Influence of Background on Iron and Steel Analysis by Inductively Coupled Plasma Atomic Emission Spectrometry

The emission intensity of background spectrum occupies a large part of measured intensity, in determining micro amounts of elements in iron and steel by inductively coupled plasma emission spectrometry. Therefore, it is necessary to eliminate the background part in order to obtain the correct intensity of analytical spectrum. Two methods have been proposed to eliminate the background:(1) The sample is analyzed with calibration solution containing same amounts of matrix elements as in the sample solution.(2) The intensity of background spectrum is measured with the neighboring line and subtracted from that of analytical line.The former is valid for the analysis of samples with known chemical composition, the latter is applicable to all unknown samples. The difficulty, however, still remains for it to find the neighboring line with which emission spectra of iron and other elements do not overlap. Both methods have been applied to the determination of trace amounts of cobalt and zinc in a steel. The background has been fully corrected by both methods, and the results obtained are well agreed with those obtained by conventional method of chemical analysis.