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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 2 (1988), S. 435-440 
    ISSN: 0268-2605
    Keywords: Methylation ; tin ; methyl iodide ; porewater ; methyltin ; salicylic acid ; fulvic acid ; sediments ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The methylation of tin(II) chloride by methyl iodide in porewater and formation of monomethyltin as the only methyltin product are described. A factorial experiment tested the effects of concentrations of tin(II), methyl iodide, and oxygen on monomethyltin yields. The experiments gave 0.18 to 12.8 % yield. Analysis of variance (ANOVA) calculations showed that all three variables were significant at the 95 % level. Comparison of yields in aqueous 23 g kg-1 sodium chloride solutions to those in porewater and to those containing fulvic acid, salicylic acid, and EDTA showed that only fulvic acid significantly reduced yields. Reasons for this observation are discussed and the findings in the model system are related to methylation of tin compounds in sediments.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 11 (1997), S. 761-769 
    ISSN: 0268-2605
    Keywords: methylmercury ; dimethylmercury ; mercury speciation ; estuarine sediment ; sodium borohydride derivatization ; atomic fluorescence spectrometry ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper presents a method capable of quantitatively separating sub-nanogram amounts of monomethylmercury cation (MeHg+) and dimethylmercury from sediments by vacuum distillation at 40 °C and 6 μm Hg pressure followed by hydride derivatization and atomic fluorescence spectrometric detection. Concentrations of MeHg+ in Great Bay Estuarine sediments ranged from 2.2 to 7.3 ng g-1 (dry weight) with a 4.7 ng g-1 average for samples taken over nine weeks of the 1996 summer. The RSD for replicate determinations of a homogenized estuarine sediment is typically less than 6%. The detection limit for the routine determinations on MeHg+ is 0.2 ng g-1 dry weight of sediment. We validated the method by determining MeHg+ concentration in reference sediment S-19, by confirming our method against an established extraction method, and by recovering 85% of 10 ng MeHgCl spiked into estuarine sediments. This paper also includes significant improvements in the hydride derivatization method for mercury compounds relative to previous work with respect to faster analysis time and lower detection limits. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 6 (1992), S. 587-595 
    ISSN: 0268-2605
    Keywords: methylmercury ; methyltin ; kinetics ; abiotic ; methylation ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The usual presence of mercury(II) with monodi-, and tri-methyltin in water, sediments, and plants in estuarine environments suggests possible abiotic formation of methylmercury via methyl transfer from methyltin compounds. Kinetics studies of reactions between mercury(II) and methyltin compounds under pseudo-first-order conditions in seawater show that relative rate of methylmercury formation under the same conditions are: monomethyltin 〈trimethyltin〉 dimethyltin. This order is explainable mainly by the speciation and charge of methyltin compounds in seawater and by the existence of mercury(II) as a tetrachloro anion. A factorial experiment with the variables pH and salinity (seawater diluted with deionized water) showed that pH, but not salinity, is significant at the 95% confidence level; and that reaction rates increase as pH increases. These results suggest the possibility of abiotic methylation of mercury(II) in seawater. Additional experiments in seawater demonstrated an absence of methylation of mercury(II) (14 days) and mercury(0) (35 days) by methyl iodide.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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