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Determining PAHs and PCBs in aqueous samples: finding and evaluating sources of error
Lidia Wolska1, Magdalena Rawa-Adkonis, Jacek Namieśnik
1Department of Analytical Chemistry, Chemical Faculty, Gdansk University of Technology (GUT), 11/12 G. Narutowicz St., Gdańsk 80-952, Poland.
Analytical and Bioanalytical Chemistry
|June 17, 2005
Summary
Greatest losses of polyaromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) during water analysis occur during sampling, transport, and storage. While extraction and enrichment steps show reliable analyte recovery, pre-analysis handling is critical for accurate trace-level determination.
Area of Science:
- Environmental Chemistry
- Analytical Chemistry
Background:
- Polyaromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) are common environmental contaminants found at trace levels in water.
- Accurate determination of PAHs and PCBs is crucial for environmental monitoring and risk assessment.
Purpose of the Study:
- To identify and quantify sources of analyte loss during multi-step determination of PAHs and PCBs in water.
- To evaluate the reliability of different analytical steps in PAH and PCB analysis.
Main Methods:
- Investigated analyte losses due to adsorption onto container walls.
- Quantified PAH and PCB recoveries during liquid-liquid extraction (LLE) and solid-phase extraction (SPE).
- Assessed losses during solvent evaporation for extract enrichment.
Main Results:
- Analyte adsorption onto container walls varied significantly (0-70%).
- High recoveries (>70%) were achieved during LLE and SPE extraction.
- Losses during extract enrichment were <24% for PAHs and <19% for PCBs.
- Sampling, transport, and storage were identified as the primary sources of analyte loss.
Conclusions:
- Neither LLE nor SPE isolation nor extract enrichment significantly reduces the reliability of PAH and PCB determination.
- Optimizing sampling, transport, and storage procedures is essential for accurate trace-level analysis of PAHs and PCBs in water.