Fraction of deuterium/hydrogen mixture is isolated by column chromatography, ionized, and the HD+1-0 band absorption measured with conventional high-resolution infrared spectrophotometer

Lord, H. C.

English

NASA Technical Reports Server

September 1972	 B72-10244 
NASA TECH BRIEF 
NASA Pasadena Office 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Direct Analysis of Hydrogen/Deuterium Mixtures - A Concept 
The problem: 
To make a direct analysis of the ratio of deuterium 
to hydrogen in a mixture which is highly diluted with 
an inert carrier gas such as helium. For very low con-
centrations of deuterium (such as in the earth's at-
mosphere), direct analysis by gas chromatography is 
not feasible and mass spectrographic analysis is com-
plicated by the presence of helium, adsorption of 
hydrogen on the walls of the sampling and ionizing 
system, fractionation by pumps, etc. 
The solution: 
Isolate a fraction of the deuterium/hydrogen mix-
ture by column chromatography, ionize it, and mea-
sure the HD+ 1-0 band adsorption with a conventional 
high-resolution infrared spectrophotometer. 
How it's done: 
Various attempts have been made to determine 
hydrogen-deuterium (HD) ratios directly by conven-
tional infrared absorption analysis of gas samples be-
cause unionized HD species have distinctive bands in
the infrared region. Unfortunately, electronic selection 
rules forbid transitions in the infrared region, and 
thus the bands are weak. However, it has been noted 
that the 1-0 band of ionized HD (HD+) should be 
106
 times more intense than that of HD; the charge 
center in HD+ is not coincident with mass center, and 
the induced dipole gives rise to absorption in the 
infrared region. With a 1-meter cell and ten passes 
of light, the detection limit for HD+ is 0.8 N/m2 
(8 x 106 atm); with the gas at 1 x 10 N/m 2 (1 atm), 
8 ppm of HD could be determined. 
A conventional gas chromatograph may be modified 
readily to include an ionizing source to convert efflu-
ent HD to HD+ ions, or the infrared analysis cell may 
be fitted with a suitable ionization device. The highest 
sensitivity for HD+ would probably be obtained by 
presetting the infrared detector to monitor particular 
absorption peaks. As shown in the diagram, ions 
formed by a tritium-foil metastable helium detector 
can be transferred to an infrared cell for measurement. 
Another cell filled with pure helium or a mixture of 
helium and a known HD concentration can serve as 
a reference. 
Hydrogen concentration can be determined easily 
with standard chromatographic detectors. 
Note: 
Requests for further information may be directed 
to:
Technology Utilization Officer 
NASA Pasadena Office 
4800 Oak Grove Drive 
Pasadena, California 91108 
Reference: TSP 72-10244 
IR Light 
Source 
Glass Cell 
Containing 
Ions 
Gases II Dumped IR Spectrometer and Recorder 
(continued overleaf) 
This document was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States	 will be free from privately owned rights.
.
https://ntrs.nasa.gov/search.jsp?R=19720000244 2020-03-17T03:27:58+00:00Z
Patent status: 
No patent action is contemplated by NASA. 
Source: Harry C. Lord of 
Caltech/JPL 
under contract to 
NASA Pasadena Office 
(NPO-11322) 
B72-10244	 Category 03.


Direct analysis of hydrogen/deuterium mixtures: A concept

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