Download or read book Development of Analytical Methods for the Speciation of Mercury in Environmental Samples from the Great Bay Estuary New Hampshire written by Matthew A. Morrison and published by . This book was released on 1997 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analytical Techniques for Mercury Speciation in Environmental Samples from Richard B Russell Reservoir written by William D. Nicholas and published by . This book was released on 1983 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Speciation of Mercury in Different Environmental Compartments written by Julien Lusilao Makiese and published by . This book was released on 2008 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of a Technique for Mercury Speciation and Quantification Using Gas Chromatography written by and published by . This book was released on 1997 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: One element of concern to DOE is mercury. Mercury was used extensively at the DOE facilities in Oak Ridge, Tennessee from 1950 to 1963 in the process of making lithium deuteride, a component of nuclear weapons. Although both the inorganic and organometallic forms of mercury are toxic to humans, the organic compounds are often more toxic. Since the toxicity of mercury is a function of its chemical form, an understanding of the interactions between commercially discharged mercury, naturally occurring mercury, and the environment in which they are present is vital. In this report, the authors have been investigating gas chromatography/mass spectrometry (GC/MS) for the analysis of both the organometallic and inorganic forms of mercury in the same environmental sample (e.g., solutions, soils, and sludges). Although gas chromatography is the classical technique for analyzing organic molecules, (e.g., organometallic compounds) little has been done on the analysis of inorganic compounds. In a previous publication, the authors described how a solid phase microextraction (SPME) fiber could be used to sample organomercurials from aqueous samples. An alkylation reaction was then carried out to transform chemically mercury nitrate into dimethylmercury; subsequent GC/MS analysis of this compound permitted quantification of the inorganic constituent. Subsequently, several different alkylation reagents have been synthesized that methylate any inorganic mercury compound to methylmercury iodide. Here, the authors report results on alkylation reaction time and the effect of pH on the population of the product.
Download or read book Mercury Speciation in Biological and Environmental Samples written by Zuzana Gajdosechova and published by . This book was released on 2015 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to evaluate ultra-trace concentrations of MeHg in various matrices, a new HPLC-CV-AFS method was developed. To achieve exceptionally low limits of detection (0.4 ng/L) Hg species are first trapped on the preconcentration column with possibility of on-line preconcentration of up to 200 mL of sample. Then trapped Hg species are eluted and separated on HPLC column and detected by CV-AFS. The robustness of the method was validated with 6 certified reference materials (DOLT-2, DOLT-4, DORM-3, TORT-2, IAEA-140/TM, ERM®-CC580), which showed recovery in the range of 88 – 104%. Moreover, a comparison between MeHg concentrations in the biological tissues carried out by species-specific isotope dilution gas chromatography inductively coupled plasma mass spectrometry and HPLC-CV-AFS showed very good correlation (R2 = 0.97) what is further advocating the reliability of the newly developed method.
Download or read book Speciation of Mercury in Environmental Samples by Chromatography Coupled with Mass Spectrometry written by Brian T. Buckley and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development and Application of an Analytical Technique for the Determination of Methylmercury Compounds in Environmental Samples Based on Isolation by Distillation Followed by Purge and trap Sample Concentration and GC MS Separation and Detection After Aqueous Phase Ethylation with Sodium Tetraethylborate written by William R. Rice and published by . This book was released on 2000 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analytical technique has been developed for the determination of methylmercury compounds in environmental samples. The technique is based on a two-stage procedure. In the first stage, methylmercury compounds are isolated from the sample matrix as methylmercury chloride (MeRgCl) by distillation. The distillation procedure is based on a series of published methods for the determination of methylmercury compounds in sediment and natural waters. In the second stage, MeRgCl is converted to the more volatile methylethylmercury (MeRgEt) by derivatization with an aqueous solution of sodium tetraethylborate. The volatile species is then determined by purge-and-trap sample concentration and gas chromatography/mass spectrometry (GC/MS) separation and detection. Initial work focused on the development of the method with optimization of the experimental parameters and operating conditions associated with the distillation and final measurement steps. The concentration of MeHgCl in standard solutions (concentration range from 0-30 ng/L as Hg), with and without nitric acid preservation, was monitored as a function of storage time to evaluate storage losses. Aqueous solutions of MeHgCl at the ng/L level are very stable for at least three months if stored (1) in the dark at 4 DC, (2) in acid-cleaned polypropylene flasks, (3) and without nitric acid preservation. Rapid loss of MeHgCl was observed for solutions acidified with nitric acid and stored under identical conditions (25% and 40% decrease in signal response after 3 and 96 days, respectively). The analytical technique was applied to the determination of methylmercury compounds in lake-bottom sediment and surface-water samples collected from Cottage Grove Reservoir, located in Lane County, Oregon. The concentration of methylmercury in a surface-water sample was 2.1 ± 0.11 ng/L as Hg(II). Recoveries of approximately 100 percent were observed for surface-water samples spiked with MeHgCl to a level of 4 ng as Hg(II). Concentrations of methylmercury in lake-bottom sediment ranged from 0.143 ± 0.008 to 35 ± 3.1 ng/g sediment as Hg(II) (wet weight). Recoveries of approximately 90 percent were observed for sediment samples spiked with MeHgCl to a level of 15 ng as Hg(II). The reproducibility of the entire analytical technique and the measurement step alone were evaluated through the analysis of replicate sediment samples. The percent relative standard deviation (RSD) of the entire analytical procedure was 2.6 percent, while the percent RSD of the measurement step alone was determined to be 1.5 percent. The absolute detection limit for MeHgCl was determined to be 4 pg as Hg(II) for the analysis of a 40-mL sample volume.
Download or read book Mercury written by Canada. Environmental Contaminants Program Steering Committee and published by [Hull, Quebec] : Environment Canada, Environmental Protection Service. This book was released on 1981-01-01 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Compendium of Analytical Methods Method summaries written by United States. Environmental Protection Agency Office of Monitoring and published by . This book was released on 1973 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sampling and Analysis of Mercury in Crude Oil written by SM. Wilhelm and published by . This book was released on 2005 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sampling and analytical procedures used to determine total mercury content in crude oils were examined. Three analytical methods were compared with respect to accuracy, precision, and detection limit. The combustion method (U.S. EPA 7473 hybrid) and a commercial extraction method (non-standard) were found adequate to provide a good combination of sensitivity and accuracy, while instrumental neutron activation analysis was found to suffer from interferences from elements other than mercury (Ni, Se) that are typically found in crude oil. Aliquot removal and processing steps were found to be important to accuracy and precision of the combustion method. Potential errors caused by incomplete homogenization and loss of volatile mercury were investigated in detail. Homogenization of oils that contain suspended mercury compounds was found important to allow retrieval of representative aliquots for analysis. Ultrasonication at slightly elevated temperature yielded the more reproducible and higher magnitude results. It was discovered that volatile mercury can be lost from sample containers when they are opened to remove aliquots. Alternative sample containers and aliquot removal techniques were developed that minimized loss of volatile mercury. Speciation experiments were utilized to determine the identity of volatile species and the rates at which they are lost from containers. Both elemental mercury and dimethylmercury were identified as volatile mercury components of one freshly sampled crude oil.
Download or read book Development Research and Validation of Environmental Speciation Methods written by G. M. Mizanur Rahman and published by . This book was released on 2004 with total page 211 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Field deployable Nano sensing Approach for Real time Detection of Free Mercury Speciation and Quantification in Surface Stream Waters and Groundwater Samples at the U S Department of Energy Contaminated Sites written by and published by . This book was released on 2014 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: The detrimental effects on human health caused by long-term exposure to trace contamination of toxic metals have been documented in numerous epidemiological and toxicological studies. The fact that metals are non-biodegradable and accumulate in the food chain poses a severe threat to the environment and human health. Their monitoring in drinking water, aquatic ecosystems, food and biological fluids samples is then essential for global sustainability. While research efforts employing established methodology continue to advance conceptual/computational models of contaminant behavior, the increasing awareness and public concern with environmental and occupational exposure to toxic metals calls for sensing devices capable to handle on-site elemental analysis in short analysis time. Field analysis with potable methodology prevents unnecessary scrutiny of un-contaminated samples via laboratory-bound methods, reduces analysis cost and expedites turnaround time for decision making and remediation purposes. Of particular toxicological interest are mercury and its species. Mercury is recognized as a major environmental pollution issue. The field-portable sensor developed in this project provides a unique and valuable tool for the on-site, real-time determination of inorganic mercury in surface waters. The ability to perform on-site analysis of mercury should prove useful in remote locations with difficult accessibility. It should facilitate data collection from statistically meaningful population sizes for a better understanding of the dose-effect role and the water-soil-plant-animal-human transfer mechanisms. The acquired knowledge should benefit the development of efficient environmental remediation processes, which is extremely relevant for a globally sustainable environment.
Download or read book Development of Enhanced Analytical Methods for Ultratrace Determination of Mercury in Natural Water written by Jessica Huber and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Method Development for Speciation Analysis of Mercury and Selenium in Marine Sediments and Fish Tissues written by Rajani Jagtap and published by . This book was released on 2014 with total page 411 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: "This research project comprises two parts, describing the development of methods for the extraction and measurement of mercury (Hg) species in marine sediments and fish tissues and selenium (Se) species in marine fish tissues. Two optimised methods for the speciation analysis of Hg and Se were developed."
Download or read book Speciation of Mercury in Environmental Samples from Gold Mining Communities in Southwestern Ghana written by Delali Tulasi and published by . This book was released on 2021 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bench and Pilot scale Evaluation of Mercury Speciation Measurement Methods written by and published by . This book was released on 1996 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 1990 Clean Air Act Amendments require the US Environmental Protection Agency (EPA) to assess the health risks associated with mercury. Since the rate of mercury deposition and the type of control strategies used may depend on the type of mercury species emitted, a proven sampling method that can reliably and accurately speciate mercury at the very low concentrations found in coal combustion flue gas is necessary. A number of mercury speciation methods have been proposed, including wet-chemistry methods, such as EPA Method 29, the Ontario Hydro method, and the tris-buffer method, as well as dry methods such as the Mercury Speciation Absorption method (MESA). In addition, a number of companies are developing continuous emissions monitors to speciate mercury by difference. Bench- and pilot-scale tests, sponsored by the Electric Power Research Institute (EPRI) and the US Department of Energy (DOE), are currently under way at the Energy and Environmental Research Center (EERC) to determine the most accurate and precise mercury speciation method available. The overall objective of the test program is to determine whether EPA Method 29 or other sampling methods can reliably quantify and speciate mercury in flue gas from coal-fired boilers at both the inlet and outlet of a particulate control device such as a pulse-jet baghouse. A specific goal of the project is to determine the precision and bias of the various mercury speciation methods as a function of process variables.
Download or read book Development of a Speciation Method for Mercury in Stationary Source Emissions written by Pamela Meads and published by . This book was released on 1995 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
