摘要:

AbstractA possible biological intermediate in the reduction and methylation of selenium oxyanions, dimethyl selenone, was synthesized, and the first experiments involving the amendment of selenium resistant bacterial cultures with this compound are reported. The amount of volatile, reduced selenium‐containing species released from these cultures into the headspace is significantly more than that produced in analogous experiments involving sodium selenate amended cultures. Dimethyl selenone is reduced in the presence of dimethyl sulfide and dimethyl disulfide in a complex growth medium, trypticase soy broth with 0.1% nitrate. This reduction occurs whether or not the reduced sulfur compounds are biologically produce

ISSN:0268-2605    

DOI:10.1002/aoc.590080602

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractIn order to obtain a continuous source of mitotic metaphases, gill tissue ofAphaius fasciatus(Pisces, Cyprinodontiformes) has been successfully employed. Results gathered after exposure of fish to R2SnClpenG, R3SnClpenGNa, to the parents R2SnCl2, R3SnCl and to penGNa (penGNa = penicillinGNa; R = methyl, butyl and phenyl) suggest that both the parent organotin (IV) chloride and organotin (IV) chloropenG derivatives are toxic while penGNa exerts no significant toxic activity. Essentially, all of the chromosome abnormalities are classifiable as irregularly staining of chromosomes, breakages, side‐arm bridges or pseudochiasmat

ISSN:0268-2605    

DOI:10.1002/aoc.590080603

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractFive trimethylarsonioribosides were prepared from naturally occurring and synthetic dimethylarsinylribosides (arsenosugars) by reducing them with 2,3‐dimercaptopropanol and quaternizing the resultant arsine with methyl iodide. The trimethylarsonioribosides prepared in this manner were the four novel compounds methyl 5‐deoxy‐5‐trimethylarsonio‐β‐D‐riboside (as the iodide), (2′R)‐2′, 3′‐dihydroxypropyl 5‐deoxy‐5‐trimethylarsonio‐β‐D‐riboside (as the formate), 3′‐[(2″, 3″ ‐dihydroxypropyl)hydroxyphosphinyloxy] ‐ 2′ ‐hydroxypropyl 5‐deoxy‐5‐trimethylarsonio‐β‐D‐riboside and 3‐(5′‐deoxy‐5′‐trimethylarsonio‐β‐D‐ribosyloxy)‐(2S)‐2‐hydro xypropanesulfonate, and the known (2′S)‐2′‐hydroxy‐3′‐(sulfooxy)propyl 5‐deoxy‐5‐trimethylarsonio‐β‐D‐riboside. They were synthesized to serve as standards for chromatographic analyses of arsenic compounds in marine samples and for investigations into the biotransformation of arsenic in marine organisms. NMR spectral and chromatographi

ISSN:0268-2605    

DOI:10.1002/aoc.590080604

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractTandem MS techniques have been used to examine the formation of cluster ions derived from organotin compounds of environmental significance. The cluster formation was based on the addition of either water or methanol molecules (common HPLC solvents) to a cationic species derived from the organotin compound. For the compounds and conditions studied, cluster adducts were only observed from trisubstituted tin cations. The results show that, in high‐pressure ionization methods used in the interface between HPLC and MS, the tin atom may be associated with a range of ions depending on the system parameters, and that care should be taken if selection ion monitoring (SIM) is to be use

ISSN:0268-2605    

DOI:10.1002/aoc.590080605

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractAn intercomparison exercise was organized between seven laboratories using various isolation procedures (extraction, distillation, ion‐exchange and alkaline digestion) and detection systems (CV AAS, cold vapour atomic absorption spectroscopy; CV AFS, cold vapour atomic fluorescence spectroscopy; GC, ECD, gas chromatography electron capture detector and HPLC with CV AFS detection) for determination of methylmercury compounds in sediment sample. All certification criteria were fulfilled and therefore the value for total concentration of methylmercury compounds was certified to be 5.46 ng g−1, with a 95% confidence interval from 4.07–5.84 ng g−1. The acceptable range, calculated as two times the confidence interval of the mean is therefore from 4.68–6.23 ng g−1. This is the first sediment reference material ever to be certified for concentration of methylmercury compounds. Comparison of the data obtained by various methodologies has shown that the most critical step is the isolation of methylmercury compounds from binding sites. Acid leaching only cannot release methylmercury compounds quantitatively. Total release of methylmercury compounds could only be achieved by alkaline digestion or distillation. This simple intercomparison exercise has shown that since large numbers of laboratories world‐wide are performing methylmercury compound analyses using various improved and specific separation methods and sensitive detection systems, certification of methylmercury compounds in different biological and environmental samples should not be a problem

ISSN:0268-2605    

DOI:10.1002/aoc.590080606

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractBiogeochemical pathways of tin species in the environment are still controversial, e.g. with regard to methylation and transmethylation phenomena, owing to the fact that the identification of methylated tin‐compounds is often difficult. The previous tentative identification of a mixed methylbutyltin compound in sediment and biological samples by GC/AAS after hydride generation gave an illustration of this problem. This compound was previously identified in sediments by other authors and also suspected to occur in a contaminated sediment sample from the Boyardville Marina, France. The retention time obtained by GC/AAS corresponded to the actual retention time of a mixed methylbutyltin calibrant. However, additional checks demonstrated that the compound detected was actually monophenyltin. This evidence was produced by a thorough analysis of a selected sediment sample by alternative techniques such as GC/AAS and GC/AES after pentylation, GC/FPD and GC/MS. The results presented highlight the need for a full identification of compounds to avoid mis‐interpretat

ISSN:0268-2605    

DOI:10.1002/aoc.590080607

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe tricarbonyl complex prepared from 1‐trifluoromethyldihydronaphthalene and Cr(CO)3(NH3)3undergoes Diels–Alder cycloaddition under high‐pressure conditions (15 kbar) to give after decomplexation by natural light and deprotection, the tetrahydrophenanthrone product in 65% yield. This new methodology allows the activation of unreactive styrenes in Diels–Alder cycloa

ISSN:0268-2605    

DOI:10.1002/aoc.590080608

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

ISSN:0268-2605    

DOI:10.1002/aoc.590080601

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY