Portable Gas Chromatograph Research Articles

In situ determination of nitrogen fixation in Antarctica using a high sensitivity portable gas chromatograph

AbstractA portable gas chromatograph was employed in the Vestfold Hills, Antarctica, during the austral summer of 1979‐80 for determining nitrogenase activity of the blue‐green alga Nostoc commune Vaucher by the acetylene reduction assay. Acetylene reduction was measured in samples taken along a transect where the vegetation changed with respect to differing topography and water availability. Submerged colonies of Nostoc recorded the highest fixation rates (6.89 nmol C2H4. cm‐2 h‐1). Damp mosscyanophyte associations growing on shallow slopes showed moderate rates of acetylene reduction (1.99 nmol C2H4. cm‐2 h‐1) whilst the drier vegetation of the steeper terrain was the least active (0.19 nmol C2H4. cm‐2 h‐1. The employment of a high sensitivity portable gas chromatograph provided an accurate and reliable method of measuring acetylene reduction.

Microdetermination of Ethylene Dibromide in Air by Gas Chromatography

Abstract Using a new, sensitive photo-ionization detector in a portable gas chromatograph that operates at ambient temperature, a method was developed for determining ethylene dibromide in air as low as 19 ppb. Vapor standards were prepared for calibration of the detector; concentrations in these standards were accurately determined by using a flame ionization detector. This detector was previously calibrated with an aqueous standard of ethylene dibromide. Using the 2 gas chromatographs, the loss of ethylene dibromide through sorption from the atmosphere of the vapor standards was determined. Solubility of ethylene dibromide in water was also established at 3 temperatures, using the flame ionization detector.

A portable gas chromatograph for macro- and microdetermination of fumigants in the field

A portable gas chromatograph for macro- and microdetermination of fumigants in the field

Controlled environment portable gas chromatograph for in- situ aircraft or ballon-borne applications

The construction of an electron-capture detector equipped gas chromatograph is described which is capable of in- situ ambient stratospheric halocarbon measurements By enclosing the plumbing of the chromatograph in a sealed chamber, a system has been developed which is immune to changes in teh ambient pressure and gas composition. This sealed chamber also provides a very clean system which is essential for the control of the ion chemistry in the detector associated with carrier gas doping techniques. Application of this instrument to some doping techniques is discussed briefly.

Portable gas chromatograph

An improved inexpensive portable gas chromatograph for the acetylene reduction assay of nitrogenase is described. The instrument is more convenient to use than a previously described model. Modifications permit the detection of hydrogen or methane.

Portable gas chromatograph for the acetylene reduction assay for nitrogenase.

Portable gas chromatograph for the acetylene reduction assay for nitrogenase.

Portable gas chromatograph and electrochemical detector for carbon monoxide

A new technique described by Energetics Science, Inc., for the analysis of carbon monoxide in ppM to percent quantities uses an electrochemical instrument as a quantitative gas-chromatographic detector and has the potential for being the basis of a truly portable gas-chromatographic system. The carrier gas used by this instrument may be either ambient air that has been scrubbed to remove CO or unscrubbed air containing a constant CO concentration, as determined by a differential signal. Thus, the instrument could be operated in a remote location.

A Portable Self-Contained Gas Chromatograph

The design and fabrication of a completely portable, self-contained gas chromatograph is described. This instrument utilizes a closed-loop hydrogen carrier gas flow as maintained by a hydrogen generator-separator. It employs an auxiliary hydrogen generator to keep a positive flow of hydrogen through the detector. The detector is an ionization cross section detector. The only maintenance required is the addition of water (5–15 cc/day) to the auxiliary hydrogen generator. Lower limit of detection for the present system is of the order of 1–10 ppm ethane.

Successful Test of an Airborne Gas Chromatograph

A portable gas chromatograph designed for real-time studies in diffusion has been successfully tested in an airborne application. A 10-mi low-level plume of colorless, odorless non-toxic sulfur hexafluoride (SF6) was laid down over northwest Andros Island, Commonwealth of Bahama Islands, by the Research Flight Facility's (NOAA) C-130. An accompanying DC-6 carrying the analyzer made 81 in-flight samples over a period of less than 3 hr. The chromatograph has a sensitivity limit of 0.03 parts per billion and completes the analysis for SF6 less than 2 min after the sample is injected into the column. Of the more than 80 in-flight chromatograms, 11 indicated positive identification of the inert tracer gas. Confirmation of the on-site analyses was provided by bottle samples taken in flight and analysed later in the laboratory.