Elution pattern

Figure 6.3 shows a comparison of elution patterns of standard polystyrene between a linear-type column and a standard-type column. Because of the high linearity of its calibration curve, the linear series has improved the efficiency of oligomer domain separation. 

In the ease of Ligure 6.39 (page 211), similar ehromatograms were apparently obtained with eaeh eolumn. However, when the elution patterns were examined with a MALLS, it was revealed that a kind of adsorption oeeurred in the ease of GF-710 HQ, and GPC elution was not eondueted properly. 

Describe the expected elution pattern for a mixture of aspartate, histidine, isoleucine, valine, and arginine on a column of Dowex-50. 

Partition column chromatography for separating several of the primary constituents of the pyrethrum extract has been reported. The elution pattern for some of the constituents of the pyrethrum mixture recovered from the partition column is shown in Table I. 

Adsorption column chromatography has been employed to separate the constituents of pyrethrum. Florisil and aluminum oxide have been used as adsorption columns to retain much of the pigmented materials. The pyrethroids may be caused to elute with several solvents. In our experience mixtures of hexane with ethyl acetate, methanol, ethyl ether, dichloromethane, or acetone have provided different elution patterns. 

Figure 1 HPAEC elution patterns of RGO 12 (bottom chromatogram) RGO 12 incubated with RG-hydrolase (second chrom. from bottom) RGO 12 incubated with RG-hydrolase and subsequently with RG-rhamnohydrolase (third chrom. from bottom) and RGO 12 incubated with RG-hydrolase and subsequently with RG-galacturonohydrolase (top chrom.). Numbers in chromatograms on the left correspond with structures on the right Explanation of symbols see table 1.

Figure 5. HPSEC elution pattern of pectin fractions of canned carrots preheated at 65°C for different times, (a) WSP, (b) OXSP, (c) HSP,...

The polysaccharides present in the pectin-rich extract ChSS were fractionated, based on their charge density for further characterisation. The elution pattern of ChSS is shown in Figure 1, and it can be seen that the relative uronide content of the fractions increased with increasing salt concentration of the eluens. 

FIGURE 6. Elution pattern of monoamine uptake blockers and amphetamine analogs from reverse-phase HPLC... 

The HPLC elution pattern is affected to some extent by the pH of the mobile phase. Moderate pH adjustment to optimize the resolution between EMA and MEMA may be performed. Retention time can be affected greatly by the history of the HPLC column and also the buffer/methanol ratio. The mobile phase ratio should be adjusted to provide adequate separation and retention. Control and fortified samples should be run in the same analytical set with treated samples. 

FIGURE 2. Panel A Elution pattern of endogenous PCP-like material from fractionated porcine brain. Activity is expressed in terms of equivalents of PCP required to inhibit 3H-PCP bindina to rat brain membranes. One unit of activity is eqivalent to 1 mole of PCP. 

The differences in the elution patterns for the two sorbents have been explained98 by invoking the zwitterionic structures for the antibiotics under the basic pH conditions employed for strata-X-C... 

To study the effect of the protease treatment cell-free suspension, with or without protease treatment, was subjected to gel-filtration chromatography on Sephadex G-75 and the elution patterns were compared (Fig. 1). In each case, two major peaks were detected by monitoring column fractions with absorbance at 280 nm. Degradation activities on mexacarbate, in the presence of FMN and light under anaerobic condition, were measured for each fraction. It was found that the highest activity was associated with peak II. It is interesting to note that protein (s) associated with peak II were detected with or without protease treatment these will be referred to as natural flavoprotein (B, Fig. 

Our first attempt was the feeding of commercially available [guanido-l C]-L-arginine to the cultures of Gonyaulax tamarensis (Ipswich strain). The toxin fraction was isolated and further fractionated to the pure toxins (7). Figure 1 shows an example of the elution pattern of the toxins from a Bio-Rex 70 column. A good correlation between the toxicity and radioactivity was observed. 

Figure 1. Elution pattern of toxins from Bio-Rex 70 column in C-labeled arginine feeding. (Fr. fraction number cpm counts per minute and MU mouse units)...

The HPLC elution pattern of anatoxin-s(s) is shown in Fig. 5 and is the last peak in the profile. Determination of LD gave an approximate value of 40 yg/kg body weight, which is five times more potent than anatoxin-a. 

Partially purified extracts of the two isolates and the Kezar Lake toxic bloom sample of >1. aeruginosa were chromatographed. The HPLC elution profiles of these are shown in Figure 1. All components of the elution profiles of isolates NRC-1 and SS-17 are closely similar, and they are each characterized by one major toxin, toxin-LR. The elution profile of the Kezar Lake bloom extract also consists primarily of toxin-LR. Moreover, it does not contain some of the minor components observed in the elution patterns of NRC-1 and SS-17. The toxin-LR content of the Kezar Lake bloom was higher than that of the isolates. 

Figure 1. HPLC elution patterns of extracts of M. aeruginosa isolate NRC—1, clone SS-17 of isolate NRC-1, and a toxic bloom sample from Kezar Lake, New Hampshire. Toxin-LR eluted at about 2.7 minutes. Smaple volumes injected were NRC-1 (17 SS-17...

When a particular component eluting at a certain retention volume is to be estimated, this approach can be outlined as follows. Since SEC is extremely reproducible, the peak shape, peak width and peak height are dependent on the amount of the species in the sample volume injected, sample volume and retention time. From these factors the SEC peaks can be simulated or elution pattern of any species within the separation range can be plotted as a function of mass vs. retention volume. The analysis data supplies the concentration of this particular species over two or more 0.5 ml intervals. A match-up computer program has to be developed so that it can pick up the peak shape and concentration based on 3 or 4 data points at known Intervals. 

Cys(Acm)U5]-endothelin I [H-Cys(Acm)-Ser-Cys-Ser-Ser-Leu-Met-Asp-Lys-Glu-Cys-Val-Tyr-Phe-Cys(Acm)-His-Leu-Asp-Ile-Ile-Trp] (22 0.41 pmol) was treated with silver(I) trifluoroacetate/DMSO/ 1M HCI in an analogous manner to that described in Section 6.1.1.1, The HPLC elution pattern of the crude peptide showed two peaks, with retention times identical to those of endothelin-I and an isomer in a ratio of 8 1. Each product was purified by HPLC to yield endothelin-I (23) and its isomer (7.5% yield 62%) these products were characterized by HPLC, FAB-MS, and amino acid analyses. 

Therefore, in this chapter and cynicism aside, those analytical techniques that were found most useful and reproducible for the successful detection, quantitation, and characterization of peptides are described. It is certainly far from being all-encompassing and readers should be encouraged to experiment with systems other than those described here when they encounter unsatisfactory elution patterns (tailing spots on TLC or tailing absorbances in liquid chromatography or CE) or what may seem to be artifactual. Abundant relevant literature is cited for reference. 

Logan and Whitmore report that the dehydration rates for irradiated oligo U and poly U are functions of the chain length (Fig. 30) and pH. Furthermore, the dehydration rate for poly U which had been irradiated and dehydrated and then irradiated again was faster than that of the first dehydration. It was observed that the elution pattern on Sephadex of the recycled poly U had changed. 

Fig. 1. —Elution Pattern of Material Precipitated by Ethanol from the Mild-Acid Hydrolyzate of Acacia elata Gum. [Bio-Gel P-300, 90 x 1.5 cm column, M sodium chloride as the eluant flow rate, 3 ml/hr sample, 2 mg in 1 ml of M sodium chloride.]...

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