Supports Chromosorb

Should be distd under reduced pressure under nitrogen and stored in the dark. Purified via the nitrosochloride [Waterman et al. Reel Trav Chim Pays-Bas 48 1191 7929]. For purification of optically active forms see Lynn [J Am Chem Sac 91 361 1919]. Small quantities (0.5mL) have been purified by GLC using helium as carrier gas and a column at 90 packed with 20 wt% of polypropylene sebacate on a Chromosorb support. Larger quantities were fractionally distd under reduced pressure in a column packed with stainless steel gauze spirals. Material could be dried with CaH2 or sodium, and stored in a refrigerator CaS04 and silica gel were not satisfactory because they induced spontaneous isomerisation. [Bates, Best and Williams 7 C/iem Soc 1521 7962.]... 

To determine the activity coefficient at infinite dilution, packed colunms were prepared containing the IL-coated chromosorb support [12-14]. The examined mixture of probe molecules was then injected under infinite dilution conditions. The value of y can be calculated from Equation 4.4, as defined by Cruickshank and coworkers [15] ... 

Tungsten was separated on DEAE-Sephadex for determination of trace amounts of alkali and alkaline-earth metals by AAS without matrix interference Dithi-zone in o-dichlorobenzene was used as the stationary phase on a Chromosorb support for the enrichment and separation of Zn,Cd,Hg and Cu By adding selective masking agents to the sample solution the adsorption of the traces was prevented the matrix was adsorbed. The separation of mercury from large amounts of copper on columns coated with silver dithizonate for example was reported. 

Chromosorb P is a pink diatomaceous earth material that has been carefully size graded and calcined. The surface area is 4-6 mVg. This material is the least inert of the Chromosorb supports but offers the highest efficiency. It is used when hydrocarbons are to be separated. 

Silanizedsupports are Chromosorb supports that have been reacted with dimethyldichlorosilane (DMCS) or some similar compound to reduce surface active sites of the diatomaceous earth material. Chromosorb supports deactivated with DMCS provide less tailing, minimized catalytic effects, and improved results with low liquid loadings. Hexamethyldisilane (HMDS) also has been used. The combination of acid washing and DMCS treating is particularly effective in reducing adsorption. 

Cyclohexanol may be analyzed by GC-FID using Carbowax 20 M on Chromosorb support or an equivalent column. It may be analyzed colorimetrically by reaction with p-hydroxybenzaldehyde in sulfuric acid (absorbance maxima at 535 and 625 nm). Cyclohexanol in air (working range 15-150 mg/m ) may be measured by sampling 10 L of anon charcoal, desorbing the adsorbent in a CS2/isopropyl alcohol mixture, and analyzing the eluant by GC-FID, using the column 10% SP-1000 on Supelcoport (NIOSH 1984, Method 1402). 10% FFAP on Chromosorb may be used as an alternative column. 

For IGC work with PU, the polymer was cured against Teflon sheet, peeled off, and powdered by pestle and mortar. About 1.0 g of powder was packed into previously washed and dried steel columns, 15 cm long and 1.2 cm in diameter. Polymer substrates, such as PVC and ABS, were deposited onto Chromosorb support (acid-washed, 60/40 mesh diatomaceous earth) following well-established procedures [6]. Small, nanoliter amounts of the volatile phase were injected into the chromatograph, with helium as the carrier gas at a flow rate of 10 cmVmin. 

Chromosorb W is the most commonly used support which is usually screened to a particle diameter range of 127 pm-149 pm, with a mean value of 138 pm (100-120... 

The diacetate was judged to be virtually pure by the submitters on the basis of a gas chromatographic analysis carried out at 150° using a glass column packed with 3% OV 17 (1 1 methyl-phenyl silicone) supported on 70-80 mesh Chromosorb W. 

Column conditions length, 1.8-m X 4-mm glass solid support, Chromosorb W, 80-100 mesh injector, 240°C column, 200° C detector, Ni, 310° C flow rate, 80-100 ml/min... 

Preliminary studies into a third variable, the partial pressure of water vapor in the system, are discussed in Part 3 of the Results and Calculations section. Each calorimetric sample ( 1 g, 13.47 mass % bitumen) came from a large sample of "reconstructed" oil sand consisting of Athabasca bitumen loaded onto a chemically inert solid support material (60/80 mesh acid washed Chromosorb W) of well-defined particle size. 

Column 2.5% SE-30 on 80-100 mesh Chromosorb G (acid-washed and dimethyl-dichlorosilane-treated), 2 m x 4 mm internal diameter glass column. It is essential that the support is fully deactivated. 

Guo et al. [53] developed a gas chromatographic method for the analysis of miconazole nitrate in creams and injections. The conditions were flame ionization detector, stationary phase of 5% SE 30 support of Chromosorb W (AS-DMCS, 80—100 mesh) packed column 3 m x 3 mm column temperature 275 °C injection temperature 290 °C and diisooctyl sebacate and internal standard. The average recoveries for creams and injections were 97.7 and 101.4%, respectively. The relative standard deviations were 2.2 and 1.3%, respectively. 

It is possible to collect the volatiles in a cold trap [22]. A more favoured technique is the collection of the gases by adsorption on some support such as one of the Chromosorbs, or Tenax GC [13,22,23]. The volatiles are then desorbed by heating and injected into a gas chromatograph. 

Braman and Tompkins [98] found that stannane (SnH4) and methylstan-nanes (CH3SnH3, (CH3)2SnH2 and(CH3)3SnH) could be separated very well on a column comprising silicone oil OV-3 (20% w/w) supported on Chromosorb W. A typical separation achieved on a water sample is shown in Fig. 10.2. 

The system used by these workers consisted of a Microtek 220 gas chromatograph and a Perkin-Elmer 403 atomic absorption spectrophotometer. These instruments were connected by means of a stainless steel tubing (2mm o.d.) connected from the column outlet of the gas chromatograph to the silica furnace of the atomic absorption spectrometer. The silica furnace was set at 1000°C. The gas chromatographic column was packed with 3% OV-1 supported on Chromosorb W. The column was temperature programmed at 15°C h to 150°C. 

The liquid stationary phase in a GLC packed column is adsorbed on the surface of a solid substrate (also called the support). This material must be inert and finely divided (powdered). The typical diameter of a substrate particle is 125 to 250 ft, creating a 60- to 100-mesh material. These particles are of two general types diatomaceous earth and Teflon . Diatomaceous earth, the decayed silica skeletons of algae, is most commonly referred to by the manufacturer s (Johns Manville s) trade name, Chromosorb . Various types of Chromosorb, which have had different pretreatment procedures applied, are available, such as Chromosorb P, Chromosorb W, and Chromosorb 101-104. The nature of the stationary phase as well as the nature of the substrate material are both usually specified in a chromatography literature procedure, and columns are tagged to indicate each of these as well. 

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