ISOTOPE
RADIO
ANALYZERS
CHROMATOGRAPHS
For neutron activation
REPORT FOR ANALYTICAL CHEMISTS
analysis
Beta Energy Resolution
2%
G a m m a Energy Resolution
3-10%
M a x i m u m source size
1 in. sq.
Coincidence Transmission
8% .51 cm 2
Coincidence Luminosity
For further
Unique pounds.
scanner
for
tritium l a b e l l e d
com-
Illustrated is the FORRO TRITIUM-
CARBON SCANNER, which gives a g r a p h i c a l representation
of
the
activity
distribution
o f t w o different radio-isotopes, e.g. tritium and c a r b o n - 1 4 , on a strip
information
write
chromatogram.
to:
THE FORRO SCIENTIFIC COMPANY 8 3 3 Lincoln Street
Evanston, Illinois
For further information, circle numbers 30A-1, 30A-2 on Readers' Service Card, page 97 A
LABORATORY CONDUCTIVITY BRIDGES .and cells
• Variable Sensitivity Control: Max. • Range: 0.2 to 2,500,000 ohms • Accuracy: within 1 % of measured resistance except at extremes of scale. • 2 Bridge source frequencies: Line and 1000 cps. • Simple, fast operation for laboratory or production use. A new, improved version of the time-proved Type RC Conductivity Bridge. Designed for use by either technical personnel or production worker. Employs standard components for easiest maintenance. Ideal for electrolytic conductivity measurements of purest distilled water to highly conductive acids. Also widely used for electrical conductivity measurements and tests.
M I C R O - D I P CELL: OPERATES O N 2 M L SAMPLE
Write for catalog on complete line of conductivity instruments and cells
Price subiect to change without notice.
Industrial
Instruments
8 9 COMMERCE ROAD, CEDAR GROVE, N. J. For further information, circle number 30 A-3 on Readers' Service Card, page 97 A 30 A
·
ANALYTICAL CHEMISTRY
mentation, the surface of the field of flavor chemistry has only been scratched. As evidence, the most common flavors cannot be reproduced. The solution of a flavor problem is still extraordinarily difficult. It requires competent organic chemists to do the patient structural determinations of unidentified spots and hills in chromatograms, the assistance of analytical chemists with their x-ray and spectroscopic tools, and many original ideas by all involved. In addition to routine analytical and basic structural studies, much supporting work has to be done. Since identifications are often based on comparisons with known compounds, pure standard compounds and meaningful spectroscopic data are needed. A study of existing data indicates that workers do not have pure compounds. Terpenes are a good example. True physical constants of such flavor constituents as ordinary alcohols and esters are also lacking. Another analytical problem, which is even more fundamental, is the effect of enzymes and oxygen on flavor constituents. Whenever a material is cut or crushed, the flavor materials are changed or liberated by oxygen or enzymes. This effect has been used by some workers to enhance flavors by using enzymes on precursors. Schools of thought in flavor work: the isolation and identification and postulation and proof, each have their place and should go hand-in-hand. To make a good guess and then prove its correctness is often the only way to approach certain problems. There is no objective method for analyzing flavor components. Until it is known how one is able to smell and to recognize a smell, it will not be possible to construct a machine capable of doing this. Infrared spectroscopy, which "fingerprints" substances, is considered a promising approach. The difficulty is that there is still no way to translate this information into understandable flavor terms. The greatest essential in flavor analysis, as in other analytical work, is a reliable test. In all of this work, the analytical chemist plays a key role. He must not only be a skilled analyst with specialization in some field of analytical chemistry, but he must be an organic, inorganic, and physical chemist and at times a biochemist and metallurgist. He must also be skilled in such specialized fields as physics and electronics. He must be able to direct, administer, and pioneer research in analytical chemistry.
