Schematic of a gas chromatograph

Fig. 9.25. Schematic of a gas chromatograph. The flow control generally consists of a standard pressure regulator plus a needle valve. Gas purification is sometimes necessary, particularly with air-and moisture-sensitive compounds. A short column of molecular sieves held at — 78°C is frequently adequate. The traps (for the collection of fractions) and flow meter are optional. The dashed lines indicate points at which communication with the vacuum line is possible.

Figure 2.1 A GC installation. Schematic of a gas chromatograph. A commercial gas chromatograph with a mass spectrometry system for detection (Model GCMS 5973 manufactured by Agilent Technologies). The instrument shown here is equipped with an auto-sampler. Below, the chromatogram for a mixture of ketones is displayed.

Figure 3.1 Schematic diagram of the principal components of a gas chromatograph. The bold line shows the path taken by sample and carrier gas resulting in the production of a chromatogram. The thin lines represent support and contr functions.

Figure 2.1—A typical gas chromatograph. Schematic of the gas chromatograph and photograph of a Model 6890-GC with programmable carrier gas pressure. The instrument shown here is equipped with an auto-samplei (reproduced by permission of Hewlett-Packard). Example of a GC-separalion.

Figure 4.13. Schematic diagram of a gas chromatograph (from R. M. Smith, Gas and Liquid Chromatography in Analytical Chemistry, Wiley, 1988)...

Fig, 6.13 Schematic diagram of a multifunctional GC-IRMS system. The device consists of a gas chromatograph coupled to an isotope ratio mass spectrometer via a pyrolysis or a combustion interface a, b and c for oxygen, hydrogen and carbon isotope analysis, respectively, and is additionally equipped with an elemental analyser (EA). After [205] with kind permission of the American Chemical Society... 

Figure 7.19 Schematic diagram of a gas chromatographic atomic emission detector...

FIGURE 18.11 Schematic diagram of the essential features of a gas chromatograph. 

GC [5,19-24]—as the name implies— is a separation technique where the applied mobile phase is a gas, while the stationary phase is a solid or a liquid. It has relatively few variants now nearly exclusive capillary GC is used. The sample is evaporated in an injector and a gas flow carries it through an open capillary tube (column) to the detector. The schematic diagram of a gas chromatograph is shown in Fig. 4. 

A schematic diagram of a gas chromatograph is shown in Figure 1. It consists of five major components ... 

The essential features of a gas chromatograph are shown schematically in Figure 25.10. The carrier gas generally is argon, helium, hydrogen, or nitrogen. The sample... 

A schematic representation of a gas chromatograph is shown in Fig. 13, and it indicates that the sample is first vaporized by injection into a heated port, then passed through a heated separation column, and finally detected. The small sample size that can be passed by capillary columns usually necessitates supplementation of specialized splitters at the injection port. A splitter accurately and reproducibly reduces the volume of sample that enters the column from standard sample injections done by syringe. Numerous detection devices exist, and the most common are summarized in Table VIII. Separation times of various species eluting from the column are often controlled by varying column temperature by a technique known as temperature programming. 

FIGURE 4 A schematic representation of the arrangement in a gas chromatograph. The coiled column, which is packed with the stationary phase, may be as long as 100 m. 

The schematic diagram of the experimental setup is shown in Fig. 2 and the experimental conditions are shown in Table 2. Each gas was controlled its flow rate by a mass flow controller and supplied to the module at a pressure sli tly higher than the atmospheric pressure. Absorbent solution was suppUed to the module by a circulation pump. A small amount of absorbent solution, which did not permeate the membrane, overflowed and then it was introduced to the upper part of the permeate side. Permeation and returning liquid fell down to the reservoir and it was recycled to the feed side. The dry gas through condenser was discharged from the vacuum pump, and its flow rate was measured by a digital soap-film flow meter. The gas composition was determined by a gas chromatograph (Yanaco, GC-2800, column Porapak Q for CO2 and (N2+O2) analysis, and molecular sieve 5A for N2 and O2 analysis). The performance of the module was calculated by the same procedure reported in our previous paper [1]. 

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