An unbreakable on-line approach towards sol-gel capillary microextraction

Area of Science:

• Analytical Chemistry
• Materials Science
• Environmental Science

Background:

• Solid phase microextraction (SPME) is a crucial technique for analyzing trace contaminants in environmental samples.
• Existing SPME devices can lack durability and efficiency, necessitating improvements for robust analytical applications.
• Polycyclic Aromatic Hydrocarbons (PAHs) are significant environmental pollutants requiring sensitive detection methods.

Purpose of the Study:

• To develop a novel, unbreakable in-tube solid phase microextraction (SPME) device utilizing sol-gel technology.
• To enhance the extraction efficiency and stability of SPME for analyzing polycyclic aromatic hydrocarbons (PAHs) in aquatic media.
• To integrate the developed SPME device with High-Performance Liquid Chromatography (HPLC) for on-line analysis.

Main Methods:

• Fabrication of an in-tube SPME device by electrodepositing a copper tube with metallic Cu, followed by self-assembled monolayers (SAMs) of 3-(mercaptopropyl) trimethoxysilane (3MPTMOS).
• Chemical bonding of poly(ethyleneglycol) (PEG) using sol-gel technology onto the SAM-coated copper tube inner surface.
• Characterization of coating homogeneity and porosity using Scanning Electron Microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis.
• Optimization of extraction parameters including sample flow rate, loading time, desorption time, and sample volume.
• Performance comparison of different coated tubes (bare copper, Cu-electrodeposited, SAMs-coated, SAMs-sol-gel coated).

Main Results:

• The SAMs-sol-gel coated loop demonstrated a 20-100 times higher extraction efficiency compared to other tested configurations.
• Achieved linearity in the range of 0.01-500 μg L⁻¹, with limits of detection (LOD) between 0.005-0.5 μg L⁻¹.
• Relative standard deviation (RSD%) values were below 8.3% at 5 μg L⁻¹ (n=5), and successful application to real water samples showed 90-104% recovery.
• The developed device exhibited excellent long-term stability, withstanding over 100 extraction/desorption cycles and exposure to various organic solvents without performance degradation.

Conclusions:

• The novel sol-gel-based in-tube SPME device offers a highly efficient, robust, and stable platform for on-line analysis of PAHs in water.
• The developed method provides sensitive and reliable results, suitable for the analysis of environmental water samples.
• The device's durability and performance make it a promising tool for routine environmental monitoring and trace analysis.