Determination of volatile organic hydrocarbons in water samples by solid-phase dynamic extraction

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Environmental Science

Background:

• Groundwater contamination by volatile halogenated hydrocarbons and benzene poses significant environmental and toxicological risks.
• Accurate and sensitive detection methods are crucial for monitoring these pollutants in environmental samples.

Purpose of the Study:

• To develop and evaluate a headspace solid-phase dynamic extraction coupled to gas chromatography-mass spectrometry (HS-SPDE-GC/MS) method.
• To determine trace levels of benzene and 11 other volatile halogenated hydrocarbons in groundwater samples.
• To optimize extraction parameters for enhanced sensitivity and efficiency.

Main Methods:

• Utilized a SPDE needle device with a poly(dimethylsiloxane) and activated carbon coating for analyte extraction.
• Analyzed extracted compounds using gas chromatography-mass spectrometry (GC/MS) in full-scan mode.
• Optimized key parameters including temperatures, salting-out, flow rates, volumes, extraction cycles, and pre-desorption time.

Main Results:

• Established method linearity over several orders of magnitude.
• Achieved method detection limits (MDLs) ranging from 12 ng/L (cis-/trans-1,2-dichloroethylene) to 870 ng/L (vinyl chloride).
• Demonstrated high precision (3.1–16%) and validated the method for environmental samples, including those from a former waste-oil recycling facility.

Conclusions:

• The developed HS-SPDE-GC/MS method is highly sensitive, efficient, and automatable for trace determination of target volatile organic compounds in groundwater.
• The method successfully identified complex contamination in real groundwater samples, highlighting its practical applicability.
• This technique provides a valuable tool for environmental monitoring and risk assessment of contaminated sites.