High-pressure liquid chromatography chromatograms

Fig. 5.2.5 a,b Denaturing high-pressure liquid chromatography chromatograms of two patient samples run at the recommended temperature (60°C) to detect mutations, a Sample without a mutation. The elution peak at 7.8 min represents homoduplexes, b Sample with a heterozygous mutation. In addition to the elution peak at 7.8 min for the homoduplexes an additional peak for heteroduplexes is visible at 7.6 min... 

Infrared spectra were recorded on a Perkin Elmer Model 567 Spectrophotometer. Ultraviolet spectra were obtained on a Cary 1756 Spectrophotometer. Gas chromatograms were recorded on a Tracor Model 220 with electron capture detector. High pressure liquid chromatography studies were conducted with a Waters Model ALC-200 with ultraviolet and refractive index detectors. 

Unfortunately the technique is used only on a limited scale for the determination of pesticides on a routine basis. Most pesticide analysts prefer gas liquid chromatography and more recently high pressure liquid chromatography to the more cumbersome handling of thin-layer chromatograms. 

Reverse phase high pressure liquid chromatography (HPLC) was used to further fractionate the sample and add another dimension of specificity (8,21). The extract was evaported to dryness and taken up in CHCI3. The entire extract was injected onto a DuPont Zorbax ODS column at 40°C using 2 cc/min. CH3OH mobile phase. Typical chromatograms are shown in Figure 2. 

In normal high pressure liquid chromatography, typical sample volumes are 20-200 p.L this can become as little as 1 nL in capillary HPLC. Pretreatment of the sample may be necessary in order to protect the stationary phase in the column from deactivation. By employing supercritical fluids such as carbon dioxide, pretreatment can be bypassed in many instances so that whole samples from industrial and environmental matrices can be introduced directly into the column. This is due to the fact that the fluid acts as both extraction solvent and mobile phase. Post-column electrochemistry has been demonstrated. For example, fast-scan cyclic voltammo-grams have been recorded as a function of time after injection of microgram samples of ferrocene and other compounds in dichloromethane solvent and which are eluted with carbon dioxide at pressures of the order of 100 atm and temperatures of 50°C the chromatogram is constructed as a plot of peak current vs. time [18]. 

Were the front-end company in high pressure liquid chromatography. Almost everything you need to make better chromatograms in the beginning is on our shelf. 

Figure 9.4 High-pressure liquid chromatography separation of 50 pg of a natural phosphatidylcholine mixture from egg yolk. The reconstructed ion chromatograms of diglyceride ions were selected from data acquired by full mass scanning from 120 amu to 820 amu. The relative intensity is shown based on the peak height. Column 3 pm Ultrasphere-ODS (4.6 mm x 7.5 cm). Mobile phase MeOH/hexane/0.1 m NH4OAC (71 5 7), 1 mlmin . Reprinted with permission from Kim, H. Y. and Salem, N. Jr, Phospholipid molecular species analysis by thermospray liquid chromatography/mass spectrometry. Anal. Chem., 58 (1), 9-14, 1986.

A new analytical procedure, recently developed in our Laboratory, involves high pressure liquid chromatography. Fig.2 reports a representative chromatogram of MTA and related adenosyl-sulfur compounds. The relative retention times permit an accurate separation of the compounds with a sensitivity limit of 50 pmoles, thus... 

High performance liquid chromatography (HPLC) takes many different forms and is a primary method of analysis in many types of laboratories. HPLC separates mixtures of compounds into their individual components by means of an interaction of the compound, a liquid mobile phase, and an inert stationary phase. The interactions between the mobile phase and stationary phase are diverse and dependent on the types of compounds undergoing separation and the extent to which separation is required. The output from the data analysis system is a chromatogram. An example of this is shown in Figure 2.1, where the small peak at the beginning is the peak for the unrestrained solute and shows the point at which the injection has been detected (change in pressure of the system). The x-axis represents the time and the y-axis represents the detector response. 

After the extraction step has been completed, the antioxidants and other additives present in the solvent can be readily analyzed. The majority of the analytical methods used for measuring the antioxidant content of polymer extract solutions are based on chromatography, such as high performance or high pressure liquid (HPLC), gas (GC), and gel permeation (GPC) or size exclusion (SEC). As most polymer antioxidants contain a phenyl ring or other chromophoric moiety in their structure, UV detection (usually between 200 and 280 nm) is ideally suited for their measurement. The chromatogram shown in Figure 1 aptly demonstrates the utility of... 

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