Matrix assisted ionization in vacuum (MAIV): For high resolution Fourier transform ion cyclotron resonance

by Wang, Beixi; Akhmetova, Evgenia; Trimpin, Sarah; Wilkins, Charles L.

A new ionization process that utilizes the matrix 3-nitrobenzonitrile (3-NBN) and Fourier transform mass spectrometry (FTMS) is described. This method, called matrix assisted ionization in vacuum (MAIV) was discovered by Trimpin and co-workers in 2012. The key feature of this new ionization technique is that it does not require use of a laser, heat, or a high voltage. Instead, it simply involves exposure of a mixt. of the matrix and sample to the vacuum of a mass spectrometer. Results with a Fourier transform ion cyclotron resonance spectrometer obtained with either a MALDI source or an ESI source with no laser applied in the MALDI source nor any high voltage applied in the ESI source are reported. Under these conditions, singly and multiply charged ions were obsd. in the mass spectra of samples. Accordingly, there is the possibility of performing electron capture dissocn. (ECD) studies under MALDI conditions. A mixt. of small peptides including angiotensin 1 & 2, leucine enkephalin, allatostatin, and bombesin was analyzed. Proteins included bovine insulin, ubiquitin, and bovine serum albumin. The 9.4 T FTMS used for these studies produced resolving powers between 23,000 and 400,000 for the present set of samples.