Glass capillary columns

Installation of Capillary Columns Glass columns, whidi are coiled when purdiased, must have straight ends to allow than to fit into imions at the injector and detector. A device is commercially available to straightoi capillary ends, but it is more usual to use a small butane flame. The column is suspended on a clamp stand and a supply of csilicone rubber tubing to produce a flow of about 0.5 ml/ min. A cool, small butane flame is used to apply... 

Fused silica columns have obvious advantages, but do not have these possibilities. The fused silica capillary columns do not solve all the problems. The activity of silicium based capillary columns (glass or fused silica) is due to the trace of metal ions, silanol groups and siloxane bridges. Whereas a leached soda-lime column is always basic, fused silica columns are always acidic. 

With the use of very low diameter columns, dead volume becomes a key problem, so manufacturers have gone to great lengths to try and minimize these effects. There are various column formats that have been employed for micro-LC, including fused silica capillary columns, glass-lined stainless steel, and glass-lined peek such as peeksil. 

Generally, alkan olamines are analyzed by gas chromatography or wet test methods. Details on gas chromatography conditions are available in the fiterature (1) for packed or glass capillary columns. 

The most common chromatogram in the distilled spirits industry is the fusel oil content. This consists of / -propyl alcohol, isobutyl alcohol, and isoamyl alcohol. Other common peaks are ethyl acetate, acetaldehyde, and methanol. The gc columns may be steel, copper, or glass packed column or capillary columns. Additional analyses include deterrninations of esters, total acids, fixed acids, volatile acids, soHds or extracts (used to determine... 

Glass capillary column (38 m X 0.2 mm i.d.) coated with heptakis (3-0-acetyl-2,6-di-0-pentyl)-/3-cyclodextrin... 

Duranglas glass capillary column (30 m X 0.23 mm i.d.) coated with SE52 (0.63 p,m Him thickness)... 

K. Groh Jr., G. Groh and K. Groh, Comprehensive quality test for glass capillary columns , / Chromatogr. 156 1-20(1978). 

Capillary columns are fabricated from thin-walled stainless steel, glass, or high-purity fused silica tubing (the last is preferred for its inertness). Typical dimensions of the columns, which are coiled, are 25-200 m long and 0.2-0.5 mm i.d. 

W G Jennings, Gas Chromatography with Glass Capillary Columns, Academic Press, New York, 1980... 

As with capillary columns, it is crucial to have an inactive surface and maintain a reasonably even temperature over the length of the interface. This is usually accomplished by using only glass in the interface. The additional connections necessary in an enrichment-type interface present new areas for leaks to occur. Connections are especially prone to develop leaks after a cooling/heating cycle. 

The purity of 1 and 2 is assessed by analytical gas-liquid chromatography (GC) on a Hewlett-Packard 5890 gas chromatograph equipped with a flame-ionization detector and fitted with a 50 m x 0.2 mm HP-5 fused silica glass capillary column using linear temperature programming from an initial temperature of 150°C for 5 min to a final temperature of 200°C for 10 min at a rate of 5°C/min. 

Chromatographic columns (glass with stopcock and solvent reservoir, 10-mm i.d.) Fused-silica capillary column, DB-1701, 60 m x 0.32-mm i.d., O.lS-qm film thickness (14% cyanopropylphenyl)methylpolysiloxane Varian 3400 gas chromatograph equipped with a temperature-programmed SPI injector, a Varian 8100 autosampler, and a Varian Saturn II lontrap mass spectrometer Centrifuge vials, 10- and 250-mL Evaporation flasks, 100- and 250-mL Separatory funnel, 250-mL... 

Hydrolytic Kinetic Resolution (HKR) of epichlorohydrin. The HKR reaction was performed by the standard procedure as reported by us earlier (17, 22). After the completion of the HKR reaction, all of the reaction products were removed by evacuation (epoxide was removed at room temperature ( 300 K) and diol was removed at a temperature of 323-329 K). The recovered catalyst was then recycled up to three times in the HKR reaction. For flow experiments, a mixture of racemic epichlorohydrin (600 mmol), water (0.7 eq., 7.56 ml) and chlorobenzene (7.2 ml) in isopropyl alcohol (600 mmol) as the co-solvent was pumped across a 12 cm long stainless steel fixed bed reactor containing SBA-15 Co-OAc salen catalyst (B) bed ( 297 mg) via syringe pump at a flow rate of 35 p,l/min. Approximately 10 cm of the reactor inlet was filled with glass beads and a 2 pm stainless steel frit was installed at the outlet of the reactor. Reaction products were analyzed by gas chromatography using ChiralDex GTA capillary column and an FID detector. 

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