Solvents - Analysis of industrial waste water

Importance of the Topic

Industrial wastewater often contains volatile organic compounds (VOCs) that pose risks to human health and environment. Reliable monitoring of these contaminants is essential for regulatory compliance and pollution control.

Objectives and Study Overview

This study aims to develop a rapid and sensitive method for screening 35 common VOCs in industrial wastewater. The approach utilizes headspace solid-phase microextraction (SPME) coupled with capillary gas chromatography and flame ionization detection (GC-FID) to achieve fast separation and accurate identification.

Methodology

Sample preparation and analysis steps:

• Addition of K2CO3 to aqueous samples in a 1:1 ratio to enhance VOC release
• Headspace SPME extraction at 50 °C for 30 min
• Splitless desorption in a large bore liner (0.75 mm ID) with pressure programming from 50 to 300 kPa
• GC temperature program from 40 °C (2 min) to 250 °C at 10 °C/min
• Hydrogen carrier gas at 0.5–3.0 bar

Used Instrumentation

• Gas chromatograph with capillary inlet configured for SPME
• SPME fiber for headspace sampling
• Agilent CP-Sil 5 CB column (0.15 mm × 25 m, 2 μm film thickness) with 5 m uncoated precolumn (0.32 mm ID)
• Flame ionization detector operated at 300 °C
• Pressure programming hardware for splitless desorption

Main Results and Discussion

The optimized method separated 35 target compounds within 18 minutes, delivering sharp peaks for both low-boiling and higher boiling analytes. Pressure programming improved peak shape for volatile species. Identified compounds included alcohols, ketones, ethers, aromatics, and heterocycles. Several unknown peaks were also detected, indicating potential further targets.

Benefits and Practical Applications

• Fast analysis suitable for high-throughput monitoring
• Simplified sample preparation without solvents
• Wide analyte range covering common VOCs in wastewater
• Applicable in environmental laboratories for compliance testing

Future Trends and Opportunities

Advances may include integration with mass spectrometry for enhanced identification, automation of SPME steps, development of novel fiber coatings for broader analyte coverage, and deployment of portable GC-SPME units for on-site analysis. Data analytics and machine learning could further streamline VOC profiling.

Conclusion

The described headspace SPME-GC-FID method offers a rapid, solvent-free solution for comprehensive VOC screening in industrial wastewater. Its speed, sensitivity, and robustness support its adoption in routine environmental monitoring.