A spectrographic procedure for the simultaneous determination of Pb, Fe, Ni, Sn, Bi, and Sb in 70/30 brass and admiralty brass is described in detail. The source is a 14-ampere low voltage d.c. arc of conventional type. A 50-mg pellet sample is arced to extinction in a cupped graphite electrode of specified dimensions. “The intermediate mode” of illumination obtained by focusing the source on the collimator lens is used. A radial sector disk placed at the slit is used to regulate the effective exposure at the plate. The step sector method of plate calibration is used. The source for the calibration is a 4-ampere d.c. arc on 3/16″ diameter copper electrodes. The calibration curve on the copper line 2882.934A is used for a wave-length region 2590A–3100A. The copper reference line of 2858.734A is chosen for comparison with the respective impurity lines. Working curves are given for the determination of Pb, Fe, Ni, Sn, and Sb in the range of 0.01–0.10 percent and Bi in the range of 0.0004–0.010 percent.
P. A. LEICHTLE, "Spectrographic Determination of Trace Elements in 70/30 Brass and Admiralty Brass. Part 1," J. Opt. Soc. Am. 34, 454-460 (1944)