for which they were designed, are capable of an amazingly high degree of precision and accuracy. I t is the remaining two phases t h a t have received the greatest attention in attempts to improve the determination. One of the early attempts to improve the combustion phase was the introduction of the " e m p t y t u b e " method by Belcher and Spooner (#) in 1943, and the subsequent improvement of the method by Belcher and I n g r a m (1). These methods involve the slow vaporization of the sample into a quartz tube maintained at a high temperature and devoid of filling or catalysts, turbulence being obtained by the internal use of baffles. This method has enjoyed popularity in E n g l a n d b u t has never been widely accepted in the United States. An interesting development in combustion tube filings is the use of various metallic oxides other t h a n t h a t of copper as catalysts for the decomposition of organic m a t e rials to carbon dioxide and water. T h e decomposition product of silver p e r m a n g a n a t e as described by Korbl (7) has proven to be of value by m a n y workers. T h e catalyst is a microporous matrix of manganese dioxide in which very fine particles of metallic silver are dispersed. T h e advantages claimed are low operating temperature, high capacity, rapidity of oxygen flow, and the ability to scavenge large amounts of the halogens and sulfur. I t is the last property t h a t perhaps removes the material from the classification of a catalyst because it will be exhausted by continued dosage with the halogens and sulfur. Another oxide catalyst which is becoming very popular is the mixed oxide of cobalt, cobalto-cobaltic oxide. I n the preparation of this material as described by Vecera (18) and his co-workers, it is advocated t h a t the cobaltic oxide be supported on fired asbestos fibers. Macdonald (9) suggests mixing the cobaltic oxide with starch before firing to obtain a material of high porosity and good mechanical strength. Low operating temperature and an extremely high activity are characteristics of this catalyst. An entirely noveï t y p e of sample
Fully Automatic Digital Integrator
CRS
First with New Features, Proved Results T h e CRS-11 you invest in n o w incorporates features that will not be matched in other equipment for years. Your investment in leadership will provide extra benefits n o w , plus extra years of outstanding performance while similar integrators are "catching u p . " T h e CRS-11 gives you accurate, reproducible data with m a x i m u m operating flexibility. It features expanded dynamic range for fully u n a t t e n d e d operation in a wider range of applications — in gas c h r o m a t o g r a p h y , spectrophotometry, amino acid analysis, and other analytical techniques.
• • • • • • • · • •
Expanded dynamic range, unattended operation Printed listings of peak areas and retention times Computer compatible output available Fully automatic peak sensing Wider range of applications — from ionization detection (capillary column chromatography) to amino acid analysis Adaptable to process as well as laboratory operation Unexcelled accuracy, resolution and reproducibility Proved solid-state, plug-in circuitry insures trouble-free performance Operates from standard 50-60 cps power lines Automatic baseline correction and stabilization accessory
For a CRS-11 demonstration on your analysis problems, for CRS-11 specifications and application data, contact. . .
INFOTRONICSC O R P . 1401 SOUTH POST OAK ROAD / HOUSTON, TEXAS 77027 Circle No. 216 on Readers' Service Card
VOL.
36, NO. 7, JUNE 1964
·
33 A
