, when compared with atomic absorption spectrophotometer (AAS) were in good agreement as revealed by the t-test.
Abstract: Arsenic, a common contaminant of groundwater, affects human health adversely. According to the World Health Organization (WHO), the maximum recommended contamination level of arsenic in drinking water is 10 μg/L. The purpose of this research was to develop user-friendly kits for detection of arsenic to measure at least up to 10 μg/L in drinking water, so that a preventive measure could be taken. Two different kits for detection of total arsenic in water are reported here. First, the arsenic in drinking water was converted to arsine gas by a strong reducing agent. The arsine produced was then detected by paper strips via generation of color due to reaction with either mercuric bromide (KIT-1) or silver nitrate (KIT-2). These were previously immobilized on the detector strip. The first one gave a yellow color and the second one grey. Both of these kits could detect arsenic contamination within a range of 10 μg/L-250 μg/L. The detection time for both the kits was only 7 min. The kits exhibited excellent performance compared to other kits available in the market with respect to detection time, ease of operation, cost and could be easily handled by a layman. The field trials with these kits gave very satisfactory results. A study on interference revealed that these kits could be used in the presence of 24 common ions present in the arsenic contaminated water. Though the kits were meant for qualitative assay, the results with unknown concentrations of real samples, when compared with atomic absorption spectrophotometer (AAS) were in good agreement as revealed by the t-test.
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TL;DR: In this article , the use of DC sputtering, physical vapor deposition as a facile method for creating ultralow loading, Au/C electrodes for use in the detection of As (III) in water was investigated.
Abstract: This study investigates the use of DC sputtering, physical vapor deposition as a facile method for creating ultralow loading, Au/C electrodes for use in the detection of As (III) in water. The sputtered nanofilm electrodes on carbon papers, substantially reduces the amount of Au consumed per electrode, <10 μg cm−2, compared to use of wire, foil, or screen-printed electrodes. Linear stripping voltammetry (LSV) was chosen for analytical simplicity and ease of automation. Electrodes using Au nanoparticles supported on Vulcan XC 72 R carbon were also investigated but were not viable for LSV analysis due to capacitive current charging of the high surface area carbon. The DC sputtered, Au nanofilm electrodes were used to create calibration curves for concentrations of As (III) between 5 and 50 μg l−1 and the standard addition method was used in a surface water sample with 5.5 μg l−1 total As. Peak areas plotted against concentration displayed strong linear correlation with meaningful detection below the USEPA maximum contaminant level (MCL) of 10 μg l−1. To our knowledge, this is the first study which utilizes the facile and mass manufacturable DC sputtering method to produce As (III) sensing electrodes. The results of this study have implications for the development of single use, low-cost nanofilm electrodes for field As (III) electroanalysis.
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TL;DR: In this article, a simplified leucomalachite green method was integrated into a microfluidic detection system for detecting arsenic in water using leu comalachite dye.
Abstract: This work describes a novel system for arsenic detection in water using leucomalachite green dye in a microfluidic platform. A simplified leucomalachite green method was integrated into a microfluidic detection system. In acidic medium arsenic is reacted with potassium iodate to liberate iodine, which in turn oxidises leucomalachite green to malachite green forming a green colour associated with an absorbance band in the visible region (λmax = 617 nm). A 1 : 1 v/v sample to reagent ratio was used for the analysis. Syringe pumps were used to introduce and transport reagents and samples into a PMMA microfluidic detection chip. The optical detection system consisted of a LED light source with a photodiode detector. The modified method can determine arsenic over the linear range of 0.3–2 mg L−1 with a limit of detection of 0.32 mg L−1. The average % RSD and recovery were 21.1% and 93.7%, respectively. The sample run time was optimised to 25 minutes. A range of environmental water samples were analysed using the modified method.
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TL;DR: In this article, a simple and green method for colorimetric determination of As(III) using a digital camera as the colorimeter was presented, which is based on chemical hydride generation of arsine (AsH3) from acidic solution of As (III) by NaBH4 as well as the sequential reaction of Arsine with Fe(III)-1,10-phenanthroline solution that produces red complex of Fe(II)-1.10-paraphrase.
Abstract: This research presents a novel, simple and green method for colorimetric determination of As(III) using a digital camera as the colorimeter. It is based on chemical hydride generation of arsine (AsH3) from acidic solution of As(III) by NaBH4 as well as the sequential reaction of arsine with Fe(III)-1,10-phenanthroline solution that produces red complex of Fe(II)-1,10-phenanthroline. The intensity of color red is related to the concentration of As(III) and acquired by image processing—Image J—software. To achieve the best sensitivity, we investigated the changes of RGB value in terms of red color intensity of the complex. Blue was the best as it showed the highest sensitivity. Under optimized conditions, the calibration curve was linear in the range of 1–25 µg mL−1 for As(III) and detection limit was 0.392 µg mL−1. The relative standard deviation (RSD) for five replicate measurements of 10, 15, 20 µg mL−1 of As(III) were 0.89, 2.43 and 3.08%, respectively. The proposed method was successfully used to determine As(III) in the industrial wastewater using standard addition method. The desirable recovery values (96–109%) indicate applicability of the proposed method for determination of As(III) in a complex matrix, such as industrial samples, in the presence of several unknown interferences without the need for any sample preparation.
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References
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TL;DR: The scale of the problem in terms of population exposed to high As concentrations is greatest in the Bengal Basin with more than 40 million people drinking water containing ‘excessive’ As as mentioned in this paper.
6,741 citations
"Low-cost field test kits for arseni..." refers background in this paper
...[5] As per WHO’s recommendation, the maximum allowable contamination level of arsenic in drinking water is 10 μg/L.[6,7] Consumption of arsenic contaminated water may cause many diseases like bladder, lung and skin cancer,[8] skin...
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TL;DR: The evidence assessed here indicates that arsenic can also cause liver, lung, kidney, and bladder cancer and that the population cancer risks due to arsenic in U.S. water supplies may be comparable to those from environmental tobacco smoke and radon in homes.
Abstract: Ingestion of arsenic, both from water supplies and medicinal preparations, is known to cause skin cancer. The evidence assessed here indicates that arsenic can also cause liver, lung, kidney, and bladder cancer and that the population cancer risks due to arsenic in U.S. water supplies may be comparable to those from environmental tobacco smoke and radon in homes. Large population studies in an area of Taiwan with high arsenic levels in well water (170-800 micrograms/L) were used to establish dose-response relationships between cancer risks and the concentration of inorganic arsenic naturally present in water supplies. It was estimated that at the current EPA standard of 50 micrograms/L, the lifetime risk of dying from cancer of the liver, lung, kidney, or bladder from drinking 1 L/day of water could be as high as 13 per 1000 persons. It has been estimated that more than 350,000 people in the United States may be supplied with water containing more than 50 micrograms/L arsenic, and more than 2.5 million people may be supplied with water with levels above 25 micrograms/L. For average arsenic levels and water consumption patterns in the United States, the risk estimate was around 1/1000. Although further research is needed to validate these findings, measures to reduce arsenic levels in water supplies should be considered.
1,097 citations
"Low-cost field test kits for arseni..." refers background in this paper
...[6,7] Consumption of arsenic contaminated water may cause many diseases like bladder, lung and skin cancer,[8] skin...
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TL;DR: It is concluded from the literature that insufficient data exists regarding these effects to allow accurate quantification of leaching rates, and also highlights the need for standardised leaching protocols.
349 citations
"Low-cost field test kits for arseni..." refers background in this paper
...The presence of arsenic in drinking water is due to either its natural presence in surface and in groundwaters,[2] or as a result of human activities such as industrial applications,[3] leather and wood treatments,[4] use of pesticides....
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TL;DR: In this paper, an optimization of the colorimetric method of Johnson and Pilson (1972) to accurately measure As concentrations in the <0.03 −5.3mol L −1 (<2 −400 gL −1 ) range in groundwater containing 2 −30mol l −1 dissolved phosphate was reported.
267 citations
TL;DR: The strengths and weaknesses of various field assays are discussed with respect to their sensitivity, ability to detect the chemical states of arsenic, performance in various media, potential interferences, and ease of operation.
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