Introduction to Modern Liquid Chromatography, Third Edition part 50 ppt

... μm 4 μm 1 2 5 10 20 50 100 200 500 1000 t G (min) 1000 500 200 100 PC 150- mm column 300-mm 600-mm 1500 -mm optimized (d p varies) 1 μm 1.5 μm 2 μm 3 μm 1 2 3 10 20 50 200 200 500 1000 t G (min) k* ... and column length were allowed to vary continuously). Each of the other curves shown in this figure correspond to values of k ∗ that vary from 1 to 10—but with particle diameter...

Ngày tải lên: 04/07/2014, 01:20

... most laboratories that deal with a need for analyzing chemical mixtures are equipped for HPLC; it is often the first choice of technique Introduction to Modern Liquid Chromatography, Third Edition, ... Do?, 4 1.2 A SHORT HISTORY OF HPLC, 6 1.3 SOME ALTERNATIVES TO HPLC, 8 1.3.1 Gas Chromatography (GC), 8 1.3.2 Thin-Layer Chromatography (TLC), 9 1.3.3 Supercritical Fluid Chromato...

Ngày tải lên: 04/07/2014, 01:20

... Switching, 79 2.7.7 Retention Predictions Based on Solute Structure, 80 Introduction to Modern Liquid Chromatography, Third Edition, by Lloyd R. Snyder, Joseph J. Kirkland, and John W. Dolan Copyright ... Chrommatogr., 5 (1967) 183. 25. J. J. Kirkland, ed., Modern Practice of Liquid Chromatography, Wiley-Interscience, New York, 1971. 26. T. Braumann, G. Weber, and L. H. Gri...

Ngày tải lên: 04/07/2014, 01:20

... ±20% or more. Despite the ability of most HPLC systems to operate at 500 0 to 6000 psi, it may be desirable to limit the column pressure drop to no more than 3000 psi (Section 3.5). As the pressure ... increase in proportion to retention time. A continual increase in peak width from the beginning to the end of the chromatogram is therefore observed; for example, see the chromatog...

Ngày tải lên: 04/07/2014, 01:20

... R s ≥ 2), normally corresponding to a one -third safety factor (vs. baseline separation with R s ≈ 1.5, for peaks of comparable size). The goal of R s ≥ 2 takes into account minor peak tailing, ... choice of column length, particle size, and flow rate will always correspond to a minimum value of h ≈ 2(orν ≈ 3). Because commercial columns are limited to certain lengths and particle sizes...

Ngày tải lên: 04/07/2014, 01:20

... laboratories have preferred columns packed with -5μm particles. Such columns are less demanding in terms of equipment (Section 3.9), and are less likely to be plugged by particulates. Today, ... peak heights are normalized to 100% for tallest peak in each chromatogram. Simulated chro- matograms based on data of [50, 51]. changes in both %B and temperature, it is possible to achieve a ma...

Ngày tải lên: 04/07/2014, 01:20

... a graphical chromatogram for a visual inspection of the quality of the data. As laboratories move to paperless records, the chromatogram may be viewed only on a computer monitor. For qualitative ... result, when a regulatory auditor reviews the data. It is expected that as additional regulatory requirements are placed on the HPLC laboratory, software manufacturers will continue to provide...

Ngày tải lên: 04/07/2014, 01:20

... Quadrupoles and Ion Traps, 188 4.14.3 Other MS Detectors, 190 4.15 OTHER HYPHENATED DETECTORS, 191 Introduction to Modern Liquid Chromatography, Third Edition, by Lloyd R. Snyder, Joseph J. Kirkland, ... 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-Arr...

Ngày tải lên: 04/07/2014, 01:20

... cell dual photodiode detector output (a) photodiode arra y (b) Figure 4.22 Schematic of a deflection refractive index (RI) detector. (a) Dual-photodiode detector; (b) photodiode array detector (lamp and flow ... heat-exchanger required Sensitive to temperature changes Reliable, fairly easy to operate Nondestructive of photodiode-array technology to the RI detector allows multiple photodio...

Ngày tải lên: 04/07/2014, 01:20

... detector response to reagents to reduce extra-column peak broadening during reaction is to use a knitted reactor, where narrow-bore flexible tubing is knitted into a series of tight radius bends to create ... fast reaction is desired to minimize the reactor volume requirements. Also reactions that go to completion tend to be more reproducible than those that only go partially to...

Ngày tải lên: 04/07/2014, 01:20