INTRACAVITY LASER SPECTROSCOPIC METHOD FOR DETERMINING TRACE AMOUNTS OF IODINE AND BARIUM IN WATER AND BIOLOGICAL SAMPLES

An intracavity laser spectroscopic method and the necessary instrument ation are described for the direct determination of trace amounts of i odine in water and in biological media. Minimal sample preparation is required for the laser probing of vapours over the surface of the heat ed liquid in a closed cell. This laser method is also applied to measu rements of ultra-low barium contents in water by sample evaporation in a standard graphite furnace electrothermal atomizer. Detection limits of 0.01 5 mg l-1 and 0.2 ng l-1 were obtained for iodine and barium, respectively, which are 2-3 orders of magnitude lower than those obtai ned using a pulsed dye laser. The precision of the method was 10% for the lowest concentrations measured. The procedure is comparatively sim ple, quick and inexpensive.