Dispersive Micro-Solid-Phase Extraction of Some Parabens From Fruit Juice Using Yolk-Shell ZIF-8-based Material (ZnO@SiO₂@C/Ni)

Parabens are widely used as antimicrobial preservatives in food, cosmetics, and industrial products due to their stability and practicality. Long-term exposure to parabens may pose risks to human health and ecosystems. Dispersive micro-solid-phase extraction (D-µSPE) is a fast and effective sample preparation method used for cleaning complex matrices and enriching analytes, ensuring reliable analytical results. To enhance analytical selectivity and sensitivity, it is essential to design sorbents with high surface area and selective adsorption properties for target analytes. Zeolite imidazole framework-derived porous carbon materials, ZnO@SiO₂@C/Ni, were used as the adsorbent in this study, featuring a yolk-shell porous structure with high surface area, chemical stability, and efficient adsorption performance for parabens extraction from food samples. To characterize the ZnO@SiO₂@C/Ni composite, various characterization techniques were employed. In this study, D-µSPE was integrated with high-performance liquid chromatography coupled with ultraviolet detection. A series of experimental parameters were systematically evaluated to enhance the extraction performance of parabens, including sample pH (6), extraction duration (20 min), elution solvent type and volume (methanol, 600 µL), breakthrough volume (20 mL), sorbent mass (10 mg), desorption time (4 min), and salt amount (in the absence of salt). Following optimization, the analytical method demonstrated strong linearity for methylparaben (MP), ethylparaben (EP), and propylparaben (PP) across a concentration range of 0.1-800 µg L^-1. The method also achieved low limits of detection of 0.03 µg L^-1 for each analyte, confirming its suitability for trace-level analysis. Also, relative standard deviations ranged from 2.3% to 6.2%, indicating consistent precision across replicate measurements. Extraction recoveries varied between 46.8% and 82.6%, and coefficients of determination for MP (R² = 0.9967), EP (R² = 0.9907), and PP (R² = 0.9970) confirmed excellent linearity and reliability of quantification. These findings support the method's suitability for trace-level detection of parabens in fruit juice matrix.