Amine compounds, RPLC

Adsorption surface, SFC, solvent Interactions, 1>>9 Air monitors. Industrial chromatography, 200 Alditol acetates, chromatogram, 32f Alkyl groups, bonded, HPLC development, 82,83 Amides, enantiomeric, separation, >l3,>l>lf Amine compounds, RPLC, 8>l Amino acids HPLC, 86,87f Ion exchange, 81 ligand exchange, >>... 

Many, if not most, pharmacologically active compounds are amines. For this reason, issues in the RPLC of substances of pharmaceutical interest tend to be similar to those encountered in the separation of amines. Incompletely endcapped silica-based phases may exhibit tailing. The use of ion pairing or ion suppression is common in the analysis of pharmacologically active substances. Also, derivatization of the amine functionality prior to analysis may be required. The RPLC retention indices of most common pharmaceutical compounds have been compiled.97... 

In LC-ESI-MS, the role of the mobile phase pH is complicated. In practice, often a compromise must be strack between analyte retention and ionization. From the perspective of generating preformed ions in solution, the optimum conditions for the ESI analysis of basic compounds, e.g., amines, would be an acidic mobile phase with a pH at 2 units below the dissociation constant pIQ of the analytes, while for acidic compounds, e.g., carboxylic acid or aromatic phenols, a basic mobile phase with a pH two units above the pK, of the analytes is preferred [97]. These conditions are uirfavourable for an analyte retention in RPLC. The analytes elute virtually umetained. In RPLC, it is important to reduce protolysis of basic and acidic analytes, i.e., to assure that the compounds are... 

The terminal AT-acetylneuraminic acid was cleaved off with neuraminidase to yield neutral carbohydrate compounds. The structures shown above only differ in the labeled -1,3- and 4-linkage between galactose and AT-acetylglucos-amine in the lactosamine residue of this triantennary oligosaccharide [269]. Neither isomer can be separated with conventional RPLC techniques. 

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