Retention phenol groups

FIGURE 2.11 Influence of substitution on solute retention. Functional groups with phenol as base. Column Lichrosorb RP CIS 250 x4 mm mobile phase water. 

Apart from one compound (II), the lignin model compounds that had free phenolic groups eluted at close to the retention times predicted by the calibration curve from the polymer standards and not from the derive tized model compounds. This could simply be a result of the underivatized models having a similar variation in hydrodynamic volume with molecular weight as the polymer standards. However, it is to be expected that solvation of the underivatized model compounds should occur with THF as solvent (10), with hydrogen bonding of one THF molecule to each under-... 

A gas-chromatographic study of aporphines and their trimethylsilyl derivatives has been carried out, and a relationship drawn between oxygenation pattern and retention time. A fluoroscopic technique has been developed that measures submicrogram quantities of apomorphine in brain tissue. The u.v. spectrum of a monophenolic aporphine shows a strong absorption between 315 and 330 nm in basic solution if the phenolic group is situated at C-9. A tabula-... 

Preferential acylation of alcohol groups with retention of phenol groups Dicarhoxylic acid monoesters from dicarhoxylic acid anhydrides... 

This technique is based on the same separation mechanisms as found in liquid chromatography (LC). In LC, the solubility and the functional group interaction of sample, sorbent, and solvent are optimized to effect separation. In SPE, these interactions are optimized to effect retention or elution. Polar stationary phases, such as silica gel, Florisil and alumina, retain compounds with polar functional group (e.g., phenols, humic acids, and amines). A nonpolar organic solvent (e.g. hexane, dichloromethane) is used to remove nonpolar inferences where the target analyte is a polar compound. Conversely, the same nonpolar solvent may be used to elute a nonpolar analyte, leaving polar inferences adsorbed on the column. 

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