Column chromatographic data

Figure 4. Output of ion-exchange column chromatographic data expressed in histogram form. The upper histogram is the 14C elution pattern of metabolites in a crop extract and the lower histogram is a 3H-labeled standard added to the extract for cochromatographic purposes.

Figure 1. Column chromatographic data for SRC s and coal liquefaction products 1. P M 308 3. P ir M 122 3. Project Lignite SRL-M5C 4. Wilsonville SRC-Pitt 8 5. P ir M 11 SR 6. CO-Steam Product 7.

To realistically evaluate the effect of extra-column dispersion on column performance, it is necessary to evaluate the maximum extra-column dispersion that can be tolerated by different types of columns. Such data will indicate the level to which dispersion in the detector and its associated conduits must be constrained to avoid abrogating the chromatographic resolution. 

Whether the optimum phase system is arrived at by a computer system, or by trial and error experiments (which are often carried out, even after computer optimization), the basic chromatographic data needed in column design will be... 

Sometimes it is claimed that the double-centered biplot of latent variables 1 and 2 is identical to the column-centered biplot of latent variables 2 and 3. This is only the case when the first latent variable coincides with the main diagonal of the data space (i.e. the line that makes equal angles with all coordinate axes). In the present application of chromatographic data this is certainly not the case and the results are different. Note that projection of the compounds upon the main diagonal produces the size component. 

Recent chromatographic data indicate that the interactions between the hydrophobic surface of a molded poly(styrene-co-divinylbenzene) monolith and solutes such as alkylbenzenes do not differ from those observed with beads under similar chromatographic conditions [67]. The average retention increase, which reflects the contribution of one methylene group to the overall retention of a particular solute, has a value of 1.42. This value is close to that published in the literature for typical polystyrene-based beads [115]. However, the efficiency of the monolithic polymer column is only about 13,000 plates/m for the isocratic separation of three alkylbenzenes. This value is much lower than the efficiencies of typical columns packed with small beads. 

Metabolites formed during the decolourization of the azo dye Reactive red 22 by Pseudomonas luteola were separated and identified by HPLC-DAD and HPLC-MS. The chemical structures of Reactive red 22 (3-amino-4-methoxyphcnyl-/fhydroxyl-sulphonc sulphonic acid ester) and its decomposition products are shown in Fig. 3.92. RP-HPLC measurements were carried out in an ODS column using an isocratic elution of 50 per cent methanol, 0.4 per cent Na2HP04 and 49.6 per cent water. The flow rate was 0.5 ml/min, and intermediates were detected at 254 nm. The analytes of interest were collected and submitted to MS. RP-HPLC profiles of metabolites after various incubation periods are shown in Fig. 3.93. It was concluded from the chromatographic data that the decomposition process involves the breakdown of the azo bond resulting in two aromatic amines [154],... 

Gas chromatographic data was obtained on a Tracor Model 220 gas chromatograph equipped with a Varian Model 8000 autosampler. The analysis column was a 1.7 m "U column, 4 mm id, filled with 3% SP-2250 packing (Supelco, Inc., Bellefonte, PA) held at 200 C. The injection temperature was 250 and the nitrogen carrier gas flow rate was 60 mL/min. The detector temperatures were 350 for electron capture and 190 for flame photometric. Detector signals were processed by a Varian Vista 401 which gave retention times and peak areas. 

As shown in the Level column of Figure 10, the various injected volumes can be designated as individual component calibration levels. By doing this, experiments 10-27 can also be used to help validate multilevel, multi-replicate calibration algorithms on a chromatographic data system. 

Figure 3. Capillary Gas Chromatogram of Volatiles from Soil, Chromatographic data adsorption 4 h on Tenax TA desorption 8 min at 200 C column fused silica 0.3 mm, 20 m, SE33 temperature programming 40 to 230 C at 5 C/min carrier gas helium (50 cm/s),...

Whether the optimum phase system is arrived at by a computer system, or by trial and error experiments (which are often carried out, even after computer optimization), the basic chromatographic data needed in column design will be identified. The phase system will define the separation ratio of the critical pair, the capacity ratio of the first eluted peak of the critical pair and the capacity ratio of the last eluted peak. It will also define the viscosity of the mobile phase and the diffusivity of the solute in the mobile phase. 

Figure (6) allows the solvent consumption of any analysis to be compared with which would be obtained from a fully optimized column. The data used is obtained from the reduced chromatogram and the extra column dispersion of the respective apparatus. It should be bourne in mind that the extra column dispersion assumed in the above calculations was equivalent to a standard deviation of 2.5 microlitres. This value for (oe) could be expected from a well designed chromatographic system. 

Cachia and his team (P) describe the column chromatographic separation of polyvinyl chloride plasticizers. The plasticization agent in the eluate was identified by infrared spectroscopy. These authors expressly state that chromatography is useful for separations only it is not intended to identify substances. However, they mention that spectroscopy, in the future, may be replaced by combining refractive index data with color tests. 

The equilibrium constant can be derived from free energy considerations of gas chromatographic data. It may also be obtained directly from the measurement of all concentrations at the specified temperature by selection of a column that can separate each component and by a quantitative method of detection. 

Chromatograph Data Reduction—Qualitative Analysis. For a given substrate, under given conditions, each compound has a characteristic retention time, which can be used for tentative identification. However, two or more compounds may have the same elution lime on a particular column. In such eases the compound may be rerun on a different column with other characteristics to reduce ambiguity. Extensive compilations of individual compound retention times on different substrates arc available... 

Fig. 2 Postcolumn derivatization scheme for aflatoxin analysis 1, mobile phase 2, HPLC pump 3, injection valve 4, precolumn 5. analytical column 6, derivatizing agent solution 7, auxiliary HPLC pump 8, T-valve 9, oil or water bath 10, reaction coil 11, fluorescence detector 12, waste 13, chromatographic data handling system.

Adequate column chromatographic methods are now opening the way toward the required progress, allowing for more complete and more accurate quantitative data on amino acid blood levels as well as on amino acid renal excretion. 

Apparatus Gas chromatograph with flame ionization detector (Flewlett-Packard 5890 Series n, or equivalent) equipped with a 5- xL syringe for 0.32-mm (id) columns. Automatic sampler (HP 7673, or equivalent). Chromatographic data system or integrator (HP 3365 Series II software, or equivalent). Retention gap, deactivated fused silica, 1-mm x 0.32-mm (id) with capillary column connectors. DB 5-HT,... 

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