Performance evaluation of a sorbent tube sampling method using short path thermal desorption for volatile organic...

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Air Quality Monitoring

Background:

• Volatile organic compounds (VOCs) are significant air pollutants.
• Accurate quantification of VOCs is crucial for environmental and health assessments.
• Traditional methods may face limitations in sensitivity, compound range, or sample integrity.

Purpose of the Study:

• To evaluate the performance of a short-path thermal desorption (TD) method for analyzing 77 VOCs.
• To assess the method's suitability for ambient air sampling in laboratory and field settings.
• To determine the method's sensitivity, reproducibility, linearity, and storage stability.

Main Methods:

• Utilized a dual sorbent system (Tenax GR, Carbosieve SIII) with short-path thermal desorption and gas chromatography.
• Conducted laboratory experiments to assess blank emissions, method detection limits, reproducibility, linearity, and desorption efficiency.
• Performed field tests analyzing replicate air samples from roadway and office environments.

Main Results:

• Achieved low blank emissions (<0.3 ng/tube for most VOCs) and a method detection limit of 0.05 +/- 0.08 ppb.
• Demonstrated good reproducibility (12 +/- 6%) and linearity (16 +/- 9% RSD).
• Showed high desorption efficiency (99 +/- 28%) and excellent sample recovery (87-102%) after storage and under high humidity.

Conclusions:

• The short-path TD method offers excellent performance and throughput for analyzing a wide range of VOCs in air.
• The method is suitable for ambient air monitoring, with minor limitations for specific compound classes or extreme sample conditions.
• This technique provides a sensitive and reliable approach for identifying and quantifying trace VOCs.