Determination of Ultraviolet Absorbers and Light Stabilizers in Food Packaging Bags by Magnetic Solid Phase Extraction Followed by High-Performance Liquid Chromatography

A sensitive and effective extraction technique based on magnetic solid phase extraction (MSPE) was developed for separating and detecting trace amounts of ultraviolet (UV) absorbers and light stabilizers in plastic packaging prior to high-performance liquid chromatography (HPLC). The magnetic Fe3O4/Au composites were synthesized by chemical co-precipitation, and a HAuCl4 solution was added to the Fe3O4 NPs, followed by the addition of hydroxylamine hydrochloride as a reducing agent for Au shell formation. The main factors affecting the adsorbability of UV absorbers, such as the effects of pH of the sample solution, the amount of adsorbent, extraction time, and desorption conditions on the magnetic nanoparticles (MNPs), were investigated and optimized. The proposed method showed good linearity in the range from 0.75 to 100 μg/mL with good presenting regression coefficients (R2) ≥0.9999. Low limits of detection (LODs) were achieved at 0.05, 0.14, and 0.04 μg mL−1 for 2-hydroxy-4-n-octoxy-benzophenone (UV-531), 2-tert-butyl-6-(5-chloro-2H-benzotriazol-2-yl)-4-methylphenol (UV-326), and 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV-328), respectively. The mean recoveries were in the range from 88.06 to 100.29% at 2.5, 5, and 10 μg mL−1 spiked levels, and the relative standard deviations (RSDs) were in the range from 0.98 to 3.56%.