Modelling of toluene solid-phase microextraction for indoor air sampling

Area of Science:

• Analytical Chemistry
• Environmental Science
• Physical Chemistry

Background:

• Solid-phase microextraction (SPME) is a valuable technique for indoor air analysis.
• Understanding adsorption kinetics is crucial for optimizing SPME performance.
• Toluene is a common indoor air pollutant requiring accurate monitoring.

Purpose of the Study:

• To develop a theoretical model for toluene adsorption kinetics on SPME fibers under static conditions.
• To investigate the influence of sampling volume and initial concentration on adsorption.
• To utilize the model for estimating detection limits and generating calibration curves.

Main Methods:

• Development of a theoretical adsorption kinetics model for SPME.
• Application of Fick's second law to model diffusion within the Carboxen coating.
• Investigation of mass transfer from the gas phase to the SPME fiber.
• Comparison of model predictions with experimental data.

Main Results:

• The model accurately predicts toluene adsorption kinetics on SPME fibers.
• Experimental data showed only an 11% difference for calibration curves and 30% for detection limits.
• Diffusion was identified as the rate-limiting step in static-mode mass transfer.
• The model provides a better understanding of adsorption mechanisms on Carboxen fibers.

Conclusions:

• The developed kinetics model enhances the understanding of toluene adsorption on Carboxen SPME fibers.
• The model can be a valuable tool for cost-effective and time-efficient SPME method development.
• Accurate estimation of sampling performance and detection limits is achievable with this model.