Corrections for the Background in Atomic Absorption Analysis for Iron and Steel

Abstract

Corrections for the Background in Atomic Absorption Analysis for Iron and Steel Yoshihide ENDO and Yuki NAKAHARA Synopsis: For the determination of trace elements in iron, steel and iron are by atomic absorption analysis, the state of and the correction for influences by "the brackground" are studied. Following three methods for the correction for backgrounds are suggested. 1) Correction with blank-test of pure iron treated in the same way as provided samples. 2) Correction with the transmittance of several elements other than the objective ones in provided solutions by the use of the emissive line near the analytical line. 3) Correction with the transmittance of several elements at the analytical line in the continuous spectrum by H2 hollow cathode lamp. The first can be applied with satisfaction to the correction for the background of Fe, but not for other coexisting elements. The second can be applied to any coexisting elements, but not at the analytical lines influenced with the spectrum interference. The third cannot be applied to the samples containing much Fe, because of the spectrum interference by the analytical line of Fe on the measurement at continuous spectrum.

Correction of spectral overlap interference by Zeeman atomic absorption spectrometry

“…Spectral interference is caused by a Pb resonance line at 216.999 nm when the atomic absorption of Sb is measured at the Sb emission line at 217.581 nm (16,22,23). Spectral interference is also caused by the Ni resonance line at 231.096 nm when the atomic absorption of Sb is measured at the Sb emission line at 231.147 nm (15,24). These cases of spectral interference were both eliminated by using the Polarized Zeeman AA technique.…”

“…Figure 8 shows the effect of this kind of interference when a conventional AA unit with D2 lamp correction is used. Because of interference of this kind, conventional AA instruments are difficult to use for the analysis of trace elements in steel (24).…”

“…We look at two typical cases of direct spectral overlap of the analytical lines of Sb with the absorption lines of Pb and Ni which were reported by Slavin et al (16,22,23) and L'vov et al (15,24), respectively. These interferences frequently cause problems in the analysis of Sb.…”

Ferrous metallurgy

“…Atomic absorption spectrometry is still a fruitful area, but the methods developed as with spectrophotometry are limited to the determination of one element at a time, because multielement light sources are not generally available. However, hollow cathode lamps containing hydrogen and emitting continuous spectra have been used (255,273), but iron interferences were reported (155). Other papers have reported interferences in atomic absorption determinations (52, 340) and the requirement to match the compositions of standards and samples.…”

“…Other papers have reported interferences in atomic absorption determinations (52, 340) and the requirement to match the compositions of standards and samples. In addition, background corrections have been performed (44,155). Although furnaces using gas mixtures such as acetylene-air and acetylene-nitrous oxide are commonly used to vaporize the sample, flameless sources such as the graphite furnace are also used (227, 324,468).…”