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Transportable real-time single-particle ion trap mass spectrometer

Journal Article · · Review of Scientific Instruments
DOI:https://doi.org/10.1063/1.1938607· OSTI ID:20722914
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  1. Oak Ridge National Laboratory, PO Box 2008, MS 6142, Oak Ridge, Tennessee 37831 (United States)

A transportable ion trap mass spectrometer for real-time detection and characterization of individual airborne particles was constructed by minimal modification of a commercial ion trap mass spectrometer. A blank flange was replaced with a flange containing an aerodynamic lens based inlet, light scattering detection optics and ablation/ionization laser optics. Four holes were drilled into the ring electrode. Timing electronics boards running off of in-place power systems were added and integrated with the existing software. The modified mass spectrometer and laser system was packaged in a rugged wheeled frame for easy transport. Particles entered the instrument through a 100 {mu}m orifice and were passed through an aerodynamic lens system that produced a well-collimated particle beam over a wide range of sizes. The particle beam passed through a skimmer into the main chamber where individual particles were optically detected and sized with two focused 532 nm diode lasers on their way to the ion trap. When the particles reached the center of the trap, they were ablated and ionized with a focused 266 nm laser. The nascent ions were then mass analyzed using standard ion trap techniques, including tandem mass spectrometry. Each detected particle was characterized with a mass spectrum and an aerodynamically determined particle size. Careful design minimized the weight and size of the instrument to 104 kg and 69x71x76 cm, with power consumption less than 1.5 kW. Tandem mass spectrometry was demonstrated for identification of ions through collision-induced dissociation (CID) up to mass spectrometry (MS). Unit mass resolution was observed in both the parent and CID mass spectra.

OSTI ID:
20722914
Journal Information:
Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 6 Vol. 76; ISSN 0034-6748; ISSN RSINAK
Country of Publication:
United States
Language:
English