Detection of volume parts per million of permanent gases in helium

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

“…The detection limits for these gases were found to be: 3.5 ppm H2, 0.06 ppm Ar, 0.03 ppm N2, 0.004 ppm 02, 0.004 ppm CH4, and 0.02 ppm CO. The results shown in Figures 3 and 5 compare well with the results previously reported for the helium detector in the multiplication region (2)(3)(4)(5)13,14,17,21). Most important is the fact that the operation of the detector in the saturation region is characterized by low standing current, low noise level, and high stability.…”

“…The metastable helium generated in the detector via a radioactive source has an ionization potential of 19.8 eV which is higher than any other atom or molecule, with the exception of neon which has an ionization potential of 21.5 eV. The sensitivity of the helium detector was reported earlier by its inventor J. E. Lovelock (1) as well as by others (2)(3)(4)(5). In spite of the high sensitivity and the universal detection mechanism of the helium detector, it remains an un-popular detector, and in most cases its use has been limited to the analysis of high purity gases, with a few other applications (6-10).…”

Radio frequency spectral emission discharge detector for fixed gases

“…In Table III, limits and useful dynamic ranges for several gas chromatographic detectors reported in the literature are listed for comparison with the radio frequency spectral emission detector proposed here. With regard to limit of detection, all of the detectors have comparable detection limit values except those of Bourke et al (11) and of Hartmann and Dimmick (12) who obtained decidedly lower values. Even so, the radio frequency spectral emission detector could have considerable use as a gas chromatographic detector because of its greater specificity than any of the other gas chromatographic detectors listed in Table III, except for the microwave detector of McCormack, Tong, and Cooke (7).…”

Determination of molecular nitrogen with a photometric detector

“…In the Atmosphere to the semiconductor (1,2), nuclear (3, 4), and other (5, 6) industries. The most prominent methods for the detection of N2 are mass spectrometry (1,2,7) and gas chromatography (3)(4)(5). For the latter, the thermal conductivity detector is preferred in the determination of relatively high levels of nitrogen (3,8) while the helium ionization detector provides the sensitivity for monitoring parts-per-million or even lower N2 concentrations (1-5).…”