This project is in the general area of analytical and surface chemistry and in the subfield of inductively coupled plasma (ICP) spectroscopy. The thrust of this experimental project continues studies initiated under NSF grant CHE-8503090 that focus on sample introduction for inductively coupled plasma atomic emission spectroscopy (ICP/AES) and inductively coupled plasma mass spectrometry (ICP/MS). A number of physical parameters which describe aerosol generation, transport, evaporation, and interactions with the plasma will be measured. These parameters include drop size distributions of aerosols, and mass transport values for analyte and solvent transport to the plasma. A key aspect of the work is an investigation of the mechanisms of solvent liquid and vapor interaction with the plasma, which appear to exert a major effect on important plasma properties, such as ionization temperature and electron density. As part of this research, a working model of aerosol generation, using pneumatic and other means of nebulization will be developed, based on experimental data obtained by laser Fraunhofer scattering. The use of a monodisperse aerosol generator (MAGIC) interface as a means of introducing desolvated analyte to both atmospheric pressure and low pressure radio frequency discharges will be investigated, and the fundamental aerodynamic, particle dynamic, and transport aspects of these interfaces will be studied. The low pressure interface will be coupled to a novel low-pressure ICP for use in both ICP/AES and ICP/MS. This research, which focusses on the historically weak link (sample introduction) in ICP-based analyses, opens the door to broader applications of analytically powerful ICP spectroscopic techniques and should enable the development of new technologies which could be capitalized upon by private sector instrument manufacturers.
