Direct Detection of Beryllium on Filters Using the Laser Spark

Abstract

A method has been developed to spectrochemically analyze beryllium particles on filters using the laser spark. The spark, formed on the filter by a cylindrical lens, is 0.1-mm wide and 4- to 8-mm long. By the rotation of the filter under the spark, a large area can be sampled in only a few minutes. The surface detection limit (SNR = 6) for particles 0.5–5 μm in diameter is 0.45 ng/cm 2 , which corresponds to 3.6 ng total Be mass on the exposed area (32-mm diam.) of a 37-mm-diam. filter. The RSD for replicate sample analysis is 4%. Several methods of calibrating the technique are discussed. The effects of particle size and some contaminants on the analysis are described. The usefulness of this method for monitoring airborne beryllium concentrations is considered.