Flame Spectrophotometry

Abstract

One of the first applications of the study of flame spectra was for qualitative analysis, and indeed some elements were first discovered from their characteristic flame spectra, e.g. rubidium by Bunsen and Kirchhoff in 1861. Quantitative spectrochemical analysis now has frequent and important applications in both industry and research, especially for trace elements. The main sources for excitation of spectra are arcs, sparks and flames. The spectrum of an element, as developed in a flame, is relatively simple, consisting normally of only a few resonance lines; identification of the lines is thus much easier than with the more complicated arc or spark spectra, and confusion with lines of other elements is less likely. With such simple spectra it is often sufficient to use spectrographs or monochromators of low resolving power, or even in some cases just interference colour filters. Also flames are much steadier sources than arcs or sparks and are capable of higher precision for quantitative measurements. Since the previous edition of this book was written there have been major improvements in the techniques of flame photometry, especially in the use of atomic absorption and atomic fluorescence by C. T. J. Alkemande, A. Walsh, T. S. West and J. B. Willis and their colleagues, and these techniques are commented on here.