Abstract

Apart from the direct inlet system which permits the introduction of substances with very low volatility and/or thermal stability into the mass spectrometer, the LKB instrument also permits the high speed recording of mass spectra of volatile compounds as single components or components of mixtures eluted from a gas chromatograph. Caution must be exercised in the interpretation of these spectra in view of posible peak or component overlap using the gas chromatographic column. At times it is useful to have another alternative system for the rapid introduction of controlled amounts of gaseous substances and/or highly volatile liquids and solids as well as reference samples such as the perfluoroalkanes directly into the ion source of the mass spectrometer for analysis. A heated molecular leak system for this purpose was developed (see Fig. 1). An inexpensive leak-inlet system which is satisfactory for the highly volatile and reference substances can be easily constructed, and thereby greatly increases the versatility of the instrument. The sample introduction tube is an 8 mm (5/16 in.) o.d. stainless steel tube inserted into the analyzer tube in the same way as a direct probe. The tube is flared at one end and attached to a Manostat flow controller, 78-425-01, or similar valve. An inner Teflon tube, 3/16 in. o.d. × 1 mm i.d., and a 3/16 in. Teflon ferrule in the flared end of the steel tube afford a chemically inert pathway and the flow restriction necessary for sensitive control at low pressures. A standard 8 mm o.d. Manostat glass joint into which has been inserted a silicone rubber plug septum (the same as that used by LKB's GC column) comprises the sample reservoir. For samples of low volatility, the glass inlet can be heated by an aluminum block containing a cartridge heater (Fig. 2).

Diode laser-based air mass flux sensor for subsonic aeropropulsion inlets

Michael F. Miller, William J. Kessler, and Mark G. Allen
Appl. Opt. 35(24) 4905-4912 (1996)

MRGC performance evaluation model of gas leak infrared imaging detection system

Jiakun Li, Weiqi Jin, Xia Wang, and Xu Zhang
Opt. Express 22(S7) A1701-A1712 (2014)

Three-dimensional reconstruction of a leaking gas cloud based on two scanning FTIR remote-sensing imaging systems

Yunyou Hu, Liang Xu, Hanyang Xu, Xianchun Shen, Yasong Deng, Huanyao Xu, Jianguo Liu, and Wenqing Liu
Opt. Express 30(14) 25581-25596 (2022)

Minimum detectable gas concentration performance evaluation method for gas leak infrared imaging detection systems

Xu Zhang, Weiqi Jin, Jiakun Li, Xia Wang, and Shuo Li
Appl. Opt. 56(10) 2952-2959 (2017)

Development of a pulsed backscatter-absorption gas-imaging system and its application to the visualization of natural gas leaks

Thomas J. Kulp, Peter Powers, Randall Kennedy, and Uta-Barbara Goers
Appl. Opt. 37(18) 3912-3922 (1998)