The determination of rare-earth elements in gallium arsenide by a dc arc was studied. An argon and oxygen atmosphere was carefully selected to enhance the selective volatilization of rare earths which comes at the very end of arcing in this matrix. The controlled atmosphere also contributed to the suppression of the CN band and allowed the use of this region. A commercially available standard was used to mix with the matrix for preparation of synthetic standards. The recovery means were within 30% of the amount added and relative coefficients of variations are within 16%. The range of determinations, below the 1 ppm levels, were reported.
