Hydroxyl-Group-Dominated Graphite Dots Reshape Laser Desorption/Ionization Mass Spectrometry for Small Biomolecular Analysis and Imaging

ACS Nano ◽  
2017 ◽  
Vol 11 (9) ◽  
pp. 9500-9513 ◽  
Author(s):  
Rui Shi ◽  
Xing Dai ◽  
Weifeng Li ◽  
Fang Lu ◽  
Yang Liu ◽  
...  
Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6848
Author(s):  
Małgorzata Kasperkowiak ◽  
Monika Kurowska ◽  
Maciej Zalas ◽  
Rafał Frański

For many applications, TiO2 must have a unique surface structure responsible for its desirable physicochemical properties. Therefore the fast and easy methods of TiO2 surface characterization are of great interest. Heated TiO2 samples and dye-modified TiO2 samples were analyzed by laser desorption/ionization mass spectrometry. In the negative ion mode, two types of ions were detected, namely (TiO2)n− and (TiO2)nOH−. It has been established that the samples can be differentiated based on the relative ion abundances, especially with respect to the free hydroxyl group population. It indicates that laser desorption ionization mass spectrometry has the potential for the investigation of the surface properties of various TiO2 materials.


Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 610
Author(s):  
Mariann Inga Van Meter ◽  
Salah M. Khan ◽  
Brynne V. Taulbee-Cotton ◽  
Nathan H. Dimmitt ◽  
Nathan D. Hubbard ◽  
...  

Agglomeration of active pharmaceutical ingredients (API) in tablets can lead to decreased bioavailability in some enabling formulations. In a previous study, we determined that crystalline APIs can be detected as agglomeration in tablets formulated with amorphous acetaminophen tablets. Multiple method advancements are presented to better resolve agglomeration caused by crystallinity in standard tablets. In this study, we also evaluate three “budget” over-the-counter headache medications (subsequently labeled as brands A, B, and C) for agglomeration of the three APIs in the formulation: Acetaminophen, aspirin, and caffeine. Electrospray laser desorption ionization mass spectrometry imaging (ELDI-MSI) was used to diagnose agglomeration in the tablets by creating molecular images and observing the spatial distributions of the APIs. Brand A had virtually no agglomeration or clustering of the active ingredients. Brand B had extensive clustering of aspirin and caffeine, but acetaminophen was observed in near equal abundance across the tablet. Brand C also had extensive clustering of aspirin and caffeine, and minor clustering of acetaminophen. These results show that agglomeration with active ingredients in over-the-counter tablets can be simultaneously detected using ELDI-MS imaging.


Author(s):  
Alef dos Santos ◽  
Edson Rodrigues-Filho ◽  
Manoel Gustavo Petrucelli Homem

Abstract Lipids are among the organic substances that can work as biosignatures, indicating life in an environment. We present an experimental investigation concerning analysis of lipids from a microbial source deposited on the Mars Global Simulant (MGS-1) regolith by geomatrix-assisted laser desorption/ionization-mass spectrometry (GALDI-MS). Our results indicate that lipids from intact microbial cells of a black yeast strain can be detected in these mimetic samples of Martian soil. These lipid molecules are predominantly associated with the occurrence of adducts in the GALDI-MS spectra. The results can be helpful in the planning of future planetary missions.


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