@article {2806,
	title = {Monitoring of toxic compounds in air using a handheld rectilinear ion trap mass spectrometer.},
	journal = {Analytical Chemistry},
	volume = {80},
	year = {2008},
	month = {2008 Feb 1},
	pages = {734-41},
	abstract = {<p>A miniature, handheld mass spectrometer, based on the rectilinear ion trap mass analyzer, has been applied to air monitoring for traces of toxic compounds. The instrument is battery-operated, hand-portable, and rugged. We anticipate its use in public safety, industrial hygiene, and environmental monitoring. Gaseous samples of nine toxic industrial compounds, phosgene, ethylene oxide, sulfur dioxide, acrylonitrile, cyanogen chloride, hydrogen cyanide, acrolein, formaldehyde, and ethyl parathion, were tested. A sorption trap inlet was constructed to serve as the interface between atmosphere and the vacuum chamber of the mass spectrometer. After selective collection of analytes on the sorbent bed, the sorbent tube was evacuated and then heated to desorb analyte into the instrument. Sampling, detection, identification, and quantitation of all compounds were readily achieved in times of less than 2 min, with detection limits ranging from 800 parts per trillion to 3 parts per million depending on the analyte. For all but one analyte, detection limits were well below (3.5-130 times below) permissible exposure limits. A linear dynamic range of 1-2 orders of magnitude was obtained over the concentration ranges studied (sub-ppbv to ppmv) for all analytes.</p>
},
	issn = {0003-2700},
	doi = {10.1364/AO.50.001792},
	author = {Keil, Adam and Hernandez-Soto, Heriberto and Noll, Robert J and Fico, Miriam and Gao, Liang and Ouyang, Zheng and Cooks, R Graham}
}
@article {2810,
	title = {Ambient mass spectrometry with a handheld mass spectrometer at high pressure.},
	journal = {Analytical Chemistry},
	volume = {79},
	year = {2007},
	month = {2007 Oct 15},
	pages = {7734-9},
	abstract = {<p>The first coupling of atmospheric pressure ionization methods, electrospray ionization (ESI) and desorption electrospray ionization (DESI), to a miniature hand-held mass spectrometer is reported. The instrument employs a rectilinear ion trap (RIT) mass analyzer and is battery-operated, hand-portable, and rugged (total system: 10 kg, 0.014 m(3), 75 W power consumption). The mass spectrometer was fitted with an atmospheric inlet, consisting of a 10 cm x 127 microm inner diameter stainless steel capillary tube which was used to introduce gas into the vacuum chamber at 13 mL/min. The operating pressure was 15 mTorr. Ions, generated by the atmospheric pressure ion source, were directed by the inlet along the axis of the ion trap, entering through an aperture in the dc-biased end plate, which was also operated as an ion gate. ESI and DESI sources were used to generate ions; ESI-MS analysis of an aqueous mixture of drugs yielded detection limits in the low parts-per-billion range. Signal response was linear over more than 3 orders of magnitude. Tandem mass spectrometry experiments were used to identify components of this mixture. ESI was also applied to the analysis of peptides and in this case multiply charged species were observed for compounds of molecular weight up to 1200 Da. Cocaine samples deposited or already present on different surfaces, including currency, were rapidly analyzed in situ by DESI. A geometry-independent version of the DESI ion source was also coupled to the miniature mass spectrometer. These results demonstrate that atmospheric pressure ionization can be implemented on simple portable mass spectrometry systems.</p>
},
	keywords = {Alkylation, Calibration, Mass Spectrometry, Molecular Structure, Molecular Weight, Pressure, Proteins, Temperature},
	issn = {0003-2700},
	doi = {10.1364/AO.50.001792},
	author = {Keil, Adam and Talaty, Nari and Janfelt, Christian and Noll, Robert J and Gao, Liang and Ouyang, Zheng and Cooks, R Graham}
}
