Citric Acid Capped Iron Oxide Nanoparticles as an Effective MALDI Matrix for Polymers

Qiaoli Liang; Jennifer Sherwood; Thomas Macher; Joseph M Wilson; Yuping Bao; Carolyn J Cassady

doi:10.1007/s13361-016-1560-4

Citric Acid Capped Iron Oxide Nanoparticles as an Effective MALDI Matrix for Polymers

J Am Soc Mass Spectrom. 2017 Mar;28(3):409-418. doi: 10.1007/s13361-016-1560-4. Epub 2016 Dec 6.

Authors

Qiaoli Liang¹, Jennifer Sherwood², Thomas Macher², Joseph M Wilson², Yuping Bao², Carolyn J Cassady³

Affiliations

¹ Department of Chemistry, The University of Alabama, Tuscaloosa, AL, 35487, USA. liang005@ua.edu.
² Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, AL, 35487, USA.
³ Department of Chemistry, The University of Alabama, Tuscaloosa, AL, 35487, USA.

PMID: 27924493
DOI: 10.1007/s13361-016-1560-4

Abstract

A new matrix-assisted laser desorption ionization (MALDI) mass spectrometry matrix is proposed for molecular mass determination of polymers. This matrix contains an iron oxide nanoparticle (NP) core with citric acid (CA) molecules covalently bound to the surface. With the assistance of additives, the particulate nature of NPs allows the matrix to mix uniformly with polar or nonpolar polymer layers and promotes ionization, which may simplify matrix selection and sample preparation procedures. Several distinctively different polymer classes (polyethyleneglycol (PEG), polywax/polyethylene, perfluoropolyether, and polydimethylsiloxane) are effectively detected by the water or methanol dispersed NPCA matrix with NaCl, NaOH, LiOH, or AgNO₃ as additives. Furtheremore, successful quantitative measurements of PEG1000 using polypropylene glycol 1000 as an internal standard are demonstrated. Graphical Abstract ᅟ.

Keywords: Citric acid capped iron oxide nanoparticles; Polymer MADLI matrix.