Sampling characteristics of octadecylsiloxane-bonded silica particle-embedded glass fiber discs for solid-phase extraction

Abstract

Forced flow planar chromatography was used to characterize the physical and retention properties of an octadecylsiloxane-bonded particle-embedded glass fiber medium used for solid-phase extraction. The carbon loading, intraparticle porosity, binding capacity, and hydrophobicity index indicate that the medium has a large volume of bonded phase essentially filling the pore volume. The interparticle porosity and specific permeability indicate favorable flow characteristics. The flow resistance parameter and the diameter of the largest pore by the bubble method are consistent with a macroscopic homogeneous medium structure free of holes and channels. The silanophilic index indicates a significant concentration of accessible silanol groups and/or other strong hydrogen-bond acid sites. A comparison of retention characteristics to a common cartridge sorbent using the solvation parameter model indicated that the cartridge sorbent had a more favorable cavity term for retention but the particle-embedded glass fiber medium was more competitive with the sample solvent, water-methanol (99:1), for the retention of polar compounds with significant dipole-type interactions and those behaving as hydrogen-bond bases. The physical and retention properties of the particle-embedded glass fiber medium confirm its suitability for use in solid-phase extraction.