title: Citric Acid Capped Iron Oxide Nanoparticles as an Effective MALDI Matrix for Polymers.
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 AgNO3as additives. Furtheremore, successful quantitative measurements of PEG1000 using polypropylene glycol 1000 as an internal standard are demonstrated. Graphical Abstract ᅟ.
authors.affiliation: Department of Chemistry, The University of Alabama, Tuscaloosa, AL, 35487, USA. liang005@ua.edu.
authors.forename: Qiaoli
authors.identifier: 0000-0002-2395-8778
authors.initials: Q
authors.lastname: Liang
authors.affiliation: Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, AL, 35487, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Sherwood
authors.affiliation: Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, AL, 35487, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Macher
authors.affiliation: Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, AL, 35487, USA.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Wilson
authors.affiliation: Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, AL, 35487, USA.
authors.forename: Yuping
authors.initials: Y
authors.lastname: Bao
authors.affiliation: Department of Chemistry, The University of Alabama, Tuscaloosa, AL, 35487, USA.
authors.forename: Carolyn J
authors.initials: CJ
authors.lastname: Cassady
keywords: Citric acid capped iron oxide nanoparticles; Polymer MADLI matrix