LASER FLASH HEATING TECHNIQUES FOR ATOMIC ABSORPTION SPECTROSCOPY.

This report comprises fundamental procedures and techniques employed to utilize a moderate power cw laser for vaporization of metallic alloys with subsequent spectrophotometric analysis. A substantial amount of data is presented for zinc, copper, lead, aluminum, nickel, and tin to illustrate areas of success and problems, the latter being fundamental to a cw laser approach. In several areas, namely absorber path length and analytical mass rate sensitivity, direct comparison is made to the conventional flame approaches of atomic absorption spectroscopy. For zinc, copper and lead, analytical mass rate sensitivities of 0.00029, 0.00047, and 0.00077 microgramsec1 percent absorption were determined. For copper, the 4 inch air-acetylene sensitivity is 0.0007 microgramsec1 percent absorption. In developing techniques, absorption sample weight dependency and sample vapor shape and size were determined for a number of conditions. Reproducibility for optimum conditions is 15 percent and generally better than 50 percent. The data and subsequent analysis and results constitute a reasonably broad base foundation to the technique of cw laser vaporization for AA spectroscopy. Author