Fused-silica column

Figure 1.2 Chromatogram of coal-tar oil obtained by using the following conditions column, Waters Spherisorb PAH 5 mm in 250 p.m id X 30 cm fused silica column oven temperature, 100°C UV detector wavelength to 254 nm mobile phase, 100 to 300 bar CO2 and 0.10 to 1.00 p.L min methanol over 30 minutes.

Figure 12.8 Mia ocolumn size exclusion chromatogram of a styrene-aaylonitrile copolymer sample fractions ti ansfeired to the pyrolysis system are indicated 1-6. Conditions fused-silica column (50 cm X 250 p.m i.d.) packed with Zorbax PSM-1000 (7p.m 4f) eluent, THF flow rate, 2.0 p.L/min detector, Jasco Uvidec V at 220 nm injection size, 20 nL. Reprinted from Analytical Chemistry, 61, H. J. Cortes et al, Multidimensional chromatography using on-line microcolumn liquid chromatography and pyrolysis gas chromatography for polymer characterization , pp. 961 -965, copyright 1989, with peimission from the American Chemical Society.

Figure 12.10 Microcolumn SEC-LC analysis of an acrylonitrile-butadiene-styrene (ABS) teipolymer sample (a) SEC ti ace (b) EC ti ace. SEC conditions fused-silica column (30 cm X 250 mm i.d.) packed with PL-GEL (50 A pore size, 5 mm particle diameter) eluent, THE at a flow rate of 2.0 mL/min injection size, 200 nL UV detection at 254 nm x represents the polymer additive fraction (6 p-L) tr ansferred to EC system. EC conditions NovaPak CIS Column (15 cm X 4.6 mm i.d.) eluent, acetonitrile-water (60 40) to (95 5) in 15 min gradient flow rate of 1.5 mL/min detection at 214 nm. Peaks identification is follows 1, styrene-acrylonitrile 2, styrene 3, benzylbutyl phthalate 4, nonylphenol isomers 5, Vanox 2246 6, Topanol 7, unknown 8, Tinuvin 328 9, Irganox 1076 10, unknown. Reprinted with permission from Ref. (14).

I Most of the GC conditions given in this book are for 0.25-mm ID columns, but 0.32- or 0.53-mm ID columns also can be used. The wide bore fused silica columns are found to be more inert, probably because of the greater film thicknesses. A splitter arrangement with a jet separator is used with 0.53-mm ID columns. This arrangement shown in Figure 11.1 has the advantage of simultaneous flame ionization quantitation. 

The catalyst testing was carried out in a gas phase downflow stainless steel tubular reactor with on-line gas analysis using a Model 5890 Hewlett-Packard gas chromatograph (GC) equipped with heated in-line automated Valeo sampling valves and a CP-sD 5 or CP-sil 13 capillary WCOT colunm. GC/MS analyses of condensable products, especially with respect to O-isotopic distribution, was also carried out using a CP-sil 13 capillary column. For analysis of chiral compounds, a Chirasil-CD capillary fused silica column was employed. 

Hewlett-Packard Model 5890 gas chromatograph equipped with a nitrogen-phosphorus detector Hewlett-Packard Model 3396 or 3396A integrator Hewlett-Packard Model 6890 or 7673A autosampler RTX-1 fused-silica column (100% polymethylsilox-ane), 30 m x 0.53-mm i.d., 0.5- um film thickness, Restek Corporation (Bellefonte, PA, USA)... 

Automated gel permeation chromatograph (Cleanup XL, Abimed Gilson) equipped with 5-mL loop and chromatographic tube, 25-mm i.d., 600-mm long, filled with 52-g of Bio-Beads, S-X3, 200 00 mesh, 33-cm gel bed length GC Gas chromatograph equipped with a split/splitless injector, autosampler, DB-1 fused-silica column, 30 mx 0.25-mm i.d., 0.25-p.m film thickness and electron capture detector... 

Fused-silica column (15 cm x 4.6 mm) of Spherisorb S5W 0.1 mL chloroform-methanol-aqueous 25% ammonia (868 125 7) [1.5 mL/min] 254 nm Normal phase HPLC analysis in whole blood and urine. [96]... 

The chromatographic procedure [11] is carried out using a wide-bore fused-silica column 30 m long and 0.53 mm in internal diameter coated with macrogel 20 000 2-nitrotere-phthalate with film thickness of 0.5 pm. In addition, for chromatography, helium should be used as the carrier gas at a flow rate of 8.0 mL/min using a flame ionization detector. 

Fused silica column (25 m x 0.2 mm) N2 coated with 5% phenylmethylsilicone germ phase HP-5 (0.33 pm)... 

FIGURE 8 Gas chromatographic separation of the volatiles of D. diemensis egg extracts (47). Conditions fused silica column OV 1 (10 m X 0.32 mm) 50°C isotherm for 2 min, then at 10°C/min to 250°C injection port 250°C detector Finnigan ion trap, ITD 800 transfer line at 270°C electron impact (70 eV) scan range, 35-250 Da/sec. For identity of numbered compounds refer to Figure 9. 

Maskarinec and Harvey [61] have described a method for the screening of solid wastes and sludges for organic compounds. The technique involves sequential extraction with acidic, basic and neutral media and the extracts are all analysed directly by gas chromatography with fused silica columns. Results achieved using the technique are discussed. The method is compared with traditional Soxhlet extraction. 

Nitrophenols in fog and atmospheric particles were determined by GC of the underiva-tized compounds and their corresponding acetate esters. Four fused-silica columns were used with three alternative detection modes, namely mass-selective detection, nitrogen-specific detection and ECD. GC-ECD of the acetate derivatives gave the best results501. A capillary GC-UVD method was developed for the determination of small amounts of nitrophenols present in the environment. The method was compared with HPLC-UVD from the point of view of selectivity and sensitivity. LOD for GC were about one-tenth of those for HPLC502. 

Gas chromatographic analysis indicates that this consists of 97-99% of citronellol and 1-3% of dihydrocitronellol column, SHIMADZU HiCap-CBP20, 25 m x 0.2-mm fused silica column temperature, 140°C injection temperature 160°C helium pressure as carrier gas, 1.0 kg/cm2 tR of geraniol, citronellol, and dihydrocitronellol are 16.2,13.7, and 8.6 min, respectively. 

After elution from the SPE cartridges, the eluents will be evaporated slowly under nitrogen gas. The concentrated samples containing metolachlor will be analyzed by GC/MS while the fractions containing the polar metabolites will be analyzed by HPLC. Both the GC and HPLC will be equipped with chiral columns. For GC/MS, a fused silica column coated with tert-butyldimethylsilyl-P-cyclodextrin will be used. This column has been shown to partially separate metolachlor isomers (13). 

Diastereomer ratios were determined by gas chromatography. Since the aldol adduct undergoes retroaldol reaction on the column, it must be silylated prior to injection. Approximately 5 mg of the crude adduct is filtered through a short plug of silica gel to remove any trace metals. The material is taken up into 1-2 mL of dichloromethane in a 2-raL flask or small test tube. To this solution are added 4-5 drops of N,N-diethyl-1,1,1-trimethylsilylamine and a small crystal of 4-(N,N-dimethylamino)pyridine (Note 11), The solution is stirred for 2 hr and injected directly onto the column. (Column conditions 30 m x 0.32 mm fused silica column coated with OB 5, 14 psi hydrogen carrier gas, oven temperature 235°C). 

A mass spectrometer adapted for chemical ionization can tolerate a solvent flow rate into the vacuum system of 5-10 yL/min. This suggested the use of a LC column operating at this low flow rate. A micropacked fused-silica column (1-3) is well suited for this application. 

A 0.5-yL syringe-loaded micro injector (Rheodyne 7520) is used for sample injection. To minimize the dead volume (< 20 nL) the fused silica column is connected directly to the injector block. 

Figure 2. Schematic diagram of column tip, second version. 1, Fused-silica column I.D. 0.22 mm 2, chromatographic bed 3, glass fiber filter frit 4, drawn-out 50 ym fused-silica tube 5, high temperature epoxy coating...

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