THE
PERKIN-ELMER
INSTRUMENT DIGEST A c o n d e n s a t i o n of some of the a r t i c l e s a p p e a r i n g in the Fall issue of THE PERKIN-ELMER INSTRUMENT NEWS, a q u a r t e r l y p u b l i c a t i o n of The PerkinElmer C o r p o r a t i o n , manufacturers of s c i e n t i f i c instruments—Infrared Spect r o m e t e r s , Tiselius Electrophoresis A p p a r a t u s , Universal M o n o c h r o m a t o r ,
Norwalk, Conn.
Flame Photometers, Continuous I n f r a r e d Analyzer, Low-Level Amplifiers—as w e l l as A s t r o n o m i c a l Equipment, Replica G r a t i n g s , Thermocouples, Photog r a p h i c Lenses, Crystal O p t i c s , a n d Special Instruments for the G o v e r n m e n t . For further information, w r i t e T h e Perkin-Elmer Corp., N o r w a l k , C o n n .
October, 1951
Vol. 2, No. H
Flame Photometer Aids Orange Production
Perkin-Elmer Spectrometer speeds product control at Hooker Electrochemical Co. BHC Product Control:
INFRARED CHECKS TOXIC ISOMER FOR HOOKER The addition of chlorine to benzene to form C G H e Cl e , or benzene hexachloride, results in a mixture of five stereoisomers. Since only the gamma isomer, now known as lindane, is an effective insecticide, chemists at Hooker Electrochemical Company, Niagara Falls, New York, have adapted the pioneer method of Daasch for determination of all five isomers of technical benzene hexachloride by infrared spectroscopy. Speedy Analysis—The instrument used is a standard Model 12-C Perkin-Elmer Infrared Spectrometer with rock salt prism and cells. The analysis takes about 10 minutes; accuracy is ±0.3 percent. Determination of all five isomers takes, with all calculations, about 90 minutes. By a more elaborate procedure, including an extraction treatment, it is possible to determine as little as 0.005 percent of any other isomer in lindane. Many hundreds of such control analyses are run every year, at a fraction of the cost by any other known method. Comparable infrared analyses are used for several other Hooker products. You can receive 8 - p a g e Instrument N e w s . Write The Perkin-E'mer Corporation, Dept. CEN, Main Avenue (Route 7), Norwalk, Conn. Featured in the Fall issue are: FLAME PHOTOMETER AIDS ORANGE PRODUCTION Study of California Crop Yields BHC PRODUCT CONTROL Infrared in Use at Hooker ELECTROPHORESIS CHECKS DRUG PURITY Product Control at Lederle
Detailed studies of soil conditions of a representative group of mature, high-producing orange orchards is being conducted by the University of California Citrus Experiment Station. Determinations by flame photometer of the calcium, sodium and potassium content of soil and leaf ash samples are expected to yield valuable information for future crop management. Comparative Studies —In recent years, some California orchards have suffered declining yields and reduced fruit sizes. The study is expected to aid the diagnosis of these problems and also furnish basic data on the type of soil capable of producing excellent citrus. Comparative soil and management studies are also under way in a group of orchards where sizes and yields are poor. In each orchard composite soil samples are taken at four levels to a depth of four feet, along with a composite leaf sample. Analyses are made for soluble salts: carbonate, bicarbonate, chloride, nitrate, sulfate, magnesium, potassium, sodium and calcium. Citrus is quite sensitive to soluble salt accumulations and, in irrigation agriculture, this condition is a perennial threat. By a simple dilution of the water extract from the soil composites, along with 25 parts per million lithium, the amounts of calcium, potassium and sodium are quickly obtained.
Th.e flame photometer is used to determine calcium, potassium and sodium in ammonium acetate extracts of the soil in connection with the exchangeable base studi-es. Without the flame photometer, tedious time-consuming methods a-re re-
Flaine Photometer—New aid for agriculture quired for the analysis. With this instrument the analysis can be made in l/25th the time taken by classical methods, by a simple dilution of the extractant. The results obtained by the flame photometer agree well with standard chemical procedures and are more simply arrived at.
P e r i S C O p e O p t i c s . . · Introduction to a little-known field Of the large family of optical instruments, most of us are familiar with telescopes and microscopes, but few of us have a first-hand acquaintance with periscopes. Today, periscopes play an important role, not only in our defense armory, but also in atomic energy development. Optical Components—The important optical components of a periscope are the objective lens and the eyepiece. A periscope with only these elements, however, would have a very restricted field of view; hence, erector lenses are incorporated into the basic design. These lenses hand the image along the length of the tube so that, at the eyepiece, the light rays are again parallel—as they were when they first entered the objective lens. By means of mirrors or prisms, any desired number of bends or elbows may be produced in a periscope. These optics must be of very high quality to cut down reflection losses
and to preserve a high degree of fine image quality. Derotation — Almost all periscopes require some mechanism permitting them to scan in various directions. However, this feature introduces a rotation of the image, distorting relative position of objects in the field of view. This is overcome by a derotation device, which is mechanically geared to rotate the image through the angle required to make it appear in its proper position. Derotation devices are usually large prisms. The Perkin-Elmer Corporation has built periscopes of all types: tank sights, fighter sighits, bombs ights—many with specialized requirements for the armed services, and many others for applications in research and industry. Digest of an article by R. M. Scott, Director of Engineering at Perkin-Elmer.
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