Oligo- and polystyrenes

Styrene oligomers were first analysed by packed-column SFC in 1969 [41], and became the most common material for evaluating the performance of SFC systems in the 1970s and early 1980s [9, 24, 41-59]. Of the molecular-mass standards available, polystyrene was chosen because of its sensitivity to UV detection and because of its extensive use as calibration standard for SEC. 

Most of the early work carried out involved the use of silica oi derivatized silica packings, and n-pentane modified with various alcohols was employed as a mobile phase. The mobile phase was pressure programmed to effect elution of successive oligomers. 

Later it became obvious that, if the modifier percentage was increased, the higher solvent strength of the mobile phase permitted elution of higher-molecular-mass species. Eluent compositions which were found suitable included n-pentane-cyclohexane [49], diethylether-1, 4-dioxane [49], n-pentane-1,4-dioxane, propane, n-butane or n-hexane-1,4-dioxane [49,54], and hexane-ethanol [56]. Most gradients involved increasing the modifier by 10-15% over a 60-minute period. 

Styrene oligomers were analysed by capillary SFC in the early 1980s, and capillary SFC-MS followed soon afterwards [51]. In 1983, Fjeldsted et al evaluated pressure programming, linear density programming and 

Publication year [Reference] Authors Application Column Mobile phase Detector Comments 

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Abe, R, Einaga, Y., Yoshizaki, T., and Yamaka, H., Excluded volume effects on the mean-square radius of gyration of oligo- and polystyrenes in dilute solutions, Macromolecules, 26, 1884-1890 (1993a). 

J-i. Horinaka, M. Maruta, S. Ito, and M. Yamamoto. Local motion of oligo- and polystyrene chain end studied by the fluorescence depolarization method. Macromolecules, 32 (1999), 1134-1139. 

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