A.S.T.M. Attracts
Large Attendance of Analytical Chemists
L. T. HALLElT, Associate Editor HE
American Society for Testing Materials, holding its 47th An-
Tnual Meeting in New York, N. y., a t the Waldorf-Astoria June 26
to 30, attracted an ever-increasing number of analytical chemists to its deliberations. Widespread interest was shown in the sessions of Committees E2 and E3 and specially in the Symposium on Analytical Colorimetry and Photometry which was divided into two sections, one on instrumental applications and the other on specific chemical problems as exemplified by the paper by M. G. Mellon of Purdue on the subject “The Chemistry in Colorimetry”. Many analysts are familiar with Committee E3, formed in 1933, whose work is well known through its standard and tentative procedures. This committee now plans a special study and revision of a number of analytical procedures with a view to incorporating certain desirable modifications designed to employ more generally instruments su& as the spectrophotometer, polarograph, etc., and a d o p tion of newer techniques which have appeared in the literature since the standard procedures now in effect were originally accepted. Committee E2, formed in 1936, dealing with spectrographic analysis, works closely with E3 because problems of preparation of samples and standardization require collaboration of these two groups. The growing intereat among analytical chemists in modern methods of analysis waa amply demonstrrited by the well-attended Symposium on Analytical Colorimetry and Photometry held on Wednesday, June 28. Instruments and the physical principles underlying their use were discussed in the morning session. while in the afternoon specific methods of application and the chemical principles involved were presented. The complete program follows; the papers will appear in A.S.T.M. publications. I. INSTRUMENTAL SECTION Fundamentale of Colorimetric Measurements. J. L. HAQUE. National Bureau of Standards. Photocells in Colorimetry. R. H. M ~ L L E R New , York University. Glass Photometric Filters. 0. A. GAQE,Corning Glass Works. Filter Photometers. A. E. RUEHLE,International Minerals & Chemical Corp. Spectrophotometer Cells. 9. E. Q.ASHLEY,General Electric Co. Trends in Analytical Chemistry. B. L. CLARKE, Bell Telephone Laboratories. Spectrophotometers. K. GIBSON,National Bureau of Standards. Instrumental Errors. C. I. LUKE,Bell Telephone Laboratories. Physical Basis of Light. R. J. KRYTER, Esterline-Angus Co.
color by modern instruments is rather simple but that to bring a colorimetric procedure to a point where a constituent can be accurately and precisely determined is often difficult. The formation of a color which will permit measurement of the concentration of the constituent in the presence of impurities is a problem where thorough training in chemistry and not in physics is the answer. The fact that calibration curves for certain colorimetric procedures do not obey Beer’s law should not in itself condemn such a method. K. Gibson, of the National Bureau of Standards, cautioned against the errors which are present in the measurement of the color of solutions which fluoresce, and pointed out that analysts should constantly keep in mind t h a t instruments can give reproducible results that are very inaccurate. The speaker indicated the importance of using a high-grade spectrophotometer in setting up a new colorimetric method. He also pointed out that color-measuring instruments as now manufactured require individual calibration when used in colorimetric determinations. Therefore it is impossible for a central laboratory to distribute standard curves which can be used universally. R. J. Kryter,, Esterline-Angus Co., demonstrated some of the properties of light as related to color measurement, showing why the eye is really a poor instrument for color analysis. The photographic plate is a slow and cumbersome means of measuring light and the photoelectric cell haa larqely taken its place in modern instruments. Ralph Muller, on leave from New York University to M.I.T. for research on electronics, predicted that as the resCtlt of war research electronic devices released after the war will give the instrumental analysts many improvements not now thought possible. Lena systems made of plastics will be possible and the iconoscope will replace the photographic plate in certain light-measuring instruments. The papers presented in the afternoon session demonstrated the use of filters and spectrophotometers in the analysis of alloys by colorimetric methods. Of particular interest was the use of spectrophotometers in analyzing complex color mixtures for more than one constituent.
Analytical Edition Advisory Board Meets at W o o d s Hole
All members of the Advisory Board of the ANALYTICAL EDITION AND ENQINEERING CHEMISTRY met a t Woods Hole, of INDUSTRIAL Mass., on Saturday, July 1, for one of its regular quarterly conferences. The Chemistry in Colorimetry. M. G. MELLON, Purdue UniverProgress of the work on the Collective Index for the first fifteen sity. Bibliography on Colorimetric Methods. J. W. STILLMAN, E. I. volumes waa reported, numerous questions of policy and procedure du Pont de Nemours & Co. were discussed, and special features for coming issues were suggested. Specific Methods for Aluminum-Base Alloys. J. J. STUMM, W. F. It was moved and seconded that the Chairman of the Division of Jobbina, Inc. CHEMICAL SOCIETY Specific Methods for Magnesium-Base Alloys. V. A. STENGER, Analytical and Micro Chemistry of the AMERICAN be invited to participate unofficially in the deliberations of the board Dow Chemical Co. Specific Methods for Other Nonferrous Alloys. C. ZICHSHKAU, a t future meetings. American Smelting and Refining Co. American RollSpecific Methods for Ferrous Alloys. A. THOMAS, ing Mill Co. II. CHEMICAL SECTION
X-Ray Diffraction Unit
Beverly Clarke, Chairman-Elect of the New York Section of the AMERICAN CHEMICAL SOCIETY and associated with the Bell Telephone Laboratories, welcomed those attending the symposium and expressed the hope that they would come back to the A.C.S. meeting in the fall, also to be held in New York September 10 to 15. The speaker emphasized the trend in analysis toward employment of physical instruments. The modern analyst must, therefore, be familiar, he pointed out, with simple electronics and the principles upon which these instruments are based, if he is to be highly successful. The handling of analytical problems requiring instruments by those primarily trained in physics was not considered the best solution of the problem. The reason for this wae brought out by Dr. Mellon’s introductory remarks, when he emphasized that measurement of
An x-ray diffraction unit developed by the North American Philips Co., 100 East 42nd St., New York, N. Y., has a four-windowed tube enclosed in a massive bronze housing. Diffraction patterns of four different specimens can be obtained simultaneously. A number of types of x-ray tubes can be provided, including targets of tungsten, molybdenum, cobalt, iron, chromium, and copper. Tubes can be changed quickly. Shockproof and rayproof, the unit utilizes full wave rectification, which permits higher output and longer life from the tube. Filament current supply is stabilized, control of kilovoltage and milliamperage is smooth and steplesa, tube is protected automatically if water supply fails, equipment has start-stop pushbutton control, and provision is made for use of automatic exposure timer.
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