Simplifying the Calculation of TVOC Using TVOC Calculation Tool and Thermal Desorption GC-MS

Importance of the Topic

Volatile organic compounds (VOCs) in air are key indicators of environmental quality in industrial, urban and indoor settings. Total volatile organic compounds (TVOC) quantitation is widely used for air pollution monitoring and regulatory compliance. Traditional manual calculation of TVOC via individual toluene conversion factors is labor-intensive and time-consuming. A streamlined, automated approach enhances laboratory efficiency and ensures rapid, reliable data for health and safety assessments.

Objectives and Study Overview

This study demonstrates a simplified TVOC quantitation workflow using Shimadzu’s TD-30R thermal desorption GC-MS system (GCMS-QP2020 NX) in combination with the TVOC Calculation Tool software. The goals were to automate TVOC calculation, generate reliable calibration curves for target VOCs, and evaluate high-throughput performance without solvent extraction.

Methodology and Instrumentation

Air samples from a laboratory environment (Laboratory A) were collected on TENAX-TA tubes at 100 mL/min for 30 minutes. Mixed standard solutions of benzene, toluene, ethylbenzene, m,p-xylene, o-xylene, 1,4-dichlorobenzene and tetradecane at concentrations from 4 ppm to 400 ppm were prepared in methanol. Standards and samples were thermally desorbed (280 °C) using nitrogen for primary desorption and helium as carrier gas. Chromatographic separation was achieved on a 60 m × 0.25 mm SH-I-1MS column with a temperature gradient from 40 °C to 250 °C. Mass spectrometric detection (m/z 35–350) was performed in scan mode.

Main Results and Discussion

Calibration curves for toluene and target compounds exhibited excellent linearity (R² > 0.9997). The TVOC Calculation Tool automatically applied toluene conversion factors to each detected peak, summed individual concentrations to report total TVOC, and produced detailed reports. Users can switch between comprehensive TVOC calculation and selective precise quantitation of designated compounds with a single click, greatly reducing manual processing time.

Practical Benefits of the Method

• High-throughput VOC analysis without solvent extraction.
• Automated TVOC calculation and report generation.
• Reduced helium consumption via nitrogen primary desorption.
• Flexible quantitation modes for all detected or selected compounds.

Future Trends and Potential Applications

Advancements may include integration of machine learning models for peak identification, miniaturized portable TD-GCMS systems for field monitoring, expanded software compatibility with other analyte classes, and real-time air quality feedback for industrial safety systems.

Conclusion

The combined TD-30R + GCMS-QP2020 NX platform with the TVOC Calculation Tool delivers a robust, user-friendly solution for accurate TVOC monitoring. Automation of calibration, quantitation, and reporting enhances laboratory productivity while maintaining high analytical performance.

References

• Y. Higashi. Simplifying the Calculation of TVOC Using TVOC Calculation Tool and Thermal Desorption GC-MS. Shimadzu Application News, First Edition Apr. 2022.