absorption band to identify the lime from the spectrum of the hollow cathode. With a double-beam instrument, this procedure is very difficult. It would seem desirable, therefore, that commercial equipment be capable of being used as a single- or a double-beam instrumen t. UNDETECTED METALS
One of the most serious problems encountered in this method of analysis is the fact that a number of met& cannot be detected by this process. These metals form refractory oxides and it is conceivable that in flame they are never reduced to the atomic state. Use of Oxycyanogen Flame. I n an effort to overcome this problem an oxycyanogcn flame was used instead of an oxyliydrogen flame. T h e possible advnntage of this system was t h a t the oxycyanogen flame reaches a temprrat,ure of 4500" C., which is ronsidrrably above that of the oxyhydrogen flame, which reaches a temperature of 3000" C. It waR hoped that at this elevated temperature the oxides formed by metals which are insensitive to this process would be broken down and that the free atoms would then be able to contribute to absorption of the signal. However, although vanadium absorbed slightly,
no absorption by AI, Mol or W occurred even a t this elevated temperature. Although it is possible that these elevated temperatures do not break down these oxides, it raises the question that insensitivity of these metala may be due to another cause. As an alternative method to the use of a high temperature flame for breaking down metal oxides, a spark may be used in conjunction with the flame. Experience in spectrography would indicate that this should be a means of breaking down metal oxides formed in the flame. Under these circumstances it is possible that metal atoms will be formed in the region of the spark and immediately above it. Hitherto, no work has been done on this proposal, but i t is hoped that results will be available shortly. CONCLUSIONS
The results to date indicate that atomic absorption spectroscopy is a technique which should have many uses in the field of analytical chemistry. There is a high degree of freedom from interference of other metals present and high sensitivity is usually encountered in all cases wherp absorption takes place. It is hoped that problems associated with solvent, feed rate, etc., will be controlled to a considerable
degree by the design of a better burner for use in this work. I t is anticipated that with increasing amount of equipment becoming available commercially, this field will grow and expand and take its place among the other major fields of analyticnl chemistry. ACKNOWLEDGMENT
The author thnnks Esso Standard, Division of Ilumblc Oil & Refining Co., for pcrmission to publish this paper. LITERATURE CITED
(1) Box, (f. F., W~llih, A., Speclrochim. Acta 16,255 (1060). (2) Crosswhite, 13. M.,Ijickc, G. H., Jxanrrneiir, ,J., .I. ODL Soc. A m . 45, 270
(I$L5g.
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(3) Fost,er W. IT., Jr., &me, D. N., ANAL.&EM. 31,2028 (1059). (4) Fiiwa, I
