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Digestion methods for speciation analysis of toxicologically important forms of arsenic in tissue by hydride generation with cryotrapping and atomic absorption spectrometry
Taurková, Petra ; Rychlovský, Petr (advisor) ; Spěváčková, Věra (referee)
This diploma thesis develops methodology of arsenic speciation analysis by selective hydride generation with cryotrapping and atomic absorption spectrometry. Using this technique it is possible to determine toxicologically important forms of arsenic, i.e arsenites, arsenates and their mono-, di-, and trimethylated forms at concentration levels below 0,1 ng.ml-1 . The first part of the thesis is focused on testing tubular membrane gas dryers with nafion membrane for drying gaseous phase containing generated hydrides. The suitability for arsenic speciation analysis was investigated and transport losses of individual arsenic species were found. The second part describes mild digestion procedures suitable for arsenic speciation analysis in tissues. Two procedures were compared, acid digestion in phosphoric acid and more recent alkalic digestion by tetramethylammonium hydroxide. Digestion procedures were tested on certified reference material DOLT - 4 (Dogfish Liver) and chicken liver matrix. Key words: Tubular nafion membrane dryers, Arsenic speciation analysis, Digestion, Phosphoric acid, Tetramethylammonium hydroxide, Chicken liver, CRM DOLT - 4, Hydride generation, Atomic absorption spectrometry
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Speciation Analysis of Selected Mercury Compounds Using HPLC, UV-Photochemical Cold Mercury Vapor Generation and its AAS Detection
Linhart, Ondřej ; Červený, Václav (advisor) ; Spěváčková, Věra (referee)
The mercury occurs in the environment in a variety of forms. Mercury compounds can be found in the soil, atmosphere, water and living organisms. Although some of the mercury substances are very toxic, they are often used in various sectors of industry, agriculture and medicine. Mercury compounds differ in their toxicity, so it is necessary to do speciation analysis. The aim of this diploma thesis was to develop and validate a new analytical method for the determination of mercury compounds in different samples. This method involves the combination of high performance liquid chromatography, UV-photochemical cold vapor mercury generation and atomic absorption spectrometry. Effective separation of mercury(II), methylmercury(I), ethylmercury(I) and phenylmercury(I) ions and subsequent comparable efficient of mercury cold vapor generation from all of forms was achieved using these techniques. The reached detection limits were 8 µg l-1 , 31 µg l-1 , 16 µg l-1 and 38 µg l-1 . At the end of experimental work, the proposed method of RP-HPLC-UV-CVG- QTAAS was used for the determination of mercury compounds in real samples (fish tissue and water samples: Labe, Vltava and tap water) and in certified reference materials (DORM-3 and DOLT-4). Several methods for extraction of mercury species from solid samples...
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Development of Instrumentation and Methodology for Elemental and Speciation Analysis of Arsenic Based on Hydride Generation and on Atomic Fluorescence Spectrometric Detection
Marschner, Karel ; Dědina, Jiří (advisor) ; Kanický, Viktor (referee) ; Spěváčková, Věra (referee)
(EN) The presented dissertation is devoted to hydride generation from arsenic species and its application for speciation analysis based on atomic fluorescence detection. Hydride generation from toxicologically relevant arsenic species was optimized in order to achieve a 100% efficiency. The resulted experimental setup was subsequently used for speciation analysis of arsenic in human urine by high performance liquid chromatography with detection by atomic fluorescence spectrometry. The accuracy of the developed method was verified by comparative analyses of human urine samples collected from five individuals with an independent reference method. The cleavage of As-C bond during the reaction of methylated arsenic species with tetrahydridoborate(1-) (THB) in acidic media was studied in detail. Pronounced demethylation of methylated arsenic species was found during the reaction of THB with HCl, H2SO4, and HClO4 while hydride generation from CH3COOH or TRIS buffer after prereduction with L- cysteine resulted in the exclusive formation of the corresponding hydrides. Firstly, this phenomenon can endanger the accuracy of arsenic speciation which is based on hydride generation of substituted arsanes. Secondly, the more complex arsenic species can be converted to the hydride. That was demonstrated on hydride...
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Novel Approaches to the Application of Electrochemical Volatile Compounds Generation in Spectrometric Methods
Červený, Václav ; Rychlovský, Petr (advisor) ; Spěváčková, Věra (referee) ; Komárek, Josef (referee)
Various possibilities for the use of electrochemical generation of volatile compounds for the determination of trace and ultratrace quantities of elements using atomic absorption spectrometry and optical emission spectrometry, respectively, were studied in this work. The Thesis is divided into four thematic sections. Electrochemical cold mercury vapor generation is common to the first two parts. The third part is devoted to electrochemical generation of the volatile form of cadmium and the last part deals with the use of the electrochemical hydride generator as a derivatization unit for speciation analysis of arsenic compounds. The optimization of each individual determination was carried out including, for example, various designs of the generator of volatile compounds (forms) of the analyte, the changes in the design of the gas-liquid separator, optimization of the concentration and the flow rate of all the solutions and the carrier gas. However, the value of the electric current employed was the most important parameter. In the first section, the in-situ trapping system of the cold mercury vapor generated in the graphite furnace (with the inner surface covered with a gold foil) of the atomic absorption spectrometer was also designed and optimized. The absolute limit of detection, 80 pg, was...
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Hydride generation study for arsenic speciation analysis with AAS and AFS detection
Svoboda, Milan ; Dědina, Jiří (advisor) ; Spěváčková, Věra (referee) ; Komárek, Josef (referee)
The general aim of this work was a development of methodology and instrumentation for speciation analysis based on the combination of the selective generation of substituted hydrides with atomic absorption or atomic fluorescence spectrometry detection. The first topic of this work was the development of methodology and instrumentation for arsenic speciation analysis based on selective generation of substituted arsines with trapping in the cryogenic trap (U-tube packed with chromosorb) with AAS detection (HG- CT-AAS). The conditions of the selective hydride generation approach as well as working procedure of the cryogenic trap were optimized (appropriate approach for hydride generation, set up of heating program of cryogenic trap, new dryer - cartidge with NaOH, elimination of unspecific absorption, decreasing of the detection limits). The second important part of the work lay in applying of the developed method for arsenic speciation analysis in a homogenized mouse liver tissue. The direct slurry sampling to hydride generator was develop. Moreover the information about oxidation state (iAsIII,V , MAsIII,V a DMAsIII,V ) was obtain. The effect of relevant experimental parameters such as tetrahydroborate concentration, TRIS buffer concentration and time of pre-reduction of the samples by L-cysteine...
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Spectrometric determination of selected metals in the samples from old ecological burden area
Zurynková, Pavla ; Kratzer, Jan (advisor) ; Spěváčková, Věra (referee)
This bachelor thesis is focused on heavy metals pollution in the Králíky town and its vicinity, located in the Pardubice region. This region was selected because there had been a Tesla factory producing fluorescent lamps. Moreover, there is also a waste disposal of the fluorescent lamps wasters and other dangerous waste located about two kilometers far from the former factory. Soil samples from the waste disposal area as well as river sediment, samples taken in the Tichá Orlice river and the Králický brook have been analyzed Mercury, cadmium, lead, chromium, nickel, copper and arsenic levels in the samples were measured by inductively coupled plasma - mass spectrometry. The total mercury content has also been measured with single-purpose atomic absorption spectrometer AMA-254. An optimization of leaching conditions of the elements was performed prior the analysis of the samples employing certified reference material. High levels of mercury, cadmium, lead, chromium, nickel and copper have been found in the waste disposal area. Regarding the sediment samples the highest levels of pollution have been detected near outfall of the sewage water from the industrial area in the Králíky town (former Tesla factory and recent metal plating industry). The concentration of heavy metals in other sediment...
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Spectrometric determination of selected metals in the samples from old ecological burden area
Zurynková, Pavla ; Kratzer, Jan (advisor) ; Spěváčková, Věra (referee)
This bachelor thesis is focused on heavy metals pollution in the Králíky town and its vicinity, located in the Pardubice region. This region was selected because there had been a Tesla factory producing fluorescent lamps. Moreover, there is also a waste disposal of the fluorescent lamps wasters and other dangerous waste located about two kilometers far from the former factory. Soil samples from the waste disposal area as well as river sediment, samples taken in the Tichá Orlice river and the Králický brook have been analyzed Mercury, cadmium, lead, chromium, nickel, copper and arsenic levels in the samples were measured by inductively coupled plasma - mass spectrometry. The total mercury content has also been measured with single-purpose atomic absorption spectrometer AMA-254. An optimization of leaching conditions of the elements was performed prior the analysis of the samples employing certified reference material. High levels of mercury, cadmium, lead, chromium, nickel and copper have been found in the waste disposal area. Regarding the sediment samples the highest levels of pollution have been detected near outfall of the sewage water from the industrial area in the Králíky town (former Tesla factory and recent metal plating industry). The concentration of heavy metals in other sediment...
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Chemical generation of volatile mercury species for speciation analysis - method optimization and analytical applications
Migašová, Michaela ; Petry-Podgórska, Inga (advisor) ; Spěváčková, Věra (referee)
Experimental conditions have been optimized for volatile species generation (VSG) of four mercury species and their subsequent atomization with detection by atomic absorption spectrometry (AAS). The species investigated were mercury (+II), methylmercury (+I), ethylmercury (+I) and phenylmercury (+I). Flow injection construction of volatile species generator and externally heated quartz tube atomizer were employed. The optimized parameters were the concentration of hydrochloric acid and sodium borohydride, the length of the reaction coil, carrier gas flow rate, atomization temperature and the amount of oxygen present in the atomizer. Furthermore, the effect of the drying tube on the signal of Hg species as well as the applicability of tin chloride as an alternative reductant instead of sodium borohydride were studied. Calibration curves were measured and the basic analytical figures of merit were determined, under optimum experimental conditions, for all four mercury species investigated. Limits of detection for Hg species ranged from 0.12 to 0.25 ng cm-3 , while sensitivity reached ca 0.10 s ng-1 at atomization temperature of 500 řC. Experiments focused on atomization temperature optimization have revealed that volatile compounds generated from organic Hg species decompose significantly. Speciation...
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Speciation analysis of mercury in liquid and gaseous samples
Žídek, Radek ; Kratzer, Jan (advisor) ; Spěváčková, Věra (referee)
Generation efficiency of four mercury species, namely elemental mercury and hydrides of methyl-, ethyl- and phenylmercury from liquid samples was quantified. The species chemically generated were quantitatively trapped on a gold-coated amalgamator to be subsequently determined by AMA-254 technique. Three types of construction of volatile species generators were compared. Generation effciciency among the species was comparable, fluctuating around 60% in the conventional flow injection generator equipped with a gas liquid separator with forced outlet. Better results were reached for elemental mercury and methylmercury hydride in an automated batch generator system. Generation efficiency was higher than 90% for these two species and between 60 to 80% for ethyl- and phenylmercury hydrides, respectively. Speciation analysis of elemental mercury and sublimate in gaseous samples was optimized. These two species dominate in flue gases produced during coal combustion or waste incineration. Combination of two sorbent tubes packed with alumina and gold-coated alumina enables selective and quantitative retention of both species. Sublimate is trapped on a column packed with alumina while elemental mercury is retained on gold-coated alumina. The capacity of both sorbents was investigated as well as the effect of...
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Speciation analysis of arsenic and mercury using postcolumn generation of their volatile compounds for needs of atomic spectroscopic methods
Linhart, Ondřej ; Červený, Václav (advisor) ; Spěváčková, Věra (referee) ; Šíma, Jan (referee)
The presented dissertation thesis deals with the use of UV-photochemical generation of volatile compounds (UV-PVG) as a derivatization technique for the combination of high-performance liquid chromatography (HPLC) and atomic absorption spectrometry (AAS) detection. Two model elements arsenic and mercury and their compounds were selected for the speciation analysis. The work was divided into several parts that follow. In the first part of the research, the apparatus for the UV-photochemical generation of the volatile mercury compounds and their detection with a new continuum source and high-resolution atomic absorption spectrometer (HR-CS AAS) with an externally heated detection tube was constructed. The analytical method was adapted for use with atomic fluorescence detection with the aim to improve sensitivity of the determination. Furthermore, apparatus for the electrochemical generation of cold mercury vapor with AAS detection was built. The construction of the apparatus was followed by optimization of the reaction conditions (concentration and flow of electrochemical reagents: sulfuric and hydrochloric acid, mobile phase, carrier medium, flow rate of the carrier gas and localization of its introduction), determination of the analytical figures of merit, and comparation of the methods. Both...
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