REPORT FOR A N A L Y T I C A L CHEMISTS
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Figure 3.
Sensitometric strip gives information concerning density and silver content
cals formed in initial oxidation reaction (olefins). The recent availability of relatively inexpensive and reliable nuclear magnetic resonance spectrometers is greatly extending use of NMR for type analyses, functional group analyses, and structure determinations. High resolution mass spectrometers can determine mass difference of one in 10,000 and are capable of doing work at molecular weights of over 1000. The drawing (Figure 1) illustrates the precise mass measurements obtainable using electronic recording. Gas chromatography is used to analyze chemicals with boiling points in the range of 300° to 400° C. This technique permits parts per billion analyses. Neutron activation shows promise of becoming a universal method for elemental analyses which will probably supplement most techniques used at present. These and other techniques, such as automatic distillation, semi-automatic units for microchemical analyses, and semi-automatic units for spectroscopic analyses, cut the time and cost of analyses drastically. In the field of plant analyzers, gas chromatographs have proven to be most useful. Other equipment is available to record vapor pressure, flash, refractive index, viscosity, and other useful physical parameters on a continuous basis. To illustrate the importance of analyzers, for example, Dr. Guertin noted that the average analyzer pays out
more in one year than the cost of the first American refinery ($15,000). Analyzers of the future, he noted, will involve activation analysis for elements, automatic colorimetric analysis for elements and functional groups, and high temperature gas chromatographs for chemicals and high boiling petroleum fractions. The refinery of the future will go from the feed stock level to final product automatically with the aid of analyzers tied into computers, which, through a control loop, will control the process. Advances in basic research will be greatly dependent on information obtained using instrumentation. Affected areas include petroleum geology, petroleum composition, catalysis, combustion, lubrication, and structure of chemicals and polymers. A basic understanding of the composition of petroleum, for example, leads to advances in petroleum geology. Gas chromatography, mass spectroscopy, infrared, and NMR have been used to establish the presence of components which corroborate theories regarding origin of petroleum from natural products.
Measuring dark, fuzzy-edged a b sorption bands against t h e usual spectroscope hairline is akin t o finding black cats in coal mines. B u t in a reversion spectrometer there are two brilliant identical spect r a running one next to the other in opposite directions. You seek no hairline. R o t a t i n g the wavelength micrometer head slides t h e two spectra along in opposite directions. Locating t h e wavelength of a particular absorption (or emission) b a n d requires only matching of t h e b a n d with itself—a task a t which the eye excells. One then simply reads the wavelength directly from t h e micrometer head. I t reads immediately to 1 Angstrom! T h e r e are m a n y applications. T h e quantitative measurement of carbon monoxide in blood is a s n a p : the shift in wavelength of an absorption b a n d (referenced t o normal blood) being proportional to the carbon monoxide content. F o r biomedical uses order the complete Clinical Hartridge Reversion Spectrometer Set, Model 26-410, price $548.50 (Spectrometer alone is $299.50). W a n t to quickly check interference filter peaks a n d bandwidths? Or measure wavelength shift as a function of filter angle? W a n t to m a k e fast, positive inspection of metal stock for particular alloy elements? Order t h e general purpose Model 26-380 Direct Reading Reversion Spectrometer, price $495. T h e striking, unambiguous spectral presentation of b o t h instruments is ideal for rapid teaching demonstrations. Get full details in our Spectroscopes, Spectrometers & Spectral Sources Brochure. I t ' s free.
THE
Photographic
Industry
The fusion of physics and electronics with analytical chemistry has led to the development of instruments which are particularly useful in the photographic industry. X-ray analysis is a good example.
Ealing
CORPORATION
33 University Road, Cambridge 38, Massachusetts Telephone : 617 — K/ 7-5760 Cable.· Ealing (Advertisement) Circle No. 131 on Readers' Service Card
VOL. 34, NO. 6, MAY 1962
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