Abstract:
Emerging contaminants (ECs), such as pharmaceuticals, are often detected in aquatic
environment in a trace level of concentration. These contaminants can interact with different
surfaces, such as natural organic matter (NOM), soil, and biological membranes. These
interactions are still not well-understood. To better understand the fate and transport of these
contaminants in aquatic environment it is necessary to study the interactions between surfaces
and ECs. In our experiments, we studied the interactions of pharmaceuticals, such as amlodipine
(AMP), and carbamazepine (CBZ), on the model NOM surfaces. To conduct this study, quartz
crystal microbalance (QCM) has been used in our experiments. QCM is a mass sensing tool that
can detect nano- to sub-microgram of adsorbed molecules and often has been applied to study
adsorption from the gas phase or non-aqueous solutions. Model NOM have been created by
thiolation. Self-assembled monolayer of different functional groups, such as amine, carboxyl,
and alkyl have been used. Our study demonstrated that AMP and CBZ interacts with the model
NOM surfaces. The QCM approach provides a systematic way to selectively study the influence
of different functional group on the binding affinity of ECs. This study also demonstrated that
QCM can be used to detect and quantify mass adsorption of ECs from aqueous solutions.
However, further investigation is needed to accurately quantify the adsorption capacity.
