Introduction to Modern Liquid Chromatography, Third Edition part 79 pot

... in particular, has developed an extensive math- ematical treatment of preparative chromatography, especially for large-scale, non- touching peak separations [4]. For separations on the laboratory ... the sample container to the column inlet (a sample pump can be a significant heat sink!). A failure to heat any part of the system can lead to sample precipitation and blockage of the in...

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... 158 4.3 Introduction to Individual Detectors, 160 4.4 UV-Visible Detectors, 160 4.4.1 Fixed-Wavelength Detectors, 163 4.4.2 Variable-Wavelength Detectors, 164 4.4.3 Diode-Array Detectors, 165 4.4.4 ... 113 3.6 Autosamplers, 113 3.6.1 Six-Port Injection Valves, 114 3.6.1.1 Filled-Loop Injection, 114 3.6.1.2 Partial-Loop Injection, 115 3.6.2 Autosampler Designs, 116 3.6.2.1 Pull -to- Fill A...

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... reasons: • to avoid an undesirable change in separation due to a sample size that is too large • to increase detection sensitivity for trace analysis, by using the largest possible sample size • to maximize ... 1 to 4, the peak begins to widen and then develops a flat top. For Equation (2.27) and the examples of Figure 2.22, we assume the delivery of an undistorted (i.e., cylindric...

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... the total of the autosampler -to- column plus column -to- detector connections. Sometimes it is advantageous to use a short piece of 0.007-in i.d. tubing between the autosampler and column, so as to ... with pressures up to 6000 psi between the pump and detector, so the tubing must be able to withstand such pressures. Also tubing used to transport the sample from the autosampler to...

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... directed to a photodetector, where it is monitored and converted to an electronic signal for data processing. Because fluorescence is emitted in all directions, it is common to monitor the emitted ... carried out at detector startup identify many potential detector problems and can provide automatic wavelength calibration. The background, or baseline absorbance, of UV detectors can incre...

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... pack- ing particles. To prevent particle aggregation, the interaction of the particle with the slurry liquid should be stronger than interactions between particles. For example, C 8 -orC 18 -modified particles ... as illustrated by the cartoon of Figure 5.25a, the liquid may be acceptable. However, if the particles tend to aggregate as in Figure 5.25b, the liquid is likely a poor cho...

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... REVERSED-PHASE CHROMATOGRAPHY (NARP), 295 6.6 SPECIAL PROBLEMS, 297 6.6.1 Poor Retention of Very Polar Samples, 297 6.6.2 Peak Tailing, 298 Introduction to Modern Liquid Chromatography, Third Edition, by ... Kirkland, Introduction to Modern Liquid Chromatography, 2nd ed., Wiley, New York, 1 979, ch. 5. 78. H. A. Claessens, M. A. Van Straten, and J. J. Kirkland, J. Chrom...

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... so that on average a change in %B by a factor of two (e.g., a change in mobile phase from 100% B to 50% B) will change values of k by a factor of 2 to 4. Similar plots of log k against log %B ... solute and mobile phase. The reader may prefer to skip to Section 8.2.2 (which provides a practical summary of the discussion below) and return to this section as appropriate. Equation (8.2...

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... column. Because of the increase in pressure due to the smaller particles, it is necessary to reduce the flow rate from 2.0 mL/min in Figure 10.3b to 1.0 mL/min in the separa- tion of Figure 10.3c. ... are usually easy to separate, the potential value of computer simulation may be at best marginal. Another barrier to the use of computer simulation is the belief that the chromatographe...

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... hand. Second, the data system and associated software must be able to convert the HPLC Introduction to Modern Liquid Chromatography, Third Edition, by Lloyd R. Snyder, Joseph J. Kirkland, and John W. ... quantification. One way to minimize this problem is to stop integration when the peak is sure to have left the detector. This can be accomplished by visually determining w...

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