Effect of Buffers in Spectrographic Analysis of Nickel by the Powder Method

Abstract

The d. c. excitation method has a high sensitivity and is a useful method when powdered samples are used. In the analysis of powdered samples by d. c. excitation method the sample is generally mixed with graphite powder. But the background of spectrum is apt to become troublesome when the sample is mixed with graphite powder alone. In determining the trace impurities the matrix element is often used as internal standard. But in simultaneous determination of trace impurities the use of matrix element as internal standard invites various problems.Spectroscopic buffer is being used to many substances for many purpQses. In the present work, repres5ing effects of background by spectroscopic buffer and effects of spectroscopic buffers on intensities of spectral lines of internal standard and measured elements are mainly studied by d. c. excitation on chemically treated powdered nickel samples.The buffers examined are potassium chloride, sodium carbonate, barium chloride, calcium carbonate, germanium dioxide, arsenic oxide.When potassium chloride or sodium carbonate mixed with graphite powder is used, the background of spectrum is reduced to such an extent that the correction of background is not needed in the wave length range from 2470 to 3500 A. But in this case the reproducibility of line ratio of measured element vs. internal standard line becomes worse. Use of buffer of low ionization potential makes the amount of the element in question, which enters the arc column, tends to vary. The effects of spectroscopic buffer on the nickel line is characteristic of the spectral lines 2914. 01, 3183. 25, 3195. 57.