RPLC chromatograms

FIGURE 18.8 Two-dimensional HPLC (NPLC/RPLC) chromatogram of Novel II 1412-70 with the corresponding chemical structure and average EO distribution as supplied by the manufacturer. Reprinted from Murphy et al. (1998b), with permission of the American Chemical Society. 

The evaluation of the RPLC chromatograms of nonionizable analytes shows that the number of sorption events varies between n = 13000 and 20000 on a 150 X 3.9-mm column and that it is not affected strongly by the retention time of the analytes [107]. Fly-times in the mobile phase between a desorption and the subsequent adsorption vary roughly between Tm = 3 to 5 ms. During that fly-time, the mobile phase travels a distance that is 1.5 to 2.3-times the particle diameter. The sojourn time in the stationary phase, however, strongly correlates with the retention of the analytes, so the retention of analytes and the selectivity of their separation are mainly due to the variations of Tg, between 8.4 ms (for k = 1.75) and 47 ms (for fc = 12.7). 

Figure 2.10. Six RPLC chromatograms illustrating the effect of mobile phase solvent strength on solute retention and resolution. LC conditions were column Waters Symmetry C18, 3pm, 75x4.6 mm, 1 mL/min, 40°C, Detection at258nm. Mobile phase is mixture of acetonitrile (ACN) and water. Solutes were nitrobenzene (NB) and propylparaben (PP).

Figure 2.12. Four RPLC chromatograms illustrating the effect of mobile phase strength and selectivity of acetonitrile (ACN) and methanol (MeOH). See Figure 2.10 for LC conditions.

Figure 3.22. Comparative RPLC chromatograms of tryptic digest illustrating the sensitivity enhancement of columns with smaller inner diameters. Diagrams courtesy of PerkinElmer, Inc.

Figure 7.24. RPLC chromatogram of a protein mixture using a column packed with polymeric material. Reprinted with permission from reference 35.

Fig. 15A,B. Change of RPLC chromatograms of the PEO-h-PLLA with A the temperature B the eluent composition near the critical condition of poly(ethylene glycol). At the critical condition (middle chromatograms in A and B) the separation takes place according to the number of L-lactide units and the elution peaks are sharp while the resolution is poor at the off-critical conditions. The numbers indicate the number of L-lactide units in the block copolymer. Column Luna C18 100 A 250x4.6 mm. Eluent mixture of CH3CN (ACN) and H2O. Reproduced from [46] with permission...

Fig.20.2D-LC (NPLC and RPLC) chromatogram of an alcohol ethoxylate (Neodol 25-12) with the corresponding chemical structure. For the first dimension NPLC was used. Column Zorbax silica, eluent H2O/CH3CN 100/20-20/80 concave gradient in 300 min with a flow rate of 0.05 ml/min. The second dimension was RPLC. Column Pecosphere C18 100 A 33x4.6 mm. Eluent CH3OH/H2O (95/5) with a flow rate of 1.5 ml/min. Reproduced from [137] with permission...

Fig. 22A,B. 2D-LC separation of a low molecular weight PS-fc-PI (2.4 kg/mol, 30.4% PI content) A NP-TGIC chromatograms of the PS-1 -PI (top) and a fraction, f6 (bottom), which separates PS-b-PI in terms of the PS block length only. Temperature program is also shown in the plot B RPLC chromatogram of the NP-TGIC fraction, f6, which separates in terms of the PI...

Fig. 23A,B. 2D-LC fractionation of high molecular weight PS-i>-PI (24kg/mol, 34.8 wt% PI content) A RPLC chromatograms of the mother PS-i>-PI solid line) and its three fractions (dash-dot line) law (1l), middle (Ij l.and high (Ijj) molecular weight portion of the PI block B NPLC chromatograms of the middle fraction of RPLC separation (solid line) and its three fractions (dash-dot line) low (Sl), middle (Sj ), and high (Sjj) molecular weight portion of the PS block. RPLC fractionates the PI block while NPLC fractionates the PS block. The range of the fraction collected is indicated with small vertical bars. Reproduced from [ 141 ] with per-...

Fig. 27. RPLC chromatograms of poly(S-co-EA)s (SEA) of different composition with high conversion. Styrene contents obtained by HPLC calibration (lines) and on-line HPLC/ H NMR (circles) experiments match each other very well. Column Nucleosil CIS 100 A 250 X4.6 mm. Eluent THF/CH3CN, gradient elution from 10/90 to 100/0 (v/v) in 25 min. Reproduced from [152] with permission...

Figure 17 A typical chromatogram of LANA reaction (scheme 3). Chromatographic conditions— 45 55 100 mM KH2P04 acetonitrile at 2.0ml/min 25 cm x 0.46 mm Supelcosil LC-DB-18 (5-p) RPLC column column temperature ambient detector wavelength 254 nm.

Figure 7.44 shows the 2D UV chromatogram (RPLC-UV/VIS (DAD)) for a five-compound test mixture of polymer additives [662]. Any spectral data collected during hyphenated chromatography-spectroscopy measurements can be readily transformed into 2D correlation spectra. 

FIGURE 8.4 2D chromatogram of a AEX x RPLC separation of reduced porcine thyro-globulin. Reprinted from Holland and Jorgenson (2000), by permission of John Wiley Sons, Ltd. 

FIGURE 8.5 2D chromatogram of a CEX x RPLC separation of an E. coli lysate. Reprinted with permission from Opiteck et al. (1997), copyright 1997, American Chemical Society. 

FIGURE 8.13 Total ion current chromatogram for a UHP-RPLC-MS separation of one anion exchange fraction (fraction numher 6 from the 30-min anion-exchange gradient). 

FIGURE 6.36 Example chromatograms and mass spectra obtained from a /rPLC system with MS capabilities. 

Although RPLC is a very powerful technique that solves the majority of separation problems, a few critical zones in the chromatogram can be indicated (Figure S) ... 

The last critical region in the chromatogram (region 3 in Figure 5) is around the injection peak. A polar compound might not be retained by the stationary phase, and as a consequence, elutes at the time of the injection peak. For this type of problem, a CE method can be an alternative. For example, Herrero et al. succeeded in distinguishing several polar compounds, which were not retained by RPLC, by the use of a CE method. 

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