Phthalates in Aqueous Alcoholic Extract

Recycled paper and board is being used more and more in a wide variety of applications, and food packaging is one of the ongoing uses that could be explored. Recently, the Council of Europe proposed limitations on the concentration of several potential migrants in recycled paper and board intended for use as food packaging materials, and the proposed limits depend on the type of food. Without doubt, the use of any recycled paper or board materials in contact with food involves previous analysis of the materials, to know the potential migrants that could be transferred to the food [13]. 

However, one of the critical points in the analysis of migrants is the extraction of the paper or board samples. Most of the published papers about the analysis of components in paper and board employ solvent extraction with ethanol [14] or toluene, both by direct immersion or using the accelerated solvent extraction procedure [15]. 

One attractive approach in this context is the use of supercritical fluid extraction (SEE) with carbon dioxide as the supercritical fluid, which can provide a fast and efficient extraction of a wide range of compounds. SEE has been shown as an excellent extraction system of different matrixes [16-26]. 

Nerin and co-workers [26] examined the applicability of SEE for the extraction of several paper and board samples of different composition, including virgin and recycled fibre. They optimised the SEE using carbon dioxide for the extraction of contaminants in 15 samples of recycled paper and board. An experimental design was used for simultaneous optimisation of the variables involved in both the extraction step and the collection of the extract. Methanol was used as modifier. Several plasticisers such as diethyl phthalate, diisobutyl phthalate, di-w-butyl phthalate, dioctyl adipate, and DEHP (from 2 to 100 pg/g of paper) were found in the recycled samples. A discriminate analysis applied to all results obtained, allowed them to classify the samples in three different groups according to the content of recycled pnlp (0, 10-30, and 80% of recycled pulp), the sample thickness (from 300 to 600 pmj, and the snrface treatment of the paper. 

The optimum conditions for collection and extraction procedures are listed in Table 6.3. SEE analysis does not require previous digestion, dissolntion, or special treatment of the samples. Each paper sample was extracted nsing the optimum conditions. The SEE extracts were directly analysed by GC-mass spectrometry (MS). 

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