title: Fast and sensitive method for detecting volatile species in liquids.
abstract: This paper presents a novel apparatus for extracting volatile species from liquids using a "sniffer-chip." By ultrafast transfer of the volatile species through a perforated and hydrophobic membrane into an inert carrier gas stream, the sniffer-chip is able to transport the species directly to a mass spectrometer through a narrow capillary without the use of differential pumping. This method inherits features from differential electrochemical mass spectrometry (DEMS) and membrane inlet mass spectrometry (MIMS), but brings the best of both worlds, i.e., the fast time-response of a DEMS system and the high sensitivity of a MIMS system. In this paper, the concept of the sniffer-chip is thoroughly explained and it is shown how it can be used to quantify hydrogen and oxygen evolution on a polycrystalline platinum thin film in situ at absolute faradaic currents down to ∼30 nA. To benchmark the capabilities of this method, a CO-stripping experiment is performed on a polycrystalline platinum thin film, illustrating how the sniffer-chip system is capable of making a quantitative in situ measurement of <1% of a monolayer of surface adsorbed CO being electrochemically stripped off an electrode at a potential scan-rate of 50 mV s(-1).
authors.affiliation: Department of Physics, Technical University of Denmark, Fysikvej, Building 312, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Trimarco
authors.affiliation: Department of Micro- and Nanotechnology, Technical University of Denmark, Ørsteds Plads, Building 344, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Thomas
authors.initials: T
authors.lastname: Pedersen
authors.affiliation: Department of Micro- and Nanotechnology, Technical University of Denmark, Ørsteds Plads, Building 344, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Ole
authors.initials: O
authors.lastname: Hansen
authors.affiliation: Department of Physics, Technical University of Denmark, Fysikvej, Building 312, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Ib
authors.initials: I
authors.lastname: Chorkendorff
authors.affiliation: Department of Physics, Technical University of Denmark, Fysikvej, Building 312, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Peter C K
authors.initials: PC
authors.lastname: Vesborg