Lipid profiling using catalytic pyrolysis/metal oxide laser ionization-mass spectrometry

Laser desorption ionization of small molecules assisted by tungsten oxide and rhenium oxide particles

“…Other attempts have made use of metal oxides such as ZnO, MnO, CoO, WO 3 , TiO 2 , SnO 2 , Fe 3 O 4 , CaO, and NiO; and bare metals such as Au, Ag, Sn, and Al . Clearly, the use of metal oxides as a base for LDI has been investigated for several compounds, and the Vorhees' research lab, responsible for studies using CaO and NiO, have coined this work as metal oxide laser ionization mass spectrometry (MOLI) …”

Identification of bacteria by fatty acid profiling with direct analysis in real time mass spectrometry

“…published a MALDI‐MS FA profiling technique employing calcium oxide (CaO) as a catalyst and a matrix replacement utilizing the same MALDI‐MS instrument used in protein profiling . The CaO cleaved lipids to fatty acid Ca adducts in positive‐ion MS and fatty acid anions in negative‐ion mode with reproducibility similar to saponification results . Linear discriminant analysis of data from ten bacterial species analyzed using CaO in both positive‐ and negative‐ion modes showed greater than 94% correct assignment …”

“…Previously reported CaO studies utilized a chloroform/methanol extraction of the bacterial cells . This extract consisted of free FAs plus lipid‐bound FAs.…”

“…used Curie point pyrolysis mass spectrometry to show that volatilized FAs from a group of Gram‐positive and Gram‐negative bacteria were species specific . In the following paper, the same extracts described by Voorhees et al . were analyzed by using DART to generate FA profiles.…”

Extension of metal oxide laser ionization mass spectrometry to analytes with varied chemical functionalities

“…Spectra generated with MgO or NiO were comprised, in positive ion mode, of predominately protonated or sodiated molecules with minimal fragmentation or spectral background interference. The increased reactivity of CaO resulted in catalytic cleavage of ester‐containing lipid molecules producing fatty acid ions …”