Chromatography apparatus

Chamber saturation is important for good separations. The inner walls of the chamber 

Another type of ascending TLC, which is often used where chamber saturation is necessary, is that carried out in a sandwich chamber (Fig.3.3). The TLC plate is sandwiched between two glass plates with only a minimum of air-space above the surface of the adsorbent. Vapor saturation can be achieved in a short time with much less solvent than is required by conventional TLC chambers. Several sandwich chambers are available from Analtech, Brinkmann, Desaga, Eastman-Kodak, etc. 

Horizontal and descending TLC are other forms of chromatography which require special equipment. The advantages of these systems are not clear. They are usually more expensive than ascending equipment, but often have other features for stepwise gradient elution or continuous solvent programming. 

One system worth mentioning is called programmed multiple development (PMD) and has been developed by Regis Chemical Co. (Morton Grove, 111., U.S.A.). The method is a 

Most of the routine TLC equipment mentioned above can be obtained from the major suppliers listed in Tables 3.1 and 3.2. These items and accessories are available in many styles, shapes and sizes, and are suitable for most analytical requirements. 

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Nanotubes may be simply a short section of a capillary tube that holds a small quantity of the solution of interest (Figure 10.2a). Alternatively, Figure 10.2b shows this inlet as the exit from a liquid chromatography apparatus, which is equipped with very narrow nanocolumns. ... 

Synthetic chiral adsorbents are usually prepared by tethering a chiral molecule to a silica surface. The attachment to the silica is through alkylsiloxy bonds. A study which demonstrates the technique reports the resolution of a number of aromatic compoimds on a 1- to 8-g scale. The adsorbent is a silica that has been derivatized with a chiral reagent. Specifically, hydroxyl groups on the silica surface are covalently boimd to a derivative of f -phenylglycine. A medium-pressure chromatography apparatus is used. The racemic mixture is passed through the column, and, when resolution is successful, the separated enantiomers are isolated as completely resolved fiactions. Scheme 2.5 shows some other examples of chiral stationary phases. 

W. D. Conway (Ed.), Countercurrent Chromatography apparatus, theory and applications, VCH Publ., New York (1990). 

Figure 4-1. Components of a simple liquid chromatography apparatus. R Reservoir of mobile phase liquid, delivered either by gravity or using a pump. C Glass or plastic column containing stationary phase. F Fraction collector for collecting portions, called fractions, of the eluant liquid in separate test tubes.

Figure 1.14 Schematic representation of the modified Soxhiet chromatography apparatus [198].

Figure 13.1 shows a simple thin layer chromatography apparatus. 

Certain gas phase chromatography apparatus allows a constant gas flow in the column when operating under programmed temperature conditions. 

A gel permeation chromatography apparatus was adapted for use in pumping and fractionating samples in order to study the adsorption characteristics of the XAD-4 quaternary resin in the OH" form. 

Figure 0-4 Principle of liquid chromatography, (a) Chromatography apparatus with an ultraviolet absorbance monitor to detect analytes at the column outlet. (fc>) Separation of caffeine and theobromine by chromatography. Caffeine is more soluble than theobromine in the hydrocarbon layer on the particles in the column. Therefore, caffeine is retained more strongly and moves through the column more slowly than theobromine.

Analysis of Volatile Matter Evolved. An attempt was made to establish the particular volatile component or components responsible for decrepitation by using a Beckman gas chromatography apparatus as described below. It was considered that comparing the analyses obtained at different temperatures with the corresponding rate of volatile matter evolution from the experimental work described previously would perhaps indicate the presence of a thermal decomposition reaction of controlling importance. 

Column chromatography apparatus, including a suitable low-pressure pump, online UV monitoring at 280 nm and a fraction collector. 

Figure 9-1 Schematic diagram of a gas-liquid chromatography apparatus. The detector is arranged to measure the difference in some property of the carrier gas alone versus the carrier gas plus effluent sample at the exit. Differences in thermal conductivity are particularly easy to measure and give reasonably high detection sensitivities.

More accurate quantitative analyses can be carried out by GC or LC. A suitable internal standard is usually required it must be chemically stable and involatile under the conditions of the experiment (prior to injection into the chromatography apparatus), and must be resolved from the other signals in the chromatogram. It is usually added to the product mixture after the reaction has been completed but before any extraction, purification or analysis steps are undertaken. Saturated hydrocarbons of Cio or above are typically used as internal standards for GC [7]. Response factors are obtained for each component of... 

Early on, gas-phase chemical separations played an important role in the investigation of the chemical properties of transactinide elements. The technique was pioneered by I. Zvara and co-workers at the Dubna laboratory and involved first chemical studies of volatile Rf, Db and Sg halides and/or oxyhalides [73,74,75] see Chapter 7 for a detailed discussion. The experimental set-ups and the techniques involved are presented in Section 4.2. A new technique, named OFGA (On-line Gas chromatography Apparatus), which allowed the a-spectrometric measurement of final products, developed by H.W. Gaggeler and co-workers was then successful in studying volatile transactinide compounds from Rf up to Bh [76,77,78,79], see Chapter 7 for a detailed discussion. In all these... 

Fig. 8. Schematic of the first gas chromatography apparatus used to chemically isolate element 104 in the form of volatile chlorides (Figure from Ref. 11, adapted from Ref. 105).

Kazuaki, T., Nishinaka, I, Asai, M., Goto, S., Sakama, M., Haba, H., Ichikawa, S., Nagame, Y., Schadel, M. Automated Liquid Chromatography Apparatus Coupled with an On-line Alpha-Particle Detection System . In 2nd International Symp. on Advanced Sci. Res., Advances in Heavy Element Research - ASR-2001 , Tokai, Ibaraki, Japan, Nov. 13-15, 2001 http //asr.tokai.jaeri.go.jp/asr2001/abstract/Tsukada.pdf... 

Figure 4. Schematic diagram of low temperature fractionation and gas chromatography apparatus...

Conway, W.D. Countercurrent Chromatography - Apparatus, Theory Applications-, VCH Weinheim, Germany, 1990. 

Column chromatography apparatus, including a suitable low-pressure pump, on-line UV monitoring at 280 nm and a fraction collector. Chromatography media Sephacryl S-200 (SF), Sephadex G-25 (SF) (Pharmacia). 

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