Abstract: Using water, 4% (volume fraction, the same below) acetic acid solution, 10% (volume fraction, the same below) ethanol solution, 20% (volume fraction, the same below) ethanol solution, 50% (volume fraction, the same below) ethanol solution, 95% (volume fraction, the same below) ethanol solution, and isooctane as food simulants, tests for migration were conducted according to GB 5009.156—2003 and GB 31604.1—2015. The soaking solutions of the first five food simulants were filtered by a 0.22 μm organic filter membrane, and the filtrate was determined by the instrument. An aliquot (10 mL) of soaking solution of 95% ethanol solution was taken and evaporated to near dryness at 50 ℃, and 8 mL of 80% (volume fraction, the same below) methanol solution was added twice to dissolve the residue. The solution obtained was diluted to 10 mL by 80% methanol solution for determination by the instrument. An aliquot (10 mL) soaking solution of isooctane was taken, and 10 mL of 80% methanol solution was added. After shaking well for about 1 min, the solution obtained was settled for about 30 min. The lower layer phase was collected, and diluted to 10 mL by 80% methanol solution. The resulting solution was passed through a 0.22 μm organic filter membrane, and the filtrate was determined by the instrument. In the analysis of ultra-high performance liquid chromatography, the ACQUITY UPLC BEH C₁₈ chromatographic column was used as the stationary phase, and 80% methanol solution was used as the mobile phase for isocratic elution. The content of irganox 245 was determined by the diode array detector at detection wavelength of 220 nm. It was shown that linear relationships between values of the mass concentration and the peak area of irganox 245 were kept in the range of 0.5-10.0 mg·L⁻¹, with lower limit of determination of 0.14-0.30 mg·L⁻¹. Test for recovery was made according to the standard addition method, giving recoveries in the range of 86.4%-104%, and RSDs (n=6) of the determined values ranged from 2.0% to 5.4%. The proposed method was used for the analysis of samples of food contact materials with different matrices, and irganox 245 was only detected in polyoxymethylene (POM) cap samples. The migration amounts in different food simulants were ranked from high to low as 50% ethanol solution, 95% ethanol solution, 20% ethanol solution, 10% ethanol solution, and 4% acetic acid solution.