UBC Theses and Dissertations
Characterization of an atmospheric pressure ion lens for electrospray ionization sources in mass spectrometry Manisali, Irina
The purpose of this project is to characterize the properties of an atmospheric pressure ion lens used to facilitate and improve the operation of electrospray ionization (ESI) sources for mass spectrometry (MS). This work is in part motivated by the inefficient transmission of ions from atmospheric pressure into vacuum, characteristic of current electrospray ion source designs. The first chapter of this thesis will be an introduction to the basic theory and the historical developments of ESI sources for MS from early designs to today's commercial geometries. The second chapter of this thesis summarizes previous research that has been done with respect to atmospheric pressure electrostatic devices for ESI sources, including work done in our laboratory. The objective of the present project is also described in more detail in this section. Descriptions of the instruments and their operation, as well as the experimental procedures used in this project are presented in the third chapter. The fourth chapter presents some of the results and it attempts to explain the observed trends with the help of simulations. The results show that the mechanism of the ion lens is not trivial. The effect 6f the ion lens is different for analytes of various charge states and is highly dependent on a number of instrumental and environmental parameters. The size and shape of the lens is also important. The ion lens was shown to stabilize the electrospray, as well as improve the signal-to-noise ratio (S/N) in some instances, while at other times it was difficult to observe any effect at all. Future work that may help optimize the operation of the ion lens is discussed in the final chapter.
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