鉛地金の定量分光分析について

Abstract

As the lead metals are of comparatively high purity, the chemical analysis is not suitable for quantitative determination of slight impurities in these metals.The authors, therefore, have studied the spectrum analysis of small amounts of impurities in lead metals, using an intermitent arc with the Shimadzu littrow type large quarts spectrograph and its accessories.The experiments were done under the following conditions: pin type electrode, electrode gap 2mm, slit width 30 micron, Feussner circuit L=0, C=0.0033μF, primary volt. 50V; Intermittence ratio of intermittent apparatus 1/20, occurrences of intermittence 1/sec, arc current A.C 220V. 5A and the step filter (26%-100%-4%) used in front of the slit.The spectrum was recorded on spectrographic plates, which were developed for 3 minutes with continuous agitation in a constant temperature tank with Fuji FD-31 developer.Spectral intensity was measured using a microphotometer and the following analytical line pairs were measured: Ag 3382.9/Pb 3220.5, Cu 3274.0/Pb 3220.5, Bi 3067.7/Pb 3220.5, Sn 3175.0/Pb 3220.5 and Sb 2598.1/Pb 3220.5Å.The ranges which were determined are 0.0001-0.007% Ag, 0.001-0.07% Cu, 0.001-0.035% Bi, 0.001-0.07% Sn and 0.002-0.14% Sb.The results obtained were summarized as follows:1) The simultaneous estimation of Ag, Cu, Bi and Sn is made easily and rapidly, but the determinatian of small amounts (<0.006%) of Sb by means of the pin type electrodes was difficult.2) Reproducibility of the spectrum value was fine within the standard deviation of 3 to 5% except for the low content of Sb.