Solvent-bar microextraction--using a silica monolith as the extractant phase holder

Area of Science:

• Analytical Chemistry
• Materials Science

Background:

• Traditional sample preparation methods for polycyclic aromatic hydrocarbons (PAHs) can be time-consuming and may involve harsh chemicals.
• Solvent-bar microextraction (SBME) offers a more efficient approach, but limitations exist with conventional solvent holders.

Purpose of the Study:

• To develop and evaluate a novel liquid-phase microextraction (LPME) technique utilizing a silica monolith as a solvent holder for solvent-bar microextraction (SBME).
• To assess the efficiency and applicability of this new method for the determination of PAHs in environmental samples.

Main Methods:

• A silica monolith was employed as a porous extractant solvent holder for SBME.
• Polycyclic aromatic hydrocarbons (PAHs) were used as model analytes.
• Optimization of extraction parameters including agitation speed, extraction time, monolith length, and salt concentration was performed.
• Method validation included linearity, limits of detection, and relative standard deviations.

Main Results:

• Optimal extraction conditions were identified as stirring at 1000 rpm for 30 min without salt, using a 4-mm silica monolith.
• Achieved low limits of detection for PAHs, ranging from 3.9 pg/mL to 28.8 pg/mL.
• Demonstrated good linearity, with relative recoveries between 87.1% and 100.7% in spiked river samples.
• The silica monolith exhibited superior resistance to extreme temperatures and pH compared to polymeric hollow fibers.

Conclusions:

• The developed silica monolith-based SBME-LPME method is highly effective for PAH determination.
• This novel application of monolithic materials in analytical chemistry, particularly for sample preparation, expands their utility.
• The method offers advantages in terms of efficiency, robustness, and compatibility with various organic solvents.