Investigation of the kinetic process of solid phase microextraction in complex sample

Area of Science:

• Environmental Chemistry
• Analytical Chemistry

Background:

• Complex matrices in aquatic systems influence the environmental behavior of hydrophobic organic compounds (HOCs).
• Polyaromatic hydrocarbons (PAHs) are a significant class of HOCs with environmental persistence.
• Solid-phase microextraction (SPME) is a common technique for analyzing HOCs in water.

Purpose of the Study:

• To investigate the effect of 2-hydroxypropyl-β-cyclodextrin (β-HPCD) on the desorption kinetics of PAHs from SPME fibers.
• To develop and validate a theoretical model for predicting PAH desorption enhancement by β-HPCD.
• To examine the influence of temperature on PAH desorption kinetics and develop a calibration method.

Main Methods:

• Automated solid-phase microextraction (SPME) with focus on the desorption step.
• Application of 2-hydroxypropyl-β-cyclodextrin (β-HPCD) to aqueous samples containing PAHs.
• Development of a theoretical model to describe and predict desorption kinetics.
• Temperature-dependent kinetic studies following the Arrhenius equation.

Main Results:

• β-HPCD significantly increased the desorption rates of selected PAHs from the SPME fiber coating.
• The proposed theoretical model accurately predicted the enhancement effect of β-HPCD on desorption kinetics.
• Desorption time constants increased with elevated sampling temperatures, consistent with the Arrhenius equation.
• Higher temperatures increased the lability of HOCs bound within the sample matrix.

Conclusions:

• β-HPCD is an effective enhancer for PAH desorption from SPME fibers in aquatic environments.
• The developed theoretical model provides a robust framework for determining kinetic parameters and understanding desorption mechanisms.
• Temperature plays a crucial role in HOC desorption kinetics, influencing both SPME efficiency and matrix lability.
• A novel calibration method based on the theoretical model enables accurate analysis of PAHs in complex samples.