Detection Of Metals In Water Research Articles

Detection of trace metals in water by filament- and plasma-grating-induced breakdown spectroscopy

Filament- and plasma-grating-induced breakdown spectroscopy (F-GIBS) was demonstrated as an efficient technique for sensitive detection of metals in water, where plasma gratings were established through synchronized nonlinear interaction of two noncollinear filaments and an additional filament was generated with another fs laser beam propagating along their bisector. A water jet was constructed vertically to the three co-planar filaments, overcoming side effects from violent plasma explosion and bubble generation. Three distinct regimes of different mechanisms were validated for nonlinear couplings of the third filament with plasma gratings. As the third filament was temporally overlapped with the two noncollinear filaments in the interaction zone, all the three filaments participated in synchronous nonlinear interaction and plasma grating structures were altered by the addition of the third filament. As the third filament was positively or negatively delayed, the as-formed plasma gratings were elongated by the delayed third filament, or plasma gratings were formed in the presence of plasma expansion of the ahead third filament, respectively. Using F-GIBS for trace metal detection in water, significant spectral line enhancements were observed.

A Review of Microfluidic Detection Strategies for Heavy Metals in Water

Heavy metal pollution of water has become a global issue and is especially problematic in some developing countries. Heavy metals are toxic to living organisms, even at very low concentrations. Therefore, effective and reliable heavy metal detection in environmental water is very important. Current laboratory-based methods used for analysis of heavy metals in water require sophisticated instrumentation and highly trained technicians, making them unsuitable for routine heavy metal monitoring in the environment. Consequently, there is a growing demand for autonomous detection systems that could perform in situ or point-of-use measurements. Microfluidic detection systems, which are defined by their small size, have many characteristics that make them suitable for environmental analysis. Some of these advantages include portability, high sample throughput, reduced reagent consumption and waste generation, and reduced production cost. This review focusses on developments in the application of microfluidic detection systems to heavy metal detection in water. Microfluidic detection strategies based on optical techniques, electrochemical techniques, and quartz crystal microbalance are discussed.

Magneto-Optical Measurements of Magnetic Nanoparticles Using Laser for Environmental Applications

The project presents the use of laser and magnetic nanoparticles like iron oxide (Fe3O4) in heavy metal detection in water. In this method, metal Nanomagnets particles result in a magnetic reagent for the rapid removal of heavy metals from solutions or water of magnitude to concentration 0.25wt%. This can be done by measuring the magneto-optical parameters (as a hysteric loop) of the solution as an indication of the change in concentrations of the detected heavy metal. The samples used in this work using the Tigris River water that supported from al-Wathba lab. water projects of the Baghdad water directorate at Baghdad-Iraq. Putting here a study of the effect of graphene and metal oxide such as cobalt and nickel which doped the ferrofluid (iron oxide) /polymer/water (Tigris river water) composite on the magneto-optical properties. The graphene adding had the best result in low threshold magnetic field which was 67mGauss, give the motive to use it in fast sensing and detecting of heavy metal in Tigris river water.

Optical Voltammetry Closed-Cell Bipolar Electrochemistry Based Sensor for Portable Low-Cost Heavy Metal Water Testing

Events such as the ongoing Flint, MI and Newark, NJ water crises highlight the need for reliable large-scale water quality assurance. Currently available options for water testing such as laboratory analysis and commercial test strips fail to adequately provide a description of potential water issues for they are expensive, time consuming and rely on technical expertise, being practically futile for the layman and for identifying and preventing large water crisis. Our group developed a new analytical apparatus and mechanism for the detection of metals in water, which is portable, quick, accurate, cost-efficient and can be readily adapted for different deployment needs. The apparatus employs a two-step protocol of optical anodic stripping voltammetry in a readily parallelizable closed-cell bipolar electrode format and is produced under a quick and cost-effective fabrication protocol. Additionally, the fabrication utilizes readily adoptable techniques such as laser cutting as opposed to costly clean-room fabrication techniques. The tool can also be further adapted to employ other commonplace technologies such as printers and smartphones. Previous work from this lab had effectively utilized electrochemiluminescence as reporting mechanism but has now moved onto more consistent light-emitting diodes with improved linearity over several orders of magnitude, increased re-usability and limits of detection now in the sub-ppb range. This new sensing scheme utilizes a simple power supply to couple an anodic stripping event at one pole of the bipolar electrode with an LED emission which is externally recorded and processed thereby avoiding additional costly, non-portable conventional potentiostatic circuitry. In this format, near 100% faradaic efficiency can be achieved as well as facile parallelization for simultaneous sensing of multiple electroactive species. The apparatus and mechanism show great promise as a new deployable analytical tool which can be further engineered to non-electroactive species such as PFAs and to even-lower cost techniques and user-friendly protocols for unprecedented large-scale water quality assurance. Figure 1

Detection of Lead in River Water Samples Applying Cantilever Nanobiosensor

Contamination of water sources with lead has been a problem because it is a toxic heavy metal. Detection and monitoring are important for both the environment and human health. In this paper, we present an application of cantilever nanobiosensors that can detect contamination traces of lead (Pb) in real river water samples. The urease and alkaline phosphatase enzymes are used in the device as a biological element with high sensitivity in Pb detection. By change in deflection of the cantilever nanobiosensor in contact with the liquid solution (water), the response was the detection of trace amounts of Pb in water. When using ultrapure water (white), the nanobiosensors did not demonstrate voltage response. The detection limit was in femtograms per milliliter (parts per trillion) for phosphatase alkaline and urease nanobiosensors with good recovery results. The matrix effect was minimized with the dilution of river water in the ratio 1:1 with the working solution. The nanobiosensors demonstrated are efficient in the detection of the presence of Pb in real samples. Thus, the developed cantilever nanobiosensors showed suitability for heavy metal detection in water and could be a promising tool in the environmental area.

OMONITERING OF HEAVY METAL POLLUTION BY BIOLUMINESCENT BACTERIAL BIOSENSORS

Objectives: The current study focuses on the isolation of bioluminescent bacteria from the gut of Sea urchin and using its luminescence property as a potential biosensor for detecting chromium toxicity in water. Methodology: Bioluminescent bacteria, JAAKP J2 was isolated from the gut of Pseudoboletia indiana species of Sea urchin collected from Pondicherry university beach. The morphological, biochemical, enzyme profiling and molecular characterization through 16S sequencing were performed to identify the strain. Growth kinetic assays and spectrophotometric analysis under chromium stress condition were performed on bioluminescent strains for luminescence inhibition studies. The bioluminescent bacteria was then immobilized in nutrient agar cubesand used as a biosensor for the detection of hexavalent chromium concentration in water samples. Findings: The morphological, biochemical and molecular characterization revealed that the isolate JAAKP J2 was closely related to Vibrio campbellii. Industrially important enzymes like Protease, Lipase, Agarase, Cellulase, Xylanase and Gelatinase were also screened in this study. The developed biosensor using bioluminescence property of the isolate was able to detect the level of chromium toxicity in water samplesat concentration not more than 9 mg L-1 . Further we have elucidated a possible hypothetical pathway for reduction in luminescence property due to ROS (Reactive oxygen species) caused by hexavalent chromium toxicity in bacteria. Novelty: The study is first of its kind in isolation of bioluminescent strain from sea urchin and using it as a biosensor for heavy metal detection in water. Our study also throws lights on futuristic approach of detecting other heavy metals like lead, zinc, cadmium, mercury in water samples by bacterial luminescence. Keywords: Bioluminescent Bacteria, Biosensor, Chromium Toxicity, Enzyme Profiling, Sea Urchin

On-line/on-site analysis of heavy metals in water and soils by laser induced breakdown spectroscopy

The enrichment method of heavy metal in water with graphite and aluminum electrode was studied, and combined with plasma restraint device for improving the sensitivity of detection and reducing the limit of detection (LOD) of elements. For aluminum electrode enrichment, the LODs of Cd, Pb and Ni can be as low as several ppb. For graphite enrichment, the measurement time can be less than 3min. The results showed that the graphite enrichment and aluminum electrode enrichment method can effectively improve the LIBS detection ability. The graphite enrichment method combined with plasma spatial confinement is more suitable for on-line monitoring of industrial waste water, the aluminum electrode enrichment method can be used for trace heavy metal detection in water. A LIBS method and device for soil heavy metals analysis was also developed, and a mobile LIBS system was tested in outfield. The measurement results deduced from LIBS and ICP-MS had a good consistency. The results provided an important application support for rapid and on-site monitoring of heavy metals in soil.

DNA origami platform development for the detection of metals in water.

Many people are becoming increasingly interested in learning the composition of their drinking water. However, for a variety of reasons, only very limited information is available to the public and even to the suppliers of drinking water. Clearly, ubiquitous water testing would be ideal, and this challenge provides motivation for the analytical chemistry community to develop new approaches to quantitation. This project seeks to address this information gap through the development of thin organic arrays, composed of DNA, which are functionalized with molecular species which can selectively bind metals of interest and enable optical detection and characterization of these reversible binding events. Progress in two areas, DNA platform development and ligand design will be presented.Tiles constructed from DNA have been generated which can present a variety of molecular species with a local periodicity of ~100 nm. Modulation of the strength and directionality of interaction of these tiles has been shown to lead to partial or local ordering of these tiles, an important step toward the construction of large scale arrays.Organic ligand systems for two metals of interest, Al and U, have been designed. These ligand designs include two modules, one module enabling covalent attachment to the DNA based platforms through a DNA linker sequence, while the other module supports a binding and reporting function. The synthesis of these ligand systems is currently in progress.Funding for this project was provided by the NASA West Virginia Space Grant Consortium and NSF Cooperative Agreement No. OIA-1458952.

Comparative analysis of quantitative method on heavy metal detection in water with laser-induced breakdown spectroscopy

The quantitative analysis models of multiple linear regression, neural network regression and support vector machine regression with laser-induced breakdown spectroscopy are established in this paper. Heavy metal Ni in water selected as research object is tested and comparativly analyzed. The average relative standard deviations of multiple linear regression, neural network regression and support vector machine regression are 7.60%, 4.86% and 2.35%, and the maximum standard deviations are 23.35%, 15.20% and 8.29% respectively, the average relative errors are 25.98%, 10.58% and 2.72%, and the maximum relative errors are 116.47%, 47.38% and 9.89% respectively. Methods and reference data are provided for the further study of fast measurement of tracing heavy metals in water by laser induced breakdown spectroscopy technique.

Sensitive detection of metals in water using laser-induced breakdown spectroscopy on wood sample substrates

Water contaminated with toxic heavy metals can be a great risk to humans. Laser-induced breakdown spectroscopy (LIBS) is a promising candidate to monitor heavy metals in aqueous solutions on site, but the sensitivity is still a major problem. To perform sensitive analysis of analyte metals in aqueous solutions with LIBS, a thin wood sample substrate was used as a liquid absorber to transform the liquid sample analysis to a solid sample analysis. We focus on investigating the performance of this technique using different laser wavelengths (266, 532, and 1064 nm) with a low pulse energy (<5 mJ) and a different number of shots (from 10 to 1000). We demonstrate that a limit of detection of 30 ppb can be achieved using low energy pulses with a 1000 shot accumulation. This technique provides a potentially simple approach for a portable micro LIBS system to monitor water samples.