title: Iron oxide nanomatrix facilitating metal ionization in matrix-assisted laser desorption/ionization mass spectrometry.
abstract: The significance and epidemiological effects of metals to life necessitate the development of direct, efficient, and rapid method of analysis. Taking advantage of its simple, fast, and high-throughput features, we present a novel approach to metal ion detection by matrix-functionalized magnetic nanoparticle (matrix@MNP)-assisted MALDI-MS. Utilizing 21 biologically and environmentally relevant metal ion solutions, the performance of core and matrix@MNP against conventional matrixes in MALDI-MS and laser desorption ionization (LDI) MS were systemically tested to evaluate the versatility of matrix@MNP as ionization element. The matrix@MNPs provided 20- to >100-fold enhancement on detection sensitivity of metal ions and unambiguous identification through characteristic isotope patterns and accurate mass (<5 ppm), which may be attributed to its multifunctional role as metal chelator, preconcentrator, absorber, and reservoir of energy. Together with the comparison on the ionization behaviors of various metals having different ionization potentials (IP), we formulated a metal ionization mechanism model, alluding to the role of exciton pooling in matrix@MNP-assisted MALDI-MS. Moreover, the detection of Cu in spiked tap water demonstrated the practicability of this new approach as an efficient and direct alternative tool for fast, sensitive, and accurate determination of trace metal ions in real samples.
authors: Institute of Chemistry, Academia Sinica, Taipei, Taiwan.
authors: Rofeamor P
authors: RP
authors: Obena
authors: Po-Chiao
authors: PC
authors: Lin
authors: Ying-Wei
authors: YW
authors: Lu
authors: I-Che
authors: IC
authors: Li
authors: Florian
authors: F
authors: del Mundo
authors: Susan dR
authors: Sd
authors: Arco
authors: Guillermo M
authors: GM
authors: Nuesca
authors: Chung-Chen
authors: CC
authors: Lin
authors: Yu-Ju
authors: YJ
authors: Chen
mesh_terms: D005290:Ferric Compounds / Q000737:chemistry*; D005618:Fresh Water / Q000737:chemistry; D007477:Ions / Q000737:chemistry; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D008670:Metals / Q000032:analysis*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D005290:Ferric Compounds; D007477:Ions; D058185:Magnetite Nanoparticles; D008670:Metals; C000499:ferric oxide