| The objective of this research is to explore the benefits and drawbacks of direct injection nebulization into inductively coupled plasmas (ICPs) for the analysis of complex sample types. In recent years, direct solution introduction into ICPs, in the absence of a spray chamber, has received a great deal of attention within the analytical chemistry community. The technique offers improvements and presents limitations compared to conventional nebulization techniques, with the improvements far exceeding the limitations. Improvements include reduced memory effect, low sample consumption (<100 muL/min), analysis of microliter-sized sample volumes, no waste generation, and improved sensitivity, precision and detection limits. The limitations encompass increased cost, greater susceptibility to clogging and melting of the nebulizer tip, and enhanced matrix effect.; Major findings of this dissertation include a reduction in wash-in and wash-out times for memory prone elements such as mercury, iodine, and boron by up to a factor of 100. Analytical performance is greatly improved and polyatomic molecular ion interferences are diminished by up to 3 orders of magnitude through the application of hexapole collision cell technology. Low sample consumption capabilities of direct injection nebulization allow complete analysis of a 100-muL drop of H2O/H2O2/HF to obtain silicon wafer surface contamination at a concentration of 0.49 to 6.5 x 109 atoms/cm2. Chromatographic separation of five arsenic species: As III, As V, DMA, MMA, and p-arsanilic acid, is conducted at 1 muL/min and 500 nL/min, with absolute detection limits in the picogram range. ICPAES studies reveal enhanced sodium matrix effects with direct injection nebulization compared to the conventional nebulizer-spray chamber arrangement and a marked reduction in the matrix effect with the use of Ar-N2 and Ar-O2 mixed gas plasmas.; In this research, the benefits and limitations of direct injection are studied and various approaches are outlined along with a number of solutions to the problems. A wide variety of complex sample types are investigated, including biological, clinical, pharmaceutical, and industrial samples, using a wide range of techniques such as spectrometric systems equipped with quadrupole filter, double focusing ICPMS, collision cell ICPMS and ICP atomic emission spectrometry (axial and radial), and high performance liquid chromatography. |
