Calibration of an In Situ Membrane Inlet Mass Spectrometer for Measurements of Dissolved Gases and Volatile Organics in Seawater

Bell, Ryan J.; Short, R.T.; Amerom, F. H. W. van; Byrne, Robert H.

doi:10.1021/es070905d

Cited by 74 publications

(79 citation statements)

References 37 publications

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“…At high flow rates, CO 2 * calibrations appropriate to circumneutral seawater can be obtained using acidified standards (e.g., Na 2 CO 3 standards acidified inline). This is important for two reasons: 1) production and preservation issues make the use of CO 2 * standards in circumneutral seawater problematic, and 2) baseline values can be easily obtained in acidified samples by stopping the sample pump, allowing for complete degassing of the sample in contact with the membrane (Bell et al 2007).…”

Section: Assessment and Discussionmentioning

confidence: 99%

“…(6) Relation of signal intensities to dissolved gas concentrations MIMS instrument response at a specified mass to charge ratio (m/z) is reported as ion current, I m/z . As a measure of instrumental background, I at m/z = 5 (i.e., I 5 ) is subtracted Bell et al (2007), membrane permeability to water and dissolved gases is affected by hydrostatic pressure. Because water is the primary contributor to baseline signal intensities (Ørsnes et al 1997), analytical accuracy of oxygen and carbon dioxide determinations can be improved by multiplying the calibration baseline values by a water correction factor, CF 17 , calculated for each field measurement in Eq.…”

Section: Mims Carbon System Measurement Theory Pco 2 Equilibriummentioning

confidence: 99%

“…Significant design modifications relative to the Bell et al (2007) instrument include the use of a single pressure vessel with all electrical and fluidic feed-throughs on a single endcap, enabling easier access inside the pressure vessel. The roughing pump is currently mounted on vibrational dampeners, and its exhaust (~90% water vapor) is scrubbed with desiccant.…”

Section: Mims Systemmentioning

confidence: 99%

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In situ determination of total dissolved inorganic carbon by underwater membrane introduction mass spectrometry

Bell

Short

Byrne

2011

Limnology & Ocean Methods

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Procedures have been developed for the determination of total dissolved inorganic carbon (DIC) in acidified seawater using an underwater mass spectrometer. Factors affecting the response of the membrane introduction mass spectrometer (MIMS) system were examined to optimize calibrations and enhance the accuracy of component ocean carbon system measurements. Laboratory studies examined the following influences on MIMS measurements of DIC: bicarbonate and carbonate contributions to the MIMS CO 2 signal intensity, linearity of MIMS response over a wide range of carbon dioxide concentrations, influence of sample salinity on membrane permeability, and capability to use acidified solutions for calibrations of both DIC and CO 2 fugacity. It was observed that (a) bicarbonate and carbonate contributions to carbon dioxide signal intensity were significant at slow flow rates, (b) MIMS response was linearly dependent on DIC within the concentration range of interest, (c) salinity has a discernable influence on membrane permeability that is, in turn, dependent on hydrostatic pressure, and (d) well calibrated MIMS measurements for both DIC and CO 2 fugacity can be obtained using acidified DIC standards. High flow rates are required during CO 2 fugacity measurements in circumneutral seawater to eliminate signal contributions from bicarbonate and carbonate.

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Section: Assessment and Discussionmentioning

confidence: 99%

Section: Mims Carbon System Measurement Theory Pco 2 Equilibriummentioning

confidence: 99%

Section: Mims Systemmentioning

confidence: 99%

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In situ determination of total dissolved inorganic carbon by underwater membrane introduction mass spectrometry

Bell

Short

Byrne

2011

Limnology & Ocean Methods

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“…In situ measurements of the methane flux from the sediment into the water column were performed with an underwater mass spectrometer (Bell et al, 2007(Bell et al, , 2011Gentz and Schlüter, 2012;Schlüter and Gentz, 2008;Short et al, 2001Short et al, , 2006Wenner et al, 2004). Fluxes were calculated on the basis of changes in gas concentrations within the chamber over time.…”

Section: Sampling Strategymentioning

confidence: 99%

Submarine groundwater discharge to the Baltic coastal zone: Impacts on the meiofaunal community

Kotwicki

Grzelak

Czub

et al. 2014

Journal of Marine Systems

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The discharge of groundwater into the sea affects surrounding environments by changing the salinity, temperature and nutrient regimes. This work reports the spatial effects of a submarine groundwater discharge (SGD) on the abundance and structure of the meiofaunal community in the shallow area of Puck Bay (Baltic Sea). Several field expeditions in the years 2009 and 2010 found that low-saline groundwater escapes into the bay from permeable, sandy, near-shore sediments. The SGD literature has grown rapidly during the current decade; however, the effects of this type of disturbance on the shallow sandy bottom fauna have thus far been little studied. We provide evidence that the discharge of groundwater has a clear effect on meiofaunal assemblages in the research area. This effect was reflected in a significant decline of certain meiofaunal taxa, mainly nematodes and harpacticoids, as well as in altered patterns of temporal distribution and small-scale (vertical) zonation of meiofaunal assemblages. Overlooking submarine groundwater discharge processes may lead to serious misinterpretations of ecological data. It is clear that groundwater discharge phenomena should be considered in future scientific studies.

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“…Each 1.3 s a dataset is recorded. A detailed consideration of the Inspectr200-200 is given by Short et al [16,26] and about the gas permeation within the membrane inlet system by Bell et al [23].…”

Section: Underwater Mass Spectrometer: Inspectr200-200mentioning

confidence: 99%

Application of membrane inlet mass spectrometry for online and in situ analysis of methane in aquatic environments

Schlüter

Gentz

2008

J. Am. Soc. Mass Spectrom.

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A method is presented for the online measurement of methane in aquatic environments by application of membrane inlet mass spectrometry (MIMS). For this purpose, the underwater mass spectrometer Inspectr200-200 was applied. A simple and reliable volumetric calibration technique, based on the mixing of two end member concentrations, was used for the analysis of CH 4 by MIMS. To minimize interferences caused by the high water vapor content, permeating through the membrane inlet system into the vacuum section of the mass spectrometer, a cool-trap was designed. With the application of the cool-trap, the detection limit was lowered from 100 to 16 nmol/L CH 4 . This allows for measurements of methane concentrations in surface and bottom waters of coastal areas and lakes. Furthermore, in case of membrane rupture, the cool-trap acts as a security system, avoiding total damage of the mass spectrometer by flushing it with water. The Inspectr200-200 was applied for studies of methane and carbon dioxide concentrations in coastal areas of the Baltic Sea and Lake Constance. The low detection limit and fast response time of the MIMS allowed a detailed investigation of methane concentrations in the vicinity of gas seepages. aAm Soc Mass T he analysis of methane as well as other trace gases like carbon dioxide, nitrous oxide, or dimethyl sulphide in aquatic environments is a major objective of basic and applied research. This includes investigations of the air-sea exchange of these greenhouse gases as well as of the release of methane from gassy sediments, hydrocarbon reservoirs, and pipelines, or through dissociation of gas hydrates. Although the spatial extent of such discharge sites is often rather small, ranging from a few square meters to several square kilometers, they are considered major drivers for the marine methane cycle in the present and past [1][2][3][4].The localization of such discharge sites as well as the detection and quantification of trace gases in lakes or the ocean relies essentially on water sampling (e.g., by Rosette Water Samplers, Hydro-Bios, Kiel, Germany) and subsequent chemical analysis by gas chromatography (GC) or infrared-spectrometry (IR) onboard the research vessel. Application of GC as well as IR requires the phase transfer of gases from the dissolved to the gaseous phase. For this purpose, head-space techniques, vacuum-degassing, or spray chambers are applied [5].Head-space techniques and vacuum-degassing are very suitable for analysis of discrete water samples but or N 2 0 in surface waters sampled along transects by research vessels. Nevertheless, the time required for equilibration and subsequent GC or IR analysis is about several tens of minutes to hours [7]. Hence, highresolution investigations, in time and space, of trace gases at natural gas seepages like pockmarks (morphological depressions at the seafloor) or hydrocarbon leakages during surveys by research vessels are rather difficult and time consuming.Compared with such rather long measuring times, application of membrane inlet mass...

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Calibration of an In Situ Membrane Inlet Mass Spectrometer for Measurements of Dissolved Gases and Volatile Organics in Seawater

Cited by 74 publications

References 37 publications

In situ determination of total dissolved inorganic carbon by underwater membrane introduction mass spectrometry

In situ determination of total dissolved inorganic carbon by underwater membrane introduction mass spectrometry

Submarine groundwater discharge to the Baltic coastal zone: Impacts on the meiofaunal community

Application of membrane inlet mass spectrometry for online and in situ analysis of methane in aquatic environments

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