An investigation of the performance of the separated air-acetylene flame in thermal-emission spectroscopy

Abstract

The advantages of the application of a nitrogen-separated air-acetylene flame in the flame-emission spectroscopy of seventeen elements is described. In this flame the secondary reaction zone is separated by a stream of nitrogen flowing parallel to the flame to prevent access of atmospheric oxygen to its base. The low flame background and noise levels have been shown to result in improvement in the detection limits for fifteen elements. In addition, whereas molybdenum and vanadium atomic emission are not detectable in the interconal zone of the conventional flame, in the separated flame detection limits of 2 p.p.m. and 10 p.p.m. have been obtained in aqueous solution for molybdenum (379·8 nm) and vanadium (318·5 nm), respectively. Separation of much of the molecular-band emission from some elements with the secondary reaction zone may result in partial suppression of spectral interference from these elements on the atomic-line emission of the elements determined. The suppression of the interference of magnesium, which occurs through MgOH emission in the secondary zone, on the determination of iron is demonstrated as an example of this effect.