Doctor of Philosophy, DalianInstiOf Chemical Phys,Chinese AcadamyofScien (2011)
Master of Science, Unlisted University (2007)
Bachelor of Science, Unlisted University (2004)
Dick Zare, Postdoctoral Faculty Sponsor
- Laser-Based Mass Spectrometric Determination of Aggregation Numbers for Petroleum- and Coal-Derived Asphaltenes ENERGY & FUELS 2014; 28 (1): 475-482
Minimization of fragmentation and aggregation by laser desorption laser ionization mass spectrometry.
Journal of the American Society for Mass Spectrometry
2013; 24 (7): 1116-1122
Measuring average quantities in complex mixtures can be challenging for mass spectrometry, as it requires ionization and detection with nearly equivalent cross-section for all components, minimal matrix effect, and suppressed signal from fragments and aggregates. Fragments and aggregates are particularly troublesome for complex mixtures, where they can be incorrectly assigned as parent ions. Here we study fragmentation and aggregation in six aromatic model compounds as well as petroleum asphaltenes (a naturally occurring complex mixture) using two laser-based ionization techniques: surface assisted laser desorption ionization (SALDI), in which a single laser desorbs and ionizes solid analytes; and laser ionization laser desorption mass spectrometry (L(2)MS), in which desorption and ionization are separated spatially and temporally with independent lasers. Model compounds studied include molecules commonly used as matrices in single laser ionization techniques such as matrix assisted laser desorption ionization (MALDI). We find significant fragmentation and aggregation in SALDI, such that individual fragment and aggregate peaks are typically more intense than the parent peak. These fragment and aggregate peaks are expected in MALDI experiments employing these compounds as matrices. On the other hand, we observe no aggregation and only minimal fragmentation in L(2)MS. These results highlight some advantages of L(2)MS for analysis of complex mixtures such as asphaltenes.
View details for DOI 10.1007/s13361-013-0636-7
View details for PubMedID 23633019