Ionic liquid-based sample pretreatment platforms: comparing solid supports and aqueous biphasic systems for enhanced bioanalytical performance

Reliable biomarker analysis in human serum is a critical bioanalytical task supporting disease detection and management. However, conventional serum pretreatment methods often fail to remove high-abundance proteins without analyte loss, potentially leading to false results, or rely on resource-intensive workflows poorly aligned with green analytical practices. Ionic liquids provide a versatile enabling technology, offering tunable interactions for selective protein depletion and enhanced biomarker recovery. In this work, their dual role in serum pretreatment is exploited through two complementary configurations, namely solid-phase extraction, where ionic liquids act as immobilized ligands, and aqueous biphasic systems, where they function as phase-forming agents. Both approaches were compared using Green Sample Preparation metrics to evaluate operational efficiency and environmental performance at the analytical level. Solid-phase extraction achieved >92% protein depletion with 89% biomarker recovery. This approach also reduced sample consumption and waste generation, demonstrating strong bioanalytical performance alongside improved alignment with Green Analytical Chemistry principles.