A sulphuric acid-impregnated silica gel clean-up procedure for the determination of n-alkanes migration from paraffin based paper packaging into cheddar cheese

A procedure for the determination of n-alkanes migration from paraffin paper packaging into fatty foods has been fully developed. First, the lipid fraction of the cheddar cheese is extracted with a mixture of diethyl ether/n-hexane (1:1). Then, a sulphuric acid-impregnated silica gel (SAISG) clean-up procedure is performed and the final extract is analysed by gas-chromatography (GC) with flame ionisation detector (FID). The procedure has been validated in terms of limits of detection and quantification, linear range, recovery, precision and robustness. The method has been used in the evaluation of the n-alkane migration from paraffin coated paper into cheddar cheese. Results after 10 days of migration test showed the typical n-alkanes (C19–C37) profile of migration with a maximum (21.1 ± 10.8 μg g−1) in n-pentacosane (C25).