"Advances in nanospray desorption electrospray ionization (nano-DESI) mass spectrometry"

Julia Laskin, William F. and Patty J. Professor or Analytical Chemistry

Purdue University, James Tarpo Jr. and Margaret Tarpo Dept of Chemistry

Host: Robbyn Anand

Abstract: Nanospray desorption electrospray ionization (nano-DESI) is an ambient ionization technique that enables label-free molecular imaging and analysis of surfaces with minimal sample pretreatment. In nano-DESI, analytes molecules are extracted from the sample into a localized liquid bridge formed between a specially-designed probe and sample surface. The extracted analytes are subsequently transferred to a mass spectrometer inlet and ionized by electrospray ionization. Quantification is performed by adding an internal standard to the solvent and normalizing the signals of endogenous analytes to the corresponding adduct of the standard. Spatial profiling and mass spectrometry imaging (MSI) experiments are performed by scanning the sample under the nano-DESI probe while acquiring mass spectra from different locations to generate two-dimensional molecular maps. Recent developments in nano-DESI MSI instrumentation by our group have enabled quantitative imaging of lipids, metabolites, drugs, glycans, and proteins in tissues with high sensitivity and spatial resolution down to 8-10 microns, using finely pulled capillaries. Furthermore, we have developed microfluidic nano-DESI probes and used them for both MSI and high-throughput analysis of a broad range of biological and environmental samples. To enhance the chemical specificity of nano-DESI MSI experiments, we have integrated it with ion mobility spectrometry, online photochemical derivatization of extracted analytes, and tandem mass spectrometry. These complementary approaches have been used for isomer-selective imaging of biomolecules in tissue samples, providing unique insights into complex biochemical pathways in biological systems.

Bio: Julia Laskin is the William F. and Patty J. Miller Professor of Analytical Chemistry at Purdue University. Her research is focused on the development of mass spectrometry-based instrumentation and experimental approaches for selective modification of substrates using beams of mass-selected ions and for quantitative molecular imaging of biological samples. 

Dr. Laskin obtained her M.Sc. in Physics from the Leningrad Polytechnical Institute (1990) and Ph.D. in Physical Chemistry from the Hebrew University of Jerusalem (1998) with Prof. Chava Lifshitz. She did her postdoctoral research with Dr. Jean Futrell at the University of Delaware and Pacific Northwest National Laboratory (PNNL). Prior to joining Purdue in 2017, she was a scientist at PNNL (2002-2017) and was promoted to the highest scientific rank in 2011.

Dr. Laskin’s research has resulted in over 330 peer-reviewed publications including invited reviews and book chapters and 11 patents. She is Past President of the American Society for Mass Spectrometry (ASMS) and an editor-in-chief of the International Journal of Mass Spectrometry. She was Vice President for Programs and President of the ASMS, a co-organizer of the 2019 ASMS Asilomar Conference on Imaging Mass Spectrometry, and a chair of the 2017 Gordon Research Conference on Gaseous Ions. Her research has been honored with several prestigious awards including Presidential Early Career Award (2007), ASMS Biemann Medal (2008), Inaugural Rising Star Award of the ACS Women Chemists Committee (2011), PNNL Director's Science and Engineering Achievement Award (2014), Medal of the Russian Society for Mass Spectrometry (2017), the Ron Hites Award (2019), The Riveros Medal of the Brazilian Mass Spectrometry Society (2022), Advances in Measurement Science Lectureship Award (2023), ACS Chemical Instrumentation Award (2025), Humboldt Research Award, and other.