Novel boronate affinity molecularly imprinted nanomaterials for selective dispersive magnetic solid-phase extraction of catecholamines from equine urine

In this study, we developed catechol-imprinted magnetic molecularly imprinted polymers (Ca-DFFPBA-MMIPs) via a dual-affinity strategy combining boronate affinity and a two-step template immobilization protocol. The Ca-DFFPBA-MMIPs exhibited high affinity and selectivity for catecholamines (norepinephrine, epinephrine, and dopamine) under neutral conditions. The adsorption capacity reached a plateau at pH 6.5–7.0, and the adsorption time was optimized to 40 minutes. The MMIPs showed excellent selectivity for the target catecholamines over structurally related interferents. The Ca-DFFPBA-MMIPs also demonstrated good reusability, retaining ≥90% of their initial adsorption capacity after seven consecutive cycles. The analytical performance of the Ca-DFFPBA-MMIPs was validated in terms of linear range, coefficient of determination (R²), limit of detection (LOD), limit of quantification (LOQ), and intra- and inter-day precision (RSD). The LODs were 12–31 ng mL⁻¹ and LOQs were 40–103 ng mL⁻¹, with RSDs of 0.87–1.13% (intra-day) and 1.75–1.95% (inter-day). The Ca-DFFPBA-MMIPs were successfully applied to the selective extraction of catecholamines from equine urine (enrichment factors of 18–27), with recoveries ranging from 64.5% to 105.7%. This study provides a new approach for the analysis of catecholamines in complex matrices and highlights the potential of Ca-DFFPBA-MMIPs as a practical nanosorbent for efficient and selective enrichment of catecholamines and related compounds.