Fractionation of extracts from paper and board food contact materials for in vitro screening of toxicity

Paper and board used as food contact materials (FCMs) are chemically complex matrices, partly due to the naturally occurring substances in paper and board, but also due to the chemical treatment of the paper used to make it suitable for food contact. In order to assure the safety of packaging materials, information on the exposure as well as on the toxicity of substances in the packaging must be obtained. This study describes a comprehensive method for the extraction and fractionation of substances present in paper and board FCMs for further investigation by in vitro testing and chemical analysis. The extraction efficiency and the fractionation process were validated by determining recoveries in extracts from paper and board fortified with five surrogates of known concentration. The recoveries for the five surrogates were between 20% and 104% in the raw extract and between 21% and 109% after extraction and fractionation. The fractionation both reduces the number of compounds to be identified and works as a sample clean-up by reducing matrix effects. Raw extracts and fractions from two paper and board FCMs were furthermore tested in the aryl hydrocarbon receptor (AhR) reporter gene assay. Both raw extracts and two of the fractions of the raw extracts gave a positive response in the AhR assay. The strategy of extraction followed by fractionation offers a powerful tool in order to make the workflow for screening FCMs for potentially adverse effects more efficient