Pharmaceuticals, personal care products, and pesticides have become more prevalent in the environment, making it important to understand sorption - transfer of these chemicals from water to soils, as it informs us of their environmental fate and potential harm. These chemicals contain both heterocyclic and non-heterocyclic cationic amine moieties.  While our mechanistic understanding and predictive capability for non-heterocyclic amine pharmaceuticals and relevant substructures is advanced, less is known about their heterocyclic counterparts. This research examines the role of (i) compound structure, particularly positive charge delocalization and (ii) soil properties (effective cation exchange capacity, exchangeable cations identify and abundance, and negative charge delocalization) on the extent of compound sorption.  The sorption of isoquinoline (ISQN), 5,6,7,8-tetrahydroisoquinoline (5,6,7,8-THIQ), and 1,2,3,4-tetrahydroisoquinoline (1,2,3,4-THIQ) was measured onto 30 well-characterized soils and select pure phase minerals. Results show that ISQN, with greater amine charge delocalization into aromatic rings (than both 1,2,3,4-THIQ and 5,6,7,8-THIQ) exhibited greater sorption to soil aluminosilicates.  Further, the pharmaceutical amine substructures with a less delocalized charge exhibited a preference for sorption to organic matter, whereas heterocyclic amines with a more delocalized charge exhibited preference for soil aluminosilicates.

Sorption of cationic heterocyclic amines to soils: Effects of charge delocalization and other factors

Where thousands of chemistry professionals meet to share ideas and advance scientific and technical knowledge. Spring 2023 abstracts, posters, and presentations will launch at the end of March.

ACS Spring 2023

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.