Green electromembrane extraction procedure based on biodegradable chitosan films for determination of polyphenolic compounds in food samples: greenness assessment of the sample preparation approach

A simple, rapid and environmentally friendly method for the electromembrane extraction of polyphenolic compounds has been developed using chitosan films (60% (w/w) chitosan, 40% (w/w)-Aliquat®336, 10–11 μm thickness) as biopolymeric membrane. In this work for the first time with this type of chitosan-based support, the use of organic solvents has been completely eliminated, which allows considering the proposed methodology as a green solvent-free procedure, as demonstrated by performing analytical greenness metric for sample preparation (AGREEprep). Under optimal experimental conditions (10 mL donor phase, pH 7; 50 μL acceptor phase, pH 9; 100 V applied voltage for 15 min) high enrichment factors (EF ≥ 60) were obtained for all the target analytes. Wide concentration ranges between 52.8 μg L− 1 and 1000 μg L− 1 , good linearity (R2 ≥ 0.996), low limit of detection (15.9–37.1 μg L− 1 ), and repeatability (relative standard deviation (RSD) values 4–10%) were achieved. Polyphenolic compounds have been successfully extracted from coffee- and tea-based dietary food supplements in different formats (pills and ampoules). For comparison purposes, target analytes have additionally been determined in green coffee beans and tea.