Piezoelectric matrix-assisted ionization

B. Banstola, C.W. Szot, A.P. Deenamulla Kankanamalage, K.K. Murray, Piezoelectric matrix-assisted ionization, Eur J Mass Spectrom 25 (2019) 202–207. doi:10.1177/1469066718816696

ABSTRACT: We have developed a new actuation method for matrix-assisted ionization with good temporal and spatial resolution using piezoelectric cantilever. A strike from the piezoelectric bimorph cantilever on a thin metal foil was used to remove materials deposited on the opposite side facing the mass spectrometer inlet. Highly charged ions of peptides and proteins were generated from dried droplet deposits and sampled into the inlet of the mass spectrometer. A lateral resolution of 1 mm was obtained with the piezoelectric sampling configuration. Singly charged lipids and gangliosides were detected from tissue with piezoelectric matrix-assisted ionization using a silica nanoparticle co-matrix.

Piezoelectric MAI at inlet to the Bruker Amazon ion trap

ASMS 2019: Deep-ultraviolet Laser Ablation Sampling for Mass Spectrometry

MOG 03:10pm
Deep-ultraviolet Laser Ablation Sampling for Mass Spectrometry
Remilekun O. Lawal; Fabrizio Donnarumma; Kermit K. Murray

193 nm excimer laser ablation setup
193 nm excimer laser ablation setup

High resolution sampling of biological systems is crucial to revealing the differences in proteins and metabolites amongst heterogeneous cells. Laser ablation sampling for mass spectrometry is a powerful method for analyzing biomolecules in tissue under ambient conditions with high spatial control while eliminating the need for external matrices. It allows off-line analysis by liquid chromatography tandem mass spectrometry and can be combined with mass spectrometry imaging for region of interest selection. The most efficient lasers currently used for ablation sampling use mid-infrared wavelengths that are diffraction limited to spot sizes tens of micrometers in diameter. Short wavelength lasers can be focused to order of magnitude smaller spot sizes for efficient ablation with minimal thermal damage to adjacent sample areas.

ASMS 2019: Charge Production by Sublimation of Organic Compounds in Matrix Assisted Ionization

WOG 03:30pm
Charge Production by Sublimation of Organic Compounds in Matrix Assisted Ionization
Bijay Banstola; Kermit K. Murray

Dual vacuum chamber used to measure sublimation electrification

Matrix assisted ionization (MAI) describes a mode of ionization in which an analyte molecule is mixed with an organic matrix and produces ions when the dried matrix and analyte containing crystals are exposed to external shock or sublime under vacuum. MAI produces highly charged ions from large biopolymers with charge distributions similar to electrospray ionization. When exposed to vacuum, the matrix crystals fracture, which may eject charged particles and clusters containing matrix and analyte or may directly eject highly charged ions. In this study, a method was developed to measure the charge produced during the sublimation of MAI matrix compounds. Sublimation charge production was measured as a function of matrix, crystal size and morphology, pH, and temperature.

ASMS 2019

Murray Group Presentations

Orals

MOG 03:10pm

Deep-ultraviolet Laser Ablation Sampling for Mass Spectrometry
Remilekun O. Lawal; Fabrizio Donnarumma; Kermit K. Murray

WOG 03:30pm


Charge Production by Sublimation of Organic Compounds in Matrix Assisted Ionization
Bijay Banstola; Kermit K. Murray

Posters

MP 765

Cellular Precision for Infrared Laser Ablation Tissue Microproteomics
Chao Dong; Fabrizio Donnarumma; Kelin Wang; Kermit K. Murray

TP 266


Forensic Sampling Using Nanoparticle Extraction and Capture
Jamira A Stephenson; Fabrizio Donnaruma; Kermit K Murray

TP 362


Optimizing Tissue Ablation for Mass Spectrometry Imaging Using Light Scattering
Achala P Deenamulla Kankanamalage; Fabrizio Donnaruma; Kermit K Murray

WP 433


Software for Automated Laser Ablation and Capture from Tissue Sections
Fabrizio Donnarumma; Touradj Solouki; Kermit K Murray

WP 518
Simultaneous Extraction of Proteins, Lipids, and Metabolites for Integrated-omics Approaches for Low Tissue Sampling Volumes
Luke T. Richardson; Amy N. W. Schnelle; Fabrizio Donnaruma; Michael E. Pettit;

ThP 050


Two-Laser Ablation Electrospray Ionization Mass Spectrometry
Kelcey B. Hines; Remilekun O. Lawal; Fabrizio Donnarumma; Kermit K. Murray

ThP 124
Influence of Traumatic Brain Injury on Bile Acid Profiles in the Brains of Rats
Amy N. W. Schnelle; Luke T. Richardson; Fabrizio Donnaruma; Ashok K. Shetty; Kermit K Murray; Touradj Solouki

ThP 413


MALDI-directed Region Selection for Laser Ablation Tissue Microsampling
Kelin Wang; Fabrizio Donnarumma; Michael Pettit; Touradj Solouki; Kermit K. Murray

Deep‐ultraviolet laser ablation electrospray ionization mass spectrometry

R.O. Lawal, F. Donnarumma, K.K. Murray, Deep-ultraviolet laser ablation electrospray ionization mass spectrometry, J. Mass Spectrom.54 (2019) 281–287. doi:10.1002/jms.4338.

Abstract
Myoglobin ionized by (a) 193 nm laser ablation electrospray and (b) electrospray
Myoglobin ionized by (a) 193 nm laser ablation electrospray and (b) electrospray

A 193‐nm wavelength deep ultraviolet laser was used for ambient laser ablation electrospray ionization mass spectrometry of biological samples. A pulsed ArF excimer laser was used to ablate solid samples, and the resulting plume of the desorbed material merged with charged electrospray droplets to form ions that were detected with a quadrupole time‐of‐flight mass spectrometer. Solutions containing peptide and protein standards up to 66‐kDa molecular weight were deposited on a metal target, dried, and analyzed. No fragmentation was observed from peptides and proteins as well as from the more easily fragmented vitamin B12 molecule. The mass spectra contained peaks from multiply charged ions that were identical to conventional electrospray. Deep UV laser ablation of tissue allowed detection of lipids from untreated tissue. The mechanism of ionization is postulated to involve absorption of laser energy by a fraction of the analyte molecules that act as a sacrificial matrix or by residual water in the sample.

RNA Sampling from Tissue Sections using Infrared Laser Ablation

K. Wang, F. Donnarumma, S.W. Herke, C. Dong, P.F. Herke, K.K. Murray, RNA sampling from tissue sections using infrared laser ablation, Anal. Chim. Acta. 1063 (2019) 91–98. doi:10.1016/j.aca.2019.02.054.

RNA Sampling from Tissue Sections using Infrared Laser Ablation
RNA Sampling from Tissue Sections using Infrared Laser Ablation

RNA was obtained from discrete locations of frozen rat brain tissue sections through infrared (IR) laser ablation using a 3-μm wavelength in transmission geometry. The ablated plume was captured in a microcentrifuge tube containing RNAse-free buffer and processed using a commercial RNA purification kit. RNA transfer efficiency and integrity were evaluated based on automated electrophoresis in microfluidic chips. Reproducible IR-laser ablation of intact RNA was demonstrated with purified RNA at laser fluences of 3-5 kJ/m2 (72±12% transfer efficiency) and with tissue sections at a laser fluence of 13 kJ/m2 (79±14% transfer efficiency); laser energies were attenuated ∼20% by the soda-lime glass slides used to support the samples. RNA integrity from tissue ablation was >90% of its original RIN value (∼7) and the purified RNA was sufficiently intact for conversion to cDNA and subsequent qPCR assay.

Patent: Tip Enhanced Laser Assisted Sample Transfer for Biomolecule Mass Spectrometry

Link

Disclosed are various embodiments for transferring molecules from a surface for mass spectrometry and other sample analysis methods, and the like. A laser is focused onto a tip of an atomic force microscope to remove and capture a quantity of molecules from the surface, so they can be transferred to a mass spectrometer or another instrument for analysis.

Tip-enhanced laser ablation and capture of DNA

F. Cao, F. Donnarumma, K.K. Murray, Tip-enhanced laser ablation and capture of DNA, Appl. Surf. Sci. 476 (2019) 658–662. doi:10.1016/j.apsusc.2019.01.104.

Abstract: Tip-enhanced laser ablation was used to extract DNA plasmid for polymerase chain reaction (PCR) amplification. A 532 nm nanosecond laser was directed onto a gold coated atomic force microscopy (AFM) tip 10 nm above a sample surface to ablate a 7.1 kbp green fluorescent protein (GFP) plasmid DNA sample on a glass coverslip. The ablated material was captured on a metal ribbon 300 µm above the sample surface. The ablation craters had diameters from 1 to 2 µm and an average volume of 0.14 µm3. PCR and nested PCR were employed for the amplification of the ablated DNA. The quantity of sample from each ablation crater for PCR amplification was 20 ag.

Tip-enhanced laser ablation and capture of DNA
The proposed technology allows topographical imaging with atomic force microscopy (AFM) and extraction of DNA via tip-enhanced laser ablation using the same tip. Plasmid DNA is imaged with a gold coated tip and extracted using a pulsed laser with a sampling size of 1 µm. The captured DNA can be amplified by polymerase chain reaction (PCR) and nested PCR.