Walnut shell-supported liquid extraction coupled with GC–MS for analysis of synthetic antioxidants in edible oils: A sustainable strategy with excellent green, blue and red analytical performance

Novel walnut shell-supported liquid extraction (WS-SLE) method was developed. • Direct extraction of edible oils without pretreatment via a 3-step process. • The miniaturized device uses agricultural waste, costing <$0.01 USD per unit. • Highly competitive for large-scale high-throughput screening of edible oils • An exceptionally green analytical method with low cost and simple operation. In this study, an environmentally friendly and convenient walnut shell-supported liquid extraction (WS-SLE) strategy was proposed for the detection of five synthetic antioxidants, including BHA, BHT, TBHQ, EQ, and Ionox-100, in edible oils. The extraction device was constructed with only agricultural waste WS powder and a 1 mL pipette tip. The original edible oil sample was directly loaded into the extraction device without prior dilution or pre-cleanup. After addition of the extraction solvent and standing extraction, the extractant was collected by pipetting. The experimental results demonstrated excellent oil-removal efficiency for all tested edible oil samples, including seven common edible oils and three complex oil samples, with values higher than 99.0%. The study comprehensively investigated and optimized parameters influencing the extraction efficiency of antioxidants. Under the optimized conditions, the method showed excellent analytical performance, including excellent linearity (R 2  ≥ 0.995), limits of detection (0.1–0.4 ng/g), limits of quantification (0.4–1.0 ng/g), accuracy (95.9%–105.0%) and precision (≤ 7.4%). Furthermore, the environmental sustainability, practical applicability, and analytical reliability of the method were systematically evaluated using SPMS, ComplexMoGAPI, BAGI, and RAPI tools. Compared to previously reported methods, the WS-SLE approach offers significant advantages in terms of minimized oil sample consumption, simplified operational workflows, enhanced detection sensitivity, and superior overall greenness. The comprehensive assessment confirmed that the proposed WS-SLE method provides a highly robust, low-cost, easily automatable, and exceptionally green strategy for routine food safety monitoring. Download: Download high-res image (342KB) Download: Download full-size image