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  • 1
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Selenonium and arsonium cations ; AAS detection ; Chromatographic optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Optimal mobile phase compositions were determined for the separation of selenonium ions [trimethylselenonium, (2-hydroxyethyl)dimethylselenonium and (2-acetoxyethyl)dimethylselenonium] and, separately, for arsonium ions (tetramethylarsonium, arsenobetaine, and arsenocholine) by HPLC with detection by atomic absorption spectrometry (AAS). Surface response methodologies were used to predict the variations in detector response (peak area), capacity factors, and selectivities as a function of the mobile phase composition. For selenonium analytes, a mixture of triethylammonium and trimethylsulfonium ions in the methanol-1% acetic acid mobile phase provided a compromise between resolving power and chromatographic efficiency. By contrast, optimum chromatography of the arsonium analytes was obtained by replacing onium additives in the mobile phase by picrylsulfonic acid. For both selenonium and arsonium analytes, the dominant interaction with the stationary phase was with residual silanols and improvements to the chromatographic performance of these analytes resulted in appreciable decreases in their limits of detection.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 3 (1989), S. 89-98 
    ISSN: 0268-2605
    Keywords: Lead-210 ; organolead ; synthesis ; migration ; plant tissue ; analysis ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An improved synthetic route to [210Pb]-(CH3)3PbCl is described in which chelated 210Pb2+ is methylated to [210Pb]-(CH3)4Pb with methylmagnesium bromide (CH3MgBr) in the presence of methyl iodide. Controlled oxidation of the product with anhydrous hydrochloric acid and purification of the crude product by reversed-phase high-pressure liquid chromotography (HPLC) resulted in [210Pb]-(CH3)3PbCl in 71% radiochemical yield. Whereas storage of the purified product at -10 °C resulted in complete conversion to Pb2+ during one year, storage in 20% acetic acid at 4 °C resulted in less than 15% decomposition during six months. Periodic complexometric extractions to remove 210Pb radioactive daughters (210Bi, 100% β, Emax = 1.16 MeV; 210Po, 100% α, E = 5.305 MeV) from the storage solution did not alter the rate of decomposition. The rate of translocation of [210Pb]-(CH3)3Pb+ across an isolated tomato cuticle was approximately twice the rate of transfer of inorganic lead(II) and was not influenced by the presence of increasing amounts of disodium ethylenediamine-tetra-acetate.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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