Title: Morphology-Driven Control of Metabolite Selectivity Using Nanostructure-Initiator Mass Spectrometry

Abstract

Nanostructure-initiator mass spectrometry (NIMS) is a laser desorption/ionization analysis technique based on the vaporization of a nanostructure-trapped liquid "initiator" phase. Here in this work, we report an intriguing relationship between NIMS surface morphology and analyte selectivity. Scanning electron microscopy and spectroscopic ellipsometry were used to characterize the surface morphologies of a series of NIMS substrates generated by anodic electrochemical etching. Mass spectrometry imaging was applied to compare NIMS sensitivity of these various surfaces toward the analysis of diverse analytes. The porosity of NIMS surfaces was found to increase linearly with etching time where the pore size ranged from 4 to 12 nm with corresponding porosities estimated to be 7-70%. Surface morphology was found to significantly and selectively alter NIMS sensitivity. The small molecule (<2k Da) sensitivity was found to increase with increased porosity, whereas low porosity had the highest sensitivity for the largest molecules examined. Estimation of molecular sizes showed that this transition occurs when the pore size is <3× the maximum of molecular dimensions. While the origins of selectivity are unclear, increased signal from small molecules with increased surface area is consistent with a surface area restructuring-driven desorption/ionization process where signal intensity increases with porosity. In contrast, large moleculesmore » show highest signal for the low-porosity and small-pore-size surfaces. We attribute this to strong interactions between the initiator-coated pore structures and large molecules that hinder desorption/ionization by trapping large molecules. Lastly, this finding may enable us to design NIMS surfaces with increased specificity to molecules of interest.« less

Authors:

Gao, Jian ^[1]; Louie, Katherine B. ^[2]; Steinke, Philipp ^[3]; Bowen, Benjamin P. ^[2]; Raad, Markus de  ^[2];

• Search DOE PAGES for author "Raad, Markus de"
• Search DOE PAGES for ORCID "0000-0001-8263-9198"

Zuckermann, Ronald N.  ^[4];

• Search DOE PAGES for author "Zuckermann, Ronald N."
• Search DOE PAGES for ORCID "0000-0002-3055-8860"

Siuzdak, Gary ^[5]; Northen, Trent R.  ^[2]

• Search DOE PAGES for author "Northen, Trent R."
• Search DOE PAGES for ORCID "0000-0001-8404-3259"

---

+ Show Author Affiliations

1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Genomics and Systems Biology Division and The Molecular Foundry; USDOE Joint Genome Institute (JGI), Walnut Creek, CA (United States)
2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Genomics and Systems Biology Division ; USDOE Joint Genome Institute (JGI), Walnut Creek, CA (United States)
3. Fraunhofer Institute for Photonic Microsystems IPMS - Center Nanoelectronic Technologies (CNT), Dresden (Germany)
4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). The Molecular Foundry
5. The Scripps Research Institute, La Jolla, CA (United States). Scripps Center for Metabolomics & Departments of Chemistry, Molecular and Computational Biology

Publication Date:

Thu May 18 00:00:00 EDT 2017

Research Org.:

Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1437961

Grant/Contract Number:  

AC02-05CH11231; SC0014079

Resource Type:

Accepted Manuscript

Journal Name:

Analytical Chemistry

Additional Journal Information:

Journal Volume: 89; Journal Issue: 12; Related Information: © 2017 American Chemical Society.; Journal ID: ISSN 0003-2700

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY