Monolithic vs. particle-based solid-phase extraction for selective separation of lead from aqueous matrices

Abstract

Effective removal of trace lead (Pb) from waste matrices is crucial to meet stringent environmental regulations designed to mitigate toxicological risks and protect human health. This study investigates the efficacy of a monolithic solid-phase extraction (m-SPE) column for the selective separation of trace Pb from aqueous matrices, comparing its performance to conventional particle-packed solid-phase extraction (p-SPE) columns. Key operational parameters, including solution pH, flow rate, washing solvent, and eluent, were optimized to maximize Pb retention on both SPE columns. Potential interference from common matrix ions was investigated and found to be minimal. Furthermore, the presence of counter anions enhanced Pb²⁺ retention on the m-SPE column, likely by promoting the formation of ion pairs. Notably, the SPE columns demonstrated reusability over multiple cycles without significant loss of efficiency. The p-SPE and m-SPE columns demonstrated satisfactory Pb²⁺ retention while exhibiting minimal retention of common elements, as confirmed by analysis of certified reference river water with elevated contents of trace elements. The m-SPE column demonstrated enhanced performance compared to the p-SPE column due to its high permeability, low backpressure, and robust porosity. These characteristics resulted in enhanced selectivity, reproducibility, and overall efficiency in the preferential separation of trace Pb from environmental matrices.