Sheet metal is directly analyzed for boron by means of spark excitation. Source inductance of 200 to 300 μh, together with rotation of the specimen during excitation, provides detectability an order of magnitude better than conventional spark excitation of steel. Sheet material of 0 050 in thickness and containing a nominal 0.004% boron is analyzed with a coefficient of variation of 3.2%.
E. F. Runge and F. R. Bryan, "A Spark Spectrographic Procedure For the Determination of Boron in Sheet Steel," Appl. Spectrosc. 15, 13-15 (1961)