High-performance liquid chromatography analytical separation

High Performance Liquid Chromatography. All separations were performed using an Altex Scientific (1780 Fourth Street, Berkeley, CA 94710) Model 320 Advance Research Chromatograph, consisting of a model lOOA dual piston analytical pump, a Model 153 UV detector, a Model 210 injection valve, and a Model 155 recorder. The columns (600 x7.5mm) evaluated were the Spherogel TSK-SW-2000 and SW-3000 (Altex). Unless otherwise stated, all separations were carried out at 23 - 25 . 

Resolution of a-substituted aldehydes. The SASP hydrazones of a-substituted aldehydes can be resolved by high-performance liquid chromatography. The separability factors are sufficient for analytical and preparative purposes. The (S,S)-isomer elutes consistently before the (S,R)-isomer. Both isomers can be cleaved to the enantiomerically pure aldehydes by ozonolysis or acid hydrolysis, with resolution yields of 35-70%. 

In modern high-performance liquid chromatography the separation of the analytes is still based on the differences in the analyte affinity for the... 

Guan, Z., Grunler, J., Piao, S. and Sindelar, P.J. (2001) Separation and quantitation of phospholipids and their ether analogues by high-performance liquid chromatography. Analytical Biochemistry 297, 137-143. 

Several high-performance liquid chromatography (HPLC) separation techniques have been used in combination with different detection methods to characterize poly(ethylene glycol)s and their amphiphilic derivatives. SEC is a particularly attractive analytical tool for the investigation of non-ionic surfactants because it can provide information for their composition, molecular weight, and molecular-weight distribution along with their micellization in selective solvents. This entry wiU survey briefly both applications with major emphasis on the choice of the most appropriate eluent and stationary phase. 

Svec, F Frechet, JMJ, Continuous Rods of Macroporous Polymer as High-Performance Liquid Chromatography Separation Media, Analytical Chemistry 64, 820, 1992. 

High performance liquid chromatography (HPLC) has been by far the most important method for separating chlorophylls. Open column chromatography and thin layer chromatography are still used for clean-up procedures to isolate and separate carotenoids and other lipids from chlorophylls and for preparative applications, but both are losing importance for analytical purposes due to their low resolution and have been replaced by more effective techniques like solid phase, supercritical fluid extraction and counter current chromatography. The whole analysis should be as brief as possible, since each additional step is a potential source of epimers and allomers. 

Siitfeld, R., Preparative liquid chromatography with analytical separation quality interval injection/displacement reversed-phase high-performance liquid chromatography, ]. Chromatogr., 464, 103, 1989. 

The spectrum of new analytical techniques includes superior separation techniques and sophisticated detection methods. Most of the novel instruments are hyphenated, where the separation and detection elements are combined, allowing efficient use of materials sometimes available only in minute quantities. The hyphenated techniques also significantly increase the information content of the analysis. Recent developments in separation sciences are directed towards micro-analytical techniques, including capillary gas chromatography, microbore high performance liquid chromatography, and capillary electrophoresis. 

Capillary electrophoresis employing chiral selectors has been shown to be a useful analytical method to separate enantiomers. Conventionally, instrumental chiral separations have been achieved by gas chromatography and by high performance liquid chromatography.127 In recent years, there has been considerable activity in the separation and characterization of racemic pharmaceuticals by high performance capillary electrophoresis, with particular interest paid to using this technique in modem pharmaceutical analytical laboratories.128 130 The most frequently used chiral selectors in CE are cyclodextrins, crown ethers, chiral surfactants, bile acids, and protein-filled... 

In another study, the authors reported a comparative study of the enantiomeric resolution of miconazole and the other two chiral drugs by high performance liquid chromatography on various cellulose chiral columns in the normal phase mode [79], The chiral resolution of the three drugs on the columns containing different cellulose derivatives namely Chiralcel OD, OJ, OB, OK, OC, and OE in normal phase mode was described. The mobile phase used was hexane-isopropanol-diethylamine (425 74 1). The flow rates of the mobile phase used were 0.5, 1, and 1.5 mL/min. The values of the separation factor (a) of the resolved enantiomers of econazole, miconazole, and sulconazole on chiral phases were ranged from 1.07 to 2.5 while the values of resolution factors (Rs) varied from 0.17 to 3.9. The chiral recognition mechanisms between the analytes and the chiral selectors are discussed. 

High performance liquid chromatography (HPLC) ESI, APCI, APPI Separation of polar, ionic, nonvolatile, high molecular weight and thermally labile analytes... 

Identification and quantification of natural dyes need high performance analytical techniques, appropriate for the analysis of materials of complicated matrices containing a small amount of coloured substances. This requirement perfectly fits coupling of modern separation modules (usually high performance liquid chromatography in reversed phase mode, RPLC, but also capillary electrophoresis, CE) with selective detection units (mainly mass spectrometer). 

In the last decade, capillary electrophoresis (CE) has become one of the most powerful and conceptually simple separation techniques for the analysis of complex mixtures. The main reasons are its high resolution, relatively short analysis times, and low operational cost when compared to high-performance liquid chromatography (HPLC). The ability to analyze ultrasmall volume samples in the picoliter-to-nanoliter ranges makes it an ideal analytical method for extremely volume-limited biological microenvironments. 

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