Saturation region of helium ionization detector for gas-solid and gas-liquid chromatography

Brazell, R.S.; Gibson, E. K.

doi:10.1021/ac50056a027

Cited by 20 publications

(5 citation statements)

References 27 publications

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“…Some peak deformities and inversions were observed during conditioning, and we plan to document such phenomena for a forthcoming paper. Since peak anomalies only appear to affect the simplest analyte species (that is, those with high ionization potentials), we agree with Andrawes et al (12) that the universal usefulness of the ionization detector as a sensitive, reliable device has been much underrated. The conditions of system purity essential to successful operation can, with some expertise, be brought under control.…”

Section: Resultssupporting

confidence: 91%

“…= 200 ppb): column, Porapak N, 200-325 mesh, 8 m length, 1 mm i.d., 20 °C; detector, 20 °C, 300 V/1.74 X 10"9 A; flow rate, 12.2 scnf'/min; sample size, 1 cm3 (vertical scale height = 7 X 10 10 A; range 2.97 to 3.67 nA). cation regions (12). Both detector types could be operated at typically 300 V with a standing current of 3 X 10~9A and noise widths of 10~nA.…”

Section: Resultsmentioning

confidence: 99%

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Miniature triaxial metastable ionization detector for gas chromatographic trace analysis of extraterrestrial volatiles

Woeller¹,

Kojiro²,

Carle³

1984

Anal. Chem.

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Gas chromatography has found highly successful application in NASA's flight programs. Gas chromatographs have been flown to both Mars and Venus where detailed compositional measurements were made. These instruments were quite small and relatively sensitive when compared to commercially available instruments; however, they do not appear adequate for future missions currently being planned. The earlier flight GC's had incorporated thermistor bead thermal conductivity cells as the detector. This detector requires very precise temperature control and only provides about 1 ppm sensitivity. Temperature stabilization causes the detector to be quite heavy, i.e., about 200 g. Greater sensitivity will be required for measurements of trace components in extraterrestrial environments. Review of other detector types revealed the metastable ionization detector as a likely candidate because of its superior thermal stability and high sensitivity. The metastable detector, first described by Lovelock as an argon ionization detector, has been studied and somewhat modified by others. The commercial design by Hartmann and Dimick was used for comparison purposes in our work. In the past, three features of the metastable detector are prominent: it has part-per-billion sensitivity, contamination must be carefully controlled, and anomalous response is common. Since it is an ionization detector, however, temperature instabilities do not cause the major perturbations experienced by the thermal conductivity detectors. This paper describes a miniature metastable ionization detector featuring an unconventional electrode configuration, whose performance characteristics parallel those of traditional design, while its weight is quite small. The prototype has been used in our laboratories routinely for 2 years, and the concept will be incorporated into a flight GC for use in the Space Shuttle.

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Section: Resultssupporting

confidence: 91%

Section: Resultsmentioning

confidence: 99%

Miniature triaxial metastable ionization detector for gas chromatographic trace analysis of extraterrestrial volatiles

Woeller¹,

Kojiro²,

Carle³

1984

Anal. Chem.

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“…Minimum detectable amounts, using a 100-pL sample, were found to be 0.3 ppm CF4, 0.05 ppm C2F6, 0.008 ppm C3F8, 0.008 ppm C4F10, and 0.01 ppm C5F12. detectable amount was about 0.3% and above this concentration the detector response is deformed to the M-shaped peak (6).…”

Section: Resultsmentioning

confidence: 89%

“…The use of the helium ionization detector has been very limited in the past due to difficulties in the operation conditions of the detector. Recently, however, it has been shown that the helium ionization detector can be operated in the saturation region of the detector field intensity to provide a reliable and sensitive response (6). In the work described here, we evaluated the helium ionization detector for the analysis of C4 to C6 perfluoro n-alkanes, and compared the detector response to the corresponding hydrocarbons.…”

Section: Literature Citedmentioning

confidence: 99%

Analysis of low molecular weight perfluoroalkanes by gas chromatography with helium ionization detection

Andrawes¹,

Gibson²,

Bafus³

1980

Anal. Chem.

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“…Bartlett et al (37) have described an electrochemical cell for detection of Hz which correlated well with results obtained by conventional GC/thermal conductivity devices. The more sensitive helium ionization detector has also been utilized in breath Hz analysis (28); however, the operational shortcomings of this device have been well documented (38,39) . A more recent analytical technique utilizing gas chromatography and a reduction gas detector has also been described (30,40) .…”

Section: Methodsmentioning

confidence: 99%

Breath Hydrogen Analysis

Ostrander,

Cohen,

Hopper

et al. 1983

J. pediatr. gastroenterol. nutr.

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Summary:Hydrogen gas (H2) is a product of the fermentation of dietary carbohydrate (CHO) by bacteria in the lumen of the gastrointestinal tract in man. Thus, H2 is actually an exogenously produced gas, which either is passed as flatus, or diffuses into the body and is exhaled. In the adult, a fairly constant fraction is expired, providing a reliable indicator of total colonic H2 production. Breath H2 analysis currently represents a useful clinical means of testing adults and older children for the malabsorption of CHO. Noninvasive and easy procedures for the collection of expired air have encouraged their increasingly widespread use in pediatrics. Evidence to date suggests that breath H2 analysis may provide the best available method for estimating semiquantitatively the degree of CHO malabsorption. The association of the results of breath H2 analysis with other clinical measures of CHO digestion and absorption is expected, but discrepancies can also be anticipated based on the nature of this particular trace gas method. The interpretation of the results of breath H2 analysis in neonates and young infants remains especially problematic because of confounding variables which are difficult to control and are measured infrequently.

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Saturation region of helium ionization detector for gas-solid and gas-liquid chromatography

Cited by 20 publications

References 27 publications

Miniature triaxial metastable ionization detector for gas chromatographic trace analysis of extraterrestrial volatiles

Miniature triaxial metastable ionization detector for gas chromatographic trace analysis of extraterrestrial volatiles

Analysis of low molecular weight perfluoroalkanes by gas chromatography with helium ionization detection

Breath Hydrogen Analysis

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