Routine analysis of hydrocarbons, PCB and PAH in marine sediments using supercritical CO2 extraction

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Marine Science

Background:

• Marine sediments are critical matrices for environmental monitoring.
• Conventional solvent extraction methods for pollutants like hydrocarbons (THC), polychlorinated biphenyls (PCB), and polycyclic aromatic hydrocarbons (PAH) are solvent-intensive and time-consuming.
• Elemental sulfur in sediments can interfere with analytical procedures.

Purpose of the Study:

• To optimize automated Supercritical Fluid Extraction (SFE) using CO2 for routine analysis of THC, PCB, and PAH in marine sediments.
• To reduce solvent consumption and manual handling time in sample preparation.
• To assess the effectiveness of SFE compared to conventional methods.

Main Methods:

• Automated Supercritical Fluid Extraction (SFE) with CO2.
• Use of activated copper (Cu) to remove elemental sulfur.
• Modification of CO2 with methanol for specific analytes.
• Comparison of SFE with conventional solvent extraction techniques.

Main Results:

• SFE achieved comparable recoveries and reproducibility for THC to conventional methods.
• Elemental sulfur was effectively removed during the SFE process using activated Cu.
• Extraction efficiencies for PCB and PAH with SFE were improved to conventional levels by modifying CO2 with methanol.

Conclusions:

• Automated SFE is a viable and efficient alternative for the routine analysis of THC, PCB, and PAH in marine sediments.
• SFE offers significant advantages in reducing solvent usage and sample processing time.
• Method optimization, including the use of activated copper and CO2 modification, is key to successful SFE application for complex matrices.