Theory and modelling approaches to passive sampling.

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Environmental Monitoring

Background:

• Passive sampling devices are increasingly used across environmental compartments.
• Understanding the underlying theory is vital for accurate results and method development.

Purpose of the Study:

• To review and describe passive sampling theory and modeling approaches.
• To enable researchers to understand assumptions and applicability of different models.

Main Methods:

• Review of existing literature on passive sampling theory and models.
• Analysis of Whitman's two-film theory and exponential models.
• Discussion of zero-sink assumption and alternative modeling approaches (steady-state, dynamic models).
• Inclusion of empirically calibrated models.

Main Results:

• Various modeling approaches exist, each with assumptions and limitations.
• Exponential models based on two-film theory are common but rely on linear kinetics.
• Dynamic models offer a comprehensive understanding of analyte accumulation and sampler response.
• Simplified models are practical, while dynamic models provide deeper insights.

Conclusions:

• A thorough understanding of passive sampling theory and models is essential for environmental monitoring.
• Dynamic models, though complex, are becoming more accessible and provide a robust framework.
• Choosing the appropriate model depends on the specific application and desired level of detail.