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 Development of a Multi species Method by GC coupling with Inductively Coupled Plasma Isotope Dilution Mass Spectrometry for the Simultaneous Determination of Alkylated Lead Mercury and Tin Compounds written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: An accurate and sensitive species-specific GC-ICP-IDMS (gas chromatography inductively coupled plasma isotope dilution mass spectrometry) method for the determination of trimethyllead and a multi-species-specific GC-ICP-IDMS method for the simultaneous determination of trimethyllead, methylmercury, and butyltins in biological and environmental samples were developed. They allow the determination of corresponding elemental species down to the low ng g-1 range. The developed synthesis scheme for the formation of isotopically labeled Me3206Pb+ can be used for future production of this spike. The novel extraction technique, stir bar sorptive extraction (SBSE), was applied for the first time in connection with species-specific isotope dilution GC-ICP-MS for the determination of trimethyllead, methylmercury and butyltins. The results were compared with liquid-liquid extraction. The developed methods were validated by the analysis of certified reference materials. The liquid-liquid extraction GC-ICP-IDMS method was applied to seafood samples purchased from a supermarket. The methylated lead fraction in these samples, correlated to total lead, varied in a broad range of 0.01-7.6 %. On the contrary, the fraction of methylmercury is much higher, normally in the range of 80-98 %. The highest methylmercury content of up to 12 μg g-1 has been determined in shark samples, an animal which is at the end of the marine food chain, whereas in other seafood samples a MeHg+ content of less than 0.2 μg g-1 was found. Butyltin species could only be determined in samples, where anthropogenic contaminations must be assumed. This explains the observed broad variation of the butylated tin fraction in the range of
Download or read book Mercury Speciation in Biological Marine Materials by Gas Chromatography with Atomic Emission Detection written by Mary Katherine Behlke and published by . This book was released on 1996 with total page 256 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 Gas Chromatography written by Colin Poole and published by Elsevier. This book was released on 2012-06-19 with total page 754 pages. Available in PDF, EPUB and Kindle. Book excerpt: A single source of authoritative information on all aspects of the practice of modern gas chromatography, from theory, to methods, to selected applications. It also provides access to core data for practical work, comparison of results, and decision making and facilitates the search for sources in related areas of study.
Download or read book The Development and Application of Advanced Methods in Gas Chromatography Mass Spectrometry for the Identification and Quantitative Analysis of Small Biogenic Molecules written by B. W. Wilson and published by . This book was released on 1977 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Speciation Studies in Soil Sediment and Environmental Samples written by Sezgin Bakirdere and published by CRC Press. This book was released on 2013-09-26 with total page 614 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent developments clearly indicate that speciation studies in biological and environmental matrices are much more important than the total element determination due to the tremendous difference in bioavailability and toxicity of various chemical forms of a particular element. Different separation-detection techniques and hyphenated systems—each with its own advantages and disadvantages with respect to precision, sensitivity and detection limit—have been developed for the identification and quantification of the species present in systems at ultra-trace levels. This book aims to evaluate the speciation analysis in depth and present a comprehensive review of state-of-the-art analytical approaches used for the speciation of elements in environmental samples.
Download or read book Development of Instrumental and Computational Methods for Accessing Information in Multi dimensional Gas Chromatography with Mass Spectrometry written by Nathanial E. Watson and published by . This book was released on 2017 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three instrumental and computational methods are demonstrated in an endeavor to create novel techniques to extract information from the troves of data generated by multi-dimensional gas chromatography with mass spectrometry. Initially, these methods are considered within the context of targeted and non-targeted experimental design. The tile-based Fisher Ratio with null distribution analysis is first evaluated and validated within the non-targeted realm. The method is shown to be fast and accurate. Forty-six of the fifty-four benchmarked changing metabolites previously discovered were found by the new methodology while consistently excluding all but one of the benchmarked nineteen false positive metabolites previously identified. This was achieved in less than 5% of the time required for the previous method. Later, the three-dimensional gas chromatograph is improved to include mass spectrometric detection. This instrument provides four dimensions (4D) of chemical selectivity and includes significant improvements to total selectivity (mass spectrometric and chromatographic), peak identification, and operational temperature range relative to previous models of the GC3 reported. Useful approaches to visualize the 4D data are presented. The GC3 - TOFMS instrument experimentally achieved total peak capacity, nc,3D, ranging from 5000 to 9600 (x̅= 7000, s = 1700) for 10 representative analytes for 50 min separations with component dimensional peak capacities averaging 406, 3.6, and 4.9 for 1D, 2D, and 3D, respectively. Using this instrument and the well understood Parallel Factor Analysis (PARAFAC) model a new option for targeted analysis is presented. Conceptualizing the GC3 - TOFMS as a one-dimensional gas chromatograph with GC × GC-TOFMS detection the instrument was allowed to create the PARAFAC target window natively. Each first dimension modulation thus created a full GC × GC-TOFMS chromatogram totally amenable to PARAFAC. A simple mixture of 115 compounds and a diesel sample were interrogated through this methodology. All test analyte targets were successfully identified in both mixtures. In addition, mass spectral matching of the PARAFAC loadings to library spectra yielded results greater than 900 in 40 of 42 test analyte cases. Twenty-nine of these cases produced match values greater than 950.
Download or read book Practical Gas Chromatography written by Katja Dettmer-Wilde and published by Springer. This book was released on 2014-11-05 with total page 904 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gas chromatography continues to be one of the most widely used analytical techniques, since its applications today expand into fields such as biomarker research or metabolomics. This new practical textbook enables the reader to make full use of gas chromatography. Essential fundamentals and their implications for the practical work at the instrument are provided, as well as details on the instrumentation such as inlet systems, columns and detectors. Specialized techniques from all aspects of GC are introduced ranging from sample preparation, solvent-free injection techniques, and pyrolysis GC, to separation including fast GC and comprehensive GCxGC and finally detection, such as GC-MS and element-specific detection. Various fields of application such as enantiomer, food, flavor and fragrance analysis, physicochemical measurements, forensic toxicology, and clinical analysis are discussed as well as cutting-edge application in metabolomics is covered.
Download or read book Instrumental Methods in Metal Ion Speciation written by Imran Ali and published by CRC Press. This book was released on 2006-03-14 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: The knowledge of metal ion speciation is essential for predicting the exact toxicities of metal ion species in the environment. Metal ions can exist in various oxidation states, each of which possesses different physical and chemical properties as well as exhibit varying toxicities. Often, toxicity data is unreliable because it is based on metal io
Download or read book The Development and Validation of Gas Chromatography mass Spectrometry Method for the Detection and Quantification of Biomarkers in Crude Oil written by Corey Lynn Knoop and published by . This book was released on 1993 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development and Application of Improvements to the Tile based Fisher Ratio Method and Fundamental Instrument Considerations for Non targeted Analysis Using Two dimensional Gas Chromatography written by Brendon Andrew Parsons and published by . This book was released on 2016 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry GC×GC--TOFMS has arguably made possible the largest increase in gas chromatograph performance since the innovation of the wall-coated open tubular (WCOT) capillary analytical column in 1979. As with the adoption of capillary columns, taking advantage of the performance possible with GC×GC--TOFMS has required the carefully study of fundamental chromatographic parameters and the development of new data analysis strategies and software to leverage the data rich output of the platform for meaningful discovery in complex chemical matrices. This dissertation presents a thorough account the development and validation of the tile-based Fisher ratio software, which aims to provide a robust and efficient method for non-targeted analysis in experiments comprised of classes of GC×GC--TOFMS chromatograms. Additionally, the software is further developed and demonstrated in a unique application to a challenging problem of forensic interest: the chemical characterization of the illicit acid alteration of diesel fuel. Finally, the chromatographic methods used in the development, validation, and demonstration of the software are carefully examined in the context of instrument performance, and compared to alternative instrumental configurations that have the potential to further increase performance.
Download or read book Sample Introduction Systems in ICPMS and ICPOES written by Diane Beauchemin and published by Newnes. This book was released on 2020-03-15 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sample Introduction Systems in ICPMS and ICPOES provides an in-depth analysis of sample introduction strategies, including flow injection analysis and less common techniques, such as arc/spark ablation and direct sample insertion. The book critically evaluates what has been accomplished so far, along with what can be done to extend the capabilities of the technique for analyses of any type of sample, such as aqueous, gaseous or solid. The latest progress made in fields, such as FIA, ETV, LC-ICP-MS and CE-ICP-MS is included and critically discussed. The book addresses problems related to the optimization of the system, peak dispersion and calibration and automatization. - Provides contributions from recognized experts that give credibility to each chapter as a reference source - Presents a single source, providing the big picture for ICPMS and ICPOES - Covers theory, methods, selected applications and discrete sampling techniques - Includes access to core data for practical work, comparison of results and decision-making
Download or read book Elemental Speciation written by Joseph A. Caruso and published by Elsevier Science Limited. This book was released on 2000 with total page 581 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hardbound. This book provides a comprehensive discussion of the major aspects involved in elemental speciation. Sample preparation, separation techniques, instrumentation and quality assurance are all discussed. In addition, individual chapters are devoted to speciation of environmental samples and speciation of biological, clinical, and nutritional samples. Individual chapters are written by leaders in the field, and the book has been organized so that the reader may learn how to collect a sample and prepare it. Ways to separate and detect analytes of interest, and steps to take to ensure the validity of the measurements are also discussed. This book is unique in its comprehensive treatment of this subject.
Download or read book Hyphenated Techniques in Speciation Analysis written by Ryszard Lobinski and published by Royal Society of Chemistry. This book was released on 2007-10-31 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: Speciation analysis is a field of trace element analytical chemistry that deals with detection, identification and determination of individual chemical forms of metals and metalloids. There has been increased awareness of the importance of elemental speciation over the last 20 years and this has lead to growing demand for analytical techniques capable of providing species-specific information. Hyphenated Techniques in Speciation Analysis offers a brief but comprehensive overview of hyphenated techniques and their various applications for the determination of chemical forms of trace elements. It brings a succinct presentation of the concept of speciation analysis, gives an overview of techniques based on coupling of chromatography with element and molecule specific detection and summarises their applications in the fields of environmental and industrial chemistry, biochemistry, nutrition, toxicology and medicine. Fully referenced, Hyphenated Techniques in Speciation Analysis is an invaluable introduction to elemental speciation analysis and also provides a practising analyst with a critical overview of research carried out in the field.
