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  • Analytical Chemistry and Spectroscopy  (9)
  • Saxitoxins  (1)
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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 16 (1993), S. 85-89 
    ISSN: 0935-6304
    Keywords: Fullerenes ; Liquid chromatography ; Mass Spectrometry ; LC-MS ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fullerene-rich soot generated by resistive heating of graphite has been gently extracted with toluene, in order to remove some C60 and C70 compounds, followed by extraction with boiling 1,2,4-trichlorobenzene at 214°C. After filtration and removal of the solvent, the residue was re-dissolved in dichloromethane and characterized by non-aqueous reversed phase liquid chromatography coupled on-line with atmospheric pressure chemical ionization mass spectrometry. Several novel fullerenes were detected, including C72, C80, C86, and C88 as well as other fullerenes up to C108 and higher. The results indicate that chromatographic separation of large fullerene molecules can be achieved with low boiling point solvents and conventional liquid chromatographic techniques.
    Additional Material: 4 Ill.
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  • 2
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Fullerenes C60 and C70, generated by combustion, have been shown previously to be produced in controlled laminar flames accompanied by other compounds having fullerene-like characteristics. Analysis of these additional compounds by hith-performance liquid chromatography, coupled on-line with mass spectrometry has identified them as isomers of the C60 and C70 fullerenes. The newly observed isomers have characteristic UV spectra and are thermally unstable, undergoing conversion to the more stable fullerenes with a half-life of about 1 h in boiling toluene (111°C). Isomers of C60 and C70 fullerenes previously have been studied theoretically, but not observed experimentally. The flame-generated material also contains C60O and C70O compounds, as well as C76 and higher carbon clusters.
    Additional Material: 5 Ill.
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  • 3
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A reverse-phase liquid chromatography/mass spectrometry (LC/MS) method, incorporating gradient elution, is described for the characterization of residual erythromycin A and its metabolites in salmon tissue. The method uses ionspray, a mild atmospheric pressure ionization technique which provides an abundant protonated molecule well suited for selected ion monitoring experiments. Tandem mass spectrometry (MS/MS) using collision-induced dissociation was used to provide structural information. The LC/MS method was tested for the analysis of salmon tissue spiked with erythromycin A at levels between 0.01 and 1 p.p.m. A simple extraction and clean-up procedure, slightly modified from that described by Takatsuki et al. (J. Assoc. Off. Anal. Chem. 70, 708 (1987)), was used in this work. Using selected ion and selected reaction monitoring techniques, the LC/MS and LC/MS/MS methods provided detection limits of 〈10 and 50 ng g-1, respectively. Confirmatory full-scan LC/MS and LC/MS/MS spectra were obtained at the 0.5 and 1 μg g-1 levels, respectively. Using a combination of these techniques, the presence of residual erythromycin A was confirmed in the tissue of fish administered medicated feed containing the antibiotic. In addition, several metabolites and degradation products of erythromycin A, including anhydroerythromycin and N-demethylerythromycin, were detected and where possible confirmed by comparison with authentic compounds. Although this analytical method has been shown to afford the necessary sensitivity and precision, application of these techniques to high-throughput quantitative analyses will require development of an improved clean-up procedure and preferably also of a suitable surrogate internal standard.
    Additional Material: 9 Ill.
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  • 4
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is presented for the analysis of shellfish tissue for domoic acid, a neurotoxic amino acid responsible for cases of amnesic shellfish poisoning. Tissue extracts are first taken through a two-stage solid-phase extraction clean-up, using reversed-phase and strong cation exchange cartridges. A two-stage derivatization, using N-methyl-bis-trifluoroacetamide followed by either N-methyl-tert-butyldimethylsilyltrifluoroacetamide or N, O-bis-trimethylsilyltrifluoroacetamide, is then used to produce an N-trifluoroacetyl-O-silyl derivative which can be analyzed by mass spectrometry with introduction via direct inlet probe, moving-belt liquid chromatograph/mass spectrometer interface, or capillary column gas chromatography. The N-trifluoroacetyl-O-tert-butyldimethylsilyl derivative, which has good stability towards hydrolysis, provides a spectrum well suited to gas chromatography/mass spectrometry (GC/MS) using selected ion recording. GC/MS data for two related compounds, kainic acid and dihydrokainic acid, are also reported. The latter is used as an internal standard for quantification of domoic acid, although the method reported is intended primarily for confirmation of the toxin and related compounds in shellfish tissue.
    Additional Material: 6 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 3 (1989), S. 145-150 
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Ion-spray mass spectrometry was investigated for the analysis of three marine neurotoxins: domoic acid, saxitoxin and tetrodotoxin. All three compounds gave positive-ion spectra with abundant ions of protonated molecules and no significant fragmentation. Domoic acid gave a negative-ion spectrum with a strong [M-H]-ion. Tandem mass spectrometry provided useful fragment-ion spectra for all compounds. Detection limits for flow injection analyses with selected-ion monitoring were determined to be 30 pg for saxitoxin, 100 pg for domoic acid and 200 pg for tetrodotoxin. Combining liquid chromatography with ion-spray mass spectrometry allowed the determination of domoic acid and some of its isomers in toxic shellfish tissue extracts.
    Additional Material: 6 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 7 (1993), S. 482-487 
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Periodate oxidation of the toxins responsible for paralytic shellfish poisoning (PSP) yields fluorescent products that are useful for trace analysis by reversed-phase liquid chromatography. Some toxins are oxidized to the same product, while others are transformed to a mixture of products; in ail cases, the products are too unstable to be isolated preparatively. A mobile phase containing heptafluorobutyric acid as an ion-pair agent was developed to improve compatibility with liquid chromatography/mass spectrometry (LC/MS) analysis. Several LC/MS techniques were investigated: chemical ionization with the moving belt interface, atmospheric-pressure chemical ionization, thermospray, continuous-flow fast-atom bombardment, and ion-spray. Only LC/ion-spray MS was able to provide spectra of the oxidized products. The products were characterized as purines resulting from: (a) breakage of the C4-C12 bond and aromatization of the remaining rings (loss of 4 hydrogens); (b) partial elimination of a carbamoyl or N-sulfocarbamoyl side-chain (this is promoted by the presence of an N-1-hydroxy group); and (c) partial hydrolysis of an N-suifocarbamoyl side-chain to a carbamoyl group.
    Additional Material: 2 Ill.
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  • 7
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: An Improved liquid chromatographic/mass spectrometric (LC/MS) method utilizing gradient elution and ion-spray ionization is described for the sensitive determination of okadaic acid and dinophysistoxin-1, the principal toxins implicated in cases of diarrhetic shellfish poisoning. The method was used to confirm the presence of both toxins, together with a recently identified isomer of okadaic acid, dinophysistoxin-2, in various samples of cultivated blue mussels (Mytilus edulis) from Canadian and European Waters. The method provided a mass detection limit of 0.4 ng for each toxin, thus allowing detection of 40 ng per g of whole mussel tissue (or approximately 10 ng/g if only the digestive glands were used in the assay). Quantitative results obtained by LC/MS were in good agreement with those obtained by derivatization and high-performance liquid chromatography with fluorescence detection.
    Additional Material: 6 Ill.
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  • 8
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron impact mass spectra of tert-butyldimethylsilyl-, cyclo-tetramethylene-tert-butylsilyl and cyclo-tetramethylene-isopropylsilyl- ether derivatives of ribo- and 2′-deoxyribonucleosides are described in detail. The interpretation of fragmentation pathways of full and mixed derivatives was aided by metastable ion decomposition studies, precise mass and deuterium labelling measurements, and spectra of mixed derivatives containing the ‘passive’ (in these spectra) trimethylsilyl group. The sterically crowded silyl groups have a powerful fragmentation directing effect. Elimination of a bulky radical, R· (tert-butyl or isopropyl), from the molecular ion produces the siliconium ion [M—R]+, which is the precursor for most of the other prominent ions in the spectra. These arise from ‘siliconium ion rearrangements’ resulting from the interaction of the positively charged siliconium ion center with electron dense regions (i.e. oxygens) in the molecule, to form cyclic silyloxonium ions which subsequently decompose. Since the interacting oxygen and silicon must be sterically accessible, the fragment ion types and their abundances are very dependent upon structure. Consequently, [M—R]+ ions formed from 2′, 3′ or 5′-O-silyl groups give rise to different sets of daughter ions which, for the most part, are not found, or have very low abundances, in the mass spectra of underivatized or trimethylsilylated nucleosides. Detailed information on sugar and base moieties and isomeric substitution is readily obtained.
    Additional Material: 2 Tab.
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  • 9
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 16 (1981), S. 129-138 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron impact mass spectra of monosilyl and mixed acyl-silyl derivatives of 2′-deoxynucleosides are described in detail. (Silyl = tert-butyldimethylsilyl, cyclo-tetramethylene-isopropylsilyl, or cyclo-tetramethylene-tert-butylsilyl; acyl = acetyl or trifluoroacetyl.) The interpretation of the fragmentation pathways was aided by metastable ion decomposition studies, precise mass and deuterium labelling measurements. Mass spectrally, the acyl substituents are mostly ‘passive’ and have (with possibly one exception) little fragmentation directing capability. In contrast, the silyl groups have powerful fragmentation directing properties. Elimination of the bulky alkyl radical R· (tert-butyl or isopropyl) from the molecular ion produces the siliconium ion, [M-R]+, which is the precursor for most of the other prominent ions in the spectra. These arise from ‘siliconium ion rearrangements’ resulting from the interaction of the positively charged siliconium ion centre with the electron dense regions (i.e. oxygens) in the molecule, to form cyclic silyloxonium ions which subsequently decompose. Since the interacting oxygen and silicon must be sterically accessible, the fragment ion types and their abundances are very dependent upon structure. Consequently, [M-R]+ ions formed from 3′- or 5′-O-silyl groups give rise to different sets of daughter ions which, for the most part, are not found, or have very low abundances, in the mass spectra of underivatized or trimethylsilylated nucleosides. Detailed information on sugar and base moieties and isomeric substitution is readily obtained.
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  • 10
    Publication Date: 2022-05-26
    Description: Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Desalination 293 (2012): 1-6, doi:10.1016/j.desal.2012.02.014.
    Description: Over the last several decades, countries throughout the world have experienced an escalating and worrisome trend in the incidence of harmful algal blooms (HABs). A concern is that highly potent algal toxins might be retained in the treated water, posing a threat to human health. Seawater contaminated with saxitoxins, domoic acid, okadaic acid, and brevetoxins was desalinated using small (〈100 mL capacity) reverse osmosis and distillation equipment. Analyses of desalinated water samples indicated efficient removal of the four toxins to greater than 99%, except brevetoxins for which some carryover was observed during distillation. Hypochlorite concentrations of 4 ppm or higher were sufficient to react with all of the saxitoxins, domoic acid and okadaic acid in the samples that contained initial toxin concentrations up to 1,250 ng.mL-1 . Brevetoxins appeared to be unaffected in experiments in which the toxins were exposed to up to 30 ppm hypochlorite in seawater at 35 °C for 60 min. These results and their implications in terms of desalination plant design and operation are discussed.
    Description: This work was also supported in part by the Woods Hole Center for Oceans and Human Health (NSF Grants OCE-0430724 and OCE-0911031; NIEHS Grant P50ES012742-01) and Effects of Inhaled Florida Red Tide Brevetoxins (NIH Grant P01 ES010594-09).
    Keywords: HAB Toxins ; Red tide ; Detoxification ; Saxitoxins ; Domoic acid ; Okadaic acid ; Brevetoxins
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
    Format: application/pdf
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