Sustainable\nand Innovative Method for Real-Time Extraction\nand Analysis of Polyphenols from Green Propolis by Pressurized Liquid\nExtraction Coupled Inline with Photodiode Array Detection (PLE-PDA)

This article proposes an innovative process for extracting\ngreen\npropolis polyphenols, integrating real-time monitoring while adhering\nto green practices. This development is significant due to the complex\npropolis composition that requires extensive extraction and analytical\nmethods, leading to an environmental impact. The study employed pressurized\nliquid extraction (PLE) combined with photodiode array detection (PDA)\nto simultaneously recover and quantify polyphenolic compounds from\ngreen propolis. The process was fully optimized regarding operational\nextraction variables, specifically the solvent-to-feed ratio, solvent\ncomposition, and temperature. An exhaustive extraction was achieved\nusing ethanol as solvent, at 130 °C, 2 mL·min<sup>–1</sup> solvent flow rate, and 1500 psi, resulting in a total polyphenolic\ncontent of 148 mg·g<sub>propolis</sub><sup>–1</sup> in\n35 min. Additionally, the ability to quantify the signal obtained\nby the PDA represents a significant advancement in real-time monitoring\nprocesses, reducing the need for toxic solvents typically required\nin offline chromatographic analysis and shortening extraction times.\nThe optimized method achieved a high green analytical score of 0.9\n(AGREE) and a Path2Green score of 0.477, demonstrating strong adherence\nto the 12 principles of green analytical chemistry and green extraction,\nrespectively. Also, high Blue Applicability Grade Index (BAGI) of 85.0 is present, demonstrating\ngreat practicality and applicability of the method. This work highlights\nan innovative technique, opening new perspectives for future innovations,\neven when complex matrices are studied.