Application of FTIR and Raman microspectroscopy to the study of food/packaging interactions.

This study assesses the suitability of Fourier transform infrared spectrometer (FTIR) and Raman spectroscopy for potential use as analytical tools to determine the diffusivity of a migrant in a plastic packaging material, one of the key points in safety assessment of food-contact materials. Despite its relative low sensitivity, FTIR-based analysis supplied data for the material on desorption of an additive (Uvitex OB) and sorption of a food constituent (olive oil) in a non-destructive and 'in situ' mode. These data allowed the determination of the diffusivity of Uvitex OB (8.0 +/- 2.5 x 10(-14) m(2) s(-1)) and olive oil (6.9 +/- 3.4 x 10(-14) m(2) s(-1)) in Linear Low Density Polyethylene (LLDPE). Raman cartography innovatively supplied the profile of additive concentration in the z-direction (thickness) of the food-contact material and confirmed that mass transfer in the system roughly followed a Fickean behaviour.