TY - JOUR
T1 - Characterization and Application of a Hybrid Optical Microscopy/Laser Ablation Liquid Vortex Capture/Electrospray Ionization System for Mass Spectrometry Imaging with Sub-micrometer Spatial Resolution
AU - Cahill, John F.
AU - Kertesz, Vilmos
AU - Van Berkel, Gary J.
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/11/3
Y1 - 2015/11/3
N2 - A commercial optical microscope, laser microdissection instrument was coupled with an electrospray ionization mass spectrometer via a low profile liquid vortex capture probe to yield a hybrid optical microscopy/mass spectrometry imaging system. The instrument has bright-field and fluorescence microscopy capabilities in addition to a highly focused UV laser beam that is utilized for laser ablation of samples. With this system, material laser ablated from a sample using the microscope was caught by a liquid vortex capture probe and transported in solution for analysis by electrospray ionization mass spectrometry. Both lane scanning and spot sampling mass spectral imaging modes were used. The smallest area the system was able to ablate was ∼0.544 μm × ∼0.544 μm, achieved by oversampling of the smallest laser ablation spot size that could be obtained (∼1.9 μm). With use of a model photoresist surface, known features as small as ∼1.5 μm were resolved. The capabilities of the system with real world samples were demonstrated first with a blended polymer thin film containing poly(2-vinylpyridine) and poly(N-vinylcarbazole). Using spot sampling imaging, sub-micrometer sized features (0.62, 0.86, and 0.98 μm) visible by optical microscopy were clearly distinguished in the mass spectral images. A second real world example showed the imaging of trace amounts of cocaine in mouse brain thin tissue sections. With use of a lane scanning mode with ∼6 μm × ∼6 μm data pixels, features in the tissue as small as 15 μm in size could be distinguished in both the mass spectral and optical images.
AB - A commercial optical microscope, laser microdissection instrument was coupled with an electrospray ionization mass spectrometer via a low profile liquid vortex capture probe to yield a hybrid optical microscopy/mass spectrometry imaging system. The instrument has bright-field and fluorescence microscopy capabilities in addition to a highly focused UV laser beam that is utilized for laser ablation of samples. With this system, material laser ablated from a sample using the microscope was caught by a liquid vortex capture probe and transported in solution for analysis by electrospray ionization mass spectrometry. Both lane scanning and spot sampling mass spectral imaging modes were used. The smallest area the system was able to ablate was ∼0.544 μm × ∼0.544 μm, achieved by oversampling of the smallest laser ablation spot size that could be obtained (∼1.9 μm). With use of a model photoresist surface, known features as small as ∼1.5 μm were resolved. The capabilities of the system with real world samples were demonstrated first with a blended polymer thin film containing poly(2-vinylpyridine) and poly(N-vinylcarbazole). Using spot sampling imaging, sub-micrometer sized features (0.62, 0.86, and 0.98 μm) visible by optical microscopy were clearly distinguished in the mass spectral images. A second real world example showed the imaging of trace amounts of cocaine in mouse brain thin tissue sections. With use of a lane scanning mode with ∼6 μm × ∼6 μm data pixels, features in the tissue as small as 15 μm in size could be distinguished in both the mass spectral and optical images.
UR - http://www.scopus.com/inward/record.url?scp=84946782579&partnerID=8YFLogxK
U2 - 10.1021/acs.analchem.5b03293
DO - 10.1021/acs.analchem.5b03293
M3 - Article
AN - SCOPUS:84946782579
SN - 0003-2700
VL - 87
SP - 11113
EP - 11121
JO - Analytical Chemistry
JF - Analytical Chemistry
IS - 21
ER -