Consolidated Electrodynamics Corporation

The electron impact mass spectrum of vitamin D3 obtained with a CEC Model 21-110B instrument (Consolidated Electrodynamics Corporation, Pasadena, CA) by direct probe sample introduction is shown in Figure 5 (22). It shows a strong molecular ion at m/z 384 and a fragmentation pattern characteristic of vitamins D2 and D3, their primary metabolites and other chemically related compounds. The fragment ion assignment is shown in Scheme III (22). 

Mass Spectra were run on a Consolidated Electrodynamics Corporation Mass Sepectrometer Type 21-103C to determine H2 yields as well as yields from dry analyses for comparison with yields obtained after dissolution of the irradiated compound. Sample tubes were broken directly in the gas sampling system to yield dry analyses results. 

Several workers have reported modifying Consolidated Electrodynamics Corporation Model 21-110 mass spectrometers for use in chemical ionization service, and chemical ionization studies with a Bendix time-of-flight mass spectrometer is also reported. Wojcik and Putrell report achieving a mass resolution of about 56,000 with the CEC 21-1 lOB mass spectrometer. In addition, Putrell has also been successful in operating at high-emission-current, high-sensitivity conditions, which corroborates Pale s observations. Conversion kits to permit the operation of conventional mass spectrometers in the chemical ionization mode and complete chemical ionization mass spectrometers are commercially available. ... 

Mass spectrometer [1], thermal conductivity [2, 3] and catalytic conversion methods [4, 5] have been used to determine trace impurities in helium. These methods are, however, inadequate for the present purpose for various reasons. The mass spectrometer, such as Consolidated Electrodynamics Corporation 21-103, is limited in sensitivity, for most contaminants, to out 25 ppm. Instruments based on the thermal conductivity method, such as those manufactured by Cow-Mac Instrument Co., Beckman Instruments and others, are satisfactory for monitoring nitrogen and hydrogen in helium, but since these gases have opposite thermal conductivity effects, this method, when used alone, gives indefinite results. Catalytic conversion methods, such as are employed in an instrument manufactured by Baker and Company for analysis of trace quantities of hydrogen and oxygen, are not responsive to other impurities and are therefore poorly adapted to an overall analysis of trace impurities in helium. 

There have since been many similar instruments, largely dedicated to measurement of mercaptans and other sufur compounds by reaction with generated bromine. An early example was the Titrilog, manufactured by Consolidated Electrodynamics Corporation in the 1950s. Others, produced by European or Japanese firms, are intended for the determination of SO2 or CO2 from combusion analyzers (47). Stock (48) has summarized the development and present status of continuous "coulometric" titrators. 

Note 2—This test method was developed on Consolidated Electrodynamics Corporation Type 103 Mass Spectrometers. Users of other instruments may have to modify operating parameters and the calibration procedure. 

---