Molecular-emission spectroscopy in cool flames. Part III. The emission characteristics of tin in diffusion flames

Abstract

Tin can be determined in the range 3 to 3000 p.p.m. by molecular-band emission from the SnH species in a nitrogen-hydrogen diffusion flame. The emission at 609·5 nm, which is almost line-like, gives a limit of detection of 1·5 p.p.m. of tin. Spectral interference from sodium is eliminated by use of a didymium filter. The presence of oxygen gives rise to a much broader spectrum, caused by tin(II) oxide formation, with a visual limit of detection of 5 p.p.m. of tin. Atomic emission can be observed only in the presence of alcohols, e.g., isopropyl alcohol, but a high concentration of ground-state tin atoms exists in the diffusion flame. Mechanisms are discussed to explain the production of tin atoms, SnH and the resonance-line emission.