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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 348 (1994), S. 792-805 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Selenium, like sulphur, exists in the environment in several oxidation states and as a variety of inorganic and organic compounds. Dissolved inorganic selenium can be found in natural waters as selenide Se (−II), as colloidal elemental selenium Se (0), as selenite anions HSeO 3 − and SeO 3 2− i.e. Se (+IV) and as the selenate anion (SeO 4 2− ) i.e. Se (+VI). Organic forms of selenium that may be found in organisms, air or in the aqueous environment, are volatile (methylselenides) or non volatile (trimethylselenonium ion, selenoamino acids and their derivatives). Knowledge of the different chemical forms and their environmental and biomedical distribution is important because of the dependence of bioavailability and toxicity on speciation. This paper reviews the different analytical methods used for the speciation of selenium compounds, with special attention to inorganic selenium and organoselenium species.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 7 (1993), S. 213-218 
    ISSN: 0268-2605
    Keywords: Butyltin ; ion chromatography ; speciation ; electrothermal atomic absorption spectrometry (ETAAS) ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new method for the determination of butyltin species by ion-exchange chromatography linked with graphite-furnace electrothermal atomic absorption spectrometry (ETAAS) is presented. The separation is achieved on a strong cation-exchange column with a 0.18 mol dm-3 solution of diammonium citrate at pH 6.5 with a step change to pH 4.0 in 60:40 methanol/water solvent. ETAAS detection is performed on-line using an oxidizing matrix modifier. Mono-, di- and tri-butyltin may be determined in a single experiment with detection limits of (respectively) 0.5, 1.1 and 0.8 ng (Sn). Applications to actual samples are reported.
    Additional Material: 5 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. 39-47 
    ISSN: 0268-2605
    Keywords: Butyltin ; HPLC-ETAA ; tropolone complexes ; water ; sediment ; environment ; speciation ; determination ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tropolone (Trop) forms in solution stable complexes with monobutyltin (MBT Trop2) and dibutyltin (DBT Trop). This property has been used to develop a separation procedure of butyltin compounds by liquid chromatography on cyanopropyl-bonded silica columns with a solution of tropolone in toluene as eluent.Tin-specific detection by on-line ETAA allowed the development of a simple procedure suitable for the determination of tributyltin and dibutyltin in water and sediment samples.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 7 (1993), S. 593-598 
    ISSN: 0268-2605
    Keywords: Selenoamino acids ; HPLC ETAAS ; speciation ; environment ; determination ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An analytical method was developed to determine selenoamino acids in the presence of other compounds. Separation has been achieved by High Performance Liquid Chromatography (HPLC) using electrothermal atomic absorption (ETAA) spectrometry as a very sensitive and element-specific detector. On-line HPLC ETAAS speciation of selenocystine and selenomethionine has been studied, using a laboratory made interface. Analytical characterization of the method has been realized with standard solutions. Using a 100μl sample loop, the detection limits were calculated as 8 μgl-1 for selenomethionine and 10 μgl-1 for selenocystine with repeatability and reproducibility of 4% and 7% respectively. The method has been applied to the determination of selenoamino acids in an extract of white clover (CRM402) certified for total selenium.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 8 (1994), S. 639-644 
    ISSN: 0268-2605
    Keywords: Interlaboratory study ; harbour sediment ; analytical quality control ; reference material ; tributyltin ; dibutyltin ; monobutyltin ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Following two interlaboratory studies on tributyltin species (TBT) in water and TBT-spiked sediment, the EC Community Bureau of Reference (BCR) (Measurements and Testing Programme) organized in 1992 an interlaboratory study on TBT in a harbour sediment (RM 424) to investigate sources of error possibly occurring in the analysis of a complicated matrix and to attempt to certify this material. The sediment was collected in the Sado Estuary (P), then carefully prepared, and its homogeneity and stability were verified. The low TBT content encountered in this material, and the high level of interferences, created difficulties with the techniques using hydride generation, whereas better agreement was obtained for other derivatization techniques with GC/FPD and GC/MS. This paper presents the results of the interlaboratory study. The reference value for TBT in this material is 20±5 ng g-1 (as TBT cation) and the indicative values for dibutyltin (DBT) and monobutyltin (MBT) are 53±19 ng g-1 (as DBT cation) and 257±54 ng g-1 (as MBT cation), respectively. Owing to the difficulties encountered, the reference material was not certified and is considered as a research material to be used for the evaluation of the performance of analytical techniques for the determination of low TBT levels in a difficult matrix.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0268-2605
    Keywords: Certified Reference Material ; coastal sediment ; analytical quality control ; tributyltin ; dibutyltin ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Determinations of tributyltin (TBT) species, along with the degradation products mono- and dibutyltin (MBT and DBT), are routinely carried out by a number of laboratories to ascertain the level of organotin contamination of the marine enviroment, particularly in water, sediment and biota. In order to improve and control the quality of such analyses the EC Community Bureau of Reference, BCR (Measurements and Testing Programme), has organized two interlaboratory studies on TBT in water and TBT in a spiked sediment which were followed by a certification campaign for butyltins in a coastal sediment (CRM 462). This material was collected in the Arcachon Bay (France), then carefully prepared (controlled oven drying) and its homogeneity and long-term stability were verified. This paper presents the certification work performed. The certified values for TBT and DBT are 70±14 ng g-1 (as TBT cation) and 128±16 ng g-1 (as DBT cation), respectively.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0268-2605
    Keywords: Speciation ; buyltin compounds ; marine biota ; hydride generation ; atomic absorption ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The determination of tributyltin (TBT) in sea food (mussel, oyster, fish) by a hydride generation-cold trapping-quartz furnace atomic absorption spectrometry procedure has been studied with emphasis on quality control. Large amounts of spiked materials have been prepared and stored either frozen, or frozen after freeze-drying. Extraction of TBT by 0.1 M hydrochloric acid in methanolic solution is efficient (88-96%) for wet samples or freeze-dried samples. It is also efficient with freshly spiked materials. Consumption of sodium borohydride by the matrix makes it necessary to use quite large amounts of reagent to obtain optimal sensitivity. Analysis of a fish-tissue Certified Reference Material seems to indicate a partial debutylation of TBT during transport and/or storage of this material.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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