Recovery of Berry Natural Products Using Pyrene-Based MOF Solid Phase Extraction

This work introduces a novel method of recovering bioactive berry natural products (BNPs) using solid phase extraction with metal-organic frameworks (MOF-SPE). Two pyrene-based MOFs with different structural topologies, Al-PyrMOF and Zr-NU-1000, were evaluated for their ability to capture and desorb BNPs, including ellagic acid, quercetin, gallic acid, and p-coumaric acid. Time-dependent BNP uptake via dispersive SPE revealed that NU-1000 outperformed Al-PyrMOF in capturing all BNPs. Our findings show NU-1000 demonstrated a higher and more consistent BNP capture profile, achieving over 90 % capture of all BNPs within 36 h, with only a 9 % variation between the most and least effectively captured BNPs. In contrast, Al-PyrMOF, displayed a staggered uptake profile, with a significant 53 % difference in capture efficiency between the most and least effectively captured BNP. However, when a BNP mixture was used at a loading concentration of 50 μg/mL, Al-PyrMOF outperformed NU-1000, capturing over 70 % of all BNPs. Al-PyrMOF also exhibited improved BNP recovery, with a minimum of two-fold greater amount recovered for all BNPs. Further testing with a BNP mixture at a concentration of 15 μg/mL demonstrated that Al-PyrMOF efficiently concentrated all BNPs, achieving a maximum extraction factor of 2.71 observed for quercetin. These findings highlight the use of Al-PyrMOF as a MOF-SPE sorbent for recovering bioactive BNPs.