Silica capillary column for

The use of a fused silica capillary column for the GC analysis of the neutral oil extract has provided the means for improving the resolution of components in a more inert system. The sultones are determined by temperature-programmed GC over CP-Sil-5 CB (methyl silicone fluid) in a 25 m x 0.2 mm fused silica capillary column using nonadecane as internal standard. A sample split ratio of 1 100 is recommended for a 3-pl injection. 

Kobayashi, H., Kajiwara, W., Inui, Y., Hara, T., Hosoya, K., Ikegami, T., Tanaka, N. (2004). Chromatographic properties of monolithic silica capillary columns for polar and nonpolar compounds in reversed-phase HPLC. Chromatographia 60, S19-S25. 

Capillary GC and GC-MS analyses A Hewlett-Packard 5880A GC was used with a 60 m x 0.32 mm Supelcowax 10 or 30 m x 0.25 mm Carbowax 20M fused silica capillary column for capillary GC analyses. The following conditions were used operation in... 

Guide for slurry packing fused-silica capillary columns for capillary electrochromatography (i) Forming the bed-retaining frit... 

There are numerons reports for the gas chromatographic determination of THC and its metabolites, ll-nor-A-9-tetrahydrocannibinol-9-carboxylic acid (THC-COOH) and ll-hydroxy-A-9-tetrahydrocannibinol (11-OH-THC) in urine and blood. THC is not normally found in urine, so it must be determined in blood at levels around 2-4 ng/mL. The TMS derivative is the most widely used derivati-zation procedure with GCMS for the determination of cannabinoids. In addition to the obvious advantages of derivatizing the THC metabolites, the acidic constituents of cannabis mnst be derivatized because they can easily decarboxylate above 80°C. Almost aU gas chromatographic procedures today use fused-silica capillary columns for this analysis. Determination of THC in blood is routinely done in forensic toxicological samples, and the detection and quantification of the two THC metabolites in mine is a routine procedure for proof of cannabis use in workplace testing. Several of the procedures used for this type of analysis are listed in Table 16.9. 

We have developed the method for quantitative analysis of urinary albumin with CE. A capillary electrophoresis systems Nanophor 01 (Institute of Analytical Instmmentation, Russian Academy of Sciences, Saint-Petersburg) equipped with a UV-detector was used to determine analyte. Separation was achieved using 45 cmx30 p.m I.D. fused silica capillary column with UV-detection at 214 nm. 

For routine separations, there are about a dozen useful phases for capillary columns. The best general-purpose columns are the dimethylpolysiloxane (DB-1 or equivalent) and the 5% phenyl, 95% dimethylpolysiloxane (DB-5 or equivalent). These relatively nonpolar columns are recommended because they provide adequate resolution and are less prone to bleed than the more polar phases. If a DB-1, DB-5, or equivalent capillary column does not give the necessary resolution, try a more polar phase such as DB-23, CP-Sil88, or Carbowax 20M, providing the maximum operating temperature of the column is high enough for the sample of interest. See Appendix 3 for fused silica capillary columns from various suppliers. 

Use of 10 pm LiChrosorb RP18 column and binary eluent of methanol and aqueous 0.1 M phosphate buffer (pH 4.0) according to suitable gradient elution program in less than 20-min run time with satisfactory precision sensitivity of spectrophotometric detection optimized, achieving for all additives considered detection limits ranging from 0.1 to 3.0 mg/1, below maximum permitted levels Simultaneous separation (20 min) of 14 synthetic colors using uncoated fused silica capillary column operated at 25 kV and elution with 18% acetonitrile and 82% 0.05 M sodium deoxycholate in borate-phosphate buffer (pH 7.8), recovery of all colors better than 82%... 

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. 

Early work relied on the use of packed columns, but all modern GC analyses are accomplished using capillary columns with their higher theoretical plate counts and resolution and improved sensitivity. Although a variety of analytical columns have been employed for the GC of triazine compounds, the columns most often used are fused-silica capillary columns coated with 5% phenyl-95% methylpolysiloxane. These nonpolar columns in conjunction with the appropriate temperature and pressure programming and pressure pulse spiking techniques provide excellent separation and sensitivity for the triazine compounds. Typically, columns of 30 m x 0.25-mm i.d. and 0.25-qm film thickness are used of which numerous versions are commercially available (e.g., DB-5, HP-5, SP-5, CP-Sil 8 CB, etc.). Of course, the column selected must be considered in conjunction with the overall design and goals of the particular study. 

Hewlett-Packard model 5890A Fused-silica capillary column, Rtx-200, 0.53-mm i.d., 15-m length, film thickness 1.5- xm (for imibenconazole)... 

Fused-silica capillary column, DB-1, 15 m x 0.32-mm i.d., 0.25-p.m film thickness, 100% dimethylpolysiloxane (for plant materials)... 

Extracolumn dispersion is a major problem for the packed fused silica capillary columns with internal diameters less than 0.35 mm. Peak standeunl deviations will be in the submicroliter range and extensive equipment modification is required for operation under optimum conditions. A reasonable compromise is to esploy injection voluMs of a few hundred nanoliters or less with detector volumes of a similar or preferably smaller size. This demands considerable ingenuity on behalf of the analyst since, as... 

The extracted fractions were esterified with either BF3-MeOH reagent or diazomethane and analyzed by GLC. Gas liquid chromatography (GLC) was conducted with a Perkin-Elmer Sigma 3 equipped with flame ionization detector. Separations were obtained on a Hewlett Packard 12 m x 0.2 mm i.d. capillary column coated with methyl silicon fluid (OV-101). The temperature was maintained at 80°C for 2 min then programmed from 80 to 220°C at 8°C/min. The injector temperature was 250°C. Mass spectra were obtained on a Hewlett Packard model 5995 GC-MS mass spectrometer, equipped with a 15 m fused silica capillary column coated with 5% phenyl methyl silicone fluid. Spectra were obtained for major peaks in the sample and compared with a library of spectra of authentic compounds. 

Fused silica capillary columns of various internal bores and of lengths in the range 25 to 50 m are mainly employed for analytical separations. A variety of polar and non-polar column types are available including those open tubular types with simple wall coatings (WCOT), those with coatings dispersed on porous solid-supports to increase adsorbent surface area (SCOT) and porous layer open tubular (PLOT) columns. Important stationary phases include polyethylene glycol, dimethylpolysiloxane and different siloxane copolymers. Various sample introduction procedures are employed including ... 

Lee et al. [30] described a micellar electrokinetic capillary chromatographic method for the determination of some antiepileptics including valproic acid. They used a fused silica capillary column (72 cm x 50 pm) and SDS as the micellar phase and multiwavelength UV detection. Reaction conditions, such as pH and concentration of running buffer were optimized. Solutes were identified by characterizing the sample peak in terms of retention time and absorption spectra. Recoveries were 93-105%. 

A GC analysis of amino acids requires a derivatisation step to increase the volatility of the amino acids. Generally, norleucine and/or norvaline are the internal standards added to the hydrolysate to check the derivatisation yield. According to the experimental method applied, the limits of detection (LOD) vary in the range 10 100 pg for each amino acid. Regarding the chromatographic columns, as most of the derivatives are esters barely polar compounds the most commonly used are fused-silica capillary columns with a low... 

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