ac050162j_si_003.pdf (74.3 kB)
Versatile New Ion Source for the Analysis of Materials in Open Air under Ambient Conditions
journal contribution
posted on 2005-04-15, 00:00 authored by Robert B. Cody, James A. Laramée, H. Dupont DurstA new ion source has been developed for rapid, noncontact analysis of materials at ambient pressure and at
ground potential. The new source, termed DART (for
“Direct Analysis in Real Time”), is based on the reactions
of electronic or vibronic excited-state species with reagent
molecules and polar or nonpolar analytes. DART has been
installed on a high-resolution time-of-flight mass spectrometer (TOFMS) that provides improved selectivity and
accurate elemental composition assignment through exact
mass measurements. Although DART has been applied
to the analysis of gases, liquids, and solids, a unique
application is the direct detection of chemicals on surfaces
without requiring sample preparation, such as wiping or
solvent extraction. DART has demonstrated success in
sampling hundreds of chemicals, including chemical
agents and their signatures, pharmaceutics, metabolites,
peptides and oligosaccharides, synthetic organics, organometallics, drugs of abuse, explosives, and toxic industrial chemicals. These species were detected on various
surfaces, such as concrete, asphalt, human skin, currency, airline boarding passes, business cards, fruits,
vegetables, spices, beverages, body fluids, horticultural
leaves, cocktail glasses, and clothing. DART employs no
radioactive components and is more versatile than devices
using radioisotope-based ionization. Because its response
is instantaneous, DART provides real-time information,
a critical requirement for screening or high throughput.