Microwave Digestion Bombs In two sizes, 23 ml and 45 ml. Rapid microwave heating can now be used to speed the treatment of inorganic, organic and biological samples in strong acid or alkali media using Parr Microwave Digestion Bombs. These bombs have a microwave-transparent outer body which encloses an inner Teflon sample holder, allowing microwave energy to be used to develop high internal temperatures and pressures without overheating the outer wall. Samples can be dissolved with heating times of one minute or less with complete safety when the bombs are used as directed. Call or write for Bulletin 4700 for complete technical details.
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The Journal of Organic Chemistry
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hile such manuscripts should address fundamental problems in organic chemistry (structure, mechanism, synthesis), we encourage submission of manuscripts in which these problems are solved with the use of techniques not traditionally associated with organic chemistry (enzyme kinetics, enzyme isolation and purification, identification of active site residues, etc.). The Journal hopes to foster integrated publications in which the chemical aspects are not separated from the biological aspects. For manuscript format, see J. Org. Chem, 1990.55 (1), 7A-10A. Send manuscripts to: C. H. HeathcocK Editor-in-Chief, The Journal of Organic Chemistry, Department of Chemistry, University of California, Berkeley, CA 94720 For subscription Information American Chemical Society Sales and Distribution 1155 Sixteenth Street, N.W., Washington, D.C. 20036 (202) 872-4363
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930 A · ANALYTICAL CHEMISTRY, VOL. 63, NO. 19, OCTOBER 1, 1991
REPORT m e n t s measured u n d e r the STPF conditions, the mean value of the ratio w 0 (calc)/ra 0 (exp) was 0.90 with a s t a n d a r d deviation of 0.25 (20). We were very inspired by these results, and after five years of subsequent work, including critical selection, calculation, and measurement of a number of fundamental constants as well as checking and updating the experimental values of mQ, we were able to reduce the s t a n d ard deviation of t h e m e a s u r e m e n t to 10% (21). These d a t a were confirmed by Freeh and Baxter (22). It is not surprising that GFAAS has come much closer to absolute analysis than other spectrochemical techniques, including flame AAS. This success can be attributed to the unique properties of the isothermal graphite tube atomizer, which ensures complete sample atomization; a known vapor column geometry; and a known and temporally constant residence time of atoms in the analytical zone, regardless of the matrix composition of the material. I believe that practical realization of absolute analysis is limited not by any technical reasons or unacceptably high errors but by a purely psychological barrier resulting from a lack of belief in its possible attainment. Therefore promotion of this approach should be started, as recommended by Holcombe and Hassell (23), with "education of the regulatory agencies, the plant engineers, and the analysts." The availability of calculated values of sensitivity is an efficient tool for revealing instrumental and methodological errors associated with incorrect selection of analytical conditions or preparation of calibration solutions, for checking the quality of manufactured instrumentation, and for evaluating the ultimate possibilities and choosing the proper ways to improve the techniques.
Conclusions I would like to stress that scientists, e n g i n e e r s , and a n a l y s t s of many countries have taken and continue to take an active part in the development of this method. In my opinion, however, during the past 20 years, Perkin Elmer has been an indisputable leader in the field of GFAAS instrumentation, and I am privileged to have had a productive and pleasant cooperation with this company for nearly a quarter of a century. But I would like to make a number of more general conclusions as well. First, ascending a staircase is easier if you go in small steps. (From this
