Pulsed discharge helium ionization detector

Wentworth, W. E.; Vasnin, S. V.; Stearns, Stanley D.; Meyer, Cordula

doi:10.1007/bf02268349

Cited by 55 publications

(20 citation statements)

References 23 publications

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“…Limits of detection for the TCD have been reported to be 10 −6 to 10 −8 g, which are in agreement with our values at these injection volumes [13]. In comparison, the total minimum quantity detected by the PDHID in our experiments was 10 −10 to 10 −12 g which is similar to results published by Wentworth et al [14]. The more sensitive PDHID can detect analytes at levels in the low ppmv range under fast separation conditions using a small volume injection loop, which is not possible with the TCD.…”

Section: Pdhid Versus Tcd Selectivity and Sensitivitysupporting

confidence: 95%

Evaluation of the pulsed discharge helium ionization detector for the analysis of hydrogen and methane in breath

Roberge

Finley

Lukaski

et al. 2004

Journal of Chromatography A

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Section: Pdhid Versus Tcd Selectivity and Sensitivitysupporting

confidence: 95%

Evaluation of the pulsed discharge helium ionization detector for the analysis of hydrogen and methane in breath

Roberge

Finley

Lukaski

et al. 2004

Journal of Chromatography A

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“…Headspace samples (1 mL) were routinely collected using a gas-tight syringe to measure H 2 and CO. Concomitantly, headspace gas concentrations in heat-killed negative controls (30 mL) were measured to confirm that observed rates of gas consumption occurred due to a biotic process. Gas concentrations in samples were measured by gas chromatography using a pulsed discharge helium ionization detector [43, 44]. This customized trace gas analyser (model TGA-6791-W-4U-2, Valco Instruments Company Inc.) is designed to analyse a suite of atmospheric gases across six orders of magnitude in concentrations.…”

Section: Methodsmentioning

confidence: 99%

Two Chloroflexi classes independently evolved the ability to persist on atmospheric hydrogen and carbon monoxide

Islam

Cordero

Feng

et al. 2018

Preprint

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23Bacteria within aerated environments often exist within a variety of dormant forms. In 24 these states, bacteria endure adverse environmental conditions such as organic 25 carbon starvation by decreasing metabolic expenditure and using alternative energy 26 sources. In this study, we investigated the energy sources that facilitate the 27 persistence of the environmentally widespread but understudied bacterial phylum 28 Chloroflexi. A transcriptome study revealed that Thermomicrobium roseum (class 29 Chloroflexia) extensively remodels its respiratory chain upon entry into stationary 30 phase due to organic carbon limitation. Whereas primary dehydrogenases associated 31 with heterotrophic respiration were downregulated, putative operons encoding 32 enzymes involved in molecular hydrogen (H2), carbon monoxide (CO), and sulfur 33 compound oxidation were significantly upregulated. Gas chromatography and 34 microsensor experiments were used to show that T. roseum aerobically respires H2 35 and CO at a range of environmentally relevant concentrations to sub-atmospheric 36 levels. Phylogenetic analysis suggests that the enzymes mediating atmospheric H2 37 and CO oxidation, namely group 1h [NiFe]-hydrogenases and type I carbon monoxide 38 dehydrogenases, are widely distributed in Chloroflexi genomes and have been 39 acquired on at least two occasions through separate horizontal gene transfer events. 40Consistently, we confirmed that the sporulating isolate Thermogemmatispora sp. T81 41(class Ktedonobacteria) also oxidises atmospheric H2 and CO during persistence. This 42 study provides the first axenic culture evidence that atmospheric CO supports bacterial 43 persistence and reports the third phylum to be experimentally shown to mediate the 44 biogeochemically and ecologically important process of atmospheric H2 oxidation. This 45 adds to the growing body of evidence that atmospheric trace gases serve as 46 dependable energy sources for the survival of dormant microorganisms. 47 48 49 Bacteria from the phylum Chloroflexi are widespread and abundant in free-living 50 microbial communities [1-4]. One reason for their success is their metabolic diversity; 51 cultured strains from the phylum include heterotrophs, lithotrophs, and phototrophs 52 adapted to both oxic and anoxic environments [5]. Cultured representatives of the 53 phylum are classified into four classes by the genome taxonomy database [6], the 54 primarily aerobic Chloroflexia and Ktedonobacteria and the anaerobic Anaerolineae 55 and Dehalococcoidia [5]. Numerous studies have provided insight into the metabolic 56 strategies anaerobic classes within Chloroflexi use to adapt to oligotrophic niches [7, 57 8]. Surprisingly little, however, is known about how aerobic heterotrophic bacteria 58 within this phylum colonise oxic environments. Global surveys have reported that 59 Chloroflexi comprise 4.3% of soil bacteria [2] and 3.2% of marine bacteria [3]. However, 60 the most dominant lineages within these ecosystems (notably Ellin6524 and SAR202) 61 have proven...

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“…The pulsed discharge helium ionization detector (PDHID) is a sensitive and universal detector used for the detection of permanent gases, volatile inorganics, and all classes of organic compounds (Wentworth et al, 1992(Wentworth et al, , 1994. In general, organic and inorganic volatiles are analyzed using a flame ionization detector (FID) and a thermal conductivity detector (TCD), respectively, although the PDHID can perform the same analyses as TCD and FID with similar or better sensitivity (Hunter et al, 1998;Woo et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Simultaneous and sensitive analysis of inorganic and organic gaseous compounds by pulsed discharge helium ionization detector (PDHID)

2012

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Pulsed discharge helium ionization detector

Cited by 55 publications

References 23 publications

Evaluation of the pulsed discharge helium ionization detector for the analysis of hydrogen and methane in breath

Evaluation of the pulsed discharge helium ionization detector for the analysis of hydrogen and methane in breath

Two Chloroflexi classes independently evolved the ability to persist on atmospheric hydrogen and carbon monoxide

Simultaneous and sensitive analysis of inorganic and organic gaseous compounds by pulsed discharge helium ionization detector (PDHID)

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