Laser-Induced Acoustic Desorption Atmospheric Pressure Photoionization via VUV-Generating Microplasmas.
We demonstrate the first application of laser-induced acoustic desorption (LIAD) and atmospheric pressure photoionization (APPI) as a mass spectrometric method for detecting low-polarity organics. This was accomplished using a Lyman-α (10.2 eV) photon generating microhollow cathode discharge (MHCD) microplasma photon source in conjunction with the addition of a gas-phase molecular dopant. This combination provided a soft desorption and a relatively soft ionization technique. Selected compounds analyzed include α-tocopherol, perylene, cholesterol, phenanthrene, phylloquinone, and squalene. Detectable surface concentrations as low as a few pmol per spot sampled were achievable using test molecules. The combination of LIAD and APPI provided a soft desorption and ionization technique that can allow detection of labile, low-polarity, structurally complex molecules over a wide mass range with minimal fragmentation. Graphical Abstract ᅟ.
School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive NW, Atlanta, GA, 30332, USA.
Kevin
K
Benham
Cryogenic Chemistry Laboratory, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91109, USA.
Robert
R
Hodyss
School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive NW, Atlanta, GA, 30332, USA.
Facundo M
FM
Fernández
School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive NW, Atlanta, GA, 30332, USA. thomas.orlando@chemistry.gatech.edu.|School of Physics, Georgia Institute of Technology, 837 State Street, Atlanta, GA, 30332, USA. thomas.orlando@chemistry.gatech.edu.
Thomas M
TM
Orlando
Atmospheric pressure photoionization; Laser-induced acoustic desorption; Low-polarity analytes; Microhollow cathode discharge; Microplasma