Pesticides and PCBs - Analysis of chloro- and sulfur pesticides, and PCBs

Significance of the Topic

The reliable detection of chlorinated and sulfur-based pesticides alongside polychlorinated biphenyls (PCBs) is critical for environmental monitoring and regulatory compliance. These persistent organic pollutants pose significant ecological and health risks due to their bioaccumulative nature and potential toxicity. Fast and efficient analytical methods enable timely decision-making in water, soil, and food safety assessments.

Study Objectives and Overview

This application note demonstrates a capillary gas chromatography (GC) method capable of separating ten target compounds—four PCBs and six chlorinated or sulfur pesticides—in under 18 minutes. The primary goal is to present a streamlined protocol for trace-level quantitation (50 pg/µL) using a single-column approach, supporting high-throughput workflows in environmental laboratories.

Methodology and Instrumentation

The procedure employs an Agilent CP-Sil 8 CB fused-silica capillary column (0.25 mm × 50 m, df 0.12 µm) optimized for pesticide and PCB separation. Key operating parameters include:

• Column temperature program: 80 °C (initial) ramp to 220 °C at 20 °C/min, then to 270 °C at 4 °C/min
• Carrier gas: Hydrogen at 125 kPa
• Injection: On-column introduction of 1 µL sample
• Detection: Electron capture detector (ECD) at 300 °C

Sample concentration was set at 50 pg/µL per analyte. Peak identity was confirmed by retention time matching to standards.

Main Results and Discussion

The method achieved baseline or near-baseline resolution of all ten analytes within an 18-minute run. Identified peaks include PCBs 31, 28, 101, 153, and 138, alongside chlorbicyclen, o,p’-DDE, α-endosulfan, endosulfan sulfate, and p,p’-DDT. Chromatograms exhibited sharp, symmetric peaks with consistent retention times, demonstrating robust column performance and repeatability. The ECD provided high sensitivity for electronegative compounds, enabling low-picogram detection.

Benefits and Practical Application

Ultrafast separation and low detection limits make this method suitable for routine environmental screening. Laboratories gain the ability to:

• Process large sample batches with minimal downtime
• Detect trace pollutant levels to meet stringent regulatory limits
• Reduce solvent and carrier gas usage through shorter run times

The single-column protocol simplifies method development and maintenance requirements.

Future Trends and Opportunities

Further improvements may include coupling to tandem mass spectrometry for enhanced selectivity and confirmation, or implementing automated sample preparation for full workflow integration. Emerging stationary phases and detector technologies could extend this approach to a broader range of semi-volatile organics and improve analysis of complex matrices.

Conclusion

This application demonstrates an efficient GC-ECD approach for simultaneous analysis of key chlorinated/sulfur pesticides and PCBs. The rapid, high-resolution separation on an Agilent CP-Sil 8 CB column supports accurate trace-level quantitation, addressing critical needs in environmental analytics.

Reference

Agilent Technologies, Inc. Application Note A00597: "Pesticides and PCBs Analysis of chloro- and sulfur pesticides, and PCBs", 2011