Detection of multiply charged protein ions using matrix-assisted laser desorption/ionization mass spectrometry and a force-dried droplet method with a 2-nitrophloroglucinol matrix

The Analyst ◽  
2022 ◽  
Author(s):  
Kangseok Yun ◽  
Iqbal Jalaludin ◽  
Shinhee Jung ◽  
Kyoung-Soon Jang ◽  
Jeongkwon Kim

Conventional dried droplet (DD) methods show poor reproducibility in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) due to the frequent induction of a heterogeneous sample distribution. Recently, a forced dried droplet...

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 6054
Author(s):  
Antonio Monopoli ◽  
Angelo Nacci ◽  
Tommaso R. I. Cataldi ◽  
Cosima D. Calvano

The effectiveness of a synthesized matrix, α-cyano-5-phenyl-2,4-pentadienic acid (CPPA), for protein analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) in complex samples such as foodstuff and bacterial extracts, is demonstrated. Ultraviolet (UV) absorption along with laser desorption/ionization mass spectrometry (LDI-MS) experiments were systematically conducted in positive ion mode under standard Nd:YLF laser excitation with the aim of characterizing the matrix in terms of wavelength absorption and proton affinity. Besides, the results for standard proteins revealed that CPPA significantly enhanced the protein signals, reduced the spot-to-spot variability and increased the spot homogeneity. The CPPA matrix was successful employed to investigate intact microorganisms, milk and seed extracts for protein profiling. Compared to conventional matrices such as sinapinic acid (SA), α-cyano-4-hydroxycinnamic acid (CHCA) and 4-chloro-α-cyanocinnamic acid (CClCA), CPPA exhibited better signal-to-noise (S/N) ratios and a uniform response for most examined proteins occurring in milk, hazelnut and in intact bacterial cells of E. coli. These findings not only provide a reactive proton transfer MALDI matrix with excellent reproducibility and sensitivity, but also contribute to extending the battery of useful matrices for intact protein analysis.


Sign in / Sign up

Export Citation Format

Share Document