HPLC chromatogram

Fig. 3. Graph based on an hplc chromatogram of a commercial PTMEG of molecular weight = 1000. The bars represent the weight percentage of the individual oligomer fractions. The degree of polymerization is the number of repeating monomer units per polymer chain.

FIGURE 4.22 HPLC chromatogram of amino acids employing precolumn derivatiza-tion with OPA. Chromatography was carried out on an Ultrasphere ODS column using a complex tetrahydrofuran methanol 0.05 M sodium acetate (pH 5.9) 1 19 80 to methanol 0.05 M sodium acetate (pH 5.9) 4 1 gradient at a flow rate of 1.7 mL/min. 

Figure 2.11 (a) HPLC chromatogram obtained for a sample of drinking water spiked with... 

Figure 1. HPLC Chromatogram of PB-DPE Fire Retardants For conditions, see text.

Figure 4.18. Peak-size correlation in an HPLC-chromatogram. The impurity profile of a chemical intermediate shown in the middle contains peaks that betray the presence of at least two reaction pathways. The strength of the correlation between peak areas is schematically indicated by the thickness of the horizontal lines below the chromatogram. The top panel gives the mean and standard deviation of some peak areas (n = 21) the two groups of peaks immediately before and after the main peak were integrated as peak groups.

The activated carbonyl of anhydrides can acylate alcohols or amines at the temperatures necessary for polymer processing. These reactions have been verified by HPLC using the polymer system described in Table 2. An examination of the HPLC chromatograms in Fig. 25 indicates that the phthalic anhydride peak (3.2 min) diminishes with increasing injection-molding temperatures and that two new peaks (4.6 and 6.9 min) increase in intensity. These new peaks corresponded to the half phthalate esters of 1,6-hexanediol and trans-... 

FIGURE 25 HPLC chromatograms of polymer samples hydrolyzed to cleave all ortho ester bonds. Samples were prepared at either 130, 145, or leO C. Polymer prepared from 3,9-bis(ethylidene-2,4,8,10-tetraoxaspiro)5,5]undecane) and a 25 75 mole ratio of trans-cyclohexane dimethanol and 1,6-hexanediol and contained 3 wt% phthalic anhydride and 7.5 wt% cyclobenzaprine hydrochloride (CBP). 

One of the first applications of the HPLC method was the investigation of differences in toxin profiles between shellfish species from various localities ( ). It became apparent immediately that there were vast differences in these toxin profiles even among shellfish from the same beach. There were subtle differences between the various shellfish species, and butter clams had a completely different suite of toxins than the other clams and mussels. It was presumed that all of the shellfish fed on the same dinoflagellate population, so there must have been other factors influencing toxin profiles such as differences in toxin uptake, release, or metabolism. These presumptions were strengthened when toxin profiles in the littleneck clam (Prototheca Staminea) were examined. It was found that, in this species, none of the toxin peaks in the HPLC chromatogram had retention times that matched the normal PSP toxins. It was evident that some alteration in toxin structure had occurred that was unique in this particular shellfish species. 

Based on peak size of HPLC chromatogram or percent above 10. 

HPLC chromatogram illustrating the release of feruloylated material and free ferulic acid when SBP (10 mg) was incubated with a mixture of endo-arabinanase (2 U) and... 

Figure 9 HPLC chromatogram of a diquat standard with UV detection...

Dendritic molecules 33 and 34 were then incubated with PGA in PBS (pH 7.4) at 37 °C. Control solutions were composed of buffer without the enzyme. The sequential fragmentation illustrated in Fig. 5.31 was monitored by observing the disappearance of dendrons 33 or 34 and the release of 4-nitroaniline by RP-HPLC. As expected, dendron 33 could not be activated by PGA and remained intact for 72 h (data not shown). However, dendron 34 showed clear activation upon incubation with PGA and its corresponding peak completely disappeared from the HPLC chromatogram as 4-nitroaniline appeared (Fig. 5.32). No 4-nitroaniline was observed in the control experiment when dendron 34 was incubated in the buffer without PGA. 

Figure 9 Typical microbore HPLC chromatogram of catalytic hydrogenation process. Column 1 x 250-mm Partisil ODS (Whatman). Mobile phase acetonitrile water tetrahydrofuran, 85 15 2 (v v v). Flow rate 0.2ml/min. Detection UV at 214 nm. Injection 1 pi.

Figure 2. HPLC chromatograms (isocratic mode, 60% methanol, 40% water) of sediment extracts from 15 study sites in west Florida coastal waters. Migration profile are compared among sediment extracts and crude extract of Nannochloris sp. cell-free culture [See Moon and co-workers (.26) for specific sites].

It is clear that, at this point, the definitive chemical characterization of the inhibitory material has yet to be done. Much is known concerning the distribution and the source of the material, and work on the biological basis if the observed inhibition is promising. However, the potential for the use of the material as an hydrilla-control agent will depend upon the identification and purification of the bio-active components detected in HPLC chromatograms. 

Figure 32 shows the HPLC chromatogram of the reaction mixture using acetonitrile and water (80 20) as solvent. 

Fig. 32 HPLC chromatogram of the reaction mixture. Column RP 18 (15 cm). Solvent H20/ CH3CN (80 20). UV detector 190 nm. Pressure 157 bar. Flow rate 1 mL/min...

FIGURE 25.3 (a) The HPLC chromatogram of the extract obtained from a yellow-pigmented sample of... 

FIGURE 16.8 HPLC chromatogram of cytochrome c and myoglobin digest, using a 250 cm x 4.6 mm ODS C18 Vydac column and a linear mobile-phase gradient, 5-50% B, in 50 min. Buffer A was 0.1% TFA in water and buffer B was 0.1 TFA in acetonitrile. UV detection was carried out at 214 nm, at room temperature (reprinted with permission from Electrophoresis). 

FIGURE 18.7 One-dimensional HPLC chromatograms of Neodol 25-12 silica NPLC column (a) and Qg RPLC column (b). Reprinted from Murphy et al. (1998b) with permission of the American Chemical Society. 

FIGURE 1.43 Representative HPLC chromatograms of vitamin D metabolites.162 (A) late-eluting peaks (B) calibrator in extracted serum (C) sample from patient with low 25(OH)D3 treated with vitamin D2 (D) sample from patient with high concentrations of 25(OH)D3. Int. Std. = internal standard mAU = milliabsorbance units. (Reproduced with permission from the American Association for Clinical Chemistry.)... 

FIGURE 1.54 HPLC chromatogram of 2-amino-3-phenyl-l-propanol generated by cleavage of its t-BOC derivative with trifluoroacetic acid and clean-up on strata-X-C. 

FIGURE 1.56 HPLC chromatograms of basified methanol (top) and acidified methanol (bottom) elution fractions from strata-X-CW. 

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