Liquid chromatography reverse phase methods

See also Bioassays Overview. Capillary Electrophoresis Overview. Electrophoresis Oven/iew Principles Two-Dimensional Gels. Gas Chromatography Overview Mass Spectrometry. Immunoassays Overview. Immunoassays, Applications Food. Immunoassays, Techniques Radioimmunoassays Enzyme Immunoassays. Liquid Chromatography Reversed Phase Liquid Chromatography-Mass Spectrometry Food Applications. Mass Spectrometry Oven/iew Principles Matrix-Assisted Laser Desorption Ionization Time-of-Flight. Radiochemical Methods Radioreceptor Assays Food and Environmental Applications. Thin-Layer Chromatography Oven/iew. 

Chong, B.E., Yan, F., Lubman, D.M., Miller, F.R. (2001). Chromatofocusing nonporous reversed-phase high-performance liquid chromatography/electrospray ionization time-of-flight mass spectrometry of proteins from human breast cancer whole cell lysates a novel two-dimensional liquid chromatography/mass spectrometry method. Rapid Com-mun. Mass Spectrom. 15, 291-296. 

At present, liquid chromatography is the method of choice for determining residues of quinolone antibacterials in edible animal products (Table 29.6). Separation is generally carried out on nonpolar reversed-phase columns containing octadecyl, octyl, phenyl, or polymeric sorbents. Either methanol or acetonitrile... 

Development of fast, accurate, and reproducible high-performance liquid chromatography (HPLC) methods has offset the use of traditional open-column and TLC methods in modern chlorophyll separation and analysis. A number of normal and reversed-phase methods have been developed for analysis of chlorophyll derivatives in food samples (unit F4.4), with octadecyl-bonded stationary phase (C]8) techniques predominating in the literature (Schwartz and Lorenzo, 1990). Inclusion of buffer salts such as ammonium acetate in the mobile phase is often useful, as this provides a proton equilibrium suitable for ionizable chlorophyllides and pheophorbides (Almela et al., 2000). 

Quinones-Torrelo et al. (1999 2001) have demonstrated a correlation of pharmacokinetic properties with results from micellar liquid chromatography. In this method micellar solutions of nonionic surfactants are used as the mobile phase in reverse-phase liquid chromatography. Interactions between the mobile and stationary phases are purported to correspond to the membrane/water interface of biological barriers as hydrophobic, steric, and electronic interactions are important for both. For a series of 18 antihistamines Quinones-Torrelo et al. (2001) showed that both volume of distribution and half-life values were better correlated with retention on these columns than with the classical log K, w descriptor. 

Heinisch, S. et al. Effect of temperature on the retention of ionizable compounds in reversed-phase liquid chromatography application to method development. J. Chromatogr. A. 2006, 1118, 234—243. 

WS The water solubility was estimated by Kurz [296] from the relationship of WS and the retention time of test chemicals in reverse-phase high-performance liquid chromatography (RP-HPLC method). 

The composition distribution of SAN copolymers can be determined by liquid chromatography. An effective method is to precipitate the polymer on a column, and then successively elute fractions that differ compositionally by increasing the polarity of the solvent [13-18]. Both normal- and reversed-phase chromatography can be used. 

FIGURE 28 1 Selection of LC modes. Methods can be chosen based on solubility and molecular mass. In most cases for non-ionic small molecules (jW < 2000), reversed-phase methods are suitable. Techniques toward the bottom of the diagram are best suited for species of high molecular mass (.it > 2000). (Adapted from High Performance Liquid Chromatography. 2nd ed.. S. Lindsay and J. Barnes, eds.. New York Wiley, 1992. With permission.)... 

For carrying out routine high pressure liquid chromatography separation, it is the reversed-phase method which is most suitable, and in particular using RP 8 or RP 18 columns. These materials are based on silica gel with a chemically bonded, non-polar stationary phase of differing polarity. 

See also Bioassays Overview Microbial Tests Bioautography. Blood and Plasma. Fluorescence Clinical and Drug Applications Food Applications. Food and Nutritional Analysis Dairy Products. Gas Chromatography Mass Spectrometry. Immunoassays, Techniques Enzyme Immunoassays. Liquid Chromatography Normal Phase Reversed Phase Food Applications. Microbiological Techniques. Radiochemical Methods Food and Environmental Applications. Vitamins Fat-Soluble. 

Law, B. The effect of eluent pH and compound acid-base character on the design of generic-gradient reversed-phase high-performance liquid chromatography (PR-HPLQ methods for use in drug discovery. J. Phaim. Biomed. 

Controlling the quality of milk and its derivatives is a very demanding field with a great need for development of more economical, time-saving, and accurate methods of ensuring product quality. This entry presents various reversed-phase (RP) high-performance liquid chromatography, HPLC/UV methods for analysis of miUt proteins, and describes how these techniques are used in the study of bovine, ovine, and human native milk proteins, casein fractions, cheese proteolysis evaluation, detection of product adulteration, enzyme hydrolysis of whey proteins, and peptide separation. 

High-performance liquid chromatography (HPLC) This method was applied to identify and quantify characteristic substances in commercially available oakmoss products. This technique provides a powerful complement to the established TLC method. The bonded reverse phase columns are used here, and all the aromatic lichen products are suitable for analysis with this method. Samples are dissolved in methanol and injected in to the appropriate portion column, through which an... 

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