Measurement of small volume temperatures of analytical flames by the two-line atomic fluorescence technique involving the use of direct-line Stokes and anti-Stokes fluorescence of indium and thallium has been examined. Spatial flame temperatures have been measured with a volume resolution of 0.3 mm by 2 mm by 5 mm in the flame. Theoretical and practical considerations of the method are given, particularly in terms of the limitation of using indium or thallium. The use of the two thallium lines (377.57 and 535.05 nm) was subject to fewer random errors than the use of the two indium lines (410.18 and 451.13 nm) for the range of temperatures studied. However, thallium lines are restricted to the measurement of temperatures above about 2000°K (for the air-acetylene and nitrous oxide-acetylene flames); for temperatures below about 2000°K, the fluorescence irradiance ratio could not be measured with sufficient signal/noise ratio due to the low intensity of the anti-Stokes fluorescence line. In the present experiment, indium lines were used for the measurement of a wide range of “low” flame temperatures (approximately 700 to 2600°K) owing to the better signal/noise ratios for both lines; indium lines were also preferable for the air-acetylene flame, even though the error produced by the random uncertainty in the fluorescence ratio was larger than for thallium. The present method has been successfully applied to the measurement of the spatial temperature profiles of analytical flames, such as argon-hydrogen(-entrained air), argon-oxygen-hydrogen, air-acetylene, and nitrous oxide-acetylene.

2129occurrence not evidenced by the empirical formulas of the mineral samples.The results of this study demonstrate the feasibility of using ion induced desorption mass spectrometry for characterizing minerals. The method is nondestructive and is free from charging effects, which often complicate the use of charged particle beams for the surface analysis of insulating materials. It is also highly sensitive to the alkali metals and confirms the natural process of substitution of these ion species for each other in mineral matrices. The results presented are not quantitative, due in large part to the pronounced matrix effects that influence secondary ion yields. The desorption process is most efficient for elements with low ionization potentials. This is evidenced by the conspicuous absence of silicon and oxygen, which are present as major components of the sample matrix. ACKNOWLEDGMENT The experimental assistance of C. D. McAfee is hereby acknowledged. The XPS and EMP analyses were performed at the Texas A&M University Surface Science Facility. Beam time for the SIMS analyses was graciously provided by J. M. Anthony a t Texas Instruments Central Research Labs in Dallas, TX, where W.R.S. participated in a short-term collaboration. Registry No. nezCf, Dunlap, B.; Colton, R. Anal. Chem. 1984, 56, 373R-416R. (5) Slodzlan, G. SIMS I I I ; Bennlnghoven. A., et al., Eds.; Springer-Verlag: Berlln, Heidelberg, New York, Tokyo, 1983; pp 115-123. (6) Conzemlus, R.; Slmons, D.; Shankai, 2.; Byrd, G. I n M/crobeam Analysls-1983; Gooley, R., Ed.; San Francisco Press: San Francis-(7) Slmons, D. Inf. J . Mass Spectrom. Ion Processes 1984 55, 15. (6) Shaeffer, 0. A. ACS Symp. Ser. 1982, No. 776. 139-148. (9) Torgerson, D.; Skowronskl, R.; Macfarlane, R. Elochem. Eiophys . Res. Commun. 1974, 60, 816-620. IO) Macfarlane, R. Acc. Chem. Res. 1982, 15, 266-275. 11) Macfarlane, R. Anal. Chem. 1983, 55, 1247A-1263A. 12) Fllpusluyckx, P. Ph.D. Dissertation, Texas ABM Unlverslty, College Station, TX, 1985. 13) Gunthler, W.; Becker, 0.; Della-Negra. S.; Knippelberg, W.; LeBeyec, Y.; W M , U.; Wien, K.; Wlesser, P.; Wurster, R. I n f . A laser-based muitldlmenslonal analytical instrument that provides selective, senslllve, and on-line detection of polycyclk aromatk cOmpOunds (PAC) is described. The effluent of a capillary GC Is interrogated by a tunable UV laser beam at collision-free pressures. Selective excitatlon/lonizatlon occurs based primarily on the spectroscoplc absorption characteristics of the analyte molecules. The laser-analyte Interaction products (cations, electrons, and photons) are

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We see that by directly measuring the activation energy using optical absorbance as just described, the logarithm function is applied to the experimental data only once, not seven times. Also no absolute measurement of either [A] or

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