Dihydrobenzoic Acid Modified Nanoparticle as a MALDI-TOF MS Matrix for Soft Ionization and Structure Determination of Small Molecules with Diverse Structures

• Published in: Journal of the American Society for Mass Spectrometry 2010-11, Vol.21 (11), p.1930-1939
• Main Authors: Tseng, Mei-Chun, Obena, Rofeamor, Lu, Ying-Wei, Lin, Po-Chiao, Lin, Ping-Yu, Yen, Yung-Sheng, Lin, Jiann-Tsuen, Huang, Li-De, Lu, Kuang-Lieh, Lai, Long-Li, Lin, Chun-Cheng, Chen, Yu-Ju
• Format: Article
• Language: English
• Subjects: Air Ionization; Analytical Chemistry; Benzoates - chemistry; Bioinformatics; Biotechnology; Chemistry; Chemistry and Materials Science; Databases, Factual; Dendrimers; Desorption; Devices; Exact sciences and technology; Fragmentation; Glycolipids - chemistry; Inorganic Chemicals - chemistry; Ionization; Ions; Ions - chemistry; Iron oxides; Isomers; Magnetite Nanoparticles - chemistry; Mass spectrometry; Molecular ions; Molecular structure; Nanocomposites; Nanomaterials; Nanoparticles; Nanostructure; Organic Chemicals - chemistry; Organic Chemistry; Photovoltaic cells; Plates (structural members); Proteomics; Protonation; Quality control; Silicon dioxide; Silicon Dioxide - chemistry; Solar cells; Spectrometric and optical methods; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - methods; Structural analysis; Tandem Mass Spectrometry
• ISSN: 1044-0305; 1879-1123
• DOI: 10.1016/j.jasms.2010.08.001

Efficient structural characterization is important for quality control when developing novel materials. In this study, we demonstrated the soft ionization capability of the hybrid of immobilized silica and 2,5-dihydrobenzoic acid (DHB) on iron oxide magnetic nanoparticles in MALDI-TOF MS with a clean background. The ratio between SiO 2 and DHB was examined and was found to affect the surface immobilization of DHB on the nanoparticle, critically controlling the ionization efficiency and interference background. Compared with commercial DHB, the functionalized nanoparticle-assisted MALDI-TOF MS provided superior soft ionization with production of strong molecular ions within 5 ppm mass accuracy on a variety of new types of synthetic materials used for solar cells, light emitting devices, dendrimers, and glycolipids, including analytes with either thermally labile structures or poor protonation tendencies. In addition, the enhancements of the molecular ion signal also provided high-quality product-ion spectra allowing structural characterization and unambiguous small molecule identification. Using this technique, the structural differences among the isomers were distinguished through their characteristic fragment ions and comprehensive fragmentation patterns. With the advantages of long-term stability and simple sample preparation by deposition on a regular sample plate, the use of DHB-functionalized nanoparticles combined with high-resolution MALDI-TOF MS provides a generic platform for rapid and unambiguous structure determination of small molecules. Enhanced, soft, background-free identification of diverse groups of small molecules by MALDI-TOF.