Novel methods for derivatization of mercury(II) and methylmercury(II) compounds for analysis

cited By 54International audienceTwo novel and convenient methods for obtaining volatile mercury and methylmercury species for analysis that allows non-volatile analyte solutions to be identified by element-specific and species-selective techniques are described. Non-volatile aqueous solutions of mercury(II) and/or methylmercury(II) compounds are converted into volatile forms (including hydrides) using NaBH4 or LiB(C2H5)3H, followed by chromatographic separation. The volatile derivatives separated on a column are detected by atomic absorption spectrometry or mass spectrometry. © 1992, Royal Society of Chemistry

Phosphine generation by mixed- and monoseptic-cultures of anaerobic bacteria.

A microbial basis for bioreductive generation of phosphine is proposed, which could account at least in part for the presence of this toxic gas in natural anaerobic environments and in sewage and landfill gases. Phosphine generation under anaerobic growth conditions was dependent upon both the culture inoculum source (animal faeces) and enrichment culture conditions. Phosphine was detected in headspace gases from mixed cultures under conditions promoting fermentative growth of mixed acid and butyric acid bacteria, either in the presence or absence of methane generation. Monoseptic cultures of certain mixed acid fermenters (Escherichia coli, Salmonella gallinarum, and Salmonella arizonae) and solvent fermenters (Clostridium sporogenes, Clostridium acetobutyricum and Clostridium cochliarium) also generated phosphine. Such fermentative bacteria participate in the multi-stage process of methanogenesis in nature. Generation of phosphine by these bacteria, rather than by methanoarchaea themselves, could explain the apparent correlation between methanogenesis and the formation of phosphine in nature.NER

Evaluation of cot mattress inner foam as a potential site for microbial generation of toxic gases.

Recent reports of biovolatilisation of phosphorus and antimony by anaerobic bacteria and of leaching of phosphorus and antimony fire-retardant additives from PVC cot mattress covers, indicate that the polyurethane inner-foam of cot mattresses could be a site for generation of toxic gases of group 15 elements. A toxic gas hypothesis for sudden infant death syndrome (SIDS) involving polyurethane foam of cot mattresses was proposed and tested experimentally. Levels of antimony, phosphorus, arsenic and bismuth were determined at four sites for 44 SIDS and 50 control (no death) cot mattress foams. There was no evidence to suggest that the levels of these elements in cot mattress foam have a causal relation to SIDS. Leaching of antimony trioxide from PVC mattress covers could account for detectable levels of this element in 52% of the cot math ess samples analysed. Volatile forms of antimony, phosphorus, arsenic and bismuth was not detected in the headspace of mixed or monoseptic cultures of anaerobic bacteria containing polyurethane foam. Past microbial activity had given rise to involatile methylated species of antimony in some of the cot mattress foams tested (61%, n = 24). Abiotic oxidation of biogenic trimethylantimony together with physical adsorption of methylantimony forms to the polyurethane foam matrix could account for the apparent absence of "escaped" volatile antimony species in culture headspaces of incubation vial. There was no evidence to suggest that levels of trimethylantimony or total methylantimony forms in cot mattress foams have a causal relation to SIDS.Scottish Cot Death Trus