| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1193015 | International Journal of Mass Spectrometry | 2015 | 10 Pages |
•A systematic study of the characteristics of the MIPDI source including mass spectrum specificities, thermal effects, desorption efficiency related to the thermal effect was explored.•A molecule having quaternary ammonium functionality was successfully detected without any auxiliary agents or devices by MIPDI.•A direct comparison of MIPDI spectra fragmentation features and EI spectra was made.
Microwave induced plasma desorption/ionization (MIPDI) mass spectrometry is a promising tool for on-line analysis of various samples without pre-treatment at atmospheric pressure. Since the first report of the MIPDI source by our group, a related instrument is emerging. Other than the advantages of any existing ambient ion source, this newly emerging ambient desorption/ionization source has unique characteristics when compared with traditional ambient pressure ionization (API) and plasma based desorption ion sources. In the work described herein, preservatives for cosmetics were chosen as sample molecules in a systematic study of the characteristics of the MIPDI source because of their variety. Description of the ionization process of the MIPDI source is given. The background spectra of reagent ions and interference ions were observed. The basic operational parameters including flow rate and microwave forward power were optimized. The mass spectrum specificities of the MIPDI source were exhibited and explained for their possible formation routes. Thermal effects were investigated by comparing the composition ratio of fragment ions in the spectra under different microwave forward powers. The desorption efficiency, related to the thermal effect, was explored. For the first time, a molecule having a quaternary ammonium functionality was successfully detected without any auxiliary agents or devices by using a desorption/ionization source. Also for the first time, a direct comparison of the fragmentation features of MIPDI spectra and EI spectra was made. It was concluded that MIPDI is a hard-soft ion source which provides a considerable population of fragment ions as well as relative stable molecular ions.
Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (72 K)Download as PowerPoint slide
