Efficient ultrasonic extraction of quercetin from Pinus koraiensis seed scales using a chitosan-Cu-Fe ionic liquid system

To increase the extraction efficiency of quercetin from Pinus koraiensis seed scales (PKSS), an innovative chitosan-Cu-Fe (CS-Cu-Fe) ionic liquid system for efficient ultrasonic-assisted extraction (UAE) of PKSS quercetin (PKSSQ) was designed. A first-order kinetic model was applied to analyse the extraction performance, and key factors influencing the process were systematically optimized. The optimal conditions were as follows: 2.00 g sample, 0.016 mol [BMIM]Br, 0.6 %, 100 W, 53°C, 12:1 mL/g, and 14 min. Under these conditions, the actual PKSSQ yield was 2.92 mg/g ± 0.02 mg/g, which closely aligned with the theoretical yield of 2.96 mg/g. The extraction kinetics were compared across different methods, and the stability of the CS-Cu-Fe system was evaluated through recovery experiments. The CS-Cu-Fe was characterized using Fourier transforms infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD), hysteresis loop (HL) measurement, electrical conductance (EC) measurement and scanning electron microscopy (SEM) of the extracted residues. CS-Cu-Fe demonstrated exceptional thermal stability, magnetic properties, and catalytic activity, significantly enhancing the PKSSQ extraction efficiency. FT-IR analysis revealed minimal spectral changes in CS-Cu-Fe, with notable EC differences. Owing to its stable core functional groups, CS-Cu-Fe maintained excellent thermal stability, crystal structure, soft magnetism, and catalytic efficiency. This study highlights the efficiency of the CS-Cu-Fe ionic liquid system in UAE of PKSSQ and the role of its stable core functional groups in improving the extraction and catalytic performance. This innovative approach provides a robust theoretical foundation for extracting and developing natural products from PKSS, with promising future applications.