REPORT FOR ANALYTICAL CHEMISTS
Courtesy
Esso Research
& Engineering Co.
THE IDEAL PRESS FOR MAKING KB* PELLETS FOR INFRARED SPECTROSCOPIC ANALYSIS Also for forming pellets for x-ray and other types of spectroscopic analysis * 2 0 Ton Capacity Hydraulic Press * Accurate alignment in op eration * Guided moving platen * Sturdy 3 column construction * Even pressure distribution for uniformly dense pellets * Self-contained * Bench mounted * Hand operated * 9 " χ 9 " platen area * 2 2 " max. vertical opening, adjustable
A multi-purpose unit with quickly adjusted vertical opening, by handwheel, per mits many different set-ups in minimum time. Used around the world for RESEARCH, C O N T R O L & TESTING. Available accessories include: Heat ing and Cooling Platens; Temp. Con trols, Auxiliary low pressure gauges; Fast air closing; Extruding units; Testing units, etc. Available in 30 and 50 ton sizes. Write for Bulletin.
LOOMIS ENGINEERING & MANUFACTURING CO. Dept. A , Route 4 6 , Caldwell, N. J. Circle No. 102 on Readers' Service Card
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ANALYTICAL CHEMISTRY
The x-ray spectrograph and diffractometer shown above are particularly useful tools in forensic chemistry where samples are often very small and must be subjected to nondestructive examinations.
duced. However, a thermal reac tion occurring in the sample causes a temperature difference between the two terminals and the current produced is amplified and recorded as a peak on a chart. This method of analysis has been applied successfully to the study of clays, soils, plasters, cements, safe insulations and, experimentally, the study of lubricating oils. Plasters, mortars, safe insulations, and other cement products are found fre quently on the tools of burglars who have used them to break into build ings and break open the safes. Typical Examinations Exemplify Variety of Approaches
The nature of the specimens re ceived frequently prohibits the use of standard schematic analysis pro cedures. As an example, small translucent particles, which ex hibited strong indications of a ni trate in microchemieal tests, were identified as nitrocellulose particles when studied on the infrared spec trophotometer. Furthermore, the infrared absorption spectrum, which reveals the amount of ni tration, enables the examiner to distinguish between the nitrocellu lose of the common lacquer and the smokeless powder explosive. This nonconsuming penetrative exami nation of a very limited specimen enables the examiner to make identifications and distinctions of vital importance to the investiga tion.
Sabotage or Accident? Follow ing the crash of a heavy bomber, reports of suspected sabotage were received. These reports were prompted by microchemieal tests at the scene, which pointed to the likelihood of a foreign strong oxi dizing agent or explosive mixture, not entirely consumed, being pres ent in the aircraft and causing its ultimate destruction. The m a t e rial in question was subjected to instrumental analysis (spectrographic and x-ray diffraction). I t was identified as the rare active crystalline compound—magnesium suicide. Further investigation re vealed t h a t the magnesium suicide was produced in the bomber as a result of intense heat from the fire following the crash and was not the initiating cause. Costly investi gations relating to saboteur activity were eliminated. Paint Studies. P a i n t covers a large variety of items which make up the hardware, vehicles, and structures of modern living. The hoodlum cracking open a safe, pry ing open a window, or crashing his car into a building during a hasty getaway often leaves paint at the scene of the crime or unknowingly carries paint from the crime scene. In both cases the paint is deposited accidentally, and thus, is usually limited in quantity. The main ob jective in both instances is to identify the paint and associate or eliminate the sources. During the course of the F B I Laboratory's
