Application of a pulse-discharge helium detector to the determination of neon in air and water

Lasa, J.; Mochalski, Paweł; Łokas, Edyta; Kędzior, L

doi:10.1016/s0021-9673(02)00844-0

Cited by 8 publications

(4 citation statements)

References 12 publications

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“…The detection limit of SF 6 in water, defined as the chromatograph response two times larger than noise, was equal to 0Ð02 fmol l 1 . Within the present work, improved chromatographic techniques for Ar (Lasa et al, 2000b) and a newly developed technique for Ne analysis in water (Lasa et al, 2002a(Lasa et al, , 2004 were used to determine both the noble gas temperatures and the air excess. Samples were taken in triplicate to 0Ð7-l glass bottles for Ne and Ar C N 2 determinations.…”

Section: Methodsmentioning

confidence: 99%

Groundwater dating with3H and SF6 in relation to mixing patterns, transport modelling and hydrochemistry

et al. 2005

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Abstract:A comprehensive study of a sandy aquifer of deltaic origin in southern Poland included water chemistry, isotopes, dissolved trace gases and transport modelling. Tritium, sulphur hexafluoride (SF 6 ) and freons (F-11, F-12 and F-113) showed the presence of modern waters in the recharge areas and shallow confined parts of the aquifer. The presence of older Holocene waters farther from the recharge areas was indicated by lack of 3 H, SF 6 contents Ä0Ð02 fmol l 1 and relatively low 14 C values. The discharge from the system is by upward seepage in the valley of a major river. Pre-Holocene waters of a cooler climate, identified on the basis of υ 18 O, υ 2 H, 14 C, Ne and Ar data, were found in some distant wells. Concentrations of N 2 , Ne and Ar determined by gas chromatography were used for calculating the noble gas temperatures, air excess needed for correction of SF 6 , and nitrogen content released by denitrification process. The time series of 3 H content available for some wells supplied quantitative information on age distributions and the total mean ages of flow through the unsaturated and saturated zones. The derived 3 H age distributions turned out to be very wide, with mean values in the range of about 30 to 160 years. For each well with determined 3 H age, the SF 6 data showed either a lower age range or the possibility of a lower age as expected due to shorter travel times of SF 6 through the unsaturated zone, which most probably also resulted in different types of age distributions of these tracers. Freons appeared to be of little use for individual age determinations. A quantitative estimation of two-component mixing from SF 6 -3 H relations is not possible unless the travel time of 3 H through the unsaturated zone is comparable to that of SF 6 . The ratio of integrals of the response function over the age range with tracer and the whole response function yields the ratio of water with tracer to total flow of water. That ratio is a tracer-dependent function of time. Transport modelling of SF 6 tracer done with MT3D code yielded initially large discrepancies between calculated and measured tracer concentrations. Some discrepancies remained even after calibration of the transport model with SF 6 . Simulation of tritium contents with a calibrated transport model yielded reasonable agreement with measured contents in some wells and indicated a need for further investigations, particularly in the eastern part of the aquifer. The existence of distinct hydrochemical zones is consistent with the tracer data; young waters with measurable 3 H and SF 6 contents are aerobic and of HCO 3 -Ca or HCO 3 -SO 4 -Ca types. Slightly elevated Na and Cl contents, as well as the highest concentrations of SO 4 and NO 3 within this zone are due to anthropogenic influences. Anaerobic conditions prevail in the far field, under the confining cover, where pre-bomb era Holocene waters dominate. In that zone, dissolved oxygen, NO 3 and U contents are reduced, and Fe, Mn and NH 4 contents increase. In the third zone, earl...

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Section: Methodsmentioning

confidence: 99%

Groundwater dating with3H and SF6 in relation to mixing patterns, transport modelling and hydrochemistry

et al. 2005

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“…However, the groundwater samples in this study are near oxygen saturation for air-water equilibrium (Table 1) and, therefore, unaffected by denitrification. Zuber et al (2005) employed Ne using a newly developed gas chromatographic technique (Lasa et al, 2002a) in conjunction with Ar (Lasa et al, 2002b) to estimate recharge temperature and excess air. Plummer et al (2003) used combined measurements of N 2 , Ar, and Ne to estimate recharge temperature, excess air, and amounts of denitrification in some agricultural waters undergoing denitrification.…”

Section: Estimation Of Recharge Temperature and Excess Airmentioning

confidence: 99%

Evidence for terrigenic SF6 in groundwater from basaltic aquifers, Jeju Island, Korea: Implications for groundwater dating

Koh

Plummer

Busenberg

et al. 2007

Journal of Hydrology

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“…Wentworth et al also showed the detector was linear for these compounds over a broad range of concentrations. GC-HePPD has since been used in a number of applications, including measurements of organic and inorganic gases in air , , neon in air and water ,and for process control in ultra high purity gases . Here we evaluate GC-HePPD for high quality measurements of atmospheric H 2 .…”

Section: Methodsmentioning

confidence: 99%

Application of Gas Chromatography with a Pulsed Discharge Helium Ionization Detector for Measurements of Molecular Hydrogen in the Atmosphere

Novelli

Crotwell

Hall

2009

Environ. Sci. Technol.

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The Earth's troposphere contains approximately 160 Tg H2 with an average surface mixing ratio approximately 530 nmole mole(-1) (ppb) and lifetime of 2 years. Atmospheric H2 is typically measured using gas chromatography (GC) followed by hot mercuric oxide reduction detection (GC-HgO). Here we describe an alternate method using GC with a pulsed-discharge helium ionization detector (HePPD). HePPD is a universal detector; when applied to H2, the GC-HePDD provides a wide linear range (0.3% over a range of 2000 ppb), a detection limit of approximately 0.03 pg, high precision (0.12%) and a stable response (+/-1.6% over nearly one year). HePPD is compared to HgO reduction using a suite of gravimetrically prepared reference gases spanning remote to urban concentrations. The method is excellent for atmospheric measurements as it provides a wide linear range with high precision, stability and reproducibility. We suggest these characteristics will improve the ability to maintain reference gases and improve measurements of atmospheric H2, thus providing better constraints on potential future changes in its sources and sinks.

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Application of a pulse-discharge helium detector to the determination of neon in air and water

Cited by 8 publications

References 12 publications

Groundwater dating with3H and SF6 in relation to mixing patterns, transport modelling and hydrochemistry

Groundwater dating with3H and SF6 in relation to mixing patterns, transport modelling and hydrochemistry

Evidence for terrigenic SF6 in groundwater from basaltic aquifers, Jeju Island, Korea: Implications for groundwater dating

Application of Gas Chromatography with a Pulsed Discharge Helium Ionization Detector for Measurements of Molecular Hydrogen in the Atmosphere

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