Polypyrrole-coated needle as an electrospray emitter for ambient mass spectrometry

2020 ◽  
Vol 12 (25) ◽  
pp. 3235-3241
Author(s):  
Giovanna L. de Araújo ◽  
Deborah V. A. de Aguiar ◽  
Igor Pereira ◽  
Lidya C. da Silva ◽  
Andréa R. Chaves ◽  
...  

A method employing a stainless steel needle coated with PPy film for analyte extraction and subsequent analysis by electrospray ionization mass spectrometry (ESI-MS) under ambient and open-air conditions are shown.

2020 ◽  
Author(s):  
Danye Qiu ◽  
Miranda S. Wilson ◽  
Verena B. Eisenbeis ◽  
Robert K. Harmel ◽  
Esther Riemer ◽  
...  

AbstractThe analysis of myo-inositol phosphates (InsPs) and myo-inositol pyrophosphates (PP-InsPs) is a daunting challenge due to the large number of possible isomers, the absence of a chromophore, the high charge density, the low abundance, and the instability of the esters and anhydrides. Given their importance in biology, an analytical approach to follow and understand this complex signaling hub is highly desirable. Here, capillary electrophoresis (CE) coupled to electrospray ionization mass spectrometry (ESI-MS) is implemented to analyze complex mixtures of InsPs and PP-InsPs with high sensitivity. Stable isotope labeled (SIL) internal standards allow for matrix-independent quantitative assignment. The method is validated in wild-type and knockout mammalian cell lines and in model organisms. SIL-CE-ESI-MS enables for the first time the accurate monitoring of InsPs and PP-InsPs arising from compartmentalized cellular synthesis pathways, by feeding cells with either [13C6]-myo-inositol or [13C6]-D-glucose. In doing so, we uncover that there must be unknown inositol synthesis pathways in mammals, highlighting the unique potential of this method to dissect inositol phosphate metabolism and signalling.


2011 ◽  
Vol 64 (6) ◽  
pp. 705 ◽  
Author(s):  
Jennifer L. Beck

Many anti-cancer drugs function by binding non-covalently to double-stranded (ds) DNA. Electrospray ionization mass spectrometry (ESI-MS) has emerged over the past decade as a sensitive technique for the determination of stoichiometries and relative binding affinities of DNA–ligand interactions. The chromosome contains nucleotide sequences, for example, guanosine-rich regions, that predispose them to the formation of higher order structures such as quadruplex DNA (qDNA). Sequences that form qDNA are found in the telomeres. The proposal that ligands that stabilize qDNA might interfere with the activity of telomerase in cancer cells has stimulated the search for ligands that are selective for qDNA over dsDNA. The insights gained from the development of ESI-MS methods for analysis of non-covalent dsDNA–ligand complexes are now being applied in the search for qDNA-selective ligands. ESI-MS is a useful first-pass screening technique for qDNA-binding ligands. This short review describes some experimental considerations for ESI-MS analysis of DNA–ligand complexes, briefly addresses the question of whether non-covalent DNA–ligand complexes are faithfully transferred from solution to the gas phase, discusses ion mobility mass spectrometry as a technique for probing this issue, and highlights some recent ESI-MS studies of qDNA-selective ligands.


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