Column temperature high-speed

Figure 6 High-speed tryptic fingerprint. Horse cytochrome c was digested with trypsin and the peptide chromatographed in acetonitrile water 0.1% TFA at various temperatures and flow rates on a 15 x 0.2-cm PS-DVB column packed with 3-p, 300-A particles, (a) 26°C and 0.5 ml/min. (b) 42°C and 0.7 ml/min. (c) 70°C and 1.1 ml/min. Detection at 220 nm. Note that the resolution rises with the speed of separation.89 (From Swadesh, ]., BioTechniques, 9, 626, 1990. With permission.)...

Another approach to increase HPLC speed is the use of higher temperatures. The viscosity of a typical mobile phase used in reversed-phase separation decreases as the column temperature is increased. This allows an HPLC system to operate at a higher flow rate without suffering too much from increased back pressure. Zirconia-based packing materials provide excellent physical and chemical stability. They have been used successfully for high-throughput bioanalysis at elevated temperatures.9... 

By simultaneous optimization of the percent organic modifier in the eluent and the column temperature to keep the retention factors fixed, very efficient, ultrafast separation can be achieved. The researchers conclude that for fast separations, the relationship between retention, temperature, and volume fraction of organic modifier needs to be taken into account. As the temperature increases, a lower volume of organic modifier is needed to speed up HPLC. Therefore, a highly retentive column... 

ELEVATED TEMPERATURE HPLC FOR HIGH-SPEED SEPARATION-EFFECTS ON VISCOSITY AND COLUMN EFFICIENCY... 

Column temperature affects the relative retention of different compounds and elevated temperature permits high-speed chromatography to be conducted.25 Figure 25-28 suggests a systematic procedure for method development in which solvent composition and temperature are the two independent variables.1 For elevated temperature operation, pH should be below 6 to retard dissolution of silica. Alternatively, zirconia-based stationary phases work up to at least 200°C. 

We report on a number of on-line chemical procedures which were developed for the study of short-lived fission products and products from heavy-ion interactions. These techniques combine gas-jet recoil-transport systems with I) multistage solvent extraction methods using high-speed centrifuges for rapid phase separation and II) thermochromatographic columns. The formation of volatile species between recoil atoms and reactive gases is another alternative. We have also coupled a gas-jet transport system to a mass separator equipped with a hollow cathode- or a high temperature ion source. Typical applications of these methods for studies of short-lived nuclides are described. 

The technique known as high speed reversed-phase HPLC was applied, and the fluorescein-labeled substrate and its product were separated within 2.5 minutes on Qg column (4.6 x 33 mm) with a 76 24 (v/v) mixture of (50 mAf sodium phosphate and 50 mM sodium acetate at pH 7) and acetonitrile. The column was run at ambient temperature at 3 mL/min, and 75 fiL... 

Figure 9.34 High speed and ultrahigh speed chromatograms of separations of substrate and product from assays of rhinovirus 3c protease. (A) high-speed HPLC separations of the fluorescein-labeled product, peak 1, and labeled substrate, peak 2, which were eluted from a Qs column at 3 mL/min by a 76 24 (v/v) mixture of buffer (SO mAf sodium phosphate and SO mAf sodium acetate in pH 7) and acetonitrile. The peptides were injected in a total volume of 7S fiL and chromatography was performed at ambient temperature. (B and C) Same peaks as above except buffer/acetonitrile ratio was 77 23 (v/v). (D) Ultrahigh-speed chromatogram using an M-pel Cg column at 80°C eluted at 4 mL/min after injection of 1 yuL of sample. (From Hopkins et al., 1991.)...

J. D. Thompson, J. S. Brown, and P. W. Carr, Dependence of thermal mismatch broadening on column diameter in high-speed liquid chromatography at elevated temperatures, A aZ. Chem. 73 (2001), 3340-3347. 

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