Analytical scale HPLC

Below the dotted line in Table I we list less fundamental differences between the two methods. Column lengths tend to be somewhat shorter in HPLC using small particle PB as a consequence of the high efficiencies that can be generated with the smaller particle sizes. For analytical scale HPLC, tube diameters of 3-4 mm are selected however, for preparative scale, tube diameters of 1 cm or above are not uncommon. 

Microbore HPLC-FTIR detection limits are about 10 times lower than analytical-scale HPLC-FTIR detection limits. The lowest reported LC-FTIR detection limits are approximately 100-1000 times higher than the best GC-FTIR detection limits. The main characteristics of flow-cell HPLC-FTIR are summarised in Table 7.44. Because of mobile-phase interferences, flow-cell HPLC-FTIR is considered as a powerful tool only for the specific detection of major components but is otherwise a method of limited potential, and SFE-SFC-FTTR has been proposed as an alternative [391]. 

This book s focus is on analytical scale HPLC, so preparative scale LC and micro LC are not discussed in detail here. In-depth treatments of these techniques are found elsewhere.LC/MS, data handling and practical HPLC operation are discussed in later chapters. 

Analytical-Scale HPLC Separations. Reverse-phase HPLC chromatography favors the distribution of the semi- and nonpolar constituents of a sample of residue organics, whereas normal-phase HPLC chromatography favors the distribution of semipolar constituents (32). This approach is illustrated in Figure 2 by the chromatograms of residue organics from a waste water sample separated by both reverse-... 

Figure 2. Absorbance (254 nm) profile of the analytical-scale HPLC separation of 25 pg of residue organics isolated from an industrially impacted influent waste water. The separations were accomplished via reverse-phase HPLC (top) and normal-phase HPLC (bottom). Mobile phases used in these separations were water (fyO), acetonitrile (CH3CN)> methylene chloride (MECL), hexane (HX), and isopropyl alcohol (IPROH), as indicated.

Preparative-Scale HPLC Separations. Results of the analytical-scale HPLC separations are used to develop an approach in the scale-up of the HPLC separations for the preparation of subfractions of the residue organics in quantities suitable for mutagenesis testing and compound isolation. If the analytical-scale separation results indicate the... 

The simplest and the most widely used forms of retention time prediction for analytical scale HPLC are based on the empirical linear dependence of the logarithm of the retention factor on the eluent composition. 

High-performance liquid chromatography (HPLC) is a versatile analytical technique using sophisticated equipment refined over several decades. An in-depth understanding of the working principles and trends is useful for more effective application of the technique. This chapter provides the reader with a concise overview of HPLC instrumentation, operating principles, recent advances, and modern trends. The focus is on the analytical scale HPLC systems and modules (pump, injector, and detectors). System dwell volume... 

Comparison of Analytical Scale HPLC with Preparative Scale HPLC... 

E. J. Klein, S. L Rivera, A Review of Criteria Functions and Response Surface Methodology for the Optimization of Analytical-Scale HPLC Separations, Marcel Dekker Inc., 2000, p. 2097-2121. 

Chromatographic separation media based on core-shell silica particles are becoming popular for achiral analytical-scale HPLC separations [42], The major advantages of these materials include the shorter diffusion path length and consequently a higher column efficiency, as well as less dependence of column performance on the linear velocity of the mobile phase, primarily due to a smaller mass transfer term in the van Deemter equation (Figure 4.2) [43]. 

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