Copper columns

CUORICINO crystals are grouped in elementary modules of four elements (see Fig. 15.7) held between two copper frames joined by copper columns. PIPE pieces are inserted between the copper and TeOz, as a heat impedance and to clamp the crystals. There is a 6 mm gap between crystals with no material in between. The four detectors are mechanically coupled some of the PTFE blocks and springs act simultaneously on two crystals. 

In one method dichloroethane extraction of the sediment, followed by elimination of elemental sulphur, mercaptans, disulphide and dibenzothiophene on a copper column is followed by a gas chromatographic... 

In a method described by Bates and Carpenter [8] for the characterization of organosulphur compounds in the lipophilic extracts of marine sediments these workers showed that the main interference is elemental sulphur (S8). Techniques for its elimination are discussed. Saponification of the initial extract is shown to create organosulphur compounds. Activated copper removes S8 from an extract and appears neither to create nor to alter organosulphur compounds. However, mercaptans and most disulphides are removed by the copper column. The extraction efficiency of several other classes of sulphur compounds is 80-90%. Extracts are analyzed with a glass capillary gas chromatograph equipped with a flame photometric detector. Detection limit is lg S and precision 10%. 

A number of metal and metalloid halides have been separated with rather conventional arrangements. For example, Keller and Freiser separated SnCl4, TiCl4, NbClj, and TaCIs at 200°C using a copper column packed with squalane on Chromsorb P (a modified diatomaceous earth).51 A variety of chlorosilanes and methylchlorosilanes have been separated using silicone oil plus diethyl ph-thalate as the stationary-phase and thermal conductivity detectors.52... 

Difluorodiazene contaminated with SiF4 and NF3 is held at —195°C. This mixture is passed through a sodium fluoride trap to remove SiF4 by the formation of Na2SiF6. Difluorodiazene may be separated from nitrogen trifluoride by gas chromatography with the use of a 25-ft. X 0.25-in. aluminum or copper column... 

Note Copper columns often cause adsorption problems incompatible with amines, anilines, acetylenes, terpenes, steroids, and strong bases. 

Extraction and extract separation. The freeze dried samples were ground and extracted with chloroform for one hour at 55°C. Free sulfur was removed by percolating the extracts over an activated copper column. Resulting extracts were separated using thin layer chromatography (Merck precoated T.L.C. Silica-gel 60f-254) with cyclohexane as the eluting solvent. Three fractions were obtained an immobile polar fraction, an "intermediate fraction, and a saturated/unsaturated hydrocarbon fraction. 

Fig. 5.28. Gas chromatogram of a mixture of sugars after reduction and acetylation. Peaks 1 = L-rhamnose 2 = D-fucose 3 = L-arabinose 4 = D-xylose 5 = D-mannose, 6 = D-galactose 7 = D-glucOse 8 = myo-inositol. Conditions copper column, 4 ft. X 1/8 in. O.D., 0.2% EGS, 0.2% EGA and 0.4% XF 1150 on Gas-Chrom P (100-120 mesh) temperature programme 120°C for 10 min, then l°C/min. (Reproduced from Carbohyd. Res., 5 (1967) 340, by courtesy of P. Albersheim.)...

Off-gas analyses were done by mass spectrometry and reactor effluent samples were analyzed by glc. Most of the glc work was done with an 8-foot 1/4-inch OD column containing 10% SE-30 on acid washed Chromsorb W. However, the separation of n-propyl-benzene from cumene had to be done with a dual 3/16-inch copper column consisting of a 12-foot section having 10% Bentone 34 and 10% Dow Corning silicone gum 550 on 60-80 mesh acid washed Chromsorb W and a 6-foot section containing 20% Apiezon L on 60-80 mesh acid washed Chromsorb P. 

Column chromatography on silica, alumina, Sephadex or Florisil has been used most often for the clean-up and fractionation of PAHs in the sample extract (Desiderie et al. 1984 Desilets et al. 1984 Oehme 1983 Quilliam and Sim 1988). HPLC can also be used for the clean-up and fractionation of PAHs in sample extract (Readman et al. 1986). A disposable Sep-Pak cartridge with an amino stationary phase was used for the clean-up of benzo[a]pyrene in cigarette smoke condensate (Dumont et al. 1993). Some soil and sediment samples containing high amounts of sulfur may require clean-up on an activated copper column (Giger and Schaffner 1978). 

Toluene and hexane are purified by distillation from sodium wire in an atmosphere of nitrogen. The nitrogen gas is purified by passing it through an activated-copper column at a temperature of 170°. 

To absorb water, Jacobs [44] used a copper column (40 x 0.6 cm I.D.) packed with phosphoric anhydride on firebrick. A single charge (3.7g of phosphoric anhydride) is sufficient to absorb water contained in fifty IO-/1I samples of aqueous solutions. 

The calcium trichloroacetate is digested at about 100 C. Carbon dioxide and chloroform are evolved and pass to tin water condensers (+10°C), then to a brine-cooled condenser just above 0 C, then to three CaCb driers in series, and finally to a brine-cooled copper condenser. The condensate is separated from water, collected in stoneware jars, and distilled in a copper kettle with copper column. Chalk is added to the still, which is operated with a 5 1 reflux ratio. The chloroform vapors are condensed in a silver coil depblegmator and collected in silver receivers. 

Isolation of the hydrocarbons from other lipids The total lipid extract may be subjected to removal of elemental sulphur by passage through an activated copper column (Blumer, 1957) and then to chromatographic separation on adsorbent columns or thin layer plates. For column chromatography, silic el is used with a short alumina bed on the top of the silic el. Both adsorbents should be partially deactivated by the addition of water (2—5%) to prevent the formation of artifacts (Blumer, 1970). Elution with a non-polar solvent such as hexane or pentane and subsequently with mixtures of non-polar and polar solvents, e.g. benzene and methanol, permits the isolation of several fractions containing saturated, unsaturated, aromatic hydrocarbons and more polar compounds (methyl esters, alcohols, acids, phenols and heterocyclic compounds). The interference from esters encountered in the isolation of aromatic hydrocarbons can be avoided prior to separation by saponification of the esters of fatty acids, which are easily removed. 

N02 was synthesized fro m NOa" by reduction in a cadmium-copper column and purified from by vacuum evaporation at pH 10.0 (20). 

Triflupromazine was well separated from other phenothiazine tranquilizers on a 80-100 mesh Gas-Chrom S glass column coated with 2% SE-30. Retention time relative to chlorpromazine at a column temp, of 205° was 0.46. Similar results were obtained on a 60-80 mesh Diatoport copper column coated with 5% SE-30.In the same system triflupromazine was separated from its sulphoxide.Another system used was a 100-120 mesh silanized Gas-chrom P glass column coated with 1% Hi-Eff-8B (cyclohexanedimethanol succinate)... 

The compressed value of copper column Size of copper column as q) 7 x 10.5 mm... 

In this work, copper columns of about 4 mm bore are convenient and most commonly used. Copper tubing has the advantage that it can be bent into suitable coils and is inert to most solutes. Capillary columns suffer from the disadvantage that the amount of stationary liquid phase is difficult to determine accurately. For solutes that react with copper, e.g. amines, glass columns may be used. They are normally used in the form of U-tubes because of the difficulty in filling them in coiled form. 

Purcell [20] was the first to suggest an adsorption open tubular capillary column with molecular sieves (see Fig. 1-5 [20]). The copper column (23 m x 1 mm) with roughened walls coated with pulverized molecular sieve 5A was used for separation of... 

Lappin and Zannucci [5] concerned themselves with polypropylene additives such as hindered phenols and ultraviolet stabilisers which are stable at 350 °C. They used a gas chromatograph equipped with a flame ionisation detector. Copper columns, 6.4 mm x 1.5 m, packed with 10% SE-30 on 40- to 60-mesh Chromsorb V were used (the column may require silylation). The injection port and detector oven were held at a constant... 

Figure 8.3 Gas chromatogram of volatiles liberated from PE heated at different temperatures for 15 minutes in air. Chromatographed on 60 m x 1.5 mm id dibutyl phthalate coated copper column at 30 °C and 100 ml/min helium flow, with flame...

S. B. Park, Rahul Joshi, and Lewis Goldmann, Reliability of Lead-Free Copper Columns in Comparison with Tin-Lead Solder Column Interconnects, Electronic Components and Technology Conference, 2004, pp. 82-89. 

Gas chromatographic separation of the pyrolysis products was achieved with a 6 x diameter copper column packed with 10% silicone oil on 60-100 mesh "Embacel" (both from May Baker Ltd., Dagenham, Essex) operated at 23 C (room temperature). The nitrogen carrier gas flow rate was 30ml min"... 

In later work Soulages modified the above method in respect of the stationary phase to permit the simultaneous determination of the lead alkyls and the scavengers. The copper column (150 cm x 0.4 cm) used was packed with 20% of 1,2,3-tris-(2-cyanoethoxy)-propane on Chromosorb P (30 to 60 mesh) precoated with 1% of potassium hydroxide and operated at 80°C with hydrogen (40 ml per min) as carrier gas. Recoveries were between 98 and 102% for each tetraalkyllead component in the range equivalent to 0.026 to 0.2 g of lead per litre. Similar results were obtained for the scavengers (dibromo- and dichloro-ethane). 

Eichler, B., Gaggeler-Koch, H., Gaggeler, H. Thermochromatography of carrier-free elements polonium in copper columns. Radiochim. Acta 26, 193-196 (1979)... 

---