Analysis of VOCs - No. 480

Analysis of Volatile Organic Compounds Using GC-MS

Significance of the Topic

Volatile organic compounds play a critical role in environmental monitoring, industrial quality control and occupational safety. Their low boiling points and high vapor pressures require sensitive analytical techniques to detect and quantify trace concentrations in air, water and materials. Reliable VOC analysis supports regulatory compliance and informs process optimization.

Objectives and Study Overview

The study demonstrates a validated workflow for the qualitative and quantitative analysis of 16 representative VOCs according to the GB/T 37884-2019 standard. Key goals include achieving full chromatographic resolution, maintaining consistent desorption efficiency and ensuring robust mass spectral detection across alcohols, aromatics, glycols and ethers.

Methodology and Instrumentation Used

An automated thermal desorption GC-MS method was employed using a TD-30R autosampler coupled to a GCMS-QP2020 NX system. Samples were loaded onto Tenax TA traps cooled to minus 20 °C, thermally desorbed at 300 °C into a SH-I-624Sil MS capillary column (60 m x 0.32 mm, 1.8 μm). Helium was used as the carrier gas under pressure control. The column oven ramped from 40 °C to 180 °C at 10 °C/min, then to 230 °C at 40 °C/min. The mass spectrometer acquired full scan data from m/z 33 to 450 with an interface temperature of 240 °C and ion source at 230 °C.

Main Results and Discussion

The total ion chromatogram resolved all target VOCs within a 20-minute runtime. Early eluting compounds such as i-butanol and benzene showed sharp peaks, while higher boilers like diethylene glycol monobutyl ether acetate were well separated later. The method demonstrated excellent repeatability in retention time and peak area. Carryover was minimized by optimized purge flows. Mass spectral patterns provided clear confirmation of each analyte’s identity.

Benefits and Practical Applications

• High sensitivity detection of diverse VOCs at trace levels
• Automated sampling reduces operator variability
• Fast cycle times enable high sample throughput
• Compliance with international VOC analysis standards
• Applicability to environmental, workplace and product testing

Future Trends and Potential Applications

Advancements in trap materials and microfabricated columns promise further reductions in desorption times and detection limits. Integration with high-resolution MS and data-processing algorithms will enhance compound identification in complex matrices. Coupling to real-time sensor networks could enable continuous monitoring in industrial and urban environments.

Conclusion

The described GC-MS approach provides a robust, reproducible platform for comprehensive VOC profiling. It meets stringent regulatory demands while delivering rapid results, making it suitable for routine environmental surveys, industrial process control and safety assessments.

Used Instrumentation

• Thermal Desorption Autosampler TD-30R
• GCMS-QP2020 NX system
• SH-I-624Sil MS column, 60 m x 0.32 mm I.D., 1.8 μm film
• Tenax TA sorbent traps

Reference

Application News 03-GCM-345-JP, Shimadzu Corporation, First Edition September 2023