Analysis of Volatile Organic Compounds in Indoor Air

Importance of the Topic

Indoor air often contains trace levels of volatile organic compounds (VOCs) that pose health risks and affect comfort. Reliable monitoring of these contaminants is essential for environmental assessments, workplace safety and regulatory compliance. Thermal desorption–gas chromatography–mass spectrometry (TD-GC-MS) provides a sensitive, selective and solvent-free approach for quantifying VOCs in air samples.

Study Objectives and Overview

The aim of this application note is to demonstrate a robust TD-GC-MS method for simultaneous identification and quantification of 11 common VOCs in indoor air. The method highlights system configuration, chromatographic separation, detection parameters and key performance characteristics, using Shimadzu’s GCMS-QP2020 NX coupled with a thermal desorption unit.

Methodology and Instrumentation

Instrumentation Used:

• GC-MS System: Shimadzu GCMS-QP2020 NX with TD-30 thermal desorption unit
• Column: SH-I-624Sil MS (60 m × 0.32 mm I.D., 1.8 µm film thickness)
• Thermal Desorption Conditions: sorbent tube desorption at 250 °C for 10 min with 70 mL/min flow; trap cooled to –25 °C then desorbed at 250 °C for 2 min
• GC Conditions: constant pressure helium carrier at 200 kPa; split injection (ratio 10:1); oven program from 35 °C (5 min) ramped at 5 °C/min to 280 °C (5 min)
• MS Conditions: transfer line at 220 °C; ion source at 230 °C; interface at 200 °C; data acquisition in Scan (m/z 20–600) and SIM modes with target and reference ions for each analyte

Main Results and Discussion

Chromatographic separation achieved baseline resolution of all 11 target VOCs, including chlorinated hydrocarbons, aromatics and a long-chain alkane. The use of SIM enhanced selectivity and improved signal-to-noise ratios for trace-level detection. The system demonstrated reproducible retention times and consistent peak shapes, ensuring reliable quantification across replicate analyses.

Benefits and Practical Applications

• High Sensitivity: SIM detection enables low-ppt level quantification of indoor air pollutants.
• Comprehensive Coverage: Simultaneous analysis of chlorinated solvents, aromatic compounds and aliphatic VOCs.
• Fast Turnaround: Automated thermal desorption reduces sample preparation time and solvent use.
• Regulatory Compliance: Method aligns with common indoor air quality monitoring standards.

Future Trends and Potential Applications

Advances may include miniaturized portable TD-GC-MS systems for on-site sampling, automated data processing using machine learning for real-time quality control, expansion of compound panels to include emerging contaminants and integration with IoT for continuous indoor air monitoring.

Conclusion

The presented TD-GC-MS method offers a reliable, high-throughput solution for indoor VOC analysis. Its sensitivity, selectivity and ease of use make it well suited for environmental laboratories, industrial hygiene assessments and quality control in manufacturing environments.

Reference

• Shimadzu Corporation. Application News M313 (JP, ENG), First Edition: September 2022, ERAS-1000-0392.