Simultaneous analysis of selenate and selenite by single-column ion chromatography

Mehra, H. C.; Frankenberger, W. T.

doi:10.1007/bf02327651

Cited by 30 publications

(7 citation statements)

References 14 publications

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“…An autoclaved solution of Na2SeO4 was added to the mixture so as to achieve concentrations of 10, 100, and 200 mg of Se per liter. Ion chromatographic analysis by the method of Mehra and Frankenberger (19) confirmed that autoclaving and subsequent shelf storage in glass bottles did not affect the stability of Se(VI). The flasks were sealed with gas-tight rubber septa (Aldrich) disinfected with 70% ethanol and were placed on orbital shakers (120 rpm) at room temperature (ca.…”

mentioning

confidence: 77%

Volatilization of Selenium by Alternaria alternata

Thompson-Eagle

Frankenberger

Karlson

1989

Appl Environ Microbiol

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Hills evaporation pond facilities contained between 0.005 and 5 mg of Se per liter. The objective of this study was to isolate Se-methylating organisms in evaporation pond water and to assess, through enrichment and manipulation of their optimal growth parameters, the environmental factors which govern microbial Se methylation. Alternaria alternata was isolated as an active Se-methylating organism. The volatile product was identified as dimethylselenide. The effects of pH, temperature, Se substrates, and methyl donors on the ability of A. alternata to methylate Se were investigated in liquid medium containing 100 mg of Se per liter. The optimum pH and temperature for methylation were 6.5 and 30°C, respectively. Selenate and selenite were methylated more rapidly than selenium sulfide and various organic Se compounds (6-selenoguanosine, 6-selenoinosine, seleno-DL-methionine, and 6-selenopurine). L-Methionine and methyl cobalamine (0.1 ,uM) stimulated dimethylselenide production. This study demonstrates that Se-methylating organisms are present in evaporation pond water and are capable of liberating substantial quantities of Se in the volatile dimethylselenide form. By determining the optimum environmental conditions which stimulate volatilization, it may be possible to design a way to remove Se from seleniferous water in situ. * Corresponding author. first time that A. alternata has been reported to be Se resistant as well as an active methylator of Se. MATERIALS AND METHODS Reagents. Sodium selenite and sodium selenate (Na2SeO4) were obtained from Alfa Products (Danvers, Mass.), and DMSe was from Strem Chemical Co. (Newburyport, Mass.). The following chemicals were obtained from Sigma Chemical Co. (St. Louis, Mo.): selenium sulfide, 6-selenoguanosine, 6-selenoinosine, seleno-DL-methionine, 6-selenopurine, methyl cobalamine, and L-methionine. Sodium tetrahydroborate was obtained from Aldrich Chemical Co. (Milwaukee, Wis.), and ammonium persulfate was from Mallinckrodt (Paris, Ky.). Water sampling. Water samples were collected from evaporation ponds 1, 2, 5, 6, and 7 at Kesterson Reservoir (Merced County, Calif.); from Lost Hills (Kern County, Calif.) A, B, and C evaporation ponds; and from cells 1 to 6 at the Peck Ranch (Fresno County, Calif.) (Fig. 1). The water was collected in Nalgene bottles, transported on blue ice, and stored at 5°C. Atomic absorption spectrometry. Water samples were analyzed for Se atomic absorption spectrometry with hydride generation. The instrument used was a Varian (Mulgrave, Victoria, Australia) Spectra AA/10 with a VGA-76 vapor generation assembly. The operational conditions were as follows: acetylene, 2.4 ml/min; air, 6.3 ml/min; nitrogen, 90 ml/min; sample flow, 6.5 ml/min; acid flow, concentrated

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confidence: 77%

Volatilization of Selenium by Alternaria alternata

Thompson-Eagle

Frankenberger

Karlson

1989

Appl Environ Microbiol

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“…The supernatant was analyzed for concentrations of selenate, selenite and acetate. Selenate ion and selenite ion were analyzed by single-column ion chromatography (HPLC), using a 4 mM p-hydroxybenzoic acid/sodium borate mobile phase [9]. A preconcentration column (Anion/R guard cartridge, Wescan) was used in place of a sample loop.…”

Section: Methodsmentioning

confidence: 99%

Selenate reduction by a Pseudomonas species: a new mode of anaerobic respiration

Macy

Michel

Kirsch

1989

FEMS Microbiology Letters

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The high levels of selenium (selenate, selenite) in agricultural drainage water in the San Joaquin Valley of California, which have led to environmental problems, might be lowered if the selenate/selenite could be reduced to elemental insoluble selenium. Two organisms have been newly isolated which do this in anaerobic coculture. One, a strictly anaerobic, Gram-positive rod, reduces selenite to elemental selenium. The other, a Pseudomonas species, was shown to respire selenate to selenite. Cells grown anaerobically in Minimal Medium on acetate plus selenate oxidized 14C-acetate to 14CO2 with concomitant reduction of selenate to selenite and small amounts of elemental selenium.

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“…Some interference by Cland Fwas reported. Mehra et al [23] developed a novel single-column IC method to determine selenium species in seleniferous soil samples. Results were 1000 times more sensitive than conductivity detection.…”

Section: Seleniummentioning

confidence: 99%