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  • 1
    Electronic Resource
    Electronic Resource
    Speciation of lead and methyllead ions in water by chromatography/atomic absorption spectrometry after ethylation with sodium tetraethylborate (1986)
    s.l. : American Chemical Society
    Analytical chemistry 58 (1986), S. 35-38 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac00292a011
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  • 2
    Electronic Resource
    Electronic Resource
    Compound interest (1988)
    [s.l.] : Nature Publishing Group
    Nature 335 (1988), S. 464-464 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Applied Organometallic Chemistry. General editor P. J. Craig. Longman. 6/yr. UK £132, US$264, elsewhere £139. ORGANOMETALLIC compounds were a subject of interest as long ago as 1760 (liqueur fumante de Cadet). These days they are widely included in polymer systems as coupling ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/335464a0
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  • 3
    Electronic Resource
    Electronic Resource
    Long term stability of organic selenium species in aqueous solutions (1998)
    Springer
    Fresenius' journal of analytical chemistry 360 (1998), S. 512-519 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Long term stability of organic selenium compounds (selenocystine, selenomethionine, trimethylselenonium ion) has been studied over a one year period for 2 analyte concentrations: 25 and 150 μg/L Se, at pH 4.5 in the dark, under different storage conditions: temperature of –20°C, 4°C, 20°C, 40°C; in Pyrex, Teflon, or polyethylene containers; in an aqueous matrix or in the presence of a chromatographic counter ion (pentyl sulfonate at 10–4 mol/L concentration). Light effects have also been tested. The stability of the selenium species was monitored by HPLC-ICP/MS. Storage conditions can drastically alter the stability of organic selenium species. Organoselenium compounds were shown to be stable in the dark over a one year period in an aqueous matrix at pH 4.5 in Pyrex containers at both 4°C and 20°C. Pyrex vials exposed to natural sunlight at room temperature resulted in a steady decrease of the selenoamino acid concentration. Teflon containers caused losses of less than 25% at both 4° C and 20° C in the dark. However, polyethylene vials presented, at all temperatures tested, a rapid decrease of the TMSe+ concentration. The stability of the Se species studied did not show significant differences between 4° C and 20° C in any container material used. Storage of solutions at 40° C led to slight differences between the Pyrex and Teflon containers. However, polyethylene presented a drastic decrease of the three species over time at this higher temperature. Solutions frozen at –20° C in polyethylene vials did not stabilize the TMSe+ signal. Finally, concentrations and matrices of the samples did not significantly affect the stability of the species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050751
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  • 4
    Electronic Resource
    Electronic Resource
    Organotin stability during storage of marine waters and sediments (1991)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 339 (1991), S. 6-14 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The stability of organotin compounds in water and sediment samples during storage and pre-treatment is of paramount importance. This study presents experiments with butyltin compounds showing that the storage of filtered natural seawater in the dark at pH 2 in pyrex glass bottles is suitable to preserve the stability of tributyltin (TBT) over 4 months both at 20–25°C and 4°C. The other butyltin compounds (mono- and dibutyltin) are stable at 4°C but display some losses at 25°C. A poor recovery of butyltins in turbid water hampered the assessment of the stability on a quantitative basis: however, it could be demonstrated on a qualitative basis that the butyltin stability is uneasily achieved in water samples with high suspended matter. Finally, wet storage and freezing are found to be suitable to preserve the tributyltin stability in sediments, as well as ovendrying (at 50°C), freeze-drying and air-drying. Mono- and dibutyltin are generally subject to changes during the storage of sediments using the different methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00324751
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  • 5
    Electronic Resource
    Electronic Resource
    Aqueous ethylation of organotin compounds in simple solution for speciation analysis by cryofocussing and detection by atomic absorption spectrometry — comparison with hydride generation (1995)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 351 (1995), S. 230-236 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A 23 factorial experimental design has been used to determine the optimum reaction conditions for organotin ethylation in simple aqueous solutions for speciation by Cryogenic Trapping/ Gas Chromatography/Atomic Absorption Spectrometry (CT/GC/AAS). The factors chosen and their levels of variation (− and +) were the pH of the solution (levels 3 and 5), the amount of NaBEt4 added (levels 1 and 9 mg) to the organotins and the time of ethylation reaction (levels 10 and 20 min). Optimum conditions were investigated for monomethyltin (MMT), diethyltin (DET) and dibutyltin (DBT) in mixed solution at a concentration of 10 ng of each Sn compound in 50 ml of solution (200 ng·l−1). The influence of the different factors on the yield of the ethylation reaction in the ranges investigated depends on the degree of substitution and the nature of the alkyl groups of the organotins. The ethylation reaction for DET and DBT is more efficient at high pH levels, MMT gives higher yields at lower pH. Both MMT and DET require a high amount of reagent, while reagent concentration has no real influence on the DBT signal. Comparison of hydride generation and ethylation as derivatisation procedures for organotin speciation has been performed in simple solutions. Under these analytical conditions, hydride generation is shown to be slightly more sensitive than ethylation by a factor of 1.4 for MMT and DET and 2 for DBT. However derivatisation using ethylation provides more reproducible results and is not affected by inorganic interferents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00321643
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  • 6
    Electronic Resource
    Electronic Resource
    Variability of butyltin determination in water and sediment samples from european coastal environments (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 4 (1990), S. 353-367 
    Details
    ISSN: 0268-2605
    Keywords: Butyltin compounds ; variability ; waters ; sediments ; collection ; treatment ; storage ; monitoring strategy ; contamination ; assessment ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A large amount of data has appeared in the literature within the last few years dealing with the monitoring of butyltin compounds in coastal environments. However, the strategies used strongly differed from one author to another, which led to difficulties in the comparison of contamination levels and the evaluation of long-term trends. In this paper, different causes of pitfalls due to uncontrolled sources of variability are addressed; they involve precautions to be undertaken for the monitoring of butylins in water and sediment, particularly: sample collection; sample pretreatment (filtration/centrifugation, acidification, sieving); sample storage (different methods for storage and drying procedures); variability over the same site; variations over a tidal cycle; and variability due to diffusion (e.g. due to flushing).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aoc.590040408
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  • 7
    Electronic Resource
    Electronic Resource
    Towards non-polluting organotin reagents for synthesis (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 9 (1995), S. 591-595 
    Details
    ISSN: 0268-2605
    Keywords: polymer ; organotin ; hydride ; reduction ; pollution ; ICP-MS ; GC/FPD ; supported reagent ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New polymer-supported organotin reagents have been prepared. The reducing ability of a polystyrene-supported organotin hydride was evaluated by reaction with haloalkanes. The level of organotin pollution was monitored in comparison with that generated by Bu3SnH, using ICP-MS analysis.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aoc.590090714
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  • 8
    Electronic Resource
    Electronic Resource
    Determination of the deprotonation constants of seleno-DL-cystine and seleno-DL-methionine and implication to their separation by HPLC (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 11 (1997), S. 21-30 
    Details
    ISSN: 0268-2605
    Keywords: seleno-DL-cystine ; seleno-DL-methionine ; pKa ; HPLC ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We have determined the deprotonation constants (pKa) of seleno-DL-cystine and seleno-DL-methionine together with those of DL-cystine and DL-methionine for comparison, by potentiometric measurements. In the case of seleno-DL-cystine, the difference between the pKa values for the two amino groups was found to be only slightly lower than that observed for DL-cystine itself. In contrast, the difference between the two pKa values for the carboxylic groups was found to be much smaller for seleno-DL-cystine than for DL-cystine. In both seleno-amino-acids, the zwitterionic species appear to be dominant in the pH range between 4 and 7, while positively charged protonated species are found to be present at pH values lower than 4. Based on a knowledge of the ionic species distributions as a function of pH, we have proposed an interpretation for the chromatographic separation of selenocystine and selenomethionine by HPLC. © 1997 by John Wiley & Sons, Ltd.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Leaching of organotin compounds from poly(vinyl chloride) (PVC) material (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 5 (1991), S. 125-129 
    Details
    ISSN: 0268-2605
    Keywords: Inorganic tin ; monobutyltin ; dibutyltin ; PVC material ; leaching ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The release of mono-and di-butyltin species (MBT and DBT) in water after leaching of five different poly(vinyl chloride) (PVC) materials was investigated under mild conditions over a period of one month in batch reactor systems. Results showed that inorganic tin, MBT and DBT compound were released from the material tested under experimental static leaching conditions. The total amount of inorganic tin and organotin compounds observed upon leaching varied considerably from one PVC material to another.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aoc.590050210
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  • 10
    Electronic Resource
    Electronic Resource
    Occurrence of methylated tin and dimethyl mercury compounds in a mangrove core from Sepetiba Bay, Brazil (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 6 (1992), S. 221-228 
    Details
    ISSN: 0268-2605
    Keywords: Mangrove ; methylation ; organotins ; dimethylmercury ; anoxic conditions ; methyltins ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Analyses of organotin and organic mercury compounds have been performed in a sediment core from Sepetiba Bay, Brazil, in order to investigate possible methylation pathways in a mangrove environment. The results have revealed that the physico-chemical conditions existing in this type of environment (high organic inputs, anaerobic conditions, microbial activity, etc.) account for high methyltin concentrations (mono-, di- and trimethyltin) in the sediments, which are dependent upon the total load of metal released (e.g. from anthropogenic sources). Furthermore, the presence of dimethylmercury and not monomethylmercury in the samples demonstrated a new pathway of transformation of mercury in the environment: this compound, thought to be unstable in sediment, is assumed to be stabilized by a conjunction of factors, such as high sulphide levels, anoxic conditions and constant inputs of methane into the medium.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aoc.590060217
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