Abstract: In this study, the quantitative analysis of mineral oil hydrocarbons (MOH) in 15 kinds of traymates was conducted, and source analysis was performed on one sample with known printing ink. The sample pretreatment was accomplished by off-line solid phase extraction using a mixed solution (n-hexane:ethanol = 1:1, V/V) as the extraction solvent. Mineral oil saturated hydrocarbon (MOSH) and mineral oil aromatic hydrocarbon (MOAH) were separated and purified on 0.3% silver nitrate silica gel column, quantified by gas chromatography-flame ionization detection (GC-FID), and qualified by gas chromatography-mass spectrometry (GC-MS). The results showed that MOH contents of four kinds of traymates purchased online were higher than those of traymates collected from a fast food restaurant. The maximum content of MOSH was 3 397.6 mg/kg, and the maximum content of MOAH was 374.6 mg/kg, which both exceed the limit value. Through source analysis, it was confirmed that MOH in printed traymates came from the ink. The limit of detection (LOD) and limit of quantitative (LOQ) of the proposed method were 2.73 and 8.19 mg/kg, respectively. The spiked recoveries were 92.1%–115.1%, with relative standard deviation (RSD) of 3.12%–11.85%. This method proved to be accurate, easy to operate and useful for quantitation and source analysis of MOH in food contact paper.

Key words: mineral oil hydrocarbons; traymate; solid phase extraction; gas chromatography-flame ionization detection; gas chromatography-mass spectrometry