As mentioned previously 1 the purpose of the present investigation is threefold: (a) to indicate sources of spectral interfcrcnccs in flame photometry and atomic absorption, (0) to add to the knowlcdgc of physical and cllemical processes in flames employed for analytical work, and (c) to study the dcvclopmcnt of analytical metllocls for tile determination of organic compounds by flame spectroscopy. Spectral interferences produced in atomic absorption by scattering and by absorption by various flame species are described in Part I Il. In this third part of the investigation, absorption of atomic resonance radiation by flames and solvents has been studied. ESI'ERXhlEN'I'AI. The experimental conditions were tllc same as those used to obtain the data reported previously'. Hollow-cathode lamps from Atomic Spectral Lamps, l'ty. Ltcl.. 13eckman Instruments, Inc., and Perkin Elmer Corp. were used. Absov~tiolz of atomic pwund state lines by fhntes and solvents Absorption of atomic lines originating in the ground state by flames is illustrated in Fig. I which shows absorption by the oxyhydrogen flame of the bismuth 3o68-A line. The beam (r-1.5
cm in diameter) from the l~ollow cathode was passed once throu# the flame 3 cm above the tip of the burner. Strong absorption of the aluminum 3082--4 and 3ogz-A lines by oxyhydrogen flames was also observed (the zinc 3076-A line was not absorbecl siqificantly).
Absorption by the flame at low wavelengths is illustrated in l'ig. 2. When nitroethane was introduced the absorption was incrcascd.
Absorption by flames into which organic solvents were aspirated and of organic solvent sprays (with no flame burning) were obtained for various atomic resonance lines, as shown in Tables I andII. The beam from the hollow-cathode lamp was passed throu& the flame or spray three times by means of reflection. The highest pass -_--* Taken in part from the Ph.D. Disscrtntion of V. J. SXIITI-I, Jlouisi;rnn State University, l3iltOll Rouge, 1gGg.