Selective extraction and high adsorption of ganoderic acid based on molecularly imprinted microporous organic networks.

Microporous organic network (MON) is a novel type of adsorbent and has wide applications in sample pretreatment. However, MON has a rigid plane and exhibits adsorption with most organic compounds, so they suffer from poor selectivity. The lack of selectivity hinders its practical application in complex matrices. This study focuses on enhancing the selectivity of MON by constructing a molecularly imprinted polymer (MIP) layer on its surface. A ganoderic acid molecularly imprinted magnetic microporous organic network composite (MMON@OA-MAA) was synthesized for the enrichment and separation of ganoderic acid (GD). The prepared MMON@OA-MAA material featured two key advantages: a high adsorption capacity (14.38-22.94 mg g-1) and excellent selectivity (α ≥ 1.5). The composite enabled hydrogen bonding, π-π interaction, and host-guest interactions with GD, which possessed active sites such as steroidal rings, hydroxyl groups, and carbonyl groups. An UPLC-MS/MS method was established and successfully applied to the efficient analysis of four trace GDs in complex Ganoderma samples, demonstrating a good linearity (r ≥ 0.9991), a low limit of detection (5.0 pg mL-1) and satisfactory recovery (81.0%-119.8%). This research was a novel attempt to combine MIP with MMON to form MMON-MIP composite, achieving the synergistic enhancement of high selectivity and large adsorption capacity. The extraction process was simple and rapid, facilitating its broader application in the field of sample pretreatment, particularly for efficient analysis of trace bioactive components in complex natural matrices.