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

Significance of the topic

The accurate monitoring of semi-volatile organic compounds (SVOCs) and endocrine disruptors in indoor air is critical due to their potential carcinogenicity and impact on human health. Common indoor materials can release SVOCs such as phthalates, PCBs, and fire retardants, which may accumulate to harmful levels in poorly ventilated spaces. Reliable passive sampling at ultra-low concentrations enhances exposure assessment and supports regulatory compliance.

Objectives and Study Overview

This study introduces a novel passive sampling approach combining three diffusive techniques with GC-MS analysis to quantify SVOCs down to parts per trillion. Key goals include:

• Determining accurate diffusive uptake rates for a broad SVOC range.
• Establishing a solvent-free spiking method for calibration that matches passive sampling recoveries.
• Developing robust GC-MS calibration and validation protocols.

Methodology

Passive sampling employed Diffusive Sorbent Pens (DSPs) deployed for 1–30 days alongside Active Sorbent Pens (ASPs) operating at 0.5 cc/min controlled by a CS1200E6 flow controller and 6 L evacuated canisters. Uptake rates were derived by co-locating three DSPs around one ASP, comparing GC-MS responses to calculate DSP flow rates. Calibration curves were generated via Vacuum Assisted Sorbent Extraction (VASE) by spiking known masses of standards onto DSPs in sealed vials, then thermally desorbing them.

Used Instrumentation

• Diffusive Sorbent Pens (DSPs), Active Sorbent Pens (ASPs), Headspace Sorbent Pens (HSPs)
• CS1200E6 flow controller and 6 L evacuated canisters
• 5800 Sorbent Pen Desorption Unit (SPDU)
• Dual-column GC setup: PDMS pre-column (5 m × 0.530 mm × 0.25 µm) and primary PDMS column (30 m × 0.250 mm × 0.5 µm)
• Single-quadrupole GC-MS with full-scan and targeted modes

Main Results and Discussion

Calculated DSP uptake rates for Diethyl Phthalate averaged 0.34 cc/min (± 0.04, 10.99 % RSD) across nine samplers. A broader compound set yielded average rates from 0.05 to 0.81 cc/min with RSDs below 37 %. Uptake rates correlated inversely with molecular size but were also influenced by chemical polarity and volatility, notably slower for acids. Good agreement between ASP and DSP measures confirmed method precision.

Benefits and Practical Applications

• Solvent-free, power-free passive sampling simplifies field deployment and reduces costs.
• Accurate uptake rates enable quantitative time-integrated measurements.
• Adaptable to routine indoor air monitoring for environmental, occupational, and public health applications.

Future Trends and Possibilities

Further work will expand the SVOC compound library, refine surrogate standard protocols, and apply targeted GC-MS/MS or GC-TOF for enhanced sensitivity. Integration with real-time ventilation studies and large-scale indoor air surveys can support epidemiological research and regulatory frameworks.

Conclusion

The combination of DSPs, ASPs, and advanced GC-MS calibration delivers a robust, solvent-free approach for quantifying SVOC uptake rates and indoor air concentrations. High reproducibility and low detection limits underscore its potential for broad environmental monitoring.

Reference

Cardin D.B., Noad V.L. 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. Application Note A-3742-02. Entech Instruments, 2018.