The Combination of 3 New Sampling Techniques Paired with GCMS for Determination of Uptake Rates and Accurate Monitoring of SVOC Endocrine Disruptors in Indoor Air - Poster

Significance of the Topic

The accurate measurement of semi‐volatile organic compounds (SVOCs) in indoor air is critical due to their prevalence as endocrine disruptors and potential health risks. Traditional active sampling methods require power and solvents, making them less practical for extended or remote monitoring. The combination of new passive sampling techniques with thermal desorption‐GCMS offers a solvent‐free, low‐power approach to quantify SVOCs at part‐per‐trillion levels.

Objectives and Study Overview

This study aimed to develop and validate a methodology for determining passive uptake rates of SVOCs using Diffusive Sorbent Pens (DSPs), Active Sorbent Pens (ASPs), and Headspace Sorbent Pens (HSPs). By co-locating passive and active samplers under controlled flow conditions, the work sought to derive compound-specific uptake rates and establish calibration procedures without the need for extensive solvent extraction.

Methodology and Instrumentation

Sampling was performed by placing DSPs around an ASP fitted to a CS1200E6 flow controller drawing 0.5 cc/min through a 6 L evacuated canister over 72 hours. After exposure, all pens were thermally desorbed in an Entech 5800 Sorbent Pen Desorption Unit (SPDU) coupled to a dual-column GCMS. The first column functioned as a pre-column to trap SVOCs, while lighter volatiles were split out. Upon transition, 100 % of retained SVOCs were directed onto the analytical column for mass spectrometric detection.

Instrumentation:

• Entech 5800 SPDU with thermal desorption and backflush capabilities
• Dual-column GCMS with splitless transfer
• CS1200E6 flow controller and 6 L evacuated canisters

Main Results and Discussion

Comparisons of GCMS peak areas from ASPs and triplicate DSPs yielded effective passive uptake rates for over 20 SVOCs. Diethyl phthalate uptake by DSPs averaged 0.34 cc/min (± 10.9 % RSD), closely matching the reference ASP rate. Uptake rates generally ranged from 0.1 to 0.5 cc/min, with higher variability observed for acidic compounds. The agreement across nine DSP replicates demonstrated reliable precision (< 33 % RSD) for most targets.

Benefits and Practical Applications

The passive sorbent pens eliminate the need for power during sampling and solvents during analysis, enabling long‐term, low‐maintenance monitoring of indoor air. Accurate uptake rates allow quantitative ambient SVOC assessments for exposure studies, building diagnostics, and regulatory compliance. The integration with thermal desorption GCMS reduces laboratory workload and environmental impact.

Future Trends and Opportunities

Next steps include spiking identified compounds onto pens via Vacuum Assisted Sorbent Extraction (VASE) to generate full calibration curves. Expanded compound lists and targeted GC/TSQ or GC/TOF analyses will push detection limits into sub-part-per-trillion ranges. Automation of DSP calibration and high‐throughput desorption will further streamline routine environmental monitoring.

Conclusion

This work establishes robust procedures for determining passive uptake rates of SVOCs using novel sorbent pens combined with thermal desorption GCMS. The methods deliver reproducible quantification of endocrine disruptors in indoor air without the drawbacks of solvent extraction or powered sampling. Ongoing calibration and method expansion will enhance sensitivity and broaden application.

Reference

Cardin DB, Noad VL. The combination of three new sampling techniques paired with GCMS for determination of uptake rates and accurate monitoring of SVOC endocrine disruptors in indoor air. Entech Instruments. 2023.