Abstract
In analysing niobium in low alloy steel with an emission spectrochemical technique using Nb II 3194.977Å as an analytical line, it was found that higher experimental values were obtained in spite of the absence of known interference line. The values of 0.004% to 0.007% were, for example, found in spite of the absence of niobium in the steel samples.
Studying this phenomenon, we found the following facts;
(1) Among the elements such as molybdenum, iron, tungsten, vanadium and titanium which were classified as interfering elements in the JIS G 1253 (1973), the interferences of titanium and molybdenum with larger spectral intensities can be corrected by the formulae,
ΔNb(%)=0.0174Ti(%)-0.0050 (Ti>0.28%)
ΔNb(%)=0.0049Mo(%)-0.0079 (Mo>1.60%)
On the other hand, vanadium do not interfere with niobium, even if vanadium of about 2% is contained in steel samples.
(2) The precision (σd) was low for the steel sample containing much manganese.
(3) It was demonstrated by this work that a spectral line of manganese is present at the wavelength position of about 3194.87Å in the vicinity of Nb II 3194.977Å.
(4) The interference of Mn 3194.87Å on the Nb II 3194.977Å can be corrected by the following formula;
ΔNb(%)=0.0034Mn(%)-0.0020 (Mn>0.80%)
By the correction of the interference of the Mn 3194.87Å, the precision (σd) of 10 steel samples was much improved and became practically sufficient for the routine analysis.
