Publication Date:
2019-02-01
Description:
We developed a portable mass spectrometric system
(“miniRuedi”) for quantificaton of the partial pressures of He, Ne
(in dry gas), Ar, Kr, N2, O2, CO2, and CH4 in gaseous and aqueous
matrices in environmental systems with an analytical uncertainty of
1−3%. The miniRuedi does not require any purification or other
preparation of the sampled gases and therefore allows maintenance-
free and autonomous operation. The apparatus is most
suitable for on-site gas analysis during field work and at remote
locations due to its small size (60 cm × 40 cm × 14 cm), low
weight (13 kg), and low power consumption (50 W). The gases
are continuously sampled and transferred through a capillary
pressure reduction system into a vacuum chamber, where they are
analyzed using a quadrupole mass spectrometer with a time
resolution of ≲1 min. The low gas consumption rate
(〈0.1 mL/min) minimizes interference with the natural mass balance of gases in environmental systems, and allows the
unbiased quantification of dissolved-gas concentrations in water by gas/water equilibration using membrane contractors (gasequilibrium
membrane-inlet mass spectrometry, GE-MIMS). The performance of the miniRuedi is demonstrated in laboratory
and field tests, and its utility is illustrated in field applications related to soil-gas formation, lake/atmosphere gas exchange, and
seafloor gas emanations.
Type:
Article
,
PeerReviewed
Format:
text
Format:
text
DOI:
10.1021/acs.est.6b03669
