Effect of High Density Poly (Vinyl Octadecanoate) Grafted Silica Stationary Phase on Physiochemical Properties and Shape Selectivity Enhancement of Polycyclic Aromatic Hydrocarbons (PAHs) in RP-HPLC

Abstract

High dense Poly (vinyl octadecanoate) grafted silica stationary phase (Sil-from-VOD) have been prepared by radical chain-transfer “grafting from” approach. Another Poly (vinyl octadecanoate) grafted silica stationary phase (Sil-to-VOD) was prepared by conventional one-step telomerization (“grafting to”) method. Both phases were characterized qualitatively and quantitatively. Thermogravimetric analysis and elemental analysis data showed that Sil-from-VOD have higher grafting density as compared with Sil-to-VOD. A combination of DRIFT-IR, ¹³C CP/MAS NMR and ²⁹Si CP/MAS NMR revealed that Sil-from-VOD have more transconformation than Sil-to-VOD while suspended-state¹H NMR proved that Sil-from-VOD was less mobile than Sil-to-VOD. Both phases along with a commercial ODS column (ODS-p) were applied to RP-HPLC and evaluated by PAHs as solutes. Sil-from-VOD, prepared by “grafting from” approach and having high density provided better retentivity and selectivity for PAHs compared to other reference columns.

Keywords:

• “grafting from”
• “grafting to”
• organic content
• polycyclic aromatic hydrocarbons
• RP-HPLC
• shape selectivity