9531437 McCormick This Small Business Technology Transfer Phase II project will develop a capacitively coupled microwave plasma (CCMP) as a microsample excitation plasma for multielement determinations with the detection limits, accuracy, precision and sample size requirements of modern graphite furnace atomic absorption spectrometry using atomic emission spectrometry. Currently, there are no widely applicable analytical methods for multielement determinations on microsamples. In the unique CCMP approach the helium plasma supported on an electrode in the microwave field envelops a tungsten cup containing the liquid (2 - 10 microliters) or solid (ca. 1mg) sample. The transient emission is detected with an echelle spectrometer using a Charge Injection Device (CID) detector. Detection limits are in the low pg range with 10 microliter liquid samples (0.5-5 ppb). Studies using the Thermo Jarrell Ash IRIS echelle spectrometer indicated that the CCMP is well suited for multielement detection. Phase II will include the design of an optimum optical interface between the plasma and the echelle spectrometer, optimization of the CID data acquisition for transient signals, refinement in the electrode, redesign of the power supply to allow more reproducible computer control of the microwave field, and a comprehensive study of potential interferences in a variety of matrices, using both liquid and solid samples. The unique combination of multielement capability, high sensitivity, low cost, and ease of use results in substantral potential markets in clinical research, medical diagnostics, and routine laboratory analysis.
