Chemically modified polymeric resins for high performance liquid chromatography, solid-phase extraction and organic separation by LC and GC

Abstract

<p>Polystyrene divinylbenzene (PS/DVB) was chemically modified by the introduction of several hydrophilic functional groups, -COCH[subscript]3, -CH[subscript]2OH, -CH[subscript]2CN, -COCH[subscript]2CH[subscript]2COOH, and one hydrophobic group, -C(CH[subscript]3)[subscript]3. Those functional groups changed the chromatographic behavior of various test compounds on PS/DVB resin. On the hydrophilically modified resins, the capacity factors (k[superscript]') of polar compounds (such as phenol, p-cresol) are increased, while the k[superscript]' of non-polar compounds (such as toluene, cumene) are decreased. The opposite is true for hydrophobically modified resin. The change of k[superscript]' of some compounds resulted in the change of separation factor [alpha] (=k[subscript]2[superscript]'/k[subscript]1[superscript]'). The modified resins offer an additional selectivity parameter for liquid chromatographic separation;The chemically modified polymeric resins (PS/DVB-COCH[subscript]3 and PS/DVB-CH[subscript]2OH) are easily wetted by water. They are excellent for solid-phase extraction (SPE), especially for polar compounds such as phenols. The recoveries of phenols and multihydroxy phenols are overwhelmingly higher than those obtained using commercial SiC[subscript]18. An HPLC system with a minicolumn (4.0 x 4.0 mm) was used to study SPE of various compounds on different stationary phases. The elution efficiency of various solvents was also studied;Sulfonated PS/DVB was used for separation of neutral, basic and weakly basic organic compounds in this research. The basic and weakly basic compounds were separated by an on-line mini-column. The neutral and basic compounds were separated by an off-line mini-column. The sulfonated PS/DVB was also used for separation of amine isomers, showing better separations than a commercial SiC[subscript]18 column;A special, 5 [mu]m non-porous, spherical PS/DVB resin was sulfonated and then packed into the split liner of a capillary gas chromatography to be an amine abstractor. When a sample mixture of basic amines and neutral compounds was injected into the liner, all the basic amines were abstracted quantitatively while all the neutral compounds passed through. The quantitative determination of passed neutral compounds was excellent. A 200-fold excess concentration of a basic compound in the presence of a neutral compound with the same retention time could be abstracted;This special non-porous PS/DVB resin was converted synthetically to a polymeric-mercuric resin, which was used as a selective abstractor of mercaptan compounds in the split liner of capillary GC. Non-mercaptan (both sulfur and non-sulfur) compounds can pass the liner and be quantitatively determined well. The injection temperature was also studied.</p>