The Experts below are selected from a list of 33678 Experts worldwide ranked by ideXlab platform
Roberto Fanelli - One of the best experts on this subject based on the ideXlab platform.
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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, 1994Co-Authors: Enrico Davoli, L. Cappellini, M Maggi, Roberto FanelliAbstract: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.
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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, 1994Co-Authors: Enrico Davoli, L. Cappellini, M Maggi, Roberto FanelliAbstract: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.
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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, 1994Co-Authors: Enrico Davoli, L. Cappellini, M Maggi, Roberto FanelliAbstract: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.
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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, 1994Co-Authors: Enrico Davoli, L. Cappellini, M Maggi, Roberto FanelliAbstract: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.
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a simple and rapid method for analyzing radon in coastal and ground waters using a radon in Air Monitor
Journal of Environmental Radioactivity, 2006Co-Authors: Jongmi Lee, Guebuem KimAbstract: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.
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measurement of 224ra and 226ra activities in natural waters using a radon in Air Monitor
Environmental Science & Technology, 2001Co-Authors: Guebuem Kim, William C Burnett, Henrieta Dulaiova, Peter W Swarzenski, Willard S MooreAbstract: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...
William H. Brune - One of the best experts on this subject based on the ideXlab platform.
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Measurement of ozone production sensor
Atmospheric Measurement Techniques Discussions, 2009Co-Authors: Miguel Cazorla, William H. BruneAbstract:Abstract. A new ambient Air Monitor, the Measurement of Ozone Production Sensor (MOPS), measures directly the rate of ozone production in the atmosphere. The sensor consists of two 11.3 L environmental chambers made of UV-transmitting Teflon film, a unit to convert NO2 to O3, and a modified ozone Monitor. In the sample chamber, flowing ambient Air is exposed to the sunlight so that ozone is produced just as it is in the atmosphere. In the second chamber, called the reference chamber, a UV-blocking film over the Teflon film prevents ozone formation but allows other processes to occur as they do in the sample chamber. The Air flows that exit the two chambers are sampled by an ozone Monitor operating in differential mode so that the difference between the two ozone signals, divided by the residence time in the chambers, gives the ozone production rate. High-efficiency conversion of NO2 to O3 prior to detection in the ozone Monitor accounts for differences in the NOx photostationary state that can occur in the two chambers. The MOPS measures the ozone production rate, but with the addition of NO to the sampled Air flow, the MOPS can be used to study the sensitivity of ozone production to NO. Preliminary studies with the MOPS on the campus of the Pennsylvania State University show the potential of this new technique.
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Measurement of Ozone Production Sensor
Atmospheric Measurement Techniques, 2009Co-Authors: Miguel Cazorla, William H. BruneAbstract:Abstract. A new ambient Air Monitor, the Measurement of Ozone Production Sensor (MOPS), measures directly the rate of ozone production in the atmosphere. The sensor consists of two 11.3 L environmental chambers made of UV-transmitting Teflon film, a unit to convert NO2 to O3, and a modified ozone Monitor. In the sample chamber, flowing ambient Air is exposed to the sunlight so that ozone is produced just as it is in the atmosphere. In the second chamber, called the reference chamber, a UV-blocking film over the Teflon film prevents ozone formation but allows other processes to occur as they do in the sample chamber. The Air flows that exit the two chambers are sampled by an ozone Monitor operating in differential mode so that the difference between the two ozone signals, divided by the exposure time in the chambers, gives the ozone production rate. High-efficiency conversion of NO2 to O3 prior to detection in the ozone Monitor accounts for differences in the NOx photostationary state that can occur in the two chambers. The MOPS measures the ozone production rate, but with the addition of NO to the sampled Air flow, the MOPS can be used to study the sensitivity of ozone production to NO. Preliminary studies with the MOPS on the campus of the Pennsylvania State University show the potential of this new technique.
M Maggi - One of the best experts on this subject based on the ideXlab platform.
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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, 1994Co-Authors: Enrico Davoli, L. Cappellini, M Maggi, Roberto FanelliAbstract: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.
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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, 1994Co-Authors: Enrico Davoli, L. Cappellini, M Maggi, Roberto FanelliAbstract: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.
