Avancerad sökning

Hittade 3 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Fundamental Studies on Direct Injection Nebulisers for Sample Introduction in ICP Spectrometry : Aerosol Properties, ICP Characteristics and Analytical Performance

   Författare :Daniel Goitom Asfaha; Wolfgang Frech; Ralph Edward Sturgeon; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ICP; ICP-MS; ICP-OES; sample introduction; DIHEN; Vulkan DIN; non-spectral interferences; noise power spectra; analytical precision; plasma diagnostic parameters; particle dynamic analysis PDA ; Analytical chemistry; Analytisk kemi;

   Sammanfattning : The performance of different types of nebulisers: Vulkan direct injection nebuliser (Vulkan DIN), direct injection high efficiency nebuliser (DIHEN), microconcentric nebuliser coupled to cyclonic or double pass spray chamber (MCN-C or MCN-DP, respectively) was investigated and compared when used for sample introduction to ICP-MS or ICP-OES. With ICP-OES, in axial viewing mode, intensity distributions across the radius of the plasma (radial intensity profiles) were determined for different spectral lines with Esum 1. LÄS MER

3. 2. Mercury species transformations in marine and biological systems studied by isotope dilution mass spectrometry and stable isotope tracers

   Författare :Lars Lambertsson; Wolfgang Frech; John Munthe; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Analytical chemistry; Mercury; methylmercury; ethylmercury; Thimerosal; speciation; methylation; demethylation; brackish water sediment; natural waters; GC-ICP-MS; species-specific isotope dilution; isotope enriched tracers; Analytisk kemi; Analytical chemistry; Analytisk kemi; analytisk kemi; Analytical Chemistry;

   Sammanfattning : This thesis focuses on the implementation of species-specific isotope dilution (SSID) methodology and stable isotope tracers to determine mercury species occurrence and transformation processes in-situ and during sample treatment. Isotope enriched tracers of methyl-, ethyl- and inorganic mercury were synthesised and applied in different combinations to marine and biological samples. LÄS MER

4. 3. Speciation analysis of butyl- and phenyltin compounds in environmental samples by GC separation and atomic spectrometric detection

   Författare :Dong Nguyen Van; Wolfgang Frech; Anders Cedergren; Erwin Rosenberg; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Organotin speciation analysis; species-specific isotope dilution; inductively coupled plasma mass spectrometry; single isotope spike; multi-isotope spike; redistribution; species transformation; preparative liquid chromatography; gas chromatography; line source atomic absorption spectrometry; continuum source atomic absorption spectrometry; Analytical chemistry; Analytisk kemi;

   Sammanfattning : The main goal of the work presented in this thesis is to improve the reliability of existing methods for speciation analysis of organotin compounds Species-specific isotope dilution (SSID) calibration in combination with gas chromatography – inductively coupled plasma mass spectrometry was used to investigate the transformation of phenyltin species during sample preparation. Isotope-enriched phenyltin species were synthesized from corresponding isotope-enriched tin metals. LÄS MER