Electrospray ionization mass spectrometer with new features

摘要

An electrospray ion source is designed for ready and simple plugging into commercial mass analyzers for mass spectrometric analysis of organic molecules. The electrospray is carried out is the ambient air and the ions and other charged species enter the mass analyuzer through a long metal capillary tube and three stages of differential pumping. The use of the long tube allows (a) convenient injection of the ions into the mass analyzer (b) optimization of the spray by direct visualization in the air (c) efficient and controlled heat transfer to the droplets and (d) efficient pumping of the region between the capillary exit and the skinner. Desolvation of the solvated ions is carried out using a combination of controlled heat transfer to the charged droplets during the transit through the tube and collisional activation in a region of reduced pressure. Desolvation with this system does not involve use of a strong countercurrent flow of heated gas. The system also may be used to obtain the collisional activated fragmentation spectra of molecule ions. The use of a metal capillary tube avoids complications from charging that arise from the use of dielectric capilliary tubes.