title: Handheld low-temperature plasma probe for portable "point-and-shoot" ambient ionization mass spectrometry.
abstract: We describe a handheld, wireless low-temperature plasma (LTP) ambient ionization source and its performance on a benchtop and a miniature mass spectrometer. The source, which is inexpensive to build and operate, is battery-powered and utilizes miniature helium cylinders or air as the discharge gas. Comparison of a conventional, large-scale LTP source against the handheld LTP source, which uses less helium and power than the large-scale version, revealed that the handheld source had similar or slightly better analytical performance. Another advantage of the handheld LTP source is the ability to quickly interrogate a gaseous, liquid, or solid sample without requiring any setup time. A small, 7.4-V Li-polymer battery is able to sustain plasma for 2 h continuously, while the miniature helium cylinder supplies gas flow for approximately 8 continuous hours. Long-distance ion transfer was achieved for distances up to 1 m.
authors.affiliation: Department of Chemistry and Center for Analytical Instrumentation Development (CAID), Purdue University, West Lafayette, Indiana 47907, United States.
authors.forename: Joshua S
authors.initials: JS
authors.lastname: Wiley
authors.forename: Jacob T
authors.initials: JT
authors.lastname: Shelley
authors.forename: R Graham
authors.initials: RG
authors.lastname: Cooks