title: Contrast-enhanced differential mobility-desorption electrospray ionization-mass spectrometry imaging of biological tissues.
abstract: Mass spectrometry imaging (MSI) performed under ambient conditions is a convenient and information-rich method that allows for the comprehensive mapping of chemical species throughout biological tissues with typical spatial resolution in the 40-200 μm range. Ambient MSI methods such as desorption electrospray ionization (DESI) eliminate necessary sample preparation but suffer from lower spatial resolution than laser-based and vacuum techniques. In order to take advantage of the benefits of ambient imaging and to compensate for the somewhat limited spatial resolution, a secondary orthogonal separation nested in the imaging scheme was implemented for more selective discernment of tissue features in the spectral domain. Differential mobility spectrometry (DMS), an ion mobility-based separation that selectively transmits ions based on their high-to-low electric field mobility differences, can significantly reduce background chemical interferences, allowing for increased peak capacity. In this work, DESI DM-MSI experiments on biological tissue samples such as sea algae and mouse brain tissue sections were conducted using fixed DMS compensation voltages that selectively transferred one or a class of targeted compounds. By reducing chemical noise, the signal-to-noise ratio was improved 10-fold and the image contrast was doubled, effectively increasing image quality.
authors.affiliation: School of Chemistry and Biochemistry, Georgia Institute of Technology , Atlanta, GA 30332, United States.
authors.forename: Rachel V
authors.initials: RV
authors.lastname: Bennett
authors.forename: Chaminda M
authors.initials: CM
authors.lastname: Gamage
authors.forename: Asiri S
authors.initials: AS
authors.lastname: Galhena
authors.forename: Facundo M
authors.initials: FM
authors.lastname: Fernández
mesh_terms: D000818:Animals; D001923:Brain Chemistry; D000460:Chlorophyta / Q000737:chemistry; D004574:Electromagnetic Fields; D007091:Image Processing, Computer-Assisted; D051379:Mice; D010944:Plants / Q000737:chemistry; D051381:Rats; D012815:Signal Processing, Computer-Assisted; D059629:Signal-To-Noise Ratio; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*