Introduction to Modern Liquid Chromatography, Third Edition part 15 pot

... 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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... Detection Limits, 157 4.2.5 Linearity, 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 ... Modification Detectors, 152 4.2.2.4 Hyphenated Techniques, 152 4.2.3 Signal, Noise, Drift, and Assay Precision, 152 4.2.3.1 Noise and Drift, 153 4.2.3.2 Signal -to- Noise...

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... 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., cylindrical) sample plug to ... another peak in the chromatogram. Poor batch -to- batch reproducibility of the column is today an infrequent problem. It is more likely to arise for complex samples where the chromatogram is c...

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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 ... (mm) a Plate Number N Totally porous 5 30 2,500–3,000 Totally porous 5 50 4,500–5,000 Totally porous 5 100 8,000–10,000 Totally porous 5 150 12,000 15, 000 Totally porous 5...

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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 ... relationship k = 1 − R F R F (8.6) In the example of Figure 8.8, the R F values of the spots vary from 0 .15 to 0.50, corresponding to 1 ≤ k ≤ 5.7. Similar k-values are expected for a corres...

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... user to explore the effects of changing column dimensions, particle size, or flow rate. Figure 10.1g shows one such simulation (for 25% B): a reduction in column length by half (from 150 to 75 ... 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...

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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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... 513 E 2 the error due to the autosampler, or E 3 the error due to signal -to- noise (Eq. 11.1). As a rule, if the RSD of an error source is less than half the total RSD, its contribution to total RSD will ... detectors (Section 4.4), are much less affected by these factors, but dirty flow cells, bubbles, and aging lamps can contribute to error in the detec- tor output. Other detectors...

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