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Air Monitor

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Roberto Fanelli – One of the best experts on this subject based on the ideXlab platform.

  • Automated high-speed analysis of selected organic compounds in urban Air by on-line isotopic dilution cryofocusing gas chromatography/mass spectrometry
    Journal of the American Society for Mass Spectrometry, 1994
    Co-Authors: Enrico Davoli, L. Cappellini, M Maggi, Roberto Fanelli

    Abstract:

    An automated environmental Air Monitor has been developed to measure selected organic compounds in urban Air. The instrument is based on a cryofocusing-thermal desorption gas chromatographic mass spectrometry technique where the mass spectrometer is a slightly modified residual gas analyzer (RGA). The RGA was chosen as a detector because the whole system must be robust for long periods, with 24-h continuous Air Monitoring. RCA are extremely simple and seemed the most reliable mass spectrometers for this purpose. Moreover, because they have no physically limited ion source, contamination is considerably reduced, so maintenance intervals are longer.

  • Automated high-speed analysis of selected organic compounds in urban Air by on-line isotopic dilution cryofocusing gas chromatography/mass spectrometry
    Journal of the American Society for Mass Spectrometry, 1994
    Co-Authors: Enrico Davoli, L. Cappellini, M Maggi, Roberto Fanelli

    Abstract:

    An automated environmental Air Monitor has been developed to measure selected organic compounds in urban Air. The instrument is based on a cryofocusing-thermal desorption gas chromatographic mass spectrometry technique where the mass spectrometer is a slightly modified residual gas analyzer (RGA). The RGA was chosen as a detector because the whole system must be robust for long periods, with 24-h continuous Air Monitoring. RCA are extremely simple and seemed the most reliable mass spectrometers for this purpose. Moreover, because they have no physically limited ion source, contamination is considerably reduced, so maintenance intervals are longer. The gas chromatograph is equipped with a computer-controlled six-way sampling valve, with a 100-mL sampling loop and thermal desorption cold trap injector. Environmental Air is enriched with an isotopically labeled internal standard in the sampling line. This internal standard is added with a validated, custom-made, permeation tube device. The “on-line” internal standard provides for high quality quantitative data because all variations in instrument sensitivity in cryofocusing or in thermal desorption efficiency are taken into account. High repetition rates (down to 5 min for a full analytical cycle) are obtained with the use of an isothermal gas chromatography program, microbore capillary column, and environmental Air sampling during the gas chromatography run.

Enrico Davoli – One of the best experts on this subject based on the ideXlab platform.

  • Automated high-speed analysis of selected organic compounds in urban Air by on-line isotopic dilution cryofocusing gas chromatography/mass spectrometry
    Journal of the American Society for Mass Spectrometry, 1994
    Co-Authors: Enrico Davoli, L. Cappellini, M Maggi, Roberto Fanelli

    Abstract:

    An automated environmental Air Monitor has been developed to measure selected organic compounds in urban Air. The instrument is based on a cryofocusing-thermal desorption gas chromatographic mass spectrometry technique where the mass spectrometer is a slightly modified residual gas analyzer (RGA). The RGA was chosen as a detector because the whole system must be robust for long periods, with 24-h continuous Air Monitoring. RCA are extremely simple and seemed the most reliable mass spectrometers for this purpose. Moreover, because they have no physically limited ion source, contamination is considerably reduced, so maintenance intervals are longer.

  • Automated high-speed analysis of selected organic compounds in urban Air by on-line isotopic dilution cryofocusing gas chromatography/mass spectrometry
    Journal of the American Society for Mass Spectrometry, 1994
    Co-Authors: Enrico Davoli, L. Cappellini, M Maggi, Roberto Fanelli

    Abstract:

    An automated environmental Air Monitor has been developed to measure selected organic compounds in urban Air. The instrument is based on a cryofocusing-thermal desorption gas chromatographic mass spectrometry technique where the mass spectrometer is a slightly modified residual gas analyzer (RGA). The RGA was chosen as a detector because the whole system must be robust for long periods, with 24-h continuous Air Monitoring. RCA are extremely simple and seemed the most reliable mass spectrometers for this purpose. Moreover, because they have no physically limited ion source, contamination is considerably reduced, so maintenance intervals are longer. The gas chromatograph is equipped with a computer-controlled six-way sampling valve, with a 100-mL sampling loop and thermal desorption cold trap injector. Environmental Air is enriched with an isotopically labeled internal standard in the sampling line. This internal standard is added with a validated, custom-made, permeation tube device. The “on-line” internal standard provides for high quality quantitative data because all variations in instrument sensitivity in cryofocusing or in thermal desorption efficiency are taken into account. High repetition rates (down to 5 min for a full analytical cycle) are obtained with the use of an isothermal gas chromatography program, microbore capillary column, and environmental Air sampling during the gas chromatography run.

Guebuem Kim – One of the best experts on this subject based on the ideXlab platform.

  • a simple and rapid method for analyzing radon in coastal and ground waters using a radon in Air Monitor
    Journal of Environmental Radioactivity, 2006
    Co-Authors: Jongmi Lee, Guebuem Kim

    Abstract:

    Abstract We have developed a simple and portable technique for measuring moderately high levels of 222 Rn ( t 1/2  = 3.8 d) in natural waters such as coastal water, groundwater, and river water. The water sample is carefully collected in a glass bottle, and the sample bottle is connected to a radon-in-Air Monitor in a closed Air-loop mode. By purging Air through the sample, radon is emanated from the water until a chemical equilibration is obtained between the two phases. The radon in the Air loop is determined using the radon-in-Air Monitor. Then, the radon in water is calculated by a radon-partitioning factor between water and Air for a measured water temperature. This technique is especially convenient for determination of 222 Rn in natural waters on field sites, since it eliminates the preparation of He gas, cold traps, and alpha-scintillation cells and counter, which are required for traditional radon emanation methods.

  • measurement of 224ra and 226ra activities in natural waters using a radon in Air Monitor
    Environmental Science & Technology, 2001
    Co-Authors: Guebuem Kim, William C Burnett, Henrieta Dulaiova, Peter W Swarzenski, Willard S Moore

    Abstract:

    We report a simple new technique for measuring low-level radium isotopes (224Ra and 226Ra) in natural waters. The radium present in natural waters is first preconcentrated onto MnO2-coated acrylic fiber (Mn fiber) in a column mode. The radon produced from the adsorbed radium is then circulated through a closed Air-loop connected to a commercial radon-in-Air Monitor. The Monitor counts alpha decays of radon daughters (polonium isotopes) which are electrostatically collected onto a silicon semiconductor detector. Count data are collected in energy-specific windows, which eliminate interference and maintain very low backgrounds. Radium-224 is measured immediately after sampling via 220Rn (216Po), and 226Ra is measured via 222Rn (218Po) after a few days of ingrowth of 222Rn. This technique is rapid, simple, and accurate for measurements of low-level 224Ra and 226Ra activities without requiring any wet chemistry. Rapid measurements of short-lived 222Rn and 224Ra, along with long-lived 226Ra, may thus be made i…