Adhesives in Food Packaging
Adhesives are formulated as complex mixtures of compounds and their exact composition is unknown because it can be covered by IP/confidential agreements related to producers and/or unknown substances can be formed by reaction between ingredients when the adhesive is applied or during the curing process. They are usually employed in packaging to manufacture laminates or to build up the final form of a packaging. As a component of food contact materials, adhesives must also comply with regulations to ensure that they do not jeopardize human health. The role of mass spectrometry (MS) to determine the composition of different types of adhesives and to identify and quantify compounds that have migrated from the adhesive to different food simulants is reviewed in this chapter. Several examples of headspace solid-phase microextraction gas chromatography–mass spectrometry (HS-SPME-GC-MS) applied to the identification of volatile and semivolatile compounds from adhesives are illustrated. Ion-trap and single- and triple-quadrupole instruments in selected ion monitoring (SIM) or multiple reaction monitoring (MRM) acquisition modes have been shown to be sensitive and selective enough for the targeted determination of adhesive compounds. However, high-resolution time-of-flight (TOF) or tandem quadrupole-TOF (Q-TOF) MS instruments capable of providing accurate mass and elemental compositions of precursor and fragment ions are required for identifying non-targeted unknown compounds such as non-intentionally added substances (NIASs). Finally, research on delamination caused by compounds that have migrated from the packed product into the laminate is also presented.