Comparison of the properties of polymeric and C8 based materials for solid phase extraction

Area of Science:

• Analytical Chemistry
• Separation Science

Background:

• Solid-phase extraction (SPE) is a crucial technique for sample preparation in analytical chemistry.
• Selecting appropriate SPE materials is vital for efficient analyte recovery and method development.

Purpose of the Study:

• To compare the extraction properties of styryldivinyl benzene (SDB) and Oasis polymeric SPE materials against a base-deactivated C8 bonded silica gel.
• To evaluate the influence of pH, eluent composition, and matrix effects on analyte extraction and recovery.

Main Methods:

• Utilized a range of acidic and basic test analytes for extraction experiments.
• Investigated extraction across a broad pH range (2-10) for polymeric phases and a narrower range (2-6) for C8 silica.
• Assessed elution efficiency using methanol-water mixtures with and without trifluoroacetic acid (TFA) or triethylamine (TEA) modifiers.
• Examined the impact of a plasma matrix on extraction performance.

Main Results:

• Both SDB and Oasis polymeric phases showed good extraction for all analytes between pH 2-10.
• C8 silica gel exhibited efficient extraction only for the most polar acidic analyte, anisic acid, within a limited pH range (2-6).
• Trifluoroacetic acid (TFA) and triethylamine (TEA) significantly impacted elution efficiency.
• Plasma matrix effects varied depending on the specific analyte.

Conclusions:

• Polymeric SPE materials (SDB and Oasis) offer a wider pH operational window for extraction compared to base-deactivated C8 silica.
• Eluent modification with ionic species (TFA, TEA) is critical for optimizing analyte recovery.
• The developed performance assessment method provides a quantitative basis for phase selection in SPE applications.