ABSTRACT
This chapter explores the properties of Plasma-assisted desorption ionization (PADI) sources which make them ideal for the types of applications. It deals with a brief introduction into the plasmas and the key areas of understanding required for the radio-frequency plasma needle/PADI source. The chapter discusses the development of the plasma needle and the characterization of its physical, chemical, and electrical properties. It examines its use in surface analysis Mass Spectroscopy (MS) applications, the key desorption/ionization mechanisms, and its applications to studying the chemicals which are relevant for food and environmental applications. Time-resolved MS also has the advantage of being able to identify transient effects in the chemistry that time-averaged data can miss, such as the periods of production and loss as a function of time. Much of the research into PADI sources for MS applications has been performed by T. L. Salter et al. and various associates.
